Raydium Semiconductor Corporation

Yu-En Lee

Chih-Wei Chu

Shu-Kuang Chou

A LED driving apparatus and an operating method thereof are disclosed. The LED driving apparatus includes a power, at least one LED string, a LED control unit, and an input voltage detection circuit. At least one LED string is coupled to the power and includes LEDs connected in series. The input voltage detection circuit is coupled to two ends of at least one LED of the LEDs respectively and used to judge whether an input voltage is lower than a LED conducting voltage. The input voltage detection circuit includes a charging capacitance to be charged when the at least one LED string is conducted. If the judged result of the input voltage detection circuit is yes, the input voltage detection circuit will control the charging capacitance having a charging voltage to discharge to the at least one LED string.

LED driving apparatus and operating method thereof

A driving circuit includes: a first voltage dividing circuit arranged to generate a first voltage-divided signal according to a supply voltage; a second voltage dividing circuit arranged to generate a second voltage-divided signal according to specific voltage; a coupling circuit coupled between the first voltage dividing circuit and the second voltage dividing circuit, and arranged to couple the first voltage-divided signal into the second voltage-divided signal to generate a coupling signal; and a control circuit arranged to generate a control signal at least according to the coupling signal and a feedback signal to control a duty cycle of a transistor, wherein the feedback is generated by the transistor.

Driving circuit having voltage dividing circuits and coupling circuit for controlling duty cycle of transistor and related circuit driving method thereof

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Taipei, Taiwan

Yu-En Lee