# US 2017/0290108 A1 · Systems and methods for overvoltage protection for led lighting

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- Number: US 2017/0290108 A1
- Document ID: US20170290108A1
- Status: Published application
- Kind: A1
- Application number: 15/235,046
- Filed: 2016-08-11
- 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/US20170290108A1

## 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 at position 1

-8. (canceled)

### Claim 9

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 of a power converter, the inductive winding including a first winding terminal and a second winding terminal, the second winding terminal being at a terminal voltage and coupled to a first diode terminal of a diode, the diode further including a second diode terminal, a voltage difference between the second diode terminal and the first winding terminal being an output voltage of the power converter; and
an overvoltage-protection detector configured to receive a feedback signal and a demagnetization signal, generate a detection signal based at least in part on the feedback signal and the demagnetization signal, and output the detection signal to the logic controller, the feedback signal being equal to the terminal voltage divided by a predetermined constant, the demagnetization signal indicating a demagnetization period for the inductive winding, the detection signal indicating whether an overvoltage protection is triggered;
wherein the logic controller is configured to, in response to the detection signal indicating the overvoltage protection is triggered, cause the power converter to shut down.

### Claim 10 (depends on 9)

The system controller of claim 9 wherein the overvoltage-protection detector includes:
a sample-and-hold circuit configured to receive the feedback signal and generate a sampled-and-held signal based at least in part on the feedback signal;
a voltage-to-voltage converter configured to receive the sampled-and-held signal and the demagnetization signal and generate a first voltage signal based at least in part on the sampled-and-held signal and the demagnetization signal; and
a comparator configured to receive a first threshold signal and generate the detection signal based on at least information associated with the first voltage signal and the first threshold signal.

### Claim 11 (depends on 10)

The system controller of claim 10 wherein the first voltage signal is approximately equal to the output voltage of the power converter divided by the predetermined constant.

### Claim 12 (depends on 10)

The system controller of claim 10 wherein the overvoltage-protection detector further includes:
a low-pass filter configured to receive the first voltage signal and generate a filtered signal based at least in part on the first voltage signal;
wherein the comparator is further configured to generate the detection signal based on at least information associated with the filtered signal and the first threshold signal.

### Claim 13 (depends on 12)

The system controller of claim 12 wherein the comparator is further configured to receive the filtered signal and generate the detection signal based at least in part on the filtered signal and the first threshold signal.

### Claim 14 (depends on 12)

The system controller of claim 12 wherein the overvoltage-protection detector further includes an average-determination circuit configured to receive the filtered signal and a second threshold signal and generate a second voltage signal based at least in part on the filtered signal and the second threshold signal.

### Claim 15 (depends on 14)

The system controller of claim 14 wherein the average-determination circuit is further configured to:
compare the filtered signal and the second threshold signal in magnitude;
in response to the filtered signal being larger than the second threshold signal in magnitude, increase the second voltage signal in magnitude; and
in response to the filtered signal being smaller than the second threshold signal in magnitude, decrease the second voltage signal in magnitude.

### Claim 16 (depends on 15)

The system controller of claim 15 wherein the comparator is further configured to receive the second voltage signal and generate the detection signal based at least in part on the second voltage signal and the first threshold signal.

### Claim 17 (depends on 9)

The system controller of claim 9 wherein the overvoltage-protection detector is further configured to receive the feedback signal from a first resistor terminal of a first resistor and a second resistor terminal of a second resistor, the first resistor terminal being coupled to the second resistor terminal, the second resistor further including a third resistor terminal biased at the terminal voltage.

### Claim 18 (depends on 9)

The system controller of claim 9 wherein the overvoltage-protection detector includes:
a sample-and-hold circuit configured to receive the feedback signal and generate a sampled-and-held signal based at least in part on the feedback signal;
a first voltage-to-current converter configured to receive the sampled-and-held signal and generate a first current signal based at least in part on the sampled-and-held signal;
a second voltage-to-current converter configured to receive a first threshold signal and generate a second current signal based at least in part on the first threshold signal;
a current generator configured to receive the first current signal and the second current signal and generate a third current signal based at least in part on the first current signal and the second current signal;
a capacitor configured to receive the third current signal and generate a voltage signal based at least in part on the third current signal; and
a controlled comparator configured to receive the voltage signal, a second threshold signal and the demagnetization signal and generate the detection signal based at least in part on the voltage signal, the second threshold signal, and the demagnetization signal.

### Claim 19 (depends on 18)

The system controller of claim 18 wherein the current generator is further configured to receive the modulation signal and the demagnetization signal and generate the third current signal based at least in part on the first current signal, the second current signal, the modulation signal, and the demagnetization signal.

### Claim 20 (depends on 18)

The system controller of claim 18 wherein the controlled comparator includes:
a first comparator configured to receive the voltage signal and the second threshold signal and generate a comparison signal based at least in part on the voltage signal and the second threshold signal; and
an edge-triggered latch configured to receive the comparison signal and the demagnetization signal and generate the detection signal based at least in part on the comparison signal and the demagnetization signal.

### Claim 21

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 of a power converter, the inductive winding including a first winding terminal and a second winding terminal, the first winding terminal being at a terminal voltage, the second winding terminal being coupled to a first diode terminal of a diode, the diode further including a second diode terminal, a voltage difference between the second diode terminal and the first winding terminal being an output voltage of the power converter; and
an overvoltage-protection detector configured to receive an input signal and a demagnetization signal, generate a detection signal based at least in part on the input signal and the demagnetization signal, and output the detection signal to the logic controller, the input signal being equal to the terminal voltage divided by a predetermined constant, the demagnetization signal indicating a demagnetization period for the inductive winding, the detection signal indicating whether an overvoltage protection is triggered;
wherein the logic controller is configured to, in response to the detection signal indicating the overvoltage protection is triggered, cause the power converter to shut down.

### Claim 22 (depends on 21)

The system controller of claim 21 wherein the overvoltage-protection detector includes:
a sample-and-hold circuit configured to receive the input signal and generate a sampled-and-held signal based at least in part on the input signal;
a voltage-to-voltage converter configured to receive the sampled-and-held signal and the demagnetization signal and generate a first voltage signal based at least in part on the sampled-and-held signal and the demagnetization signal; and
a comparator configured to receive a first threshold signal and generate the detection signal based on at least information associated with the first voltage signal and the first threshold signal.

### Claim 23 (depends on 22)

The system controller of claim 22 wherein the first voltage signal is approximately equal to the output voltage of the power converter divided by the predetermined constant.

### Claim 24 (depends on 22)

The system controller of claim 22 wherein the overvoltage-protection detector further includes:
a low-pass filter configured to receive the first voltage signal and generate a filtered signal based at least in part on the first voltage signal;
wherein the comparator is further configured to generate the detection signal based on at least information associated with the filtered signal and the first threshold signal.

### Claim 25 (depends on 24)

The system controller of claim 24 wherein the comparator is further configured to receive the filtered signal and generate the detection signal based at least in part on the filtered signal and the first threshold signal.

### Claim 26 (depends on 24)

The system controller of claim 24 wherein the overvoltage-protection detector further includes an average-determination circuit configured to receive the filtered signal and a second threshold signal and generate a second voltage signal based at least in part on the filtered signal and the second threshold signal.

### Claim 27 (depends on 26)

The system controller of claim 26 wherein the average-determination circuit is further configured to:
compare the filtered signal and the second threshold signal in magnitude;
in response to the filtered signal being larger than the second threshold signal in magnitude, increase the second voltage signal in magnitude; and
in response to the filtered signal being smaller than the second threshold signal in magnitude, decrease the second voltage signal in magnitude.

### Claim 28 (depends on 27)

The system controller of claim 27 wherein the comparator is further configured to receive the second voltage signal and generate the detection signal based at least in part on the second voltage signal and the first threshold signal.

### Claim 29 (depends on 21)

The system controller of claim 21 wherein the overvoltage-protection detector is further configured to receive the input signal from a first resistor terminal of a first resistor and a second resistor terminal of a second resistor, the first resistor terminal being coupled to the second resistor terminal, the second resistor further including a third resistor terminal biased at the terminal voltage.

### Claim 30 (depends on 21)

The system controller of claim 21 wherein the overvoltage-protection detector includes:
a sample-and-hold circuit configured to receive the input signal and generate a sampled-and-held signal based at least in part on the input signal;
a first voltage-to-current converter configured to receive the sampled-and-held signal and generate a first current signal based at least in part on the sampled-and-held signal;
a second voltage-to-current converter configured to receive a first threshold signal and generate a second current signal based at least in part on the first threshold signal;
a current generator configured to receive the first current signal and the second current signal and generate a third current signal based at least in part on the first current signal and the second current signal;
a capacitor configured to receive the third current signal and generate a voltage signal based at least in part on the third current signal; and
a controlled comparator configured to receive the voltage signal, a second threshold signal and the demagnetization signal and generate the detection signal based at least in part on the voltage signal, the second threshold signal, and the demagnetization signal.

### Claim 31 (depends on 30)

The system controller of claim 30 wherein the current generator is further configured to receive the modulation signal and the demagnetization signal and generate the third current signal based at least in part on the first current signal, the second current signal, the modulation signal, and the demagnetization signal.

### Claim 32 (depends on 30)

The system controller of claim 30 wherein the controlled comparator includes:
a first comparator configured to receive the voltage signal and the second threshold signal and generate a comparison signal based at least in part on the voltage signal and the second threshold signal; and
an edge-triggered latch configured to receive the comparison signal and the demagnetization signal and generate the detection signal based at least in part on the comparison signal and the demagnetization signal.

### Claim at position 26

-36. (canceled)

### Claim 37

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 of a power converter, the inductive winding including a first winding terminal and a second winding terminal, the second winding terminal being at a terminal voltage and coupled to a first diode terminal of a diode, the diode further including a second diode terminal, a voltage difference between the second diode terminal and the first winding terminal being an output voltage of the power converter;
receiving a feedback signal and a demagnetization signal, the feedback signal being equal to the terminal voltage divided by a predetermined constant, the demagnetization signal indicating a demagnetization period for the inductive winding;
generating a detection signal based at least in part on the feedback signal and the demagnetization signal;
outputting the detection signal, the detection signal indicating whether an overvoltage protection is triggered; and
in response to the detection signal indicating the overvoltage protection is triggered, causing the power converter to shut down.

### Claim 38 (depends on 37)

The method of claim 37 wherein the generating a detection signal based at least in part on the feedback signal and the demagnetization signal includes:
generating a sampled-and-held signal based at least in part on the feedback signal;
receiving the sampled-and-held signal;
generating a voltage signal based at least in part on the sampled-and-held signal and the demagnetization signal;
receiving a first threshold signal; and
generating the detection signal based on at least information associated with the voltage signal and the first threshold signal.

### Claim 39 (depends on 38)

The method of claim 38 wherein the voltage signal is approximately equal to the output voltage of the power converter divided by the predetermined constant.

### Claim 40 (depends on 37)

The method of claim 37 wherein the generating a detection signal based at least in part on the feedback signal and the demagnetization signal includes:
generating a sampled-and-held signal based at least in part on the feedback signal;
receiving the sampled-and-held signal;
generating a first current signal based at least in part on the sampled-and-held signal;
receiving a first threshold signal;
generating a second current signal based at least in part on the first threshold signal;
receiving the first current signal and the second current signal;
generating a third current signal based at least in part on the first current signal and the second current signal;
receiving the third current signal;
generating a voltage signal based at least in part on the third current signal;
receiving the voltage signal, a second threshold signal and the demagnetization signal; and
generating the detection signal based at least in part on the voltage signal, the second threshold signal, and the demagnetization signal.

### Claim 41 (depends on 40)

The method of claim 40 wherein:
the receiving the first current signal and the second current signal includes receiving the first current signal, the second current signal, the modulation signal, and the demagnetization signal; and
the generating a third current signal based at least in part on the first current signal and the second current signal includes generating the third current signal based at least in part on the first current signal, the second current signal, the modulation signal, and the demagnetization signal.

### Claim 42

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 of a power converter, the inductive winding including a first winding terminal and a second winding terminal, the first winding terminal being at a terminal voltage, the second winding terminal being coupled to a first diode terminal of a diode, the diode further including a second diode terminal, a voltage difference between the second diode terminal and the first winding terminal being an output voltage of the power converter; and
receiving an input signal and a demagnetization signal, the input signal being equal to the terminal voltage divided by a predetermined constant, the demagnetization signal indicating a demagnetization period for the inductive winding;
generating a detection signal based at least in part on the input signal and the demagnetization signal; and
outputting the detection signal, the detection signal indicating whether an overvoltage protection is triggered; and
in response to the detection signal indicating the overvoltage protection is triggered, causing the power converter to shut down.

### Claim 43 (depends on 42)

The method of claim 42 wherein the generating a detection signal based at least in part on the input signal and the demagnetization signal includes:
generating a sampled-and-held signal based at least in part on the input signal;
receiving the sampled-and-held signal;
generating a voltage signal based at least in part on the sampled-and-held signal and the demagnetization signal;
receiving a first threshold signal; and
generating the detection signal based on at least information associated with the voltage signal and the first threshold signal.

### Claim 44 (depends on 43)

The method of claim 43 wherein the voltage signal is approximately equal to the output voltage of the power converter divided by the predetermined constant.

### Claim 45 (depends on 42)

The method of claim 42 wherein the generating a detection signal based at least in part on the input signal and the demagnetization signal includes:
generating a sampled-and-held signal based at least in part on the input signal;
receiving the sampled-and-held signal;
generating a first current signal based at least in part on the sampled-and-held signal;
receiving a first threshold signal;
generating a second current signal based at least in part on the first threshold signal;
receiving the first current signal and the second current signal;
generating a third current signal based at least in part on the first current signal and the second current signal;
receiving the third current signal;
generating a voltage signal based at least in part on the third current signal;
receiving the voltage signal, a second threshold signal and the demagnetization signal; and
generating the detection signal based at least in part on the voltage signal, the second threshold signal, and the demagnetization signal.

### Claim 46 (depends on 45)

The method of claim 45 wherein:
the receiving the first current signal and the second current signal includes receiving the first current signal, the second current signal, the modulation signal, and the demagnetization signal; and
the generating a third current signal based at least in part on the first current signal and the second current signal includes generating the third current signal based at least in part on the first current signal, the second current signal, the modulation signal, and the demagnetization signal.