Low cost high power factor LED driver
AssigneeNoveltek Semiconductor Corp.
InventorsMin-Chu Chien, Chin-Yen Lin
Life of this patent
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Abstract
A controller for a power supply having a primary side and a secondary side includes a mapping circuit for generating a feedback signal corresponding to an output current of the secondary side, a power switch coupled to the primary side for conducting a connection according to a modulation signal, a constant current block, for generating a first current signal according to the feedback signal; and a control unit, for generating the modulation signal to control the power switch according to the first current signal.
Claims34
A controller for a power supply having a primary side and a secondary side, the controller comprising:
- a mapping circuit, coupled to the primary side, for generating a feedback signal corresponding to variations of an output current of the secondary side;
- a power switch, comprising a first terminal coupled to the primary side, a second terminal and a third terminal, for conducting a connection between the first terminal and the third terminal according to a modulation signal received by the second terminal, and generating a current sense signal at the third terminal;
- a constant current block, for generating a first current signal according to the feedback signal and the current sense signal;
- and
- a control unit, for generating the modulation signal to control the power switch according to the first current signal, the feedback signal, the current sense signal and a voltage signal from the power supply.
A power supply comprising:
- a transformer comprising:
- a primary side winding for providing a primary side current;
- and
- a secondary side winding for providing a secondary side current for the output current, wherein a ratio between the secondary current and the primary current is a constant;
- and
- a controller for the power supply, comprising:
- a mapping circuit, coupled to the primary side, for generating a feedback signal corresponding to variations of an output current of the secondary side;
- a power switch, comprising a first terminal coupled to the primary side, a second terminal and a third terminal, for conducting a connection between the first terminal and the third terminal according to a modulation signal received by the second terminal, and generating a current sense signal at the third terminal;
- a constant current block, for generating a first current signal according to the feedback signal and the current sense signal;
- and
- a control unit, for generating the modulation signal to control the power switch according to the first current signal, the feedback signal, the current sense signal and a voltage signal from the power supply.
Dependencies are inferred from the claim text.