Apparatus, dimmable light emitting diode driver and control method
AssigneeSilergy Semiconductor Technology (Hangzhou) LTD
InventorsHuiqiang Chen, Jianxin Wang
Life of this patent
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Abstract
An apparatus can include: a linear drive circuit configured to control a drive current flowing through an LED load; a control circuit configured to acquire a conduction angle signal of a silicon-controlled rectifier dimmer and control the linear drive circuit; and the control circuit being configured to control the drive current to be decreased to reduce a current ripple and to maintain the silicon-controlled rectifier dimmer in a turn-on state when the conduction angle signal is less than a predetermined value.
Claims21
An apparatus, comprising:
- a) a current drive circuit configured to provide a driving current to drive a light-emitting diode (LED) load, wherein the current drive circuit comprises a first transistor connected in series with the LED load;
- b) a control circuit comprising a reference voltage, and being configured to control the first transistor in the driving circuit to generate the driving current in accordance with a conduction angle of a silicon-controlled rectifier dimmer;
- and
- c) the control circuit being configured to control the reference voltage to be decreased gradually with a decrease of the conduction angle, in order to decrease the driving current to avoid flicker of the LED load.
A dimmable light-emitting diode (LED) drive circuit, comprising:
- a) a rectification circuit coupled to the silicon-controlled rectifier dimmer, wherein the rectification circuit is configured to generate a direct current bus voltage;
- and
- b) a bleeder circuit coupled to the rectification circuit, and being configured to sink a bleeder current;
- c) a current drive circuit configured to provide a driving current to drive an LED load;
- d) first and second sensing circuits coupled in series with the LED load, wherein the bleeder circuit is coupled to a common node between the first and second sensing circuits;
- and
- e) a control circuit comprising a reference voltage, and being configured to control the driving circuit in accordance with a conduction angle of a silicon-controlled rectifier dimmer.
Dependencies are inferred from the claim text.