# US 9,520,711 B1 · Gate drive integrated circuit with input line overvoltage protection for a half-bridge power converter

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- Number: US 9,520,711 B1
- Document ID: US9520711B1
- Status: Granted
- Kind: B1
- Application number: 14/490,946
- Filed: 2014-09-19
- Granted: 2016-12-13
- Earliest claimed: 2013-10-04
- Assignees: Universal Lighting Technologies, Inc.
- Applicants: Universal Lighting Technologies, Inc.
- Inventors: Wei Xiong
- Web page: https://patentgrep.com/patent/US9520711B1

## CPC

- H02H 7/1222: {responsive to abnormalities in the input circuit, e.g. transients in the DC input}
- H02M 7/538: in a push-pull configuration (H02M7/5375 takes precedence {; with oscillating arrangements H02M7/53832, H02M7/53846})
- H05B 41/2828: {using control circuits for the switching elements (H05B41/2827 takes precedence)}
- H05B 41/2853: {against abnormal power supply conditions}
- H05B 45/39: Circuits containing inverter bridges
- H05B 47/24: Circuit arrangements for protecting against overvoltage
- H02H 9/046: {responsive to excess voltage appearing at terminals of integrated circuits}
- Y02B 20/00: Energy efficient lighting technologies, e.g. halogen lamps or gas discharge lamps
- Y02B 20/30: Semiconductor lamps, e.g. solid state lamps [SSL] light emitting diodes [LED] or organic LED [OLED]
- H02H: EMERGENCY PROTECTIVE CIRCUIT ARRANGEMENTS (indicating or signalling undesired working conditions G01R, e.g. G01R31/00, G08B; locating faults along lines G01R31/08; emergency protective devices H01H)
- H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P)
- H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS

## Abstract

A driver circuit provides power from a power source to a load. The driver circuit includes a surge protector, an input stage (e.g., full wave rectifier), a controller and an output stage (e.g., a half bridge inverter). The input stage receives power from the power source and provides a direct current (DC) power rail. The controller operates the output stage to provide power from the DC power rail to the load. The controller includes an overvoltage sensing module that shuts down the output stage when the DC power rail exceeds a predetermined voltage. Ceasing operation of the output stage protects the output stage from damage while the DC power rail is above the predetermined voltage.

## Claims

### Claim 1

A driver circuit operable to provide power from a power source to a load, said driver circuit comprising:
an input stage operable to receive power from the power source and provide a direct current (DC) power rail, wherein a voltage of the DC power rail is substantially proportional to a voltage of the power source;
an output stage operable to receive power from the DC power rail and provide output power to the load when operating,
wherein the output stage comprises a half-bridge inverter comprising a pair of switches, at least one of the pair of switches having a rated voltage;
a controller configured to:
operate the output stage such that the output stage provides power to the load;
determine a voltage of the DC power rail; and
cease operating the output stage when the determined voltage of the DC power rail exceeds a predetermined threshold of approximately the rated voltage of the at least one switch of the pair of switches, such that the output stage ceases providing power to the load; and wherein the controller comprises
a pulse width modulation module configured to provide gate drive signals to the output stage, and
an overvoltage sensing module configured to
determine the voltage of the DC power rail and
disable the pulse width modulation module by blocking a bias voltage of the controller from the pulse width modulation module when the determined voltage of the DC power rail exceeds the predetermined threshold.

### Claim 2 (depends on 1)

The driver circuit of claim 1, wherein:
the driver circuit further comprises a surge protector operable to limit the voltage of power received from the power source at the input stage.

### Claim 3 (depends on 1)

The driver circuit of claim 1, wherein:
the power source is an alternating current (AC) power source; and
the input stage comprises a full wave rectifier such that the voltage of the AC power source, as limited by a surge protector, passes through the full wave rectifier to the controller and the output stage.

### Claim 4 (depends on 1)

The driver circuit of claim 1, wherein the controller comprises:
a pulse width modulation module configured to provide gate drive signals to the output stage; and
an overvoltage sensing module configured to:
determine the voltage of the DC power rail; and
disable the pulse width modulation module when the determined voltage of the DC power rail exceeds the predetermined threshold such that the pulse width modulation module does not provide gate drive signals to the output stage.

### Claim 5 (depends on 1)

The driver circuit of claim 1, wherein the controller comprises:
a pulse width modulation module configured to provide gate drive signals to the output stage as a function of a duty cycle, wherein the controller is configured to determine the duty cycle as a function of the power provided to the load by the drive circuit; and
an overvoltage sensing module configured to:
determine the voltage of the DC power rail; and
reduce the duty cycle of the pulse width modulation module to zero percent when the determined voltage of the DC power rail exceeds the predetermined threshold.

### Claim 6 (depends on 1)

The driver circuit of claim 1, wherein:
the driver circuit further comprises a voltage regulator operable to receive power from the DC power rail and provide a bias voltage to the controller;
the controller is configured to receive a bias voltage from the voltage regulator; and
the controller further comprises an overvoltage sensing module connected to the DC power rail.

### Claim 7 (depends on 1)

The driver circuit of claim 1, wherein:
the driver circuit further comprises a voltage regulator operable to receive power from the DC power rail and provide a bias voltage to the controller;
the controller comprises a pulse width modulation module configured to provide gate drive signals to the output stage; and
the controller further comprises an overvoltage sensing module configured to:
determine the voltage of the DC power rail; and
block the bias voltage from the voltage regulator to the pulse width modulation module when the determined voltage of the DC power rail exceeds the predetermined threshold.

### Claim 8 (depends on 1)

The driver circuit of claim 1, wherein:
the driver circuit further comprises a voltage regulator operable to receive power from the DC power rail and provide a bias voltage for the controller; and
the voltage regulator is internal to the controller.

### Claim 9

A light fixture operable to provide light in response to receiving power from a power source, said light fixture comprising:
a light source operable to provide light in response to receiving power;
a driver circuit operable to provide power from the power source to the light source, said driver circuit comprising:
an input stage operable to receive power from the power source and provide a direct current (DC) power rail, wherein a voltage of the DC power rail is substantially proportional to a voltage of the power source;
an output stage operable to receive power from the DC power rail and provide output power to the light source when operating, wherein the output stage comprises a half-bridge inverter comprising a pair of switches, at least one of the pair of switches having a rated voltage;
a controller configured to:
operate the output stage such that the output stage provides power to the load;
determine a voltage of the DC power rail; and
cease operating the output stage when the determined voltage of the DC power rail exceeds a predetermined threshold of approximately the rated voltage, such that the output stage ceases providing power to the load; and
a housing configured to support the light source and the driver circuit; and
wherein the controller comprises
a pulse width modulation module configured to provide gate drive signals to the output stage, and
an overvoltage sensing module configured to
determine the voltage of the DC power rail, and
disable the pulse width modulation module by blocking a bias voltage of the controller from the pulse width modulation module when the determined voltage of the DC power rail exceeds the predetermined threshold.

### Claim 10 (depends on 9)

The light fixture of claim 9, wherein:
the driver circuit further comprises a surge protector operable to limit the voltage of power received from the power source at the input stage.

### Claim 11 (depends on 9)

The light fixture of claim 9, wherein:
the power source is an alternating current (AC) power source; and
the input stage comprises a full wave rectifier such that the voltage of the AC power source, as limited by the surge protector, passes through the full wave rectifier to the output stage and an overvoltage sensing module of the controller.

### Claim 12 (depends on 9)

The light fixture of claim 9, wherein the controller comprises:
a pulse width modulation module configured to provide gate drive signals to the output stage; and
an overvoltage sensing module configured to:
determine the voltage of the DC power rail; and
disable the pulse width modulation module when the determined voltage of the DC power rail exceeds the predetermined threshold such that the pulse width modulation module does not provide gate drive signals to the output stage.

### Claim 13 (depends on 9)

The light fixture of claim 9, wherein the controller comprises:
a pulse width modulation module configured to provide gate drive signals to the output stage as a function of a duty cycle, wherein the controller is configured to determine the duty cycle as a function of the power provided to the load by the drive circuit; and
an overvoltage sensing module configured to:
determine the voltage of the DC power rail; and
reduce the duty cycle of the pulse width modulation module to zero percent when the determined voltage of the DC power rail exceeds the predetermined threshold.

### Claim 14 (depends on 9)

The light fixture of claim 9, wherein:
the driver circuit further comprises a voltage regulator operable to receive power from the DC power rail and provide a bias voltage to the controller;
the controller is configured to receive a bias voltage from the voltage regulator; and
the controller further comprises an overvoltage sensing module connected to the DC power rail.

### Claim 15 (depends on 9)

The light fixture of claim 9, wherein:
the driver circuit further comprises a voltage regulator operable to receive power from the DC power rail and provide a bias voltage to the controller;
the controller comprises a pulse width modulation module configured to provide gate drive signals to the output stage; and
the controller further comprises an overvoltage sensing module configured to:
determine the voltage of the DC power rail; and
block the bias voltage from the voltage regulator to the pulse width modulation module when the determined voltage of the DC power rail exceeds the predetermined threshold.

### Claim 16 (depends on 9)

The light fixture of claim 9, wherein:
the driver circuit further comprises a voltage regulator operable to receive power from the DC power rail and provide a bias voltage for the controller; and
the voltage regulator is internal to the controller.

### Claim 17 (depends on 9)

The light fixture of claim 9, wherein the light source is a fluorescent lamp.

### Claim 18 (depends on 9)

The light fixture of claim 9, wherein the light source comprises a light emitting diode.