Patent Description:
The DC-DC converter converts an input voltage and supplies an output voltage having a required voltage level. In the DC-DC converter, a transient voltage may be generated according to voltage switching. A snubber circuit may be applied to the DC-DC converter to prevent component damage due to transient voltage and to remove EMI radiation noise.

In order to remove noise, it is necessary to optimize the snubber circuit by changing and designing a snubber value such as resistance and capacitance of the snubber circuit, and when the snubber circuit is embedded in an IC device, it is difficult to change the snubber value of the snubber circuit unless the IC device is replaced.

<CIT> discloses a voltage regulator circuit designed to attenuate ringing in the switch node of a buck converter. The voltage regulator includes high-side and low-side field-effect transistors (FETs), an inductor, and a conductive net connecting these components. An attenuation circuit, which includes an electronic switch, is coupled to the conductive net to control the amount of attenuation. The switchable snubber circuit is turned on by the controller to attenuate voltage spikes when needed, thereby reducing power dissipation during normal operation. The controller monitors the voltage or current and activates the snubber circuit when the measured values exceed set thresholds.

<CIT> discloses a snubber circuit, a control circuit, and an information processing apparatus aimed at reducing noise in circuits with switching elements, such as converters or inverters. The snubber circuit includes a first capacitor and a first resistor with a variable resistance value, which can be controlled by a control circuit. The information processing apparatus can measure radiation noise and adjust the resistance value of the snubber circuit based on the acquired noise information. The snubber circuit can also include multiple resistors and capacitors, with switching elements to vary their connections, further enhancing noise reduction capabilities.

In a DC-DC converter including a snubber circuit, when the snubber circuit is embedded in an IC device, a DC-DC converter capable of variably applying a snubber value is provided.

Advantageous embodiments are subject to the dependent claims.

According to an embodiment of the invention, an electric power converter includes an integrated circuit including at least one power transistor and a snubber circuit connected in parallel to the at least one power transistor, and a selection resistor connected between a power supply voltage supplied to the integrated circuit and the snubber circuit, in which the snubber circuit includes at least two snubbers, and each of the at least two snubbers includes a resistor, a first transistor, and a capacitor connected in series, and the selection resistor is connected to a gate of the first transistor of any one of the at least two snubbers. The electric power converter further comprises a resistance box circuit. The resistance box circuit comprises, for each snubber, an individual resistance box connected to a gate of the first transistor of any the respective one of the at least two snubbers and to a power supply voltage (VCC) through selection terminals of the integrated circuit. At least one of the individual resistance boxes for the snubbers includes a selection resistor. Each selection resistor connects the gate of the transistor of the snubber corresponding to the respective individual resistance box to the power supply voltage (VCC) thereby turning on the transistor of said snubber corresponding to the respective individual resistance box.

The first transistor of any one of the at least two snubbers may be turned on by the power supply voltage supplied through the selection resistor.

The first transistor of the remaining snubber except any one of the at least two snubbers may be turned off.

The integrated circuit may further include a switch control circuit configured to receive the power supply voltage and control a switching operation of the at least one power transistor.

According to another embodiment of the invention, there is provided an electric power converter including: an integrated circuit including at least one power transistor and a snubber circuit connected in parallel to the at least one power transistor; and at least two selection resistors connected between a power supply voltage supplied to the integrated circuit and the snubber circuit, in which the snubber circuit includes at least two resistors, at least two first transistors connected in series to the at least two resistors, respectively, at least two capacitors, and at least two second transistors connected in series to the at least two capacitors, respectively. The electric power converter further comprises a resistance box circuit comprising a plurality of individual resistance boxes for the snubber circuit. Each of the individual resistance boxes is connected to either a gate of one of the first transistors and to a power supply voltage (VCC) through selection terminals of the integrated circuit, or to a gate of one of the second transistors and to the power supply voltage (VCC) through the selection terminals. At least two of the individual resistance boxes for the snubber circuit include a selection resistor. Each selection resistor connects either the gate of one of the first transistors or the gate of one of the second transistors to the power supply voltage (VCC) through the selection resistor of the respective individual resistance box to thereby turn on the respective first transistor or the respective second transistor. A first selection resistor of the at least two selection resistors is connected to the gate of one of the first transistors connected in series to any one of the at least two resistors, and a second selection resistor of the at least two selection resistors is connected to the gate of one of the second transistors connected in series to any one of the at least two capacitors.

A first transistor connected in series to any one of the at least two resistors may be turned on by the power supply voltage supplied through the first selection resistor, and a second transistor connected in series to any one of the at least two capacitors may be turned on by the power supply voltage supplied through the second selection resistor.

The first transistor connected in series to the remaining resistors except any one of the at least two resistors may be turned off, and the second transistor connected in series to the remaining capacitors except any one of the at least two capacitors may be turned off.

The integrated circuit may further include a switch control circuit configured to receive the power supply voltage and control the at least one power transistor.

The at least two selection resistors may include a third selection resistor that may be connected to a gate of a first transistor connected in series to another of the at least two resistors, and a resistance value of the snubber circuit may be a parallel synthesis resistance of one of the at least two resistors and another resistor.

The at least two selection resistors may include a third selection resistor that may be connected to a gate of a second transistor connected in series to another of the at least two capacitors, and a capacitance value of the snubber circuit may be a parallel synthesis capacitance of one of the at least two capacitors and another capacitor.

The electric power converter may be a DC-DC converter.

According to the present disclosure, in a DC-DC converter including a snubber circuit, when the snubber circuit is embedded in an IC device, a DC-DC converter capable of selectively configuring a snubber circuit among a plurality of snubbers or variably applying a resistance value and a capacitance of the snubber circuit may be provided.

Hereinafter, exemplary embodiments disclosed in the present specification will be described in detail with reference to the accompanying drawings, in which the same or similar components are given the same or similar reference numerals, and redundant descriptions thereof will be omitted. In the following description, the suffix "module" and/or "unit" for the constituent elements are given or mixed in consideration of the ease of description only, and do not have meanings or roles that are distinguished from each other. In addition, in describing the exemplary embodiments disclosed in the present specification, when it is determined that the detailed description of the related known technology may obscure the gist of the exemplary embodiments disclosed in the present specification, the detailed description thereof will be omitted. In addition, the accompanying drawings are merely provided to easily understand the exemplary embodiments disclosed in the present specification.

Terms including ordinal numbers such as first, second, etc. may be used to describe various elements, but the elements are not limited by the terms. The terms are used only for the purpose of distinguishing one component from another component.

In the present application, it should be understood that the term "include" or "have" indicates that a feature, a number, a step, an operation, a component, a part, or a combination thereof described in the specification is present, but does not exclude the possibility of presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof in advance.

<FIG> illustrate a converter circuit for converting an input DC voltage into a DC voltage, which allows a snubber circuit to be variously configured.

<FIG> is a block diagram schematically illustrating a converter according to an exemplary embodiment.

The converter <NUM> may DC-DC-convert an input voltage Vin and output an output voltage Vout. The converter <NUM> includes an integrated circuit (IC) <NUM>, a resistance box <NUM>, and an output unit <NUM>. The converter <NUM> may be mounted on a printed circuit board (PCB).

The power supply voltage VCC may be supplied to the IC <NUM> through the terminal P1, and the power supply voltage VCC is supplied to the resistance box <NUM>.

The input voltage Vin may be supplied to the IC <NUM> through the terminal P2. The IC <NUM> may DC-DC-convert an input voltage Vin and transmit an output voltage to the output unit <NUM> through a terminal P4 and a terminal P5. The input voltage Vin may be connected to the terminals P2 and P3.

The resistance box <NUM> selects a configuration of the IC <NUM> through the plurality of selection terminals P11 to P13. Although <FIG> illustrates that the IC <NUM> includes three selection terminals P11 to P13, the disclosure is not limited thereto, and the IC <NUM> may be implemented to include two or more selection terminals.

The IC <NUM> may convert an input voltage through a plurality of transistors and a switch control circuit. The IC <NUM> may include a switch control circuit <NUM>, a first power transistor Q1, a first resistor R1, a first capacitor C1, a second power transistor Q2, a snubber circuit <NUM>, and an inductor L.

The switch control circuit <NUM> may generate transistor control signals QCS1 and QCS2 for controlling switching operations of the first and second power transistors Q1 and Q2 by using the power supply voltage VCC input through the terminal P1 as a power source. Switching operations of the first power transistor Q1 and the second power transistor Q2 may be controlled according to transistor control signals QCS1 and QCS2 supplied from the switch control circuit <NUM>.

The first resistor R1 and the first capacitor C1 are connected to each other in series, and are connected to the first power transistor Q1 in parallel. One end of the first power transistor Q1 is connected to one end of the switch control circuit <NUM>. The other end of the first power transistor Q1 is connected to a node to which one end of the second power transistor Q2, a terminal P21 of the snubber circuit <NUM>, and one end of the inductor L are connected. The other end of the second power transistor Q2 is connected to a node to which the other end of the switch control circuit <NUM> and the terminal P22 of the snubber circuit <NUM> are connected. Terminal P23 of snubber circuit <NUM> is connected to terminal P5 of IC <NUM>. The other end of the inductor L is connected to a terminal P4, and a terminal P23 of the snubber circuit <NUM> is connected to a terminal P5.

The output unit <NUM> may include a capacitor C and a load R. In the output unit <NUM>, one end of the output voltage Vout is connected to a node to which one end of the capacitor C and one end of the load R are connected, and the other end of the output voltage Vout is connected to a node to which the other end of the capacitor C and the other end of the load R are connected.

The on-level of the transistor control signals QCS1 and QCS2 is a high level, and the off-level thereof is a low level. When the first power transistor Q1 is turned on and the second power transistor Q2 is turned off by the transistor control signal QCS1 of the high level and the transistor control signal QCS2 of the low level, the input voltage Vin is supplied to the inductor L so that the current flowing through the inductor L may increase. When the first power transistor Q1 is turned off and the second power transistor Q2 is turned on by the transistor control signal QCS1 of the low level and the transistor control signal QCS2 of the high level, the current flowing through the inductor L may decrease while flowing through the second power transistor Q2. A current flowing through the inductor L may be supplied to the load R, and the output voltage Vout may be smoothed to a constant level by the capacitor C. The switch control circuit <NUM> may sense the output voltage Vout and may control switching operations of the first and second power transistors Q1 and Q2 so that the output voltage Vout may be maintained at a predetermined level.

Hereinafter, the operation of the snubber circuit <NUM> according to the internal circuit configuration of the resistance box <NUM> will be described with reference to <FIG> and <FIG>.

<FIG> is a circuit diagram illustrating an example of implementing a snubber circuit and a resistance box according to a first embodiment of the invention.

The snubber circuit according to an example illustrated in <FIG> is configured to operate in a snubber unit in which a resistor, a capacitor, and a transistor are connected in series.

The snubber circuit <NUM> includes a first snubber <NUM>, a second snubber <NUM>, a third snubber <NUM>, and a plurality of gate resistors RG21 to RG23. The first snubber <NUM> includes a resistor R21, a capacitor C21, and a transistor Q21, the second snubber <NUM> includes a resistor R22, a capacitor C22, and a transistor Q22, and the third snubber <NUM> includes a resistor R23, a capacitor C23, and a transistor Q23.

Although <FIG> illustrates that the snubber circuit <NUM> includes three snubbers <NUM> to <NUM>, the present disclosure is not limited thereto, and the snubber circuit <NUM> may be implemented as including two or more snubbers. As illustrated in <FIG>, the number of selection terminals P11 to P13 may be increased or decreased based on the number of snubbers included in the snubber circuit <NUM>.

One end of the first snubber <NUM>, one end of the second snubber <NUM>, and one end of the third snubber <NUM> are connected to a terminal P21, and the other end of the first snubber <NUM>, the other end of the second snubber <NUM>, and the other end of the third snubber <NUM> are connected to a node to which the terminal P22 and the terminal P23 are connected.

The terminal P21 is connected to a node to which one end of the resistor R21, one end of the resistor R22, and one end of the resistor R23 are connected.

The other end of the resistor R21 is connected to one end of the transistor Q21. The other end of the transistor Q21 is connected to one end of the capacitor C21. One end of the gate resistor RG21 is connected to the gate end of the transistor Q21, and the other end of the gate resistor RG21 is connected to the selection terminal P11.

The other end of the resistor R22 is connected to one end of the transistor Q22. The other end of the transistor Q22 is connected to one end of the capacitor C22. One end of the gate resistor RG22 is connected to the gate end of the transistor Q22, and the other end of the gate resistor RG22 is connected to the selection terminal P12.

The other end of the resistor R23 is connected to one end of the transistor Q23. The other end of the transistor Q23 is connected to one end of the capacitor C23. One end of the gate resistor RG23 is connected to the gate end of the transistor Q23, and the other end of the gate resistor RG23 is connected to the selection terminal P13.

The other end of the capacitor C21, the other end of the capacitor C22, and the other end of the capacitor C23 are connected to the node to which the terminal P22 and the terminal P23 are connected.

The snubber circuit <NUM> according to the exemplary embodiment illustrated in <FIG> operates through at least one selected from among the first snubber <NUM>, the second snubber <NUM>, and the third snubber <NUM> according to the configuration of the resistance box <NUM>.

The resistance box <NUM> includes a plurality of individual resistance boxes <NUM> to <NUM>. In <FIG>, the resistance box <NUM> is illustrated as including three individual resistance boxes <NUM> to <NUM>, but the present disclosure is not limited thereto, and the resistance box <NUM> may be implemented as including two or more individual resistance boxes. The number of individual resistance boxes may be increased or decreased based on the number of selection terminals P11 to P13.

Each of a plurality of individual resistance boxes <NUM> to <NUM> may include a selection resistor. Alternatively, each of a plurality of individual resistance boxes <NUM> to <NUM> may be an open circuit. Hereinafter, a resistance box that does not include the selection resistor among the plurality of individual resistance boxes <NUM> to <NUM> will be described as being open.

Hereinafter, an exemplary embodiment of the individual resistance boxes <NUM> to <NUM> included in the resistance box <NUM> will be described with reference to <FIG>.

<FIG> is a circuit diagram illustrating an example of a resistance box according to an exemplary embodiment.

In the example of <FIG>, the selection resistor RS1 is included in the individual resistance box <NUM>, and the selection resistor is not included in the remaining individual resistance boxes <NUM> and <NUM>.

The power supply voltage VCC supplied to the resistance box <NUM> may supply a current to a corresponding selection terminal (e.g., P11) among the plurality of selection terminals P11 to P13 through an individual resistance box (e.g., <NUM>) including a selection resistor among the plurality of individual resistance boxes <NUM> to <NUM>.

In the converter <NUM> using the snubber circuit <NUM> and the resistance box <NUM> of <FIG> and <FIG>, the transistor Q21 is turned on by the power supply voltage VCC supplied through the resistor RS1 and the resistor RG21. When the transistor Q21 is turned on, the first snubber <NUM> is connected in parallel to the second power transistor Q2. That is, the first snubber <NUM> may operate with respect to a transient voltage that may occur during a switching operation of the second power transistor Q2.

When the transistor Q21 is turned on, the resistance value of the snubber circuit <NUM> may be the resistance value of the resistor R21, and the capacitance of the snubber circuit <NUM> may be determined as the capacitance of the capacitor C21.

Hereinafter, an operation of the snubber circuit <NUM> according to an internal circuit configuration of the resistance box <NUM> capable of controlling a resistor and a capacitor of the snubber, respectively, will be described with reference to <FIG>.

<FIG> is a circuit diagram illustrating an example of implementing a snubber circuit and a resistance box according to a second embodiment of the invention.

The snubber circuit according to an exemplary embodiment illustrated in <FIG> may not operate in a snubber unit, unlike the snubber circuit according to an exemplary embodiment illustrated in <FIG>.

The snubber circuit <NUM> includes a plurality of resistors R21 to R23, a plurality of capacitors C21 to C23, a plurality of transistors Q21 to Q23, Q211, Q221, and Q231, and a plurality of gate resistors RG21 to RG23, RG211, RG221, and RG231.

The other end of the resistor R21 is connected to one end of the transistor Q21. One end of the gate resistor RG21 is connected to the gate end of the transistor Q21, and the other end of the gate resistor RG21 is connected to the selection terminal P11. One end of the transistor Q211 is connected to one end of the capacitor C21. One end of the gate resistor RG211 is connected to the gate end of the transistor Q211, and the other end of the gate resistor RG211 is connected to the selection terminal P14.

The other end of the resistor R22 is connected to one end of the transistor Q22. One end of the gate resistor RG22 is connected to the gate end of the transistor Q22, and the other end of the gate resistor RG22 is connected to the selection terminal P12. One end of the transistor Q221 is connected to one end of the capacitor C22. One end of the gate resistor RG221 is connected to the gate end of the transistor Q221, and the other end of the gate resistor RG221 is connected to the selection terminal P15.

The other end of the resistor R23 is connected to one end of the transistor Q23. One end of the gate resistor RG23 is connected to the gate end of the transistor Q23, and the other end of the gate resistor RG23 is connected to the selection terminal P13. One end of the transistor Q231 is connected to one end of the capacitor C23. One end of the gate resistor RG231 is connected to the gate end of the transistor Q231, and the other end of the gate resistor RG231 is connected to the selection terminal P16.

The other end of the transistor Q21, the other end of the transistor Q211, the other end of the transistor Q22, the other end of the transistor Q221, the other end of the transistor Q23, and the other end of the transistor Q231 are connected to the node NN.

The snubber circuit <NUM> according to the exemplary embodiment illustrated in <FIG> operates through at least one selected according to the configuration of the resistance box <NUM> among the plurality of resistors R21 to R23 and at least one selected according to the configuration of the resistance box <NUM> among the plurality of capacitors C21 to C23.

The resistance box <NUM> includes a plurality of individual resistance boxes <NUM> to <NUM>. In <FIG>, the resistance box <NUM> is illustrated as including six individual resistance boxes <NUM> to <NUM>, and the number of selection terminals P11 to P16 is illustrated as six.

In the example of <FIG>, the individual resistance box <NUM> includes the selection resistor RS1, the individual resistance box <NUM> includes the selection resistor RS5, and the remaining individual resistance boxes <NUM> to <NUM> and <NUM> do not include the selection resistor.

The power supply voltage VCC supplied to the resistance box <NUM> may supply a current to a corresponding one of the plurality of selection terminals P11 to P16 (e.g., P11 and P15) through an individual resistance box (e.g., <NUM> and <NUM>) including a selection resistor among the plurality of individual resistance boxes <NUM> to <NUM>.

In the converter <NUM> using the snubber circuit <NUM> and the resistance box <NUM> of <FIG> and <FIG>, the transistor Q21 is turned on by the power supply voltage VCC supplied through the resistor RS1 and the resistor RG21, and the transistor Q221 is turned on by the power supply voltage VCC supplied through the resistor RS5 and the resistor RG221. The resistor R21 and the capacitor C22 are connected in parallel to the second power transistor Q2 by the transistor Q21 and the transistor Q221 being turned on.

By the transistor Q21 and the transistor Q221 being turned on, the resistance value of the snubber circuit <NUM> may be the resistance value of the resistor R21, and the capacitance of the snubber circuit <NUM> may be determined as the capacitance of the capacitor C22.

Also, in the converter <NUM> using the snubber circuit <NUM> of <FIG>, the resistance value of the snubber circuit <NUM> may be determined as a composite resistance using a plurality of resistors, or the capacitance of the snubber circuit <NUM> may be determined as a composite capacitance using a plurality of capacitors.

Hereinafter, an exemplary embodiment of a resistance box that allows the snubber circuit <NUM> to have a composite resistance or a composite capacitance will be described with reference to <FIG>.

In the example of <FIG>, the individual resistance box <NUM> includes the selection resistor RS1, the individual resistance box <NUM> includes the selection resistor RS3, the individual resistance box <NUM> includes the selection resistor RS5, and the remaining individual resistance boxes <NUM>, <NUM>, and <NUM> do not include the selection resistor.

The power supply voltage VCC supplied to the resistance box <NUM> may supply a current to a corresponding selection terminal (e.g., P11, P13, and P15) among the plurality of selection terminals P11 to P16 through an individual resistance box (e.g., <NUM>, <NUM>, and <NUM>) including a selection resistor among the plurality of individual resistance boxes <NUM> to <NUM>.

In the converter <NUM> using the snubber circuit <NUM> and the resistance box <NUM> of <FIG> and <FIG>, the transistor Q21 is turned on by the power supply voltage VCC supplied through the resistor RS1 and the resistor RG21, the transistor Q23 is turned on by the power supply voltage VCC supplied through the resistor RS3 and the resistor RG23, and the transistor Q221 is turned on by the power supply voltage VCC supplied through the resistor RS5 and the resistor RG221. When the transistor Q21, the transistor Q23, and the transistor Q221 are turned on, the resistor R21, the resistor R23, and the capacitor C22 are connected in parallel to the second power transistor Q2.

By the turn-on of the transistor Q21, the transistor Q23, and the transistor Q221, the resistance value of the snubber circuit <NUM> may be a parallel synthesis resistance value of the resistor R21 and the resistor R23, and the capacitance of the snubber circuit <NUM> may be determined as the capacitance of the capacitor C22.

In the example of <FIG>, the selection resistor RS1 is included in the individual resistance box <NUM>, the selection resistor RS5 is included in the individual resistance box <NUM>, the selection resistor RS6 is included in the individual resistance box <NUM>, and the selection resistor is not included in the remaining individual resistance boxes <NUM> to <NUM>.

The power supply voltage VCC supplied to the resistance box <NUM> may supply a current to a corresponding selection terminal (e.g., P11, P15, and P16) among the plurality of selection terminals P11 to P16 through an individual resistance box (e.g., <NUM>, <NUM>, and <NUM>) including a selection resistor among the plurality of individual resistance boxes <NUM> to <NUM>.

In the converter <NUM> using the snubber circuit <NUM> and the resistance box <NUM> of <FIG> and <FIG>, the transistor Q21 is turned on by the power supply voltage VCC supplied through the resistor RS1 and the resistor RG21, the transistor Q221 is turned on by the power supply voltage VCC supplied through the resistor RS5 and the resistor RG221, and the transistor Q231 is turned on by the power supply voltage VCC supplied through the resistor RS6 and the resistor RG231. When the transistor Q21, the transistor Q221, and the transistor Q231 are turned on, the resistor R21, the capacitor C22, and the capacitor C23 are connected in parallel to the second power transistor Q2.

By the turn-on of the transistor Q21, the transistor Q221, and the transistor Q231, the resistance value of the snubber circuit <NUM> may be the resistance value of the resistor R21, and the capacitance of the snubber circuit <NUM> may be determined as the parallel synthesis capacitance of the capacitor C22 and the capacitor C23.

The snubber circuit <NUM> may include a plurality of resistors as illustrated in <FIG> and <FIG>, or may include a plurality of capacitors as illustrated in <FIG> and <FIG>. Alternatively, the snubber circuit <NUM> may include a resistance box in which the resistance box illustrated in <FIG> and the resistance box illustrated in <FIG> are combined to include a plurality of resistors and a plurality of capacitors.

Claim 1:
An electric power converter comprising:
an integrated circuit (<NUM>) including at least one power transistor (Q1, Q2) and a snubber circuit (<NUM>) connected in parallel to the at least one power transistor (Q1, Q2); and
characterized in that
wherein the snubber circuit (<NUM>) includes at least two snubbers (<NUM>, <NUM>, <NUM>), and
wherein each of the at least two snubbers (<NUM>, <NUM>, <NUM>) includes a resistor (R21, R22, R23), a transistor (Q21, Q22, Q23), and a capacitor (C21, C22, C23) connected in series, and
in that the electric power converter further comprises a resistance box circuit (<NUM>) comprising, for each snubber (<NUM>, <NUM>, <NUM>), an individual resistance box (<NUM>, <NUM>, <NUM>) connected to a gate of the transistor (Q21, Q22, Q23) of the respective one of the at least two snubbers (<NUM>, <NUM>, <NUM>) through a corresponding selection terminal (P11, P12, P13) of the integrated circuit (<NUM>) and
connectable to a power supply voltage (VCC),
wherein at least one of the individual resistance boxes (<NUM>) for the snubbers (<NUM>) includes a selection resistor, wherein each selection resistor is configured to connect the gate of the transistor (Q21, Q22, Q23) of the snubber (<NUM>) corresponding to the respective individual resistance box (<NUM>) to the power supply voltage (VCC) to turn on the transistor (Q21) of said snubber (<NUM>) corresponding to the respective individual resistance box (<NUM>).