Single transformer-based gate driver

The disclosure relates to a devices, systems and methods implementing a single transformer-based gate driver. In one embodiment, single transformer-based gate driver includes an RF source; a PWM controller; an edge detector and pulse generating circuit operably connected to the RF source and PWM controller; a transformer comprising a primary side and a secondary side, the primary side of the transformer operably connected to an output of the edge detector and pulse generating circuit, the secondary side of the transformer operably connected to a rectifier circuit and a signal recovery circuit; and a drive circuit operably connected to the rectifier circuit and the signal recovery circuit.

BACKGROUND

Electrical switching devices, such as transistors, generally require an input current or voltage to switch the state of the switching device. The switching current or voltage may be greater than the current or voltage that the circuit controlling the switching device can produce. This is common in applications where the controller is a microcontroller or other integrated circuit, and the switching device is a high-power device such as a power MOSFET (metal-oxide-semiconductor field effect transistor). Gate driver circuits are used to amplify the output current or voltage of the control circuit to produce a current and/or voltage large enough to switch the state of the switching device.

Some gate driver circuits use a transformer to electrically isolate the controller from the switching device. Previous attempts to build a gate driver with a transformer require a secondary power source, and/or a second transformer to power the drive circuit, resulting in additional size, materials, and manufacturing costs.

Therefore, what is needed are devices, methods, and systems implementing a single transformer-based gate driver. In particular, devices, methods, and systems implementing a single transformer-based gate driver that are capable of transmitting a pulse width modulation signal or patterned gating signal and amplifying the signal to the switching device.

SUMMARY

Disclosed and described herein are embodiments of devices, methods, and systems for implementing a single transformer-based gate driver.

In one aspect, the present disclosure relates to a single transformer-based gate driver. In one embodiment, the single transformer-based gate driver includes an RF source; a PWM controller; an edge detector and pulse generating circuit operably connected to the RF source and PWM controller; a transformer comprising a primary side and a secondary side, the primary side of the transformer operably connected to an output of the edge detector and pulse generating circuit, the secondary side of the transformer operably connected to a rectifier circuit and a signal recovery circuit; and a drive circuit operably connected to the rectifier circuit and the signal recovery circuit.

In one embodiment, the drive circuit is operably connected to a switch.

In one embodiment, the switch is a power transistor.

In one embodiment, a protection circuit is operably connected between the rectifier circuit and the drive circuit.

In one embodiment, a fault detection circuit is operably connected to the protection circuit.

In one embodiment, the fault detection circuit is operably connected to the PWM controller.

In one aspect, the present disclosure relates to a method for driving a power switching device. In one embodiment, the method includes: providing an RF signal and a PWM signal; modulating the RF signal with the PWM signal to create a primary signal; applying the primary signal through a primary side of a transformer; receiving a secondary signal to the secondary side of the transformer; rectifying the secondary signal to produce a power signal; deriving a recovered PWM signal from the secondary signal; and driving a drive circuit using the recovered PWM signal and the power signal.

In one embodiment, the drive circuit drives a switch.

In one embodiment, the switch is a transistor.

In one embodiment, the power signal is passed through a protection circuit before being applied to the drive circuit.

In one embodiment, the protection circuit is used to generate a protection circuit signal, and the protection circuit signal is used to drive a fault transfer circuit.

In one embodiment, the fault transfer circuit produces a fault transfer circuit signal.

In one embodiment, the fault transfer circuit signal controls the state of the converter.

DETAILED DESCRIPTION

FIG. 1is a schematic of an embodiment of a single transformer-based gate driver100. The input signals include a pulse width modulation (PWM) signal and a second input signal. Control signals other than PWM signals may be used in some embodiments of the present disclosure, including patterned gating signals. In some embodiments, the second input signal may be a Radio Frequency (RF) signal, as shown inFIG. 1. The edge detector and pulse generating circuit102modulates the second input signal with the PWM signal and the resulting signal passes through the primary side106of the transformer104. Higher frequency RF signals may allow for smaller transformers104to be used. In some embodiments, the RF signal is in the range of GHz. The signal from the primary side106of the transformer104passes to the secondary side108of the transformer104. The secondary side108of the transformer104includes a rectifier circuit112and a signal recovery circuit110. The signal recovery circuit110may extract information about the original signal from the signal on the secondary side108of the transformer104. This extracted information may include the rising edge and falling edge of the original gate signal. In some embodiments, the extracted information is used to approximate or reconstruct the original PWM signal. The rectifier circuit112powers a drive circuit114. The drive circuit114receives a drive signal from the signal recovery circuit110. The configuration of rectifier circuit112and signal recovery circuit110allows for both power and gate signals to be transmitted across the transformer104, which electrically isolates the circuit connected to the primary side106of the transformer104from the circuit connected to the secondary side108of the transformer104. The drive circuit114then acts as a gate driver, producing a PWM input to the switching device116that is sufficient to drive the switching device116. The present disclosure contemplates that the input to the switching device116may have different current, voltage, or power characteristics than the input control signal. Therefore, some embodiments of the present disclosure may act as an act as an amplifier.

FIG. 2is a schematic of an embodiment of a single transformer-based gate driver200including a protection circuit202. The protection circuit202is operably connected between the rectifier circuit112and the drive circuit114. Similarly,FIG. 3includes both a protection circuit202, a fault transfer circuit302, and a fault detection circuit304. Other circuits may be added to these embodiments to achieve different objectives, including other protection and control circuits.

FIG. 4is an illustration of an experimental result, showing the pulse width modulation (PWM) input and PWM output according to embodiments described herein. VGSshows the PWM signal that has been recovered from the input PWM signal (shown as PWMIN). VPrishows the voltage on the primary side of the transformer, which includes the RF signal that has been modulated with the PWM signal.

FIG. 5is an illustration of the relationship between the voltages and time periods of signals within some embodiments of a single transformer-based gate driver. The x-axis shows time, and the y-axis shows a voltage. The PWM Input, depicted in the first graph, is converted into pulses by the pulse generating circuit. The pulses are shown in the second graph “Pulse generator output.” The third graph “Primary side Switch Input” illustrates a non-limiting example of a control input signal. The fourth graph illustrates the voltage waveform across the primary and secondary windings of the transformer as VPri,Sec. Additionally, the fourth graph depicts the output of the rectifier as “VRectifier,out.” The fifth graph, “Recovered PWM Output” shows the PWM signal that that drives the gate of the switching device. The “Recovered PWM Output” signal is produced by using a signal recovery circuit to replicate the original PWM signal to drive the gate of the switching device.

FIG. 6is an illustration of the relationship between the voltages and time periods of signals within an embodiment of a single transformer-based gate driver implementing a fault transfer circuit. The illustration also shows an operation of the fault transfer circuit in an embodiment of the single transformer-based gate driver implementing a fault transfer circuit. The x-axis shows time, and the y-axis shows voltage. The PWM Input, depicted in the first graph, is converted into pulses by the pulse generating circuit. The pulses are shown in the second graph “Pulse generator output.” The third graph “Primary side Switch Input” illustrates a non-limiting example of a control input signal. The fourth graph illustrates the voltage waveform across the primary and secondary windings of a transformer as VPri,Sec. Additionally, the fourth graph shows the output of the rectifier as “VRectifier,out.” Finally, the fourth graph also illustrates voltage waveforms after the fault transfer circuit is activated. The fifth graph, “Recovered PWM Output” shows the PWM that that drives the gate of the switching device. The “Recovered PWM Output” signal is produced by using a signal recovery circuit to replicate the original PWM signal to drive the gate of the switching device. The fourth and fifth graphs show how an implementation of the fault transfer circuit operates in some embodiments of the single transformer-based gate driver.

Throughout this application, various publications may be referenced. The disclosures of these publications in their entireties are hereby incorporated by reference into this application in order to more fully describe the state of the art to which the methods and systems pertain.