# US 2017/0290107 A1 · Systems and methods for overvoltage protection for led lighting

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- Number: US 2017/0290107 A1
- Document ID: US20170290107A1
- Status: Published application
- Kind: A1
- Application number: 15/140,347
- Filed: 2016-04-27
- Published: 2017-10-05
- Earliest claimed: 2016-03-29
- Assignees: On-Bright Electronics (Shanghai) Co., Ltd.
- Applicants: On-Bright Electronics (Shanghai) Co., Ltd.
- Inventors: Zhuoyan Li; Liqiang Zhu; Jiqing Yang; Lieyi Fang
- Web page: https://patentgrep.com/patent/US20170290107A1

## CPC

- H02H 7/1213: {for DC-DC converters}
- H02H 1/0007: {concerning the detecting means (in general G01R or other subclasses of G01; reed switches H01H71/2445)}
- H02H 3/202: {for DC systems}
- H05B 45/3725: Switched mode power supply [SMPS]
- H05B 47/24: Circuit arrangements for protecting against overvoltage
- G05F 1/571: with overvoltage detector
- H02M 3/156: with automatic control of output voltage or current, e.g. switching regulators
- H02M 3/33515: {with digital control}
- 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)
- H05B: ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
- G05F: SYSTEMS FOR REGULATING ELECTRIC OR MAGNETIC VARIABLES
- 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)
- Y02B: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS

## Abstract

System controller and method for a power converter. For example, a system controller for a power converter includes a logic controller configured to generate a modulation signal, and a driver configured to receive the modulation signal, generate a drive signal based at least in part on the modulation signal, and output the drive signal to a switch to affect a current flowing through an inductive winding for a power converter. Additionally, the system controller includes a voltage-to-voltage converter configured to receive a first voltage signal, the modulation signal, and a demagnetization signal, and to generate a second voltage signal based at least in part on the first voltage signal, the modulation signal, and the demagnetization signal.

## Claims

### Claim 1

A system controller for a power converter, the system controller comprising:
a logic controller configured to generate a modulation signal;
a driver configured to receive the modulation signal, generate a drive signal based at least in part on the modulation signal, and output the drive signal to a switch to affect a current flowing through an inductive winding for a power converter;
a voltage-to-voltage converter configured to receive a first voltage signal, the modulation signal, and a demagnetization signal, and to generate a second voltage signal based at least in part on the first voltage signal, the modulation signal, and the demagnetization signal; and
a comparator configured to receive a first threshold signal, generate a comparison signal based on at least information associated with the second voltage signal and the first threshold signal, and output the comparison signal to the logic controller;
wherein:
the modulation signal indicates an on-time period for the switch;
the demagnetization signal indicates a demagnetization period for the inductive winding; and
the second voltage signal is approximately equal to the first voltage signal multiplied by a ratio of the on-time period to a sum of the on-time period and the demagnetization period in magnitude.

### Claim 2 (depends on 1)

The system controller of claim 1 wherein the second voltage signal is equal to the first voltage signal multiplied by the ratio of the on-time period to the sum of the on-time period and the demagnetization period in magnitude.

### Claim 3 (depends on 1)

The system controller of claim 1 wherein:
the comparison signal indicates whether an overvoltage protection is triggered; and
the logic controller is configured to, in response to the comparison signal indicating the overvoltage protection is triggered, cause the power converter to shut down.

### Claim 4 (depends on 1)

The system controller of claim 1, and further comprising:
a low-pass filter configured to receive the second voltage signal and generate a third voltage signal based at least in part on the second voltage signal;
wherein the comparator is further configured to generate the comparison signal based on at least information associated with the third voltage signal and the first threshold signal.

### Claim 5 (depends on 4)

The system controller of claim 4 wherein the comparator is further configured to receive the third voltage signal and generate the comparison signal based at least in part on the third voltage signal and the first threshold signal.

### Claim 6 (depends on 4)

The system controller of claim 4, and further comprising an average-determination circuit configured to receive the third voltage signal and a second threshold signal and generate a fourth voltage signal based at least in part on the third voltage signal and the second threshold signal.

### Claim 7 (depends on 6)

The system controller of claim 6 wherein the average-determination circuit is further configured to:
compare the third voltage signal and the second threshold signal in magnitude;
in response to the third voltage signal being larger than the second threshold signal in magnitude, increase the fourth voltage signal in magnitude; and
in response to the third voltage signal being smaller than the second threshold signal in magnitude, decrease the fourth voltage signal in magnitude.

### Claim 8 (depends on 7)

The system controller of claim 7 wherein the comparator is further configured to receive the fourth voltage signal and generate the comparison signal based at least in part on the fourth voltage signal and the first threshold signal.

### Claim at position 9

-32. (canceled)

### Claim 33

A method for a power converter, the method comprising:
generating a modulation signal;
receiving the modulation signal;
generating a drive signal based at least in part on the modulation signal;
outputting the drive signal to a switch to affect a current flowing through an inductive winding for a power converter;
receiving a first voltage signal, the modulation signal, and a demagnetization signal;
generating a second voltage signal based at least in part on the first voltage signal, the modulation signal, and the demagnetization signal;
receiving a first threshold signal;
generating a comparison signal based on at least information associated with the second voltage signal and the first threshold signal; and
outputting the comparison signal;
wherein:
the modulation signal indicates an on-time period for the switch;
the demagnetization signal indicates a demagnetization period for the inductive winding; and
the second voltage signal is approximately equal to the first voltage signal multiplied by a ratio of the on-time period to a sum of the on-time period and the demagnetization period in magnitude.

### Claim 34 (depends on 33)

The method of claim 33 wherein the second voltage signal is equal to the first voltage signal multiplied by the ratio of the on-time period to the sum of the on-time period and the demagnetization period in magnitude.

### Claim 35 (depends on 33)

The method of claim 33, and further comprising:
in response to the comparison signal indicating the overvoltage protection is triggered, causing the power converter to shut down.

### Claim 36 (depends on 33)

The method of claim 33, and further comprising:
receiving the second voltage signal;
performing low-pass filtering to the second voltage signal; and
generating a third voltage signal based at least in part on the second voltage signal;
wherein the generating a comparison signal based on at least information associated with the second voltage signal and the first threshold signal includes generating the comparison signal based on at least information associated with the third voltage signal and the first threshold signal.

### Claim at position 14

-46. (canceled)