Semiconductor Components Industries, LLC

Fairchild Korea Semiconductor Ltd.

Moon-Ho Choi

Hang-Seok Choi

Ji-Hoon Jang

Won-Tae Lee

Hyeong Seok Baek

Gwan-Bon Koo

Chen-Hua Chiu

A resonant converter includes a first switch on a primary side and a second switch coupled to the first switch, a first synchronous rectification switch on a secondary side conducted according to a switching operation of the first switch, a second synchronous rectification switch on the secondary side conducted according to a switching operation of the second switch, and a switch control circuit configured to detect a waveform of one end voltage of at least one of the first synchronous rectification switch and the second synchronous rectification switch, determine one of a below region and an above region, and differently control conduction duration of the first and second synchronous rectification switches according to a determined result.

Resonant converter and driving method thereof

An LED driver is provided. The LED driver comprises a plurality of driving units and a fold circuit. The driving units are coupled to an LED string including a plurality of LEDs for driving the LEDs. The fold circuit is coupled to the LED string and divides the LED string into a plurality of LED segments when an input voltage is lower than a threshold voltage. The LED segments are coupled to each other in parallel, and the input voltage is supplied to the LED segments.

LED driver

A control circuit for LED and an active bleeder thereof are provided. The control circuit comprises an LED driver and the active bleeder. The LED driver drives at least one LED and generates a current-sense signal. The current-sense signal is correlated to an LED current. The active bleeder comprises a bleeder circuit. The bleeder circuit is coupled to the LED driver to receive the current-sense signal and sinks a bleeding current in accordance with the current-sense signal for keeping the current flowing through the dimmer higher than the holding current.

Control circuit for LED and active bleeder thereof

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Bucheon-si, South Korea

Moon-Ho Choi