LED driver and control method thereof
AssigneeRichtek Technology Corporation
InventorJing-Meng Liu
Life of this patent
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Abstract
A LED driver providing a LED lighting current to a LED path, extracts the LED lighting current information from the LED path to produce a first signal including an AC component and a DC component, and extracts the DC component information of the first signal to produce a second signal to regulate an average of the LED lighting current. This LED driver implements real constant average current regulation for a LED lighting apparatus, eliminates the need of output capacitor as well as rectifier diode in most applications to simplify the circuit of the power stage, and is applicable to power stages of various modes.
Claims63
A LED driver eliminating the need of output capacitor, comprising:
- an output terminal providing a LED path with a LED lighting current including an AC component and a DC component;
- a first circuit acquiring a first signal relating to the LED lighting current;
- a second circuit extracting a DC component of the first signal to generate a second signal;
- and
- a power stage responsive to the second signal to regulate the LED lighting current.
A control method for a LED driver eliminating the need of output capacitor, comprising the steps of:
- providing a LED lighting current for a LED path;
- from the LED path, extracting a first signal including an AC component and a DC component;
- processing the first signal to generate a second signal representing the DC component of the first signal;
- and
- regulating an average of the LED lighting current according to the second signal.
A lighting apparatus, comprising:
- a LED path having at least one LED thereon;
- a power stage providing the LED path with a LED lighting current including an AC component and a DC component;
- and
- a feedback loop acquiring an information of the DC component of the LED lighting current to control the power stage to regulate the LED lighting current.
Dependencies are inferred from the claim text.