RESISTOR EMULATION AND GATE BOOST

• US 20170302151A1
• Filed: 11/09/2015
• Published: 10/19/2017
• Est. Priority Date: 11/11/2014
• Status: Active Grant

• Current Assignee: Maschinenfabrik Reinhausen GmbH (Richard Scheubeck Beteiligungs-Gmbh & Co. KG)
• Original Assignee: Maschinenfabrik Reinhausen GmbH (Richard Scheubeck Beteiligungs-Gmbh & Co. KG)
• Inventors: SNOOK, Mark, LEEDHAM, Robert John, LYLE, Robin
• Granted Patent: US 10,199,916 B2
• Time in Patent Office: Days
• CPC Class Codes: H02M 1/0009 Devices or circuits for detecting current in a converter
• CPC Class Codes: H02M 1/0054 Transistor switching losses periodically suspending operation of switching converter in low power mode H02M1/0035
• CPC Class Codes: H02M 1/08 Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
• CPC Class Codes: H02M 7/5387 in a bridge configuration
• CPC Class Codes: H03K 17/0406 in composite switches
• CPC Class Codes: H03K 17/042 by feedback from the output circuit to the control circuit H03K17/0403, H03K17/0406 take precedence
• CPC Class Codes: H03K 17/063 in field-effect transistor switches
• CPC Class Codes: H03K 17/0822 in field-effect transistor switches
• CPC Class Codes: H03K 17/0828 in composite switches
• CPC Class Codes: H03K 17/165 by feedback from the output circuit to the control circuit
• CPC Class Codes: H03K 17/168 in composite switches
• CPC Class Codes: H03K 5/08 by limiting; by thresholding; by slicing, i.e. combined limiting and thresholding H03K5/07 takes precedence; comparing one pulse with another H03K5/22; providing a determined threshold for switching H03K17/30
• CPC Class Codes: Y02B 70/10 Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes

Abstract

Power switch driver for driving a control terminal of a power switch to drive a load, the power switch driver having a in negative feedback circuit to control current delivered to the control terminal, the negative feedback circuit comprising:—a current output circuit comprising at least one of a current source and a current sink, the current output circuit for providing a said current of a said control terminal and configured to receive an output current control signal to control magnitude of the current provided by the current output circuit;—a terminal voltage input circuit for receiving a voltage from a said control terminal and to output an indication of said voltage;—an amplifier coupled to amplify the terminal voltage indication to generate an amplifier output; and—a reference voltage input circuit for receiving a reference voltage, comprising at least one resistor, the reference voltage input circuit coupled to a charge supply input of the amplifier, wherein—the power switch driver is configured to generate the output current control signal dependent on the amplifier output, and—the power switch driver is configured to reduce the current provided by the current output circuit responsive to an increase in the voltage received by the terminal voltage input circuit.

Claims

1. A power switch driver for driving a control terminal of a power switch to drive a load, the power switch driver having a negative feedback circuit to control current delivered to the control terminal, the negative feedback circuit comprising:

a current output circuit having at least one of a current source and a current sink, the current output circuit for providing the current of the control terminal and configured to receive an output current control signal to control magnitude of the current provided by the current output circuit;

a terminal voltage input circuit for receiving a voltage from the control terminal and to output an indication of the voltage;

an amplifier coupled to amplify the terminal voltage indication to generate an amplifier output; and

a reference voltage input circuit for receiving a reference voltage, having at least one resistor, the reference voltage input circuit coupled to a charge supply input of the amplifier, wherein

the power switch driver is configured to generate the output current control signal dependent on the amplifier output, and

the power switch driver is configured to reduce the current provided by the current output circuit responsive to an increase in the voltage received by the terminal voltage input circuit.

2. The power switch driver of claim 1, wherein the current output circuit is configured to emulate the reference voltage input circuit.

3. The power switch driver of claim 1, wherein the at least one resistor comprises a controllable resistor.

4. The power switch driver of claim 1, wherein the terminal voltage input circuit has a coupling to the reference voltage input circuit, to effectively increase the impedance presented to the control terminal.

5. The power switch driver of claim 1, wherein the power switch driver has an offset voltage input circuit having an input line to receive an offset voltage and having a comparator to compare an indication of the voltage of the terminal voltage input circuit to the offset voltage, the offset voltage input circuit to allow a limit of variation of the voltage from the power switch control terminal to be set by the offset voltage when the power switch driver is operated to drive the power switch.

6. The power switch driver of claim 1, further comprising a coupling switch to disable dependency of control of the amplifier on the voltage of the terminal voltage input circuit, the driver having a current detector for monitoring a current through the load and is configured to disable the dependency when the current detector indicates the monitored current below a threshold current, the power switch driver to provide a substantially constant the current of the current output circuit when the dependency is disabled.

7. A power converter comprising the power switch driver of claim 6, the power converter having at least one half bridge circuit having a series connection of a first power switch and a second power switch, the first and second power switches configured to alternately pass current for driving the load coupled to an output line of the half bridge circuit, each power switch coupled in parallel with a diode, wherein the power converter comprises the power switch driver to drive a respective power switch, wherein the at least one resistor of the power switch driver comprises a controllable resistor, the power converter further comprising:

a turn-on detector to indicate at least a start of a turn-on period of increasing current through at least one of the power switches, wherein

the power converter is configured to control the coupling switch of at least one power switch driver based on the turn-on detector indication to allow the dependency of control of the amplifier of the driver on the voltage of the terminal voltage input circuit of the driver during the turn-on period.

8. The power converter of claim 7, wherein the turn-on detector is configured to detect an increase in rate of change of the current through the at least one power switch and a subsequent decrease in the rate of change to indicate pendency of the turn-on period.

9. The power converter of claim 7, configured to control the coupling switch of the power switch driver to allow the dependency of control of the amplifier of the driver on the voltage of the terminal voltage input circuit of the driver during a period subsequent to the turn-on period, the power converter configured to increase resistance of the controllable resistor of the driver at the start of the subsequent period.

10. The power converter of claim 7, configured to control the coupling switch the power switch driver to disable the dependency of control of the amplifier of the driver on the voltage of the terminal voltage input circuit of the driver during a period subsequent to the turn-on period, the power converter to deliver a substantially constant the current of the current output circuit of the driver during the subsequent period.

11. The power converter of claim 7, further comprising a timing detector to indicate at least one of:

a reversal of direction of rate of change of the current through the at least one power switch at a start of the subsequent period;

a decrease in the rate of change of the current through the at least one power switch at the end of the subsequent period; and

a voltage across the power switch below a threshold value at the end of the subsequent period, wherein

the power converter is configured to perform the control of the coupling switch to control a duration of the dependency responsive to the indication.

12. A power converter comprising the power switch driver of claim 1, the power converter having at least one half bridge circuit having a series connection of a first power switch and a second power switch, the first and second power switches configured to alternately pass current for driving the load coupled to an output line of the half bridge circuit, each power switch coupled in parallel with a commutation diode, wherein the power converter comprises the power switch driver to drive a respective one of the power switches, wherein the at least one resistor of the power switch driver comprises a controllable resistor, the power converter further comprising:

a timer circuit to measure duration of at least one phase of a switching cycle of the power switch, wherein

the power converter is configured to adjust resistance of the controllable resistor in response to the measured duration.

13. A power converter for driving an inductive load having a winding, the power converter having at least one half bridge circuit having a series connection of a first power switch and a second power switch, the first and second power switches configured to alternately pass current for driving the load coupled to an output line of the half bridge circuit, wherein the power converter comprises at least one power switch driver according to claim 1 to drive a respective said one of the power switches, wherein the at least one resistor of the power switch driver comprises a controllable resistor, the power converter further comprising:

a current detector for monitoring a current through the load, wherein

the power converter is configured to increase the resistance of the controllable resistor of the driver when the current detector indicates the monitored current below a threshold current.

14. The power converter of the claim 13, wherein the power switch driver coupled to drive the respective power switch comprises the current detector configured to monitor a current through the respective power switch, the power switch driver configured to increase the resistance of the controllable resistor of the power switch driver when the current detector detects the monitored current below the threshold current.

15. The power converter of claim 13, configured to increase the resistance of the controllable resistor substantially in inverse proportion to the monitored current.

16. The power converter of claim 13, the increase of the resistance for reducing rate of change of voltage on the output line during current commutation from at least one of said first and second power switches of the half bridge circuit.

17. The power converter of claim 13, wherein there at least two of the half bridge circuits, the power converter configured for driving the load by passing the current through the first power switch of a first of the two half bridge circuits and a second power switch of a second of the two half bridge circuits, the power converter configured to increase the resistance of the controllable resistor of at least one of the first power switch of the first half bridge circuit and the second power switch of the second half bridge circuit, the increase for damping a rate of change of voltage across the winding of a the load.

33. A power converter comprising the power switch driver of claim 1.

34. The power switch driver of claim 1, wherein the power switch comprises one of an IGBT, MOSFET, H EMT or JFET, the power switch having silicon carbide, gallium nitride and/or silicon.

18-32. -32. (canceled)

35-60. -60. (canceled)