INTEGRATED BIDIRECTIONAL FOUR QUADRANT SWITCHES WITH DRIVERS AND INPUT/OUTPUT CIRCUITS

An electronic system is disclosed. The electronic system includes an electronic package having a base with a plurality of external terminals, and further having an electrically insulative material at least partially encapsulating the base, a controller circuit disposed within the electronic package and referenced to a first ground, a first and second driver circuits disposed within the electronic package and referenced to a second ground and arranged to receive isolated control signals from the controller circuit, and a bidirectional switch disposed within the electronic package and referenced to the second ground and arranged to receive drive signals from the first and second driver circuits. In one aspect, the first and second driver circuits are isolated from the controller circuit via capacitors, or magnetics, or optocouplers, or magneto resistors.

FIELD

The described embodiments relate generally to power converters, and more particularly, the present embodiments relate to integrated bidirectional four quadrant switches having drivers and input/output circuits used in power converter circuits.

BACKGROUND

Electronic devices such as computers, servers and televisions, among others, employ one or more electrical power conversion circuits to convert one form of electrical energy to another. Some electrical power conversion circuits convert a high (or low) DC voltage to a lower (or higher) DC voltage using a circuit topology called DC-DC converter. As many electronic devices are sensitive to size and efficiency of the power conversion circuit, new power converters can provide relatively higher efficiency and lower size for the new electronic devices.

SUMMARY

In some embodiments, an electronic system is disclosed. The electronic system includes an electronic package including a base having a plurality of external terminals, and further including an electrically insulative material at least partially encapsulating the base; a controller circuit disposed within the electronic package and referenced to a first ground; a first and second driver circuits disposed within the electronic package and referenced to a second ground, and arranged to receive isolated control signals from the controller circuit; and a bidirectional switch disposed within the electronic package and referenced to the second ground and arranged to receive drive signals from the first and second driver circuits.

In some embodiments, the first and second driver circuits are isolated from the controller circuit via capacitors, magnetics, optocouplers or magneto resistors.

In some embodiments, the bidirectional switch is a first bidirectional switch and the first bidirectional switch includes a first gate terminal, a second gate terminal, a first source terminal and a second source terminal.

In some embodiments, the first source terminal is coupled to a first external terminal of the plurality of external terminals and the second source terminal is coupled to a second external terminal of the plurality of external terminals.

In some embodiments, the bidirectional switch is gallium nitride (GaN) based.

In some embodiments, the first driver circuit is coupled to the first gate terminal, and the second driver circuit is coupled to the second gate terminal.

In some embodiments, the first driver circuit is disposed on a first die, the second driver circuit is disposed on a second die, the controller circuit is disposed on a third die and the bidirectional switch is disposed on a fourth die.

In some embodiments, the fourth die further includes a sense device arranged to transmit a signal, to the controller circuit, including at least one of a magnitude and polarity of a current through the bidirectional switch.

In some embodiments, the first driver circuit is arranged to transmit a first drive signal to the first gate terminal in response to receiving a first control signal from the control circuit and the second driver circuit is arranged to transmit a second drive signal to the second gate terminal in response to receiving a second control signal from the control circuit.

In some embodiments, the system further includes a second bidirectional switch and a third bidirectional switch coupled in parallel to the first bidirectional switch.

In some embodiments, an AC power supply referenced to the second ground is coupled between the first source terminal and the second source terminal, and the second bidirectional switch and the third bidirectional switch are arranged to harvest energy from the AC power supply for operating the first and second driver circuits.

In some embodiments, the second bidirectional switch includes a depletion mode (D-mode) section and an enhancement mode (E-mode) section.

In some embodiments, the second bidirectional switch is coupled in series with an energy harvesting capacitor.

In some embodiments, the bidirectional switch is arranged to store energy harvested from a main input and use the harvested energy to provide power to the first and second driver circuits.

In some embodiments, the second bidirectional GaN switch is coupled in series with a first energy harvesting capacitor and the third bidirectional GaN switch is coupled in series with a second energy harvesting capacitor.

In some embodiments, the input/output circuit is electrically isolated from the first and second driver circuits via one or more isolation capacitors.

In some embodiments, the first driver circuit is disposed on a first die, the second driver circuit is disposed on a second die, the input/output circuit is disposed on a third die, and the first bidirectional GaN switch is disposed on a fourth die.

In some embodiments, the fourth die further includes a sense device arranged to transmit a signal, to the input/output circuit, including at least one of a magnitude and polarity of a current through the first bidirectional GaN switch.

In some embodiments, the first driver circuit is arranged to transmit a first drive signal to the first gate terminal in response to receiving a first control signal from the input/output circuit and the second driver circuit is arranged to transmit a second drive signal to the second gate terminal in response to receiving a second control signal from the input/output circuit.

In some embodiments, the second bidirectional GaN switch and the third bidirectional GaN switch are coupled in parallel to the first bidirectional GaN switch.

In some embodiments, a method of forming an electronic component is disclosed. The method includes: providing an electronic package including a base having a plurality of external terminals; forming an electrically insulative material at least partially encapsulating the base; disposing a controller circuit within the electronic package, the controller circuit referenced to a first ground; disposing a first and second driver circuits within the electronic package, the first and second driver circuits referenced to a second ground, and arranged to receive isolated control signals from the controller circuit; and disposing a bidirectional switch within the electronic package, the bidirectional switch referenced to the second ground and arranged to receive drive signals from the first and second driver circuits.

In some embodiments, a method of operating a circuit is disclosed. The method includes: providing an electronic package including a base having a plurality of external terminals, and further including an electrically insulative material at least partially encapsulating the base; providing an input/output circuit disposed within the electronic package and referenced to a first ground; providing a first and second driver circuits disposed within the electronic package and referenced to a second ground, and arranged to receive isolated control signals from the input/output circuit; providing a bidirectional switch disposed within the electronic package and referenced to the second ground and arranged to receive drive signals from the first and second driver circuits; receiving, by the input/output circuit, input data; transmitting, by the input/output circuit, intermediate data corresponding to the input data; receiving, by the first and second driver circuits, the intermediate data; producing, by the first and second driver circuits, output data corresponding to the input data; and driving, by the first and second driver circuits, the bidirectional switch with the output data.

DETAILED DESCRIPTION

Circuits, devices and related techniques disclosed herein relate generally to power converters. More specifically, circuits, devices and related techniques disclosed herein relate to integrated bidirectional four quadrant switches having drivers and input/output circuits used in power converter circuits. In some embodiments, a bidirectional switch capable of operating in four quadrants of operation can be integrated with drivers and input/out circuits within one semiconductor package. In various embodiments, the bidirectional switch may be a gallium nitride (GaN) based switch having two gate terminals and two source terminals. In some embodiments, the source terminals may be floating during operation and the gate terminals may be floating during operation, therefore the driver circuits may be arranged to operate with respect to floating nodes. In various embodiments, an electronic package may include a base with a plurality of external terminals, and further including an electrically insulative material at least partially encapsulating the base. The electronic package may also include a controller circuit disposed within the electronic package and referenced to a first ground, a first and second driver circuits disposed within the electronic package and referenced to a second and third ground and arranged to receive isolated control signals from the controller. The electronic package may further include a bidirectional switch disposed within the electronic package and referenced to the second and third ground and arranged to receive drive signals from the first and second driver circuits. In some elements, the controller circuit may include input/output circuits.

In various embodiments, the driver circuits can be coupled to the gate terminals of the bidirectional switch where the driver circuits are galvanically isolated from the input/output circuits. In this way, the integrated bidirectional switch can enable use of ground-referenced input digital signals that provide control signals to the integrated bidirectional switch. Further, the integrated bidirectional switch can be employed in various applications such as, but not limited to, relatively high-power power conversion circuits. In some embodiments, a semiconductor package for an integrated bidirectional switch may include a bidirectional switch disposed on a first die, a first driver circuit disposed on a second die, a second driver circuit disposed on a third die and an input/output circuit disposed on a fourth die. In various embodiments, the first die may be GaN-based, and the second, third and fourth die may be silicon (Si) based. In some embodiments, the first, second, third and fourth die may be GaN-based.

In some embodiments, the gate terminals of the bidirectional switch may be driven separately, thereby separate driving schemes may be used for driving each gate terminal that is referenced to its corresponding source terminal, where each of the source terminals may be at highly different voltage potentials. The bidirectional switch and the driver circuits for each gate terminal can be isolated from each other as well as isolated from the input/output circuit. In various embodiments, the isolation can be achieved by capacitors, magnetics, optocouplers or magneto resistors. In some embodiments, isolation capacitors can be used to provide the isolation between the controller and the drivers/bidirectional switch. In various embodiments, the capacitors may be high-voltage capacitors. In some embodiments, the isolation capacitors may include two series connected capacitors, where one capacitor may be disposed on a die that includes the input/output (control) circuits and the other capacitor can be disposed on a die that includes the driver circuit. In various embodiments, the isolation capacitors may be completely disposed on the die that includes the driver circuit. In some embodiments, the isolation capacitors may include a plurality of cross-coupled capacitors. In various embodiments, the plurality of cross-coupled capacitors may include high voltage common centroidal layout capacitors. In some embodiments, the plurality of capacitors may be arranged in a non-cross-coupled configuration. In various embodiments, the electronic package may include one or more mismatch compensation capacitors. In some embodiments, the plurality of cross-coupled capacitors can be formed from conductive semiconductor layers.

In some embodiments, an integrated half-bridge circuit may include two bidirectional switches coupled connected in series to form the half-bridge circuit along with drivers and input/output circuits integrated within a single semiconductor package. In various embodiments, voltage sensing circuits may be included in the integrated bidirectional switch such that voltage potential between the high-side and the low-side drivers can be detected and fed back to the co-packaged drivers and to the input/output circuit and to a controller. The detected voltage potential can then be used to control a conductivity state of the bidirectional switch and/or transmitted to a microcontroller.

In various embodiments, an input/output circuit may be split into two circuits that are disposed on two separate dies within the integrated bidirectional switch package. This may be done in some applications, such as industrial applications, where the integrated bidirectional switch complies with functional safety regulations. These are applications can have relatively higher safety levels, therefore redundancy may be used for these safety-critical functions, particularly to turn off devices to protect them. Thus, two input/output circuits on two separate dies may be used in order to provide backup and reliability.

In some embodiments, the integrated bidirectional switch may include a plurality of parallel connected bidirectional switches that are arranged to self-power the high-side driver. Current approaches that provide power to an isolated high-side driver can be cumbersome because schemes such as bootstrapping may not work due to use of isolation. Disclosed embodiments of the disclosure enable use of self-powering of the isolated high-side drivers, thereby reducing system complexity and saving system costs. In various embodiments, disclosed self-powering techniques can be used to provide power to the low-side drivers and/or to the input/output circuits.

In various embodiments, a current flowing in the bidirectional switch can be sensed and the information can be used to autonomously drive the gate terminals of the bidirectional switch. In some embodiments, the information from the sensed current can be utilized to improve turn-off behavior of the switch, to improve soft turn-off and to improve soft turn-on of the switch, as well as have the bidirectional switch perform functions that otherwise may have been performed in a microcontroller. Various inventive embodiments are described herein, including methods, processes, systems, devices, and the like.

Several illustrative embodiments will now be described with respect to the accompanying drawings, which form a part hereof. The ensuing description provides embodiment(s) only and is not intended to limit the scope, applicability, or configuration of the disclosure. Rather, the ensuing description of the embodiment(s) will provide those skilled in the art with an enabling description for implementing one or more embodiments. It is understood that various changes may be made in the function and arrangement of elements without departing from the spirit and scope of this disclosure. In the following description, for the purposes of explanation, specific details are set forth in order to provide a thorough understanding of certain inventive embodiments. However, it will be apparent that various embodiments may be practiced without these specific details. The figures and description are not intended to be restrictive. The word “example” or “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment or design described herein as “exemplary” or “example” is not necessarily to be construed as preferred or advantageous over other embodiments or designs.

Integrated Bidirectional Switch

FIG.1Aillustrates an integrated bidirectional four quadrant switch with drivers and input/output circuits, according to certain embodiments. The integrated bidirectional four quadrant switch with driver and input/output circuits may also be referred to as integrated bidirectional switch. In some embodiments, the input/output circuits may include controller circuits.FIG.1Ashows an integrated bidirectional four quadrant switch with drivers and input/output circuits100that can include a bidirectional switch102. The bidirectional switch102can include a first source terminal104, a first gate terminal106, a drain terminal108, a second source terminal110, a second gate terminal112, and a connection to the substrate114. The bidirectional switch102can be disposed on a first die116. In some embodiments, the first die may be GaN-based.

A bi-directional switch can have an advantage being capable of operating in four quadrants of operation of a transistor, i.e., it can block voltages in both directions and current can flow in both directions in the switch. This can be useful in power converter applications where the current may flow in either direction, for example, when a free-wheeling situation in a power converter, a bidirectional switch can allow the free-wheeling current to flow from its source terminal to its drain terminal with a relatively small voltage drop across its source-to-drain terminal. The characteristics of bidirectional switches can particularly be useful in GaN-based switches where the GaN-based switch may not include a free-wheeling diode, or the free-wheeling diode may have a relatively large voltage drop when a free-wheeling current flows through it. Use of a bidirectional switch capable of four quadrant operation can improve power efficiency of the power converter. Further, the bidirectional switch can have blocking properties in both directions.

Current approaches to form a bidirectional switch by coupling two devices in series back-to-back may use relatively large die area and have relatively high series resistance because the total resistance may be twice that of each back-to-back device since they are in series. And the die area consumed may be twice of a single switch because there are two of them. Thus, there may be a factor of four increase in specific on-resistance (RSP) compared to a unidirectional switch. Use of GaN-based lateral bidirectional switch enables a reduction of RSP of the power switch, for example, a GaN-based directional switch may have an RSP that is 1.2× as compared to a unidirectional switch. This is nearly a factor of four improvement as compared to a back-to-back device. Thus, a GaN-based lateral bidirectional switch can be almost as area efficient as a unidirectional switch. The GaN-based lateral bidirectional switch can include two source terminals, two gate terminals and a common drain.

Bidirectional switches may use precise control of their gate voltages in order to operate efficiently. Further, monitoring of the voltages at the terminals of the bidirectional switch may be used to operate the bidirectional switch reliably. Embodiments of the disclosure enable integration of bidirectional switches along with associated drivers and input/output circuits in a single semiconductor package in order to provide precise control of the bidirectional switches and operate the bidirectional switches reliably. Further, embodiments of the disclosure enable precise control of voltage levels at the terminals of the bidirectional switch where the bidirectional switch operates in an isolated high-side configuration. Thus, the integrated bidirectional switch can operate reliably and efficiently, thereby saving system costs. Current approaches may use a relatively large number of external components that can result in relatively high system costs, as well as reduced reliability.

The integrated bidirectional switch100can further include a second die120having a first driver124and a third die122having a second driver126. First driver124can be coupled to the first gate terminal106and the second driver126can be coupled to the second gate terminal112. The first source terminal104can be connected to a pin source-high (SH) and the second source terminal110can be connected to a pin source-low (SL). The integrated bidirectional switch100can also include a fourth die118having an input/output circuit128. The input/output circuit128can be coupled to the first driver124and the second driver126via differential isolation capacitors130and132, respectively. In some embodiments, the differential isolation capacitor130can be formed by series connected capacitors, where one capacitor may be disposed on the second die120and the other capacitor disposed on the fourth die118. In various embodiments, the differential isolation capacitor132can be formed by series connected capacitors, where one capacitor may be disposed on the third die122and the other capacitor disposed on the fourth die118.

The integrated bidirectional switch100can be formed in a single semiconductor package that includes first, second, third and fourth dies. These dies may be electrically isolated from each other, thereby allowing the control of conductivity state of the bidirectional switch with input signals that are reference to separate ground levels. The single semiconductor package may be a quad-flat no-lead (QFN), small-outline-integrated-circuit package (SOIC), dual-in-line package (DIP), or any other suitable semiconductor package.

The input/output circuit128may include I/O pins for driver circuitry for isolated power supply (pins D1/D2/SGND), signal input and control logic (pins VDD, INH, INL, SGND), and temperature sensor and signal output (pin TEMP). The temperature can be sensed, and the sensed information can be provided to external circuitry. The input/output circuit128may further include transmitter circuit for transmitting driving signals across the isolation capacitors130and132to the first and second drivers, respectively. The first and second drivers124and126, respectively, may include receiver circuits for receiving driving signals from the input/output circuit128. The first and second drivers124and126may further include voltage regulator and driver circuits for driving the first gate terminal106and the second gate terminal112, respectively (pins VDDH/L, VDD6H/L, GNDH/L). The voltage regulator can be used to adjust a drive voltage to the gate of the bidirectional switch. The first and second drivers124and126may further include sensor circuits for sensing voltage potential across the terminals of the bidirectional switch102, and/or sensing a current flowing in the bidirectional switch102. The sensed voltage and/or current can be used to provide over-voltage and over-current protection.

When INH signal goes high, the input/output circuit128can transmit a high signal across the isolation capacitors130to the first driver124. The first driver124can receive the INH signal and cause a voltage at the first gate terminal106to go high, thereby causing the high-side of the bidirectional switch102to turn-on. When INL signal goes high, the input/output circuit128can transmit a high signal across the isolation capacitors132to the second driver126. The second driver126can receive the INL signal and cause a voltage at the second gate terminal112to go high, thereby causing the low-side of the bidirectional switch102to turn-on. When both the high-side and the low-side of the bidirectional switch102are on, a current may flow from the first source terminal104to the second source terminal110, or vice-versa depending on the voltage potentials at the source terminals. When both of the INH or INL signals are low, there is no current flow in the bidirectional switch102, and the bidirectional switch is in blocking mode of operation. In some embodiments, there may be only one control input (VIN), that can drive both outputs to turn ON or OFF.

FIG.1Billustrates an integrated bidirectional four quadrant switch with drivers and input/output circuits, according to some embodiments.FIG.1Billustrates an integrated bidirectional four quadrant switch with drivers and input/output circuits170that is similar to integrated bidirectional four quadrant switch with drivers and input/output circuits100ofFIG.1, except that driver circuits124and126may be coupled to the substrate114. In the illustrated embodiment, the co-packaged drivers may include a circuit to detect the state of the bidirectional switch and control the substrate potential accordingly. The substrate potential may control a back gating effect in GaN power transistors, which may cause a shift in an on-resistance of the bidirectional switch. The gate driver circuit may sense the substrate voltage with using this connection and can control the voltage of the substrate and the charge state of the substrate as a function of a sensed substrate voltage. The gate driver circuits may also control a desired state of the bidirectional switch. In some environments, other parameters may be used by the gate driver circuit such as, but not limited to, operating temperature, magnitude and/or polarity of the current in the bidirectional switch and voltage across the switch. The substrate connection can be driven with a positive or negative voltage, current, or current pulses that correspond to the required charge to be injected, to control the potential to the desired level. The voltage or current or current pulse level and length may be varied from switching cycle to switching cycle, or within one switching cycle. The gate driver circuit may use the substrate potential control to reduce ON-resistance variations due to back gating, and may also use it to temporarily increase the ON-resistance under certain circumstances, including but not limited to suppressing ringing or heating up the bidirectional switch in case of low operating temperature.

Integrated Half-Bridge with Two Bidirectional Switches

FIG.2illustrates an integrated half-bridge circuit with two bidirectional four quadrant switches with drivers and input/output circuits, according to certain embodiments.FIG.2shows an integrated half-bridge circuit200with two bidirectional switches coupled in series forming a half-bridge. The integrated half-bridge circuit200can include a first bidirectional switch202and a second bidirectional switch204, where the first bidirectional switch202is coupled in series to the second bidirectional switch204at a switch node250. The first bidirectional switch202may be disposed on a first die206and the second bidirectional switch204may be disposed on a second die208. In some embodiments, the first and the second bidirectional switches202and204may be disposed on the same die. In various embodiments, the first and second dies206and208, respectively, may be GaN-based.

The integrated half-bridge circuit200can further include a third die210having a first driver220, a fourth die212having a second driver222, a fifth die214having a third driver224, and a sixth die216having a fourth driver226. The first driver220can be coupled to a first gate terminal of the first bidirectional switch202and the second driver222can be coupled to a second gate terminal of the first bidirectional switch202. The third driver224can be coupled to a first gate terminal of the second bidirectional switch204and the fourth driver226can be coupled to a second gate terminal of the second bidirectional switch204. The integrated half-bridge circuit200can further include a seventh die228having an input/output circuit218. The input/output circuit218can be coupled to the first, second, third and fourth drivers via differential isolation capacitors.

The integrated half-bridge circuit200can be formed in a single semiconductor package that includes the first, second, third, fourth, fifth, sixth and seventh dies. The single semiconductor package may be a quad-flat no-lead (QFN), small-outline-integrated-circuit package (SOIC), dual-in-line package (DIP), or any other suitable semiconductor package.

The input/output circuit218may include I/O pins for driver circuitry for isolated power supply (pins D1, D2, SGND), signal input and control logic (pins VDD, INH, INL, SGND) and temperature sensor and signal output (pin TEMP). The input/output circuit218may further include transmitter circuit for transmitting driving signals across the isolation capacitors to the first to fourth drivers. The first to fourth drivers220to226, respectively, may include receiver circuits for receiving driving signals from the input/output circuit218. They may further include voltage regulator and driver circuits for driving the gate terminals of the first bidirectional switch202and the second bidirectional switch204, respectively (pins VDDH/L/M, VDD6H/L/M, GNDH/L/M). The second and third drivers222and224may share a same source connection (SM). The supply and ground nodes for the second and third drivers may be referred to as VDDM, VDD6M, GNDM, with M meaning Middle, as it is in the middle of the half bridge. The first to fourth drivers may further include sensor circuits for sensing voltage potentials across the terminals of the first and second bidirectional switches202and204, respectively, and/or sensing a current flowing in the first and second bidirectional switches202and204.

When INH signal goes high, the input/output circuit218can transmit a high signal across the isolation capacitors to the first and second drivers220and222, respectively. The first and second drivers can receive the INH signal and cause a voltage at the first and second gate terminals of the first bidirectional switch202to go high, thereby causing the first bidirectional switch202to turn-on. Thus, the switch node250may get pulled to a voltage of the high-side. When INL signal goes high, the input/output circuit218can transmit a high signal across the isolation capacitors to the third and fourth drivers224and226, respectively. The third and fourth drivers can receive the INL signal and cause a voltage at the first and second gate terminals of the second bidirectional switch204to go high, thereby causing the second bidirectional switch204to turn-on, thus a voltage at the switch node250can go to the voltage of the low-side. In some embodiments, when the gate drivers are continuously aware of the voltage polarity across each bidirectional switch, the driver driving the section of the bidirectional switch operating in reverse current can remain ON continuously, instead of switching, as the other section of the GaN of the bidirectional switch. This can reduce the dynamic current consumption of one of the drivers. The driver can be arranged to determine itself whether to remains ON or not as needed, regardless of the status of the input control signal. In this way, the driver can determine the state of operation and act accordingly. For example, to limit dynamic current consumption, when220and222determine the voltage polarity, the integrated half-bridge circuit200can be arranged to keep one of the switches always ON (the one that is anyway passing in reverse direction for a given polarity) and control ON/OFF only the other switch. In various embodiments, this logic can be integrated in each of the drivers220and222(and/or for drivers224and226).

In some embodiments, such as in applications where the input and output power of the converter may be conveyed by a current, not a voltage, embodiments of the disclosure enable independent control of the turn-on and turn-off of the two bidirectional switches. The input current can thus be steered into the output, by turning ON the bidirectional switch202and simultaneously keeping OFF bidirectional switch204. When the bidirectional switch204is turned ON, the current is commuting away from the load and back to returning to the input directly. This mode of operation is also called “current-source inverter”.

In various embodiments, an input power source may be connected to the terminal SH of bidirectional switch202, and another input power source may be connected to the terminal SL of bidirectional switch204. The load can be connected to the terminal SM. In this setup, the power to the load can be selected from either input, thus enabling operation in applications with redundant power supplies that are not allowed to fail. For example, if one of the power inputs is not available, the corresponding bidirectional switch can be turned OFF and the power supply be repaired or replaced, while the load continues to be supplied by the other power supply still in operation. Some example applications are, but not limited to, where one of the power supplies may consist of batteries, and the other power input may come from the grid, enabling continuous operation even if the grid power fluctuates or is interrupted.

Integrated Bidirectional Switch with Sensors

FIG.3illustrates an integrated bidirectional four quadrant switch with drivers, input/output circuits, and current and voltage sensors, according to certain embodiments.FIG.3shows an integrated bidirectional switch300that can include a bidirectional switch302. The bidirectional switch302can include a first source terminal304, a first gate terminal306, a drain terminal308, a second source terminal310, a second gate terminal312, and a first substrate connection314. The bidirectional switch302can be disposed on a first die316. In some embodiments, the first die may be GaN-based.

The integrated bidirectional switch300can further include a second die320having a first driver328and a first sensing circuit321. The integrated bidirectional switch300can further include a third die322having a second driver330and a second sensing circuit323. First driver328can be coupled to the first gate terminal306. In some embodiments, the gate driver328may be coupled to the substrate connection314and can be arranged to control a voltage of the substrate, for example, clamp the substrate voltage in presence of a spurious or overvoltage condition in the substrate. The first sensing circuit321may be coupled to the first source terminal304by a connection324and can be arranged to sense a status of the voltage at the source terminal304and may be further arranged to sense a status of operation of the directional switch (for example, the section that328is connected to), for example, sense a polarity and a magnitude of a current flow in the directional switch302. In some embodiments, the first sensing circuit321may further be arranged to sense operating temperature of the bidirectional switch.

The second driver330can be coupled to the second gate terminal312. In some embodiments, the gate driver330may be coupled to the substrate connection314and can be arranged to control a voltage of the substrate, for example, clamp the substrate voltage in presence of a spurious or overvoltage condition in the substrate. A second sensing circuit323may be coupled to the second source terminal310by a connection326and can be arranged to sense a status of the voltage at the source terminal310and may be further arranged to sense a status of operation of the directional switch (for example, the section that330is connected to), for example sense a polarity and a magnitude of a current flow in the directional switch302. In some embodiments, the second sensing circuit323may further be arranged to sense operating temperature of the bidirectional switch. The first source terminal304can be connected to a pin source-high (SH) and the second source terminal310can be connected to a pin source-low (SL). In some embodiments, operating parameters of the bidirectional switch may be used by the gate driver circuits such as, but not limited to, operating temperature, magnitude and/or polarity of the current in the bidirectional switch and voltage across the switch.

The integrated bidirectional switch300can also include a fourth die318having an input/output circuit329. In some embodiments, the input/output circuit329may include control circuits. The input/output circuit329can be coupled to the first driver328and the first sensing circuit321via differential isolation capacitors332, respectively. The input/output circuit329can be further be coupled to the second driver330and the second sensing circuit323via differential isolation capacitors334, respectively. In some embodiments, the differential isolation capacitors332can be formed by series connected capacitors, where one capacitor may be disposed on the third die322and the other capacitor disposed on the fourth die318.

The integrated bidirectional switch300can be formed in a single semiconductor package that includes first, second, third and fourth dies. These dies may be electrically isolated from each other, thereby allowing the control of conductivity state of the bidirectional switch with input signals that are reference to separate ground levels. The single semiconductor package may be a quad-flat no-lead (QFN), small-outline-integrated-circuit package (SOIC), dual-in-line package (DIP), or any other suitable semiconductor package.

The input/output circuit329may include I/O pins for driver circuitry for isolated power supply (pins D1/D2/SGND), signal input and control logic (pins VDD, INH, INL, SGND), and receiver circuitry for the current and voltage signals from the secondary side (pin SENSE). The input/output circuit329may further include transmitter circuit for transmitting driving signals across the isolation capacitors332and334to the first and second drivers, respectively. The first and second drivers328and330may include receiver circuits for receiving driving signals from the input/output circuit329. The first and second drivers328and330may further include voltage regulator and driver circuits for driving the first gate terminal306and the second gate terminal312, respectively (pins VDDH/L, VDD6H/L, GNDH/L). The voltage regulator can be used to adjust a drive voltage to the gate of the bidirectional switch. The first and second sensing circuits321and323may include sensor circuits for sensing voltage at the terminals of the bidirectional switch302, and/or sensing a current flowing in the bidirectional switch302.

The first and second sensing circuits321and323may further include analog-to digital (A/D) conversion circuits and transmitter circuitry for transmitting the signals corresponding to the sensed voltage and currents to the input/output circuit. The signals corresponding to the sense currents/voltages can be used for autonomous control of the bidirectional switch302. The signals corresponding to the sensed voltage and currents can be transmitted to an external microcontroller by the input/output circuit. The signals corresponding to the sense currents/voltages can be transmitted by the input/output circuit using multiple pins, or using a single pin where the data is multiplexed. The signals corresponding to the sense currents can be used to detect when the current crossed zero from positive to negative, and/or from negative to positive flow. The input/output circuit signals can be arranged to receive a turn-on or turn-off signal and transmit it to the drivers upon sensing a relatively low voltage or current in the bidirectional switch302(auto-resonant operation).

An auto-resonant operation may be where in a quasi-resonant power application, the resonant nature of the load in combination with additional passive components can be used to achieve turn-on or turn-off of the power switches at low or zero voltage or current across the switch. This may be done in to reduce switching losses, and is sometimes referred to as soft switching. In contrast, switching at high voltage or current levels (also referred to as hard switching) may generate relatively high switching losses and can present elevated stress levels to the power switch. In some embodiment, the voltage and current can be sensed that enables precise determination of the voltage and current across the bidirectional switch local to the driver circuit. The sensed voltage and/or current can be used to adjust the precise switch timing to turn ON or OFF at the right moment, without intervention of a microcontroller. As the signals are available locally to the driver, they do may not have to be sent through the isolated signal transfer, subsequent connections to the system controller, and suffer from processing delays in the controller due to limited computing power. Therefore, the switching action can be signaled by the controller but the exact timing can be determined by the driver, yielding even lower losses and EMI emissions.

The input/output circuit may further be arranged to turn on the bidirectional switch when a relatively high voltage is sensed across the bidirectional switch302in either direction. The turn-on time can be for a pre-determined time and pulse length, or until the voltage or current in the bidirectional switch302have reached relatively low levels (auto-clamping).

When INH signal goes high, the input/output circuit329can transmit a high signal across the isolation capacitors332to the driver328. The driver328can receive the INH signal and cause a voltage at the first gate terminal306to go high, thereby causing the high-side of the bidirectional switch302to turn-on. When INL signal goes high, the input/output circuit329can transmit a high signal across the isolation capacitors334to the second driver330. The second driver330can receive the INL signal and cause a voltage at the second gate terminal312to go high, thereby causing the low-side of the bidirectional switch to turn-on. When both the high-side and the low-side of the bidirectional switch302are on, a current may flow from the first source terminal304to the second source terminal310, or vice-versa depending on the voltage potentials at the source terminals. When either of the INH or INL signals are low, there is no current flow in the bidirectional switch102, and the bidirectional switch is in blocking mode of operation.

Integrated Bidirectional Switch with Multiple Input/Output Circuits

FIG.4illustrates an integrated bidirectional four quadrant switch with drivers, current and voltage sensors, and multiple input/output circuits disposed on separate dies, according to certain embodiments.FIG.4shows an integrated bidirectional switch400that is similar to the integrated bidirectional switch300except that there are two input/output circuits that are disposed on separate dies. The integrated bidirectional switch400can include a bidirectional switch402. The bidirectional switch402can be disposed on a first die404. In some embodiments, the first die may be GaN-based.

The integrated bidirectional switch400can further include a second die420having a first driver and a first sensing circuit. The integrated bidirectional switch400can further include a third die422having a second driver and a second sensing circuit. The integrated bidirectional switch400can also include a fourth die418having a first input/output circuit428, and a fifth die426having a second input/output circuit438. The first input/output circuit428can be coupled to the first driver and the first sensing circuit, and the second input/output circuit438can be coupled to the second driver and the second sensing circuit, respectively, via differential isolation capacitors. Use of two separate input/output circuits disposed on two separate dies within the integrated bidirectional switch package can enable some applications, such as industrial applications, where the integrated bidirectional switch complies with functional safety regulations. These applications may have a safety integrity level (SIL) such as, for example, SIL 3 or SIL 4. SIL is defined as the relative level of risk-reduction provided by a safety function. Therefore, redundancy is used for these safety-critical functions, particularly to turn off devices to protect them. Thus, two input/output circuits on two separate dies are used to provide redundancy in control and monitoring of the bidirectional switch, in order to satisfy the safety-critical functions.

The integrated bidirectional switch400can be formed in a single semiconductor package that includes first, second, third, fourth and fifth dies. These dies may be electrically isolated from each other, thereby allowing the control of conductivity state of the bidirectional switch with input signals that are reference to separate ground levels. The single semiconductor package may be a quad-flat no-lead (QFN), small-outline-integrated-circuit package (SOIC), dual-in-line package (DIP), or any other suitable semiconductor package.

The first and second input/output circuits428and438may include separate control circuits for both sides of the bidirectional switch402, signal input and control logic (pins VDD, INH, INL, SGND) and receiver circuits for the status signals (FBH, FBL). The first and second input/output circuits428and438may further include transmitter circuits for transmitting driving signals to the first and second drivers across the isolation capacitors. The first and second drivers may include receiver circuits for receiving driving signals from the first and second input/output circuits428and438, respectively. The first and second drivers may further include voltage regulator and driver circuits for driving the gate terminals of the bidirectional switch402. The voltage regulator can be used to adjust a drive voltage to the gate of the bidirectional switch. The first and second sensing circuits may include sensor circuits for sensing voltage at the terminals of the bidirectional switch402, and/or sensing a current flowing in the bidirectional switch402.

The first and second sensing circuits may further include analog-to digital (A/D) conversion circuits and transmitter circuitry for transmitting the signals corresponding to the sensed voltage and currents to the input/output circuit. The signals corresponding to the sense currents/voltages can be used for autonomous control of the bidirectional switch402. The signals corresponding to the sensed voltage and currents can be transmitted to an external microcontroller by the input/output circuit. The signals corresponding to the sense currents/voltages can be transmitted by the input/output circuit using multiple pins, or using a single pin where the data is multiplexed. The signals corresponding to the sense currents can be used to detect when the current crossed zero from positive to negative, and/or from negative to positive flow. The input/output circuit signals can be arranged to receive a turn-on or turn-off signal and transmit it to the drivers upon sensing a relatively low voltage or current in the bidirectional switch402. The input/output circuit may further be arranged to turn on the bidirectional switch when a relatively high voltage is sensed across the bidirectional switch402in either direction. The turn-on can be for a pre-determined time and pulse length, or until the voltage or current in the bidirectional switch402have reached relatively low levels (auto-clamping). In various embodiments, a high voltage signal may have a range from 100 V to 1200 V, while in other embodiments it may have a range from 200 V to 800 V, while yet in other embodiments it may have a range from 500 V to 600 V. As appreciated by one of ordinary skill in the art having the benefit of this disclosure, the voltage values of the signals can be set to any suitable value.

In some embodiments, the first and second sensing circuits321and323of the integrated bidirectional switch300with may be configured such that a sensing switch is coupled in parallel to the bidirectional switch302. The sensing switch can sense a magnitude and a polarity of current in the bidirectional switch302, and feed it to an amplifier to generate a first signal. The current sense switch may be further arranged to transmit the first signal including at least one of the magnitude and polarity of the current through the bidirectional switch302to a driver circuit. The driver circuit can be arranged to transmit control signals to the gate terminals of the bidirectional switch based on the first signal.

FIG.5illustrates an integrated half-bridge circuit with two bidirectional four quadrant switches with drivers, current and voltage sensors, and multiple input/output circuits disposed on separate dies, according to certain embodiments.FIG.5shows an integrated half-bridge circuit500that is similar to the integrated bidirectional switch400except that there are two bidirectional switches coupled in series to form the half-bridge circuit. In some embodiments, the two bidirectional four quadrant switches can be disposed on separate dies. In various embodiments, the two bidirectional four quadrant switches may be disposed on the same die. The integrated half-bridge circuit500can include a first bidirectional switch502coupled in series with a second bidirectional switch504. The first bidirectional switch502can be disposed on a first die506and the second bidirectional switch504can be disposed on a second die508. In some embodiments, the first and second dies may be GaN-based. In various embodiments, the first and second dies may be Si-based.

The integrated half-bridge circuit500can further include a third die520having a first driver511and a first sensing circuit. The integrated half-bridge circuit500can further include a fourth die522having a second driver512and a third driver514. The integrated half-bridge circuit500can also include a fifth die524having a fourth driver516and a second sensing circuit. The integrated half-bridge circuit500can further include a sixth die518having a first input/output circuit528, and a seventh die526having a second input/output circuit538. The first input/output circuit528can be coupled to the first and second drivers511and512, respectively, and to the first sensing circuit via differential isolation capacitors. The second input/output circuit538can be coupled to the third and fourth drivers514and516, respectively, and to the second sensing circuit via differential isolation capacitors. Similar to the integrated bidirectional switch400, Use of two separate input/output circuits disposed on two separate dies within the integrated bidirectional switch package can enable applications such as industrial, where the integrated bidirectional switch complies with functional safety regulations.

The half-bridge circuit500can be formed in a single semiconductor package that includes first, second, third, fourth, fifth, sixth and seventh dies. These dies may be electrically isolated from each other, thereby allowing the control of conductivity state of the bidirectional switch with input signals that are reference to separate ground levels. The single semiconductor package may be a quad-flat no-lead (QFN), small-outline-integrated-circuit package (SOIC), dual-in-line package (DIP), or any other suitable semiconductor package.

Integrated Bidirectional Switch with Self-Powered Drivers

FIG.6A1illustrates an integrated bidirectional four quadrant switch with self-powered drivers, according to certain embodiments. FIG.6A1shows an integrated bidirectional switch with self-powered drivers600that can include a bidirectional switch stage605, a bidirectional switch stage607and a bidirectional switch stage609. The bidirectional switch stage605can include a bidirectional switch602that may have an enhancement-mode (E-mode) upper section and an E-mode lower section. The bidirectional switch stage607can include a bidirectional switch620that may have an E-mode upper section and a D-mode lower section. The bidirectional switch stage609can include a bidirectional switch640that may have a D-mode upper section and an E-mode lower section. In some embodiments, the bidirectional switch602, bidirectional switch620and the bidirectional switch640may be disposed on the same GaN-based die. In various embodiments, the bidirectional switch602, bidirectional switch620and the bidirectional switch640may be disposed on the separate GaN-based die. In some embodiments, the bidirectional switch602, bidirectional switch620may be disposed on the same die while the bidirectional switch640is disposed on a separate die. Other combinations of the disposing of the bidirectional switches on various GaN-based die are within the scope of this disclosure.

FIG.6A2illustrates an integrated bidirectional four quadrant switch with self-powered drivers with E-mode upper and lower sections, according to some embodiments. FIG.6A2shows an integrated bidirectional switch with self-powered drivers680. As illustrated in FIG.6A2, the bidirectional switch620may include an E-mode upper section and an E-mode lower section. In various embodiments, the bidirectional switch640may include an E-mode upper section and an E-mode lower section. In certain embodiments, the bidirectional switches602,620and640may be GaN-based. In some embodiments, each of the bidirectional switches602,620and640can be disposed on a single die that is isolated from the other dies. In various embodiments, the bidirectional switches602,620and640can all be disposed on a single die. In some embodiments, a startup supply circuit687can be coupled to bidirectional switch with self-powered drivers680, where a supply for die660and die670can be arranged to provide supply power during startup of the circuit.

In the bidirectional switch with self-powered drivers600and680, the bidirectional switch stage605can perform the switching functions while bidirectional switch stage607and bidirectional switch stage609may be arranged to self-power the drivers for the bidirectional switch stages605,607and609. For example, the bidirectional switch stage605can be used in an inverter, as an AC relay, or in other applications. The size of the bidirectional switch602can be relatively large compared to the bidirectional switches620and640. In some embodiments, the bidirectional switches620and640can have relatively high on-resistance (RDSON) and may carry relatively low currents.

In the illustrated embodiment, the drivers driving gate terminals of the bidirectional switch602,620and640can be self-powered, i.e., the drivers can operate without having a power supply. This can be advantageous when the drivers are isolated because providing a power supply for an isolated high-side driver can be cumbersome. Current approaches, such as bootstrapping techniques, may use relatively large number of external components to provide the high-side isolated drivers with a power supply which can increase system costs and can make the system less reliable. Embodiments of the disclosure enable self-powering the drivers for bidirectional switches thereby reducing system complexity and costs, and increasing the reliability of the system. Further, embodiments of the disclosure can integrate self-powered drivers with bidirectional switches along with input/output circuits in a single semiconductor package, thereby reducing system costs and enabling relatively high operational frequencies.

In some embodiments, energy from a first source to a second source of a bidirectional switch can be harvested to power drivers driving the bidirectional switch. The energy may be harvested and stored on an energy harvesting capacitor during a time period when input voltage is high and can be used to power the drivers when the input voltage is zero or is not available. Thus, the energy may be harvested when an input voltage is within a certain acceptable range such that the energy harvesting may not draw excessive power by harvesting the energy from high voltage. Embodiments of the disclosure enable harvesting the energy from source to source and taking the energy for the drive function when the input voltage is within an acceptable range. In some embodiments, such as AC applications where the input voltage may be a sinusoidal, harvesting of energy can be performed when the input voltage is close to zero where the input voltage is high enough to deliver a charge for the drive function but not too high to cause excess power loss. In various embodiments, energy from a first source to a second source of a bidirectional switch can be harvested to power drivers for the bidirectional switch. In some embodiments, the first and second sources may be coupled to AC mains.

The bidirectional switch602can have a source terminal606coupled to a high-side source pin693(SH), a gate terminal610, a drain terminal612, a substrate connection608, a gate terminal614and a source terminal616coupled to a low-side source pin691(SL). A first driver circuit can be coupled to the gate terminal610and a second driver circuit can be coupled to the gate terminal614. The bidirectional switch602can be disposed on a first die604. The bidirectional switch620can be a hybrid switch, i.e., the upper section can be an E-mode and the lower section may be a D-mode. The bidirectional switch620can a have a source terminal622coupled to a high-side source pin, a gate terminal626, a drain terminal630, a substrate connection628, a gate terminal632and a source terminal634. The bidirectional switch620can be disposed on a second die624. The source terminal634can be coupled to an energy harvesting capacitor636, and the energy harvesting capacitor636can be coupled to the low-side source pin. The bidirectional switch640can be a hybrid switch, i.e., the upper section can be a D-mode and the lower section may be an E-mode. The bidirectional switch640can a have a source terminal644coupled to an energy harvesting capacitor642where the energy harvesting capacitor642may be coupled to the high-side source pin. The bidirectional switch640can a further include a gate terminal648, a drain terminal652, a connection to substrate650, a gate terminal654and a source terminal654that is coupled to SL. The bidirectional switch640can be disposed on a third die646.

As illustrated in FIG.6A2, the integrated bidirectional switch with self-powered drivers680can further include a first comparator664disposed on a fourth die660and a second comparator674dispose on a fifth die670. The fourth die660can further include a reference voltage662that is provided to the input of the comparator664. The fifth die670can further include a reference voltage672that is provided to the input of the comparator664. The fourth and fifth dies can further include an impedance divider circuit that is arranged to measure a voltage difference between the source terminals622and634, and source terminals644and656, respectively. Voltage references662and672can be used to determine proper switching levels of the comparators664and674. The comparator664can generate signals that are sent to relatively small gate drivers (disposed on fourth die) to drive gate terminals626and648. The comparator674can generate signals that are sent to relatively small gate drivers (disposed on fifth die) to drive gate terminals632and654. In some embodiments, gate terminal654may be coupled to the source terminal656and gate terminal626may be coupled to source terminal622. In this way, the gate terminals of the D-mode sections are controlled by the comparator/driver circuits. Further, the signals generated by the comparators664and674can be used to provide status signals for control of the bidirectional switch602. In some embodiments, the fourth die can also include the driver circuit for the gate610, while in various embodiments the fifth die can also include the driver circuit for the gate614. The fourth die may be powered by VDDL versus SL and the fifth die may be powered by VDDH versus SH.

In some embodiments, a size of the energy harvesting capacitor636can be, for example, one microfarad. The energy harvesting capacitor636can be charged by the bidirectional switch620which may have, for example, 100 milliohms of on-resistance. Therefore, the charging time would be on the order of 10 to 100 nanoseconds. A size of the bidirectional switch620can be selected so that the charging time of the energy harvesting capacitor is set properly such that it is fast and such that there is relatively small amount of current flowing through the bidirectional switch620. Similar to bidirectional switch620, the size of the bidirectional switch640can be selected such that it can generate an appropriate charging time for the energy harvesting capacitor642. As appreciated by one of ordinary skill in the art having the benefit of this disclosure, the size of the energy harvesting capacitors can be set to any suitable value. Further, the value of the on-resistance of the bidirectional switches that are arranged to charge the energy harvesting capacitors can be set to any suitable value.

As illustrated in FIG.6A1, in some embodiments, the gate terminal626of the bidirectional switch620may be coupled to the source terminal622. Thus, the upper section of the bidirectional switch620may be in a diode-connected configuration. In this way, the energy harvesting capacitor636can be charged to a threshold voltage of the D-mode upper section, and would subsequently turn itself off automatically. In various embodiments, such as but not limited to FIG.6A2, the gate terminal626of the bidirectional switch620can be coupled to an output of the comparator664, where the comparator664would control the charge on the energy harvesting capacitor and where the comparator can turn on or off the gate terminal626depending on what the voltage levels. In this way, the energy harvesting capacitor636can be charged to voltage levels different from the threshold voltage of the D-mode upper section.

In some embodiments, such as but not limited to FIG.6A1, the gate terminal654of the bidirectional switch640may be coupled to the source terminal656. Thus, the lower section of the bidirectional switch640may be in a diode-connected configuration. In this way, the energy harvesting capacitor642can be charged to a threshold voltage of the D-mode lower section, and would subsequently turn itself off automatically. In various embodiments, the gate terminal654of the bidirectional switch640can be coupled to an output of the comparator674, where the comparator674may control the charge on the energy harvesting capacitor642. In some embodiments, the comparator can turn on or off the gate terminal654depending on what the voltage levels. In various embodiments,648can be controlled to stop or not charge capacitor642. In various embodiments, the energy harvesting capacitor642can be charged to voltage levels different from the threshold voltage of the lower section.

In some embodiments, for an input voltage that is sinusoidal, the voltage levels at SH and SL can be alternating. The voltage at SH can be positive where the voltage at SL is negative, or the voltage at SH can be negative where the voltage at SL is positive. When a voltage at the drain terminal622gets to a level that is in a predetermined voltage range, for example 12 to 18 volts, the bidirectional switch620can be turned on and can charge the energy harvesting capacitor636to a voltage, for example, 18 volts. When the voltage gets higher, then the bidirectional switch620may be turned off, thus it may act like a window comparator that will charge the capacitor only when that voltage difference between SH and SL is in the right range. During a time period when the bidirectional switch620is on, the energy harvesting capacitor636can be charged, thus the energy harvesting capacitor636and the bidirectional switch620are sized such that there is sufficient charge on that capacitor to power the circuits during a time when the voltage is not in the correct range. As appreciated by one of ordinary skill in the art having the benefit of this disclosure, the predetermined voltage range can be set to any suitable value.

In some embodiments, when a voltage at the source terminal656gets to a predetermined level, for example 12 to 18 volts, the bidirectional switch640can be turned on and can charge the energy harvesting capacitor642to a voltage of, for example, 18 volts. When the voltage gets higher, then the bidirectional switch640may be turned off, thus it may act like a window comparator that will charge the capacitor642only when that voltage difference between SH and SL is in the right range. During a time period when the bidirectional switch640is on, the energy harvesting capacitor642can be charged, thus the energy harvesting capacitor642and the bidirectional switch640are sized such that there is sufficient charge on that capacitor to power the circuits during a time when the voltage is not in the correct range.

Self-Powered Operation Using Bidirectional Switches with E-Mode and D-Mode Sections

The section above described the operation of the bidirectional switch with self-powered drivers600when all stages are enhancement mode. In the above section, the comparator664can turn off the bidirectional switch620when the input voltage is a predetermined window, and for inverse polarity, the comparator674can turn off the bidirectional switch640when the input voltage is a predetermined window. In some embodiments, the energy harvesting capacitors636and642may have no charge to begin with. Embodiments of the disclosure can enable power up from zero charge on the energy harvesting capacitor by utilizing depletion mode (D-mode) in lower section of bidirectional switch620and depletion mode in the upper section of the bidirectional switch640.

For example, the D-mode section may have a threshold voltage of −20 V. Therefore, the D-mode section would conduct when the gate terminal is tied to the source terminal, and it would charge up the energy harvesting capacitor to a voltage of 20 V, at which point it would turn itself off because the source voltage would then be at 20 V, gate-to-source voltage would be −20, and the D-mode section would then turn itself off. During this time period, the source terminal may be at a higher potential compared to the drain terminal and the transistor would be operating in reverse-conduction. The D-mode lower section of the bidirectional switch620and the D-mode upper section of the bidirectional switch640can enable startup. The E-mode sections on the opposite end can be configured in a diode connected arrangement where the gate and source terminals are coupled together, and the E-mode section may act as rectifying the input signal such that it is conductive when the energy harvesting capacitor is being charged, and can act in blocking mode when the circuit is preventing discharge of the energy harvesting capacitor. As appreciated by one of ordinary skill in the art having the benefit of this disclosure, the threshold voltage of the D-mode section can be set to any suitable value. In some embodiments, bidirectional switch with self-powered drivers600can use bidirectional switches with D-mode sections which can enable the circuit to function without using comparators.

When capacitor636is discharged, the gate terminal632of bidirectional switch620(lower section; D-mode) can be connected to node SL, therefore an effective gate-source voltage of the lower section of bidirectional switch620can be the same as the voltage across capacitor636with a reversed polarity. As the voltage SH-SL increases (FIG.6B), bidirectional switch620can start conducting current (FIG.6C), because a depletion-mode switch can conduct current even when there is zero volt across the gate to source terminals. Therefore, the voltage695(VDDL) can increase (FIG.6D) and reach a level of a threshold voltage of the lower section of the bidirectional switch620VTHQ3,D. In some embodiments, VTHQ3,Dmay have a value of 18 to 20V. When voltage695(VDDL) reaches the threshold voltage VTHQ3,D, the lower section of the bidirectional switch620(D-mode) may be turned off, and the current through bidirectional switch620decreases to zero, even though the voltage SH-SL continues to rise. During this event the upper section of the bidirectional switch620, which is connected as diode (gate tied to source), may be in reverse conduction, as the voltage at the source terminal can be higher than the voltage at the drain terminal630. In some embodiments, a turn-on can occur when a voltage difference is in a range of, for example, 12-18V and when the capacitors that are being charged as a consequence of the voltage being in the range of, for example, 12-18V.

When the voltage SH-SL is decreasing again, the lower section of the bidirectional switch620(D-mode) may re-enter conduction and recharge capacitor636. When the voltage SH-SL changes polarity, the upper section of the bidirectional switch620can be in blocking state and no current may flow, thus preventing the discharge of capacitor636during this period. The circuits coupled to capacitor636may discharge the capacitor636, and voltage695(VDDL) can decrease. For each subsequent cycle of the voltage SH-SL, the capacitor636can be recharged to the threshold voltage VTHQ3,D, where this next charging period may be shorter than during initial charging at startup. In particular, the flow of current will start later, as the remaining voltage on capacitor636can provide a larger value from which to start from. The bidirectional switch620may be sized so that the current delivered to capacitor636is relatively high enough to maintain VDDL above the appropriate supply voltage to the connected circuits. The bidirectional switch620can be sized small enough so as to operate as a current source.

Table 1 further describes an example method of operation of bidirectional switch with self-powered drivers600(or680), particularly operating bidirectional switches620and640.

TABLE 1Input voltage SH-SL++−−GateBidirectionalBidirectionalBidirectionalBidirectionalswitch 640 Upperswitch 620 Upperswitch 640 Upperswitch 620 UpperStatusOFF or ONON (reverseON till VDDHOFFdepending on themode diode)reaches Vth of theVDDH voltage vs.D-Modethe Vth of theD-modeGateBidirectionalBidirectionalBidirectionalBidirectionalswitch 640 Lowerswitch 620 Lowerswitch 640 Lowerswitch 620 LowerStatusOFFON till VDDLON (reverseOFF or ONreaches Vth of themode diode)depending on theD-ModeVDDL voltagevs. the Vth of theD-mode
The control logic can also be rephrased as: 1) When a voltage at the “other” source of the bidirectional switch is negative with respect to the local source, turn both sections of the bidirectional switch off; 2) When the voltage at the “other” source is positive with respect to the local source, turn the bidirectional switch referenced to the local source OFF; 3) When the voltage at the “other” source is positive with respect to the local source, turn the capacitor-connected bidirectional switch on if the voltage is in between a predetermined range (e.g., 12 to 18 V).

Table 2 further describes an example method of operation of bidirectional switch with self-powered drivers600(or680), showing status of the comparator output. Table 2 provides examples of comparator signals that can be used by the controller to determine the bidirectional switch status.

TABLE 2SH-SLComparator Output Status>18 VHigh positive voltage across the switch;Switch is blocking.12 to 18 VCharging the supply cap possible5 to 12 VVoltage too low for charging;Confirm switch is on−5 to 5 VZero crossing or loss of high voltage;Confirm switch is on<5 VNegative voltage across the switch;Switch is reverse-conducting.
As appreciated by one of ordinary skill in the art having the benefit of this disclosure, the voltage values for SH-SL can be set to any suitable value.

FIG.7illustrates an integrated bidirectional four quadrant switch700that is similar to the integrated bidirectional switch300, according to certain embodiments. The integrated bidirectional four quadrant switch700may include an input/output circuit having include I/O pins for signal input and control logic (pins VDD, INHL, SET, SGND), transmitter circuitry for driving signals, receiver circuitry for the current and voltage signals from the secondary side (pin SENSE) and signal processing circuitry for current control. The control circuit can receive the sensed current information from one or both ends of the bidirectional switch, and may process the current information signal along with the input signal to control the bidirectional switch702. In particular, the control circuit can implement a turn-on or turn-off sequence so as to turn on or off one end of the bidirectional switch before the other. It could also decide to keep the switch operating in reverse direction always ON while toggling the other switch ON/ODD accordingly to the INHL input control.

When the current through the bidirectional switch702gets to be relatively high, the control circuit can turn off the bidirectional switch702(overcurrent protection). In some embodiments, the turn-off can be latched, so that a power supply cycle or reset signal can be used for a new turn-on. In some embodiments, the turn-off can be slow, to make a soft turn-off, so that no voltage surge can occurs due to high energy accumulated in parasitic inductors of the power switches. In various embodiments, the turn-off can be for a relatively short time period, such that the next rising edge may turn the switch back on. In some embodiments, the turn-off can be staggered, where the turn-off sequence consists of pulses with configurable frequency that are progressively getting relatively shorter, to reach zero during a predefined time period. In various embodiments, the similar technique can be used to turn on or off the bidirectional switch702upon a turn-on/off signal at the input.

The control circuit can also implement a configurable current rise or fall time, using the same scheme of staggered pulses, upon turn-on and turn-off. The current rise/fall times may be different for turn-on and turn-off, and may depend on other parameters such as temperature or current or voltage levels. The pulses during current ramp-up may be shortened if the current is approaching or exceeding maximum level. The pulses during current ramp-down may be blanked if the current already has reached zero.

FIGS.8A to8Dshow an input signal and current waveforms for the integrated bidirectional four quadrant switch700, according to certain embodiments. Using the sensed current information, the turn-off or turn-on of the bidirectional switch702can be configured correspondingly. The turn-off or turn-on can be hard or staggered, depending on the load conditions, and the parasitic inductance and capacitance in the system.FIG.8Ashows an input signal.FIG.8Bshows turn-off in a severe overload situation, where another turn-on is not allowed until the load is cleared.FIG.8Cshows a mild overload situation, or current-limited repetitive turn-on. This can be used in safety-critical applications.FIG.8Dshows controlled current ramp-up or ramp-down to prevent current spikes (only ramp-down shown).

Integrated Semiconductor Packages

FIG.9Aillustrates a simplified partial plan view of an electronic package900that includes a bidirectional switch, a first and second driver circuits, and an input/output circuit, according to some embodiments of the disclosure. As shown inFIG.9A, the bidirectional switch can be disposed on a first die, first driver circuit can be disposed on a second die, second driver circuits can be disposed on a third die, and the input/output circuit can be disposed on a fourth die. The first, second, third and fourth dies are separate dies and can be arranged in a top-cooled shrink small-outline package (SSOP). In some embodiments, the first die can further include a second bidirectional switch and a third bidirectional switch. The second and third bidirectional switches can be arranged to harvest energy from an input signal at an input terminal (S1 to S2) and used the harvested energy to supply power to the first and second driver circuits. In various embodiments, the second bidirectional switch can have a D-mode section and an E-mode section. In some embodiments, the third bidirectional switch can have a D-mode section and an E-mode section.

The electronic package900can include a bidirectional switch912, a first driver circuit906, a second driver circuit908and an input/output circuit910. The bidirectional switch912can have a substrate connection that is coupled to a package pin914. The first and second driver circuits906and908, respectively, can be coupled to the bidirectional switch912by wirebonds. The first and second driver circuits906and908, respectively, can also be coupled to the input/output circuit910by wirebonds. The first and second driver circuits906and908, respectively, can also be coupled to their corresponding package pins by wirebonds. The input/output circuit910circuit can be coupled to its corresponding package pins920and922by wirebonds. Pins902can be coupled to the first source (S1) of the bidirectional switch912and pins904can be coupled to the second source (S2) of the bidirectional switch912. The electronic package900can also include a spacer928that may be formed from, for example, Alumina (Al2O3) or aluminum nitride, or an insulating tape. The spacer928can be electrically isolating. In some embodiments, the spacer may have low thermally conductive characteristics. Most of the heat dissipation can occur by the bidirectional switch through the top. The spacer can be disposed under the first and second driver circuits906and908, respectively, and the input/output circuit910dies, thereby isolating the first and second driver circuits906and908, respectively, and the input/output circuit910from the bidirectional switch912, as well as isolating the first driver circuit906from the second driver circuit908. An electrically insulative encapsulant can be formed around the electronic package900.912could include several bidirectional switches in parallel, 2 of them with D- and E-Mode devices for implementing energy harvesting. In this case, the package900might have additional low power pins for connecting external decoupling capacitors636and642.

FIG.9Billustrates a simplified partial plan view of an electronic package950that includes a bidirectional switch, a first and second driver circuits, and an input/output circuit, according to some embodiment of the disclosure. The electronic package950is similar to the electronic package900with additional three connections980per side. The electronic package950can be used to package the circuit illustrated in FIG.6A1or in FIG.6A2. The three connections980in the electronic package950may be used for connection of gates indicated by “D” and “E” transistor end, as well as where the source of the “D” is connected to CENT. In some embodiments, the bidirectional switches620and640may be disposed on the same die as the main bidirectional switch602. In various embodiments, the bidirectional switches620and640may be disposed on separate dies.

The electronic package950can include a bidirectional switch962, a first driver circuit956, a second driver circuit958and an input/output circuit950. In some embodiments, the input/output circuit may include a controller. The bidirectional switch962can have a substrate connection that is coupled to a package pin964. The first and second driver circuits956and958, respectively, can be coupled to the bidirectional switch962by wirebonds. The first and second driver circuits956and958, respectively, can also be coupled to the input/output circuit960by wirebonds. The first and second driver circuits956and958, respectively, can also be coupled to their corresponding package pins by wirebonds. The input/output circuit910circuit can be coupled to its corresponding package pins970and972by wirebonds. Pins952can be coupled to the first source (S1) of the bidirectional switch962and pins954can be coupled to the second source (S2) of the bidirectional switch962. The electronic package950can also include a spacer978that may be formed from, for example, Alumina (Al2O3) or aluminum nitride, or an insulating tape. The spacer978can be electrically isolating. In some embodiments, the spacer may have low thermally conductive characteristics. Most of the heat dissipation can occur by the bidirectional switch through the top. The spacer can be disposed under the first and second driver circuits956and958, respectively, and the input/output circuit960dies, thereby isolating the first and second driver circuits956and958, respectively, and the input/output circuit960from the bidirectional switch962, as well as isolating the first driver circuit956from the second driver circuit958. An electrically insulative encapsulant can be formed around the electronic package950.962could include several bidirectional switches in parallel, two of them with depletion mode and enhancement mode devices used for energy harvesting functions. The package950may include additional low power pins for connecting external decoupling capacitors636and642.

FIG.10illustrates a simplified partial plan view of an electronic package1000that includes a bidirectional switch, a first and second driver circuits, and an input/output circuit, according to an embodiment of the disclosure. As shown inFIG.10, each of a bidirectional switch1012, first and second driver circuits1006and1008, respectively, and input/output circuit1010can be disposed on a separate die and can be arranged in a top-cooled power small-outline package (PSOP). The bidirectional switch1012can have a substrate connection that is coupled to a corresponding package pin. The first and second driver circuits1006and1008, respectively, can be coupled to the bidirectional switch1012by wirebonds. The first and second driver circuits1006and1008, respectively, can also be coupled to the input/output circuit1010by wirebonds. The first and second driver circuits1006and1008, respectively, can also be coupled to their corresponding package pins by wirebonds. The input/output circuit1010circuit can be coupled to its corresponding package pins by wirebonds. The electronic package1000can also include a spacer1028that may be formed from, for example, Alumina (Al2O3) or aluminum nitride, or an insulating tape. The spacer1028can be electrically isolating. In some embodiments, the spacer may have low thermally conductive characteristics. Most of the heat dissipation can occur by the bidirectional switch through the top. The spacer can be disposed under the first and second driver circuits1006and1008, respectively, and the input/output circuit1010dies, thereby isolating the first and second driver circuits1006and1008, respectively, and the input/output circuit1010from the bidirectional switch1012, as well as isolating the first driver circuit1006from the second driver circuit1008. An electrically insulative encapsulant can be formed around the electronic package1000.

FIG.11Aillustrates a simplified partial plan view of an electronic package1100that includes a bidirectional switch, a first and second driver circuits, and an input/output circuit, according to an embodiment of the disclosure.FIG.11Billustrates a simplified partial cross-sectional view of the electronic package1100. As shown inFIGS.11A and11B, each of a bidirectional switch1112, first and second driver circuits1106and1108, respectively, and input/output circuit1110can be disposed on a separate die and can be arranged in a quad flat no-lead (QFN) package. In some embodiments, the electronic package1100can be an 8×8 QFN package. The bidirectional switch1112can have a substrate connection that is coupled to a corresponding package pin. The first and second driver circuits1106and1108, respectively, can be coupled to the bidirectional switch1112by wirebonds. The first and second driver circuits1106and1108, respectively, can also be coupled to the input/output circuit1110by wirebonds.

The first and second driver circuits1106and1108, respectively, can also be coupled to their corresponding package pins by wirebonds. The input/output circuit1110circuit can be coupled to its corresponding package pins by wirebonds. The electronic package1100can also include a spacer1128that may be formed from, for example, Alumina (Al2O3) or aluminum nitride, or an insulating tape. The spacer1028can be electrically isolating. The spacer1128can be electrically isolating. In some embodiments, the spacer may have low thermally conductive characteristics. The spacer can be disposed under the first and second driver circuits1106and1108, respectively, and the input/output circuit1110dies, thereby isolating the first and second driver circuits1106and1108, respectively, and the input/output circuit1110from the bidirectional switch1112, as well as isolating the first driver circuit1106from the second driver circuit1108. In this way, the electronic package1100may be used, for example, in A/C circuit breakers. An electrically insulative encapsulant can be formed around the electronic package1100.

FIG.11Aillustrates a 6×6 QFN. Other configurations of QFN packages are within the scope of this disclosure such as, but not limited to, 6×8 QFN having a similar configuration as the 6×6 QFN with relatively longer dimension in the horizontal dimension. In the 6×8 QFN, the right-hand part may be relatively longer, and the pins may be disposed to the right, and the bidirectional switch1112may be relatively longer showing a relatively larger die size for lower on-resistance.

In some embodiments, the isolation of the driver circuits and the bidirectional switch can be achieved by using floating pads of copper or floating copper inner-connects that are not connected to any external lead. This can be a pre-molded frame technology where the frame is half etched and then molded and then etched again to disconnect the leads.

FIG.12illustrates a simplified partial plan view of an electronic package1200that includes a bidirectional switch, a first and second driver circuits, and an input/output circuit, according to an embodiment of the disclosure. The electronic package1200can be a QFN package. As shown inFIGS.12, electronic package1200can include a bidirectional switch1212disposed on a first die, and a thin QFN (TQFN) package1216that may include first and second driver circuits, and an input/output circuit. The TQFN package1216can be configured to act as an isolator for the first and second driver circuits, and input/output circuit. In some embodiments, the TQFN1216may be attached to the electronic package1200upside down and use the terminal as bonding pad for final assembly of the electronic package1200. An electrically insulative encapsulant can be formed around the electronic package1200.

FIG.13illustrates a simplified partially transparent plan view of an electronic package1300in accordance with the disclosed embodiments. Electronic package1300may be or include any of the components, features, or characteristics of any of the electronic packages and/or components previously described, and the electronic package may be included in circuits as previously discussed. As shown inFIG.13, electronic package1300includes a package base1305that has a plurality of external terminals1310and an electrically conductive die attach pad1315partially encapsulated in an electrically insulative polymer1320. A bidirectional switch1325is attached to the die attach pad1315using solder, silver sintering material, an adhesive or other suitable material. A transmitter die1330and first and second receiver dies1335A,1335B, respectively, are attached to the electrically insulative polymer1320using an adhesive or other suitable material. One or more wirebonds1340are used to electrically connect the transmitter die1330, the first and second receiver dies1335A,1335B, respectively, and the external terminals1310. The physical arrangement and interconnections shown inFIG.13are for example only and other electronic packages may have other suitable arrangements and interconnections.

FIG.14illustrates a simplified cross-section of the electronic package1300illustrated inFIG.13. As shown inFIG.14, electronic package1300includes a package base1305that is partially encapsulated by a mold cap1405that extends across a top surface1410of the package base. Package base1305includes a die attach pad1315and a plurality of external terminals1310that may be made from an electrically conductive material such as copper or other suitable material. The electrically insulative polymer1320at least partially encapsulates the die attach pad1315and the plurality of external terminals1310, providing electrical insulation between the electrically conductive regions. The bidirectional switch1325is thermally and/or electrically attached to the die attach pad1315. Transmitter die1330is attached to a region of the electrically insulative polymer1320and is electrically isolated from the die attach pad1315and the plurality of external terminals1310. One or more wirebonds1340electrically connect the transmitter die1330and the external terminals1310. In other embodiments metallic clips, flip-chips or other suitable interconnects can be used. Mold cap1405is formed from an electrically insulative material and encapsulates the transmitter die1330, the bidirectional switch1325as well as the one or more wirebonds1340.

FIGS.15A-15Dillustrate steps associated with a method1600(seeFIG.16) of forming an electronic package1500, according to embodiments of the disclosure. More specifically,FIGS.15A-15Dillustrate simplified cross-sectional views of the electronic package with each view corresponding to a particular step of method1600. Electronic package1500may be similar to electronic package1300illustrated inFIGS.13and14with like reference numbers referring to similar features. Electronic package1500may be or include any of the components, features, or characteristics of any of the electronic packages and/or components previously described, and the electronic package may be included in circuits as previously discussed.

In a first step1610, a plurality of electrically conductive features may be formed. As shown in section15(a) ofFIG.15, the electrically conductive features in this particular embodiment include first and second external terminals1310A,1310B, respectively, and die attach pad1315. In some embodiments the electrically conductive features may be formed using a build-up process employing various plating and lithography masks, while in other embodiments the electrically conductive features may be formed with a removal process including etching, machining or other material removal process. The electrically conductive features may be formed from any suitable metal or combination of metals including, but not limited to, copper, nickel, tin, aluminum, gold, palladium or iron.

In a second step1620the electrically conductive features may be partially encapsulated in an electrically insulative polymer1320. As shown in section15(b) ofFIG.15, the electrically insulative polymer1320fills in gaps between the electrically conductive features forming a relatively coplanar top surface1410of a base1305of the electronic package1500. The electrically insulative polymer1320may be made from any suitable material that does not conduct electricity and may be formed using injection molding or other suitable process.

In a third step1630one or more dies are attached to the top surface1410of the base1305and one or more wirebonds1340are used to electrically connect the one or more die to one another and/or to the electrically conductive features. As shown in section15(c) ofFIG.15, a bidirectional switch1325is attached to die attach pad1315and transmitter and/or receiver dies1330,1335A,1335B are attached to electrically insulative polymer1320. Wirebonds1340electrically connect the transmitter and/or receiver dies to each other and to one or more external terminals1310. Wirebonds1340also electrically connect the transmitter and/or receiver dies to the bidirectional switch1325and further connect the bidirectional switch to the one or more external terminals1310.

In a fourth step1640a mold cap1405is formed. As shown in section15(d) ofFIG.15, the mold cap1405is formed across top surface1410of package base1305and encapsulates the transmitter and/or receiver dies1330,1335A,1335B and the bidirectional switch1325as well as the one or more wirebonds1340. Mold cap1405may be formed from any suitable electrically insulative material and may be formed via injection molding, transfer molding or other suitable process.

It will be appreciated that method1600is illustrative and that variations and modifications are possible. Steps described as sequential may be executed in parallel, order of steps may be varied, and steps may be modified, combined, added or omitted.

In some embodiments, combination of the circuits and methods disclosed herein can be utilized to form and operate integrated bidirectional switch with driver and input/output circuits. Although circuits and methods are described and illustrated herein with respect to several particular configuration of an integrated bidirectional switch with driver and input/output circuits, embodiments of the disclosure are suitable for forming other integrated bidirectional switches with driver and input/output circuits. Further, embodiments of the disclosure can be utilized in power converter circuits, such as but not limited to, AC-DC power converters, AC-AC power converters, and boost power converters.

In the foregoing specification, embodiments of the disclosure have been described with reference to numerous specific details that can vary from implementation to implementation. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense. The sole and exclusive indicator of the scope of the disclosure, and what is intended by the applicants to be the scope of the disclosure, is the literal and equivalent scope of the set of claims that issue from this application, in the specific form in which such claims issue, including any subsequent correction. The specific details of particular embodiments can be combined in any suitable manner without departing from the spirit and scope of embodiments of the disclosure.

Additionally, spatially relative terms, such as “bottom or “top” and the like can be used to describe an element and/or feature's relationship to other element(s) and/or feature(s) as, for example, illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use and/or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as a “bottom” surface can then be oriented “above” other elements or features. The device can be otherwise oriented (e.g., rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

In the preceding detailed description, numerous specific details have been set forth to provide a thorough understanding of claimed subject matter. However, it will be understood by those skilled in the art that claimed subject matter may be practiced without these specific details. In other instances, methods and apparatuses that would be known by one of ordinary skill have not been described in detail so as not to obscure claimed subject matter. Therefore, it is intended that claimed subject matter not be limited to the particular examples disclosed, but that such claimed subject matter may also include all aspects falling within the scope of appended claims, and equivalents thereof.