LED driver with silicon controlled dimmer, apparatus and control method thereof
AssigneeSilergy Semiconductor Technology (Hangzhou) LTD
InventorsQiukai Huang, Jianxin Wang, Huiqiang Chen
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Abstract
An apparatus can include: a bleeder circuit coupled to a DC bus of an LED driver having a silicon-controlled dimmer; the bleeder circuit being configured to control a voltage of the DC bus to vary in a predetermined manner by drawing a bleed current through a bleed path when in a first mode, and to cut off the bleed path when in a second mode; and a controller configured to control the bleeder circuit to be in the first mode before the silicon-controlled dimmer is turned on.
Claims19
An apparatus, comprising:
- a) a bleeder circuit coupled between a DC bus of a light-emitting diode (LED) driver having a silicon-controlled dimmer, and an LED driving sub-circuit having an LED load and a first transistor coupled in series;
- b) a controller configured to control, when said silicon-controlled dimmer is off, said bleeder circuit to control a voltage of said DC bus that is generated across two output terminals of a rectifier bridge, wherein said rectifier bridge is coupled to said silicon-controlled dimmer, and said DC bus voltage is configured to provide a load driving voltage to said LED load;
- and
- c) said bleeder circuit being configured to control said DC bus voltage to be approximate to a predetermined load driving voltage that is said load driving voltage when said silicon-controlled dimmer conducts at a maximum conduction angle.
A method of controlling a bleeder circuit coupled between a DC bus of a light-emitting diode (LED) driver having a silicon-controlled dimmer, and an LED driving sub-circuit having an LED load and a transistor coupled in series, the method comprising:
- a) controlling, by said bleeder circuit when said silicon-controlled dimmer is off, a voltage of said DC bus generated across two output terminals of a rectifier bridge, wherein said rectifier bridge is coupled to said silicon-controlled dimmer, and said DC bus voltage is configured to provide a load driving voltage to said LED load;
- and
- b) controlling, by said bleeder circuit, said DC bus voltage to be approximate to a predetermined load driving voltage that is said load driving voltage when said silicon-controlled dimmer conducts at a maximum conduction angle.
Dependencies are inferred from the claim text.