# US 9,435,833 B2 · Resistance detection for integrated circuit driver based on parasitic inductance

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- Number: US 9,435,833 B2
- Document ID: US9435833B2
- Status: Granted
- Kind: B2
- Application number: 14/338,386
- Filed: 2014-07-23
- Published: 2016-01-28
- Granted: 2016-09-06
- Earliest claimed: 2014-07-23
- Assignees: Freescale Semiconductor, Inc.
- Applicants: Freescale Semiconductor, Inc.
- Inventors: Ibrahim S. Kandah; Kim R. Gauen
- Web page: https://patentgrep.com/patent/US9435833B2

## CPC

- G01R 19/165: Indicating that current or voltage is either above or below a predetermined value or within or outside a predetermined range of values
- G01R 19/0084: {Measuring voltage only}
- H03K 17/18: Modifications for indicating state of switch
- H03K 17/60: the devices being bipolar transistors (bipolar transistors having four or more electrodes H03K17/72)
- H03K 2017/066: {Maximizing the OFF-resistance instead of minimizing the ON-resistance}
- H03K 2217/0081: Power supply means, e.g. to the switch driver
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)
- H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M)

## 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.

## Claims

### Claim 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.

### Claim 2 (depends on 1)

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

### Claim 3 (depends on 1)

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.

### Claim 4 (depends on 3)

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

### Claim 5 (depends on 3)

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.

### Claim 6 (depends on 5)

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

### Claim 7 (depends on 5)

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.

### Claim 8 (depends on 1)

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

### Claim 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.

### Claim 10 (depends on 9)

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.

### Claim 11 (depends on 10)

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.

### Claim 12 (depends on 11)

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.

### Claim 13 (depends on 12)

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.

### Claim 14 (depends on 13)

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

### Claim 15 (depends on 13)

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