# US 11,115,019 B2 · Dynamic short circuit protection

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- Number: US 11,115,019 B2
- Document ID: US11115019B2
- Status: Granted
- Kind: B2
- Application number: 15/917,476
- Filed: 2018-03-09
- Published: 2019-09-12
- Granted: 2021-09-07
- Earliest claimed: 2018-03-09
- Assignees: Ford Global Technologies, LLC
- Applicants: Ford Global Technologies, LLC
- Inventors: Xi Lu; Chingchi Chen
- Web page: https://patentgrep.com/patent/US11115019B2

## CPC

- H03K 17/0828: {in composite switches}
- H03K 5/24: the characteristic being amplitude
- 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

Circuitry includes a pair of switches arranged in series, and a gate driver. The gate driver, responsive to a magnitude of current through one of the switches exceeding a threshold, discharges a gate of the one through a first resistor. The gate driver also, responsive to a voltage across a parasitic inductance of the switch becoming zero, discharges the gate through a second resistor but not the first resistor.

## Claims

### Claim 1

Circuitry comprising:
a pair of switches arranged in series; and
a gate driver configured to
responsive to a magnitude of current through one of the switches exceeding a threshold, discharge a gate of the one through a first resistor, and
responsive to a voltage across a parasitic inductance of the one becoming zero, discharge the gate through a second resistor but not the first resistor,
wherein the gate driver includes a comparator arranged to detect the voltage.

### Claim 2 (depends on 1)

The circuitry of claim 1, wherein the gate driver includes logic gates arranged to toggle state responsive to output of the comparator to discharge the gate through the second resistor but not the first resistor.

### Claim 3 (depends on 1)

The circuitry of claim 1, wherein a resistance of the first resistor is less than a resistance of the second resistor.

### Claim 4 (depends on 1)

The circuitry of claim 1, wherein the switches are transistors.

### Claim 5

A test apparatus comprising:
a pair of complementary-controlled insulated-gate bipolar transistors;
an inductor in parallel with one of the insulated-gate bipolar transistors; and
gate drive circuitry configured to, responsive to voltage across a parasitic inductance of the other of the insulated-gate bipolar transistors becoming zero during a short circuit event, disconnect a gate of the other of the insulated-gate bipolar transistors from a first resistor and connect the gate to a second resistor to alter a rate of discharge of the gate.

### Claim 6 (depends on 5)

The apparatus of claim 5, wherein the gate drive circuitry includes a comparator arranged to detect the voltage.

### Claim 7 (depends on 6)

The apparatus of claim 6, wherein the gate drive circuitry includes logic gates arranged to toggle state responsive to output of the comparator to disconnect the gate of the other of the insulated-gate bipolar transistors from the first resistor and connect the gate to the second resistor.

### Claim 8 (depends on 5)

The apparatus of claim 5, wherein a resistance of the first resistor is less than a resistance of the second resistor.

### Claim 9

A method for discharging a gate of one of a pair of series connected switches, comprising:
responsive to a magnitude of current through the one of the switches exceeding a threshold, discharging by a controller a gate of the one through a first resistor, and
responsive to a voltage across a parasitic inductance of the one becoming zero, discharging by the controller the gate through a second resistor but not the first resistor, wherein a resistance of the first resistor is less than a resistance of the second resistor.

### Claim 10 (depends on 9)

The method of claim 9 further comprising detecting by a comparator the voltage.

### Claim 11 (depends on 9)

The method of claim 9, wherein the switches are transistors.