Lighting circuit and control method thereof
AssigneeJoulwatt Technology Co., Ltd.
InventorsWanyue He, Guoqiang Liu
Life of this patent
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Abstract
A lighting circuit and a control method thereof are provided. The lighting circuit includes a triac dimmer connected between an alternating current (AC) input power supply and a rectifier circuit, where the rectifier circuit is configured to output a bus voltage after phase cutting, and further includes a turn-on angle detection circuit configured to detect a turn-on state of the triac dimmer and output a first detection signal that represents a relationship between a turn-on angle of the triac dimmer and a first angle, and a bleeder circuit connected to the rectifier circuit and configured to control turn-off time of the bleeder circuit based on the first detection signal and a sampling signal representing a current of a light-emitting diode (LED) load.
Claims15
A lighting circuit, comprising a triac dimmer and a rectifier circuit, wherein the triac dimmer is connected between an alternating current (AC) input power supply and the rectifier circuit, the rectifier circuit is configured to output a bus voltage after phase cutting, and the lighting circuit further comprises:
- a turn-on angle detection circuit configured to detect a turn-on state of the triac dimmer, and output a first detection signal, wherein the first detection signal represents a relationship between a turn-on angle of the triac dimmer and a first angle;
- and
- a bleeder circuit connected to the rectifier circuit and configured to receive a sampling signal representing a current of a light-emitting diode (LED) load and the first detection signal, and control a turn-on state of the bleeder circuit based on the first detection signal and the sampling signal;
- wherein
- when the first detection signal represents that the turn-on angle is less than or equal to the first angle, and turn-on time of the triac dimmer reaches first time, when the sampling signal is greater than or equal to a first threshold, the bleeder circuit keeps on;
- or when the sampling signal is less than the first threshold, the bleeder circuit is turned off.
A control method of a lighting circuit, wherein the lighting circuit comprises a triac dimmer and a rectifier circuit, the triac dimmer is connected between an AC input power supply and the rectifier circuit, the rectifier circuit is configured to output a bus voltage after phase cutting, and the control method comprises:
- detecting a turn-on state of the triac dimmer, and obtaining a first detection signal, wherein the first detection signal represents a relationship between a turn-on angle of the triac dimmer and a first angle;
- and
- controlling a turn-on state of a bleeder circuit based on the first detection signal and a sampling signal representing a current of an LED load, wherein the bleeder circuit is connected in parallel to an output terminal of the rectifier circuit, wherein
- when the first detection signal represents that the turn-on angle is less than or equal to the first angle, and turn-on time of the triac dimmer reaches first time, when the sampling signal is greater than or equal to a first threshold, the bleeder circuit keeps on;
- or when the sampling signal is less than the first threshold, the bleeder circuit is turned off;
- or
- when the first detection signal represents that the turn-on angle is greater than the first angle, before the LED load is turned on and during turn-on of the LED load, the bleeder circuit keeps on, and the bleeder circuit is turned off when the sampling signal drops to the first threshold.
Dependencies are inferred from the claim text.