Method and circuit for testing the functionality of a transistor component

Patent metadata

Field	Value
Publication number	US-11519955-B2
Application number	US-202117174927-A
Country	US
Kind code	B2
Filing date	Feb 12, 2021
Priority date	Feb 14, 2020
Publication date	Dec 6, 2022
Grant date	Dec 6, 2022

Abstract

In an embodiment, a method for testing a functional integrity of a transistor component, the method includes causing a first change of a charge state of an internal capacitance between control terminals of the transistor component; determining a capacitance value of the internal capacitance based on the first change of the charge state; causing a second change of the charge state of the internal capacitance; and evaluating a resistance value of an internal resistance between the control terminals based on the determined capacitance value and the second change of the charge state.

First claim

What is claimed is:

1. A method for testing a functional integrity of a transistor component, the method comprising:
causing a first change of a charge state of an internal capacitance between control terminals of the transistor component;
determining a capacitance value of the internal capacitance based on the first change of the charge state;
causing a second change of the charge state of the internal capacitance; and
evaluating a resistance value of an internal resistance between the control terminals based on the determined capacitance value and the second change of the charge state.

2. The method as claimed in claim 1 , wherein:
the transistor component has a threshold voltage and
the first change of the charge state of the internal capacitance takes results in an increase of a difference between a control voltage applied between the control terminals and the threshold voltage.

3. The method as claimed in claim 2 , wherein the first and second change of the charge state of the internal capacitance take place when the control voltage reaches a turn-on level.

4. The method as claimed in claim 1 , wherein determining the capacitance value comprises measuring a period of time during the first change of the charge state, during which time period a control voltage applied between the control terminals changes from a first defined voltage level to a second defined voltage level.

5. The method as claimed in claim 4 , wherein the causing the first change of the charge state comprises charging the internal capacitance with an essentially constant charging current.

6. The method as claimed in claim 4 , wherein causing the first change of the charge state comprises applying an essentially constant voltage to a series circuit comprising the internal capacitance and a charging resistor.

7. The method as claimed in claim 1 , wherein
causing the first change of the charge state comprises charging the internal capacitance gradually via charge pulses; and
determining the capacitance value comprises performing one of the following steps during the first change of the charge state:
determining a period of time during which a control voltage applied between the control terminals changes from a first defined voltage level to a second defined voltage level, or
determining a number of charge pulses which cause the control voltage applied between the control terminals to change from the first defined voltage level to the second defined voltage level.

8. The method as claimed in claim 1 , wherein causing the second change of the charge state of the internal capacitance comprises discharging the internal capacitance only via the internal resistance between the control terminals.

9. The method as claimed in claim 8 , wherein evaluating the resistance value of the internal resistance between the control terminals comprises measuring a period of time during which a control voltage applied between the control terminals changes from a first defined voltage level to a fourth defined voltage level.

10. The method as claimed in claim 1 , further comprising:
causing a third change of the charge state of the internal capacitance before or after the second change of the charge state; and
evaluating the resistance value of an external resistor connected between the control terminals, based on the third change of the charge state, wherein causing the third change of the charge state comprises discharging the internal capacitance via the internal resistance and the external resistor.

11. The method as claimed in claim 1 , further comprising:
causing a fourth change of the charge state of the internal capacitance before or after the second change of the charge state; and
evaluating the functional integrity of a driver circuit connected to the control terminals, wherein causing the fourth change of the charge state comprises discharging the internal capacitance via an electronic switch of the driver circuit.

12. An electronic circuit comprising:
a test circuit configured to be connected to control terminals of a transistor component, the test circuit configured to:
cause a first change of a charge state of a first capacitance present between control terminals of the transistor component,
determine a capacitance value of the first capacitance based on the first change of the charge state,
cause a second change of the charge state of the first capacitance present between the control terminals of the transistor component, and
determine a resistance value of a resistance present between the control terminals based on the determined capacitance value and the second change of the charge state.

13. The electronic circuit as claimed in claim 12 , wherein the test circuit is configured to cause the first change of state of the first capacitance by increasing a difference between a control voltage between the control terminals and a threshold voltage of the transistor component.

14. The electronic circuit as claimed in claim 13 , wherein the test circuit is configured to cause the first change of the charge state of the first capacitance and the second change of the charge state of the first capacitance when the control voltage reaches a turn-on level.

15. The electronic circuit as claimed claim 12 , wherein the test circuit is configured to:
during the first change of the charge state, determine a period of time from when a control voltage applied between the control terminals changes from a first defined voltage level to a second defined voltage level; and
determine the capacitance value based on the determined period of time.

16. The electronic circuit as claimed in claim 15 , wherein the test circuit is configured to cause the first change of the charge state by charging the first capacitance with an essentially constant charging current.

17. The electronic circuit as claimed in claim 15 , wherein the test circuit is configured to cause the first change of the charge state by applying an essentially constant voltage to a series circuit comprising the first capacitance and a charging resistor.

18. The electronic circuit as claimed in claim 12 , wherein the test circuit is configured to:
cause the first change of the charge state by applying a plurality of charge pulses to the first capacitance;
and determine the capacitance value by:
determining a period of time during which a control voltage applied between the control terminals changes from a first defined voltage level to a second defined voltage level; or
determining a number of charge pulses which cause the control voltage between the control terminals to change from the first defined voltage level to the second defined voltage level.

19. The electronic circuit as claimed in claim 18 , wherein the test circuit is configured to cause the second change of the charge state of the first capacitance by discharging the first capacitance only via the resistance present between the control terminals.

20. A test circuit comprising:
a signal generator configured to be coupled between a control terminal and a reference terminal of a switching transistor;
a measurement circuit configured to be coupled between the control terminal of the reference terminal of the switching transistor;
a controller configured to:
cause the signal generator to charge an internal capacitance of the switching transistor from a first voltage level to a second voltage level;
determine a value of the internal capacitance based on a time that it takes to charge the internal capacitance the first voltage

Assignees

• Infineon Technologies Ag

Inventors

• Graf Alfons

Classifications

• G01R31/2607 Primary

  Circuits therefor (G01R31/2642 takes precedence) · CPC title

• G01R31/2621 Primary

  for testing field effect transistors, i.e. FET's · CPC title

• G01R31/2608

  for testing bipolar transistors · CPC title

• G01R27/2605

  Measuring capacitance (capacitive sensors G01D5/24) · CPC title