Control circuit, LED driving chip, LED driving system and LED driving method thereof
AssigneeShanghai Bright Power Semiconductor Co., Ltd.
InventorJianjing Lyu
Life of this patent
Estimating the term…
Abstract
The present invention discloses a control circuit, a LED driving system, and a LED driving method. The control circuit receives a feedback signal from the power converter and generate a ZCD pulse signal accordingly, indicating one or more moments when the feedback signal decreases to zero, and receives a dimming signal and generate a minimum turn-off time signal accordingly, indicating the moment when a minimum turn-off time is passed. The control circuit generates a first turn-on signal according to the ZCD pulse signal and the minimum turn-off time signal to control a switching device within the power converter to turn on when the feedback signal decreases to zero and the minimum turn-off time is passed.
Claims15
A control circuit for a power converter wherein the control circuit receives a feedback signal from the power converter and generate a zero current detection (ZCD) pulse signal accordingly, indicating one or more moments when the feedback signal decreases to zero, and receives a dimming signal and generates a minimum turn-off time signal accordingly, indicating the moment when a minimum turn-off time is passed, and wherein the control circuit generates a first turn-on signal according to the ZCD pulse signal and the minimum turn-off time signal to control a switching device within the power converter to turn on when the feedback signal decreases to zero and the minimum turn-off time is passed;
- the control circuit is further provided with a FB pin and a demagnetization detection module, of which the demagnetization detection module is configured to connect with the FB pin and receive the feedback signal obtained from the power converter.
An LED driving system, including an AC power supply, a rectifier, a bus capacitor, a magnetic device, a switching device, and one or more LED loads, wherein the AC power supply is coupled to the magnetic device to drive the LED loads;
- and wherein the LED driving system further comprises a control circuit, which receives a feedback signal from the magnetic device and generate a ZCD pulse signal accordingly, indicating one or more moments when the feedback signal decreases to zero, and receives a dimming signal and generate a minimum turn-off time signal accordingly, indicating the moment when a minimum turn-off time is passed, and wherein the control circuit generates a first turn-on signal according to the ZCD pulse signal and the minimum turn-off time signal to control the switching device to turn on when the feedback signal decreases to zero and the minimum turn-off time is passed;
- the control circuit is further provided with a FB pin and a demagnetization detection module, of which the demagnetization detection module is configured to connect with the FB pin and receive the feedback signal obtained from a power converter.
An LED driving method applied in an LED driving system, wherein the LED driving method comprising:
- receiving a feedback signal obtained from a power converter and generating a ZCD pulse signal accordingly by a demagnetization detection module, wherein the ZCD pulse signal indicates one or more moments when the feedback signal decreases to zero;
- and
- receiving a dimming signal and generating a minimum turn-off time signal accordingly, which indicates the moment when a minimum turn-off time is passed;
- and
- generating a first turn-on signal according to the ZCD pulse signal and the minimum turn-off time signal;
- generating a switch control signal according to the first turn-on signal, controlling a switching device to turn on when the feedback signal decreases to zero and the minimum turn-off time is passed.
Dependencies are inferred from the claim text.