Macroblock, Inc.

Li-Wei Yen

Lon-Kou Chang

Chang-Yu Wu

Hsing-Fu Liu

Jyun-Ji Chen

A dynamic damper in a lighting driving circuit for limiting an inrush current includes a damper circuit and a timing circuit comprising capacitor. The damper circuit is connected to the timing circuit. When an input voltage is provided to the dynamic damper, the capacitor begins to be charged and the capacitance-voltage of the capacitor rises. The damper circuit enters to a first working state and generates a dynamic damper resistor value. When the capacitance-voltage of the capacitor is greater than a first threshold voltage, the damper circuit enters to a second working state and the dynamic damper resistor value begins to decrease. When the capacitance-voltage of the capacitor is greater than a second threshold voltage, the damper circuit enters to a short-circuit state, and the dynamic damper resistor value decreases to zero to facilitate the normal work of the power source converter.

Dynamic damper and lighting driving circuit comprising the dynamic damper

An adaptive bleeder circuit is applicable to a power converter, in which the power converter has a transformer primary side and a transformer secondary side, and the power converter enables input power to be selectively input or not input to the transformer primary side through a pulse-width-modulated signal. The adaptive bleeder circuit includes a switched bleeder circuit, and the bleeder circuit switch dynamically adjusts a turn on/off ratio (or referred to as duty ratio) of the switch element according to the TRIAC holding current and the converter input current of an alternating current (AC) TRIAC. When the input current is less than the holding current, the bleeder circuit increases conduction time ratio of the pulse-width-modulated signal, such that the input current recovers to the holding current to maintain normal conduction of the AC TRIAC.

Adaptive bleeder circuit

An auto-selecting holding current circuit is applicable to a converter. A primary side of the converter has a Triode for Alternating Current (TRIAC) and a bleeder circuit. The auto-selecting holding current circuit includes a first sensor module, a second sensor module and a reference voltage selecting circuit. The first sensor module detects an input current drop time or an input voltage drop time to output a sense signal. The second sensor module receives a current detector signal and outputs a critical current signal to detect a holding-current value range of the TRIAC. The reference voltage selecting circuit outputs a reference current signal to the bleeder circuit, and the reference current signal corresponds to a holding-current value of the TRIAC. Therefore, the bleeder circuit maintains normal operation of the TRIACs with different holding-current values.

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Hsinchu, Taiwan

Li-Wei Yen