Resistance detection for integrated circuit driver based on parasitic inductance

Patent metadata

Field	Value
Publication number	US-9435833-B2
Application number	US-201414338386-A
Country	US
Kind code	B2
Filing date	Jul 23, 2014
Priority date	Jul 23, 2014
Publication date	Sep 6, 2016
Grant date	Sep 6, 2016

Abstract

An IC driver includes a resistor detector to detect whether at least a threshold resistance is present between a pin of the IC driver and the gate of an IGBT. The resistor detector can include a comparator that compares a voltage at the collector of the IGBT to a threshold reference voltage (e.g., ground). In response to drive signals of the IC driver being switched off, a parasitic inductance causes a voltage drop at the emitter of the IGBT, and a commensurate voltage drop at the IGBT collector. If the resistance between the IC driver pin and the IGBT gate is lower than a specified level, the voltage drop at the IGBT collector will be such that the collector voltage falls below the threshold reference voltage. In response, the comparator asserts a signal indicating a fault.

First claim

What is claimed is:

1. An integrated circuit (IC) driver, comprising:
a first pin to be coupled to a first current electrode of an insulated gate bipolar transistor (IGBT);
a second pin to provide a control signal to a gate electrode of the IGBT; and
a resistor detector to detect a resistance at the second pin, the resistor detector comprising:
a first comparator including;
a first terminal coupled to the first pin;
a second terminal coupled to a first reference voltage; and
an output terminal to assert a first signal based on a comparison of a second signal at the first terminal and the first reference voltage.

2. The IC driver of claim 1 , wherein the first reference voltage comprises a ground reference voltage.

3. The IC driver of claim 1 , further comprising:
a second comparator including:
a first terminal coupled to the first pin;
a second terminal coupled to a second reference voltage; and
an output terminal to assert a second signal in response to the IGBT entering a desaturation state.

4. The IC driver of claim 3 , wherein the first reference voltage and the second reference voltage are different.

5. The IC driver of claim 3 , further comprising:
a third pin; and
wherein the IGBT comprises the first current electrode coupled to the first pin, a second current electrode coupled to the third pin, and a gate electrode to receive the control signal.

6. The IC driver of claim 5 , wherein the third pin is coupled to a capacitor.

7. The IC driver of claim 5 , further comprising:
a fourth pin to be coupled to the gate electrode of the IGBT; and
a second transistor comprising a first current electrode coupled to a third reference voltage, a second current electrode coupled to the fourth pin, and a control electrode to receive a second control signal.

8. The IC driver of claim 1 , wherein the electrode of the IGBT is a collector electrode of the IGBT.

9. A system, comprising:
an insulated gate bipolar transistor (IGBT), comprising a collector electrode, an emitter electrode, and a gate electrode; and
an integrated circuit (IC) driver comprising:
a first pin coupled to the collector electrode of the IGBT;
a second pin to provide a control signal to the gate electrode of the IGBT; and
a resistor detector to detect a resistance at the second pin, the resistor detector comprising
a first comparator including;
a first terminal coupled to the first pin;
a second terminal coupled to a first reference voltage; and
an output terminal to assert a first signal based on a comparison of a second signal at the first terminal and the reference voltage.

10. The system of claim 9 , wherein the IC driver further comprises:
a second comparator including:
a first terminal coupled to the first pin;
a second terminal coupled to a second reference voltage; and
an output terminal to assert a first signal in response to the IGBT entering a desaturation state.

11. The system of claim 10 , wherein the IC driver further comprises:
a third pin; and
a first transistor comprising a first current electrode coupled to the first pin, a second current electrode coupled to the third pin, and a control electrode to receive a first control signal.

12. The system of claim 11 , further comprising:
a capacitor comprising a first terminal coupled to the third pin and a second terminal coupled to a ground reference voltage.

13. The system of claim 12 , wherein the IC further comprises:
a fourth pin coupled to the gate electrode of the IGBT; and
a second transistor comprising a first current electrode coupled to a third reference voltage, a second current electrode coupled to the fourth pin, and a control electrode to receive a second control signal.

14. The system of claim 13 , further comprising:
a diode coupled between the first pin and the collector electrode of the IGBT.

15. The system of claim 13 , further comprising:
a resistor coupled between the fourth pin and the gate electrode of the IGBT.

Assignees

• Freescale Semiconductor Inc

Inventors

• Kandah Ibrahim S
• Gauen Kim R

Classifications

• H03K2217/0081

  Power supply means, e.g. to the switch driver · CPC title

• H03K2017/066

  Maximizing the OFF-resistance instead of minimizing the ON-resistance · CPC title

• G01R19/0084

  Measuring voltage only · CPC title

• G01R19/165 Primary

  Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values · CPC title

• H03K17/60 Primary

  the devices being bipolar transistors (bipolar transistors having four or more electrodes H03K17/72) · CPC title