Protecting semiconductor switches in switched mode power converters

Patent metadata

Field	Value
Publication number	US-2020021284-A1
Application number	US-201916456922-A
Country	US
Kind code	A1
Filing date	Jun 28, 2019
Priority date	Jul 12, 2018
Publication date	Jan 16, 2020
Grant date	—

Abstract

Driver circuitry for driving a power semiconductor switch having a control input and main terminals is described. The driver circuitry includes control terminal driver circuitry coupled to the control input and configured to provide a drive signal, a sense terminal coupled to the main terminal, a current mirror coupled to the sense terminal to mirror a current input into the sense terminal during turn-off, a first current comparator configured to compare a current signal received from the current mirror to a first current threshold and output a first signal representative of the comparison, and a second comparator configured to compare a signal received from the sense terminal to a turn-on threshold and output a second signal representative of the comparison. The turn-on threshold represents a highest voltage of the main terminal during turn-on. The first current threshold represents a highest voltage of the main terminal during turn-off.

First claim

1 . Driver circuitry for driving a power semiconductor switch, the power semiconductor switch having a control input and main terminals, the driver circuitry comprising:
a control terminal driver circuitry coupled to the control input of the power semiconductor switch and configured to provide a drive signal thereto; a sense terminal coupled to a main terminal of the power semiconductor switch; a current mirror coupled to the sense terminal and configured to mirror a current input into the sense terminal during turn-off; a first current comparator configured to compare a current signal received from the current mirror to a first current threshold and output a first signal representative of a result of the comparison, wherein the first current threshold represents a highest voltage of the main terminal during turn-off; and a second comparator configured to compare a signal received from the sense terminal to a turn-on threshold and output a second signal representative of a result of the comparison, wherein the turn-on threshold represents a highest voltage of the main terminal during turn-on.

2 . The driver circuitry of claim 1 , further comprising switching circuitry switchable to couple the current mirror to the sense terminal during turn-off and in the OFF state and decouple the current mirror from the sense terminal during turn-on and in the ON state.

3 . The driver circuitry of claim 2 , wherein the switching circuitry is configured to receive a drive state signal indicative of whether the power semiconductor switch is in the OFF state or in the ON state.

4 . The driver circuitry of claim 1 , wherein:
the first current threshold also represents the highest voltage of the main terminal in the OFF state; and the turn-on threshold also represents the highest voltage of the main terminal in the ON state.

5 . The driver circuitry of claim 1 , wherein the control terminal driver circuitry is configured to reduce a rate of turn-off in response to the first signal indicating that a voltage of the main terminal during turn-off exceeds the first current threshold.

6 . The driver circuitry of claim 1 , further comprising timer circuitry configured to time a duration during which the second signal indicates that the signal received from the sense terminal exceeds the turn-on threshold during turn-on.

7 . The driver circuitry of claim 1 , wherein the first comparator, the second comparator, and the switching circuitry are in a single semiconductor package, wherein the sense terminal is a terminal of the package.

8 . The driver circuitry of claim 1 , wherein the first current threshold is a variable threshold.

9 . The driver circuitry of claim 1 , wherein an input impedance of the sense terminal is lower during turn-off than during turn-on, wherein the input impedance of the sense terminal is less than 200 kOhms during turn-off and greater than 10 MOhms during turn-on, wherein the input impedance of the sense terminal is less than 10 kOhms during turn-off and greater than 100 MOhms during turn-on.

10 . Driver circuitry for driving a power semiconductor switch, the power semiconductor switch having a control input and main terminals, the driver circuitry comprising:
a control terminal driver circuitry coupled to the control input of the power semiconductor switch and configured to provide a drive signal thereto; a sense terminal coupled to a main terminal of the power semiconductor switch; a first current comparator configured to compare, during turn-off, a signal received from the sense terminal to a turn-off threshold and output a first signal representative of a result of the comparison, wherein the turn-off threshold represents a highest voltage of the main terminal during turn-off; and a second comparator configured to compare, during turn-on, a signal received from the sense terminal to a turn-on threshold and output a second signal representative of a result of the comparison, wherein the turn-on threshold represents a highest voltage of the main terminal during turn-on.

11 . The driver circuitry of claim 10 , further comprising switching circuitry switchable to couple the first current comparator to the sense terminal during turn-off and in the OFF state and decouple the first current comparator from the sense terminal during turn-on and in the ON state.

12 . The driver circuitry of claim 11 , wherein the switching circuitry is configured to receive a drive state signal indicative of whether the power semiconductor switch is in the OFF state or in the ON state.

13 . The driver circuitry of claim 10 ; wherein the turn-off threshold also represents the highest voltage of the main terminal in the OFF state; and the turn-on threshold also represents the highest voltage of the main terminal in the ON state.

14 . The driver circuitry of claim 10 , wherein the control terminal driver circuitry is configured to reduce a rate of turn-off in response to the first signal indicating that a voltage of the main terminal during turn-off exceeds the turn-off threshold.

15 . The driver circuitry of claim 10 , wherein the driver circuitry further comprises a current mirror coupled between the sense terminal and the first comparator.

16 . The driver circuitry of claim 10 , further comprising timer circuitry configured to time a duration during which the second signal indicates that the signal received from the sense terminal exceeds the turn-on threshold during turn-on.

17 . The driver circuitry of claim 11 , wherein the first comparator, the second comparator, and the switching circuitry are in a single semiconductor package, wherein the sense terminal is a terminal of the package.

18 . The driver circuitry of claim 10 , wherein the turn-off threshold is a variable threshold.

19 . The driver circuitry of claim 10 , wherein an input impedance of the sense terminal is lower during turn-off than during turn-on, wherein the input impedance of the sense terminal is less than 200 kOhms during turn-off and greater than 10 MOhms during turn-on, wherein the input impedance of the sense terminal is less than 10 kOhms during turn-off and greater than 100 MOhms during turn-on.

Assignees

• Power Integrations Inc

Inventors

• Thalheim Jan

Classifications

• H02M1/08 Primary

  Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters · CPC title

• H02H1/0007

  concerning the detecting means (in general G01R or other subclasses of G01; reed switches H01H71/2445) · CPC title

• H02M1/32 Primary

  Means for protecting converters other than automatic disconnection · CPC title

• H03K5/24

  the characteristic being amplitude · CPC title

• H03K17/0828

  in composite switches · CPC title