Patent ID: 8072194

Claim:
A boost snubber circuit structure, applied to a power supply having a boost circuit for obtaining an input power to modulate to a boost level and a power conversion unit for converting the input power at a boost level into an output power, and the boost circuit comprising: a boost unit, having at least one energy storage element, for obtaining the input power, and the boost unit being coupled to a switch element; a boost control unit, for generating a driving signal to drive the switch element to an ON state, and using a voltage difference between a reference voltage and a detection signal to determine a duration of outputting the driving signal; and a boost snubber unit, for obtaining the voltage difference between the detection signal and the reference voltage from the boost unit, and adding a modulation voltage to the reference voltage or the detection signal to modulate the voltage difference between the detection signal and the reference voltage, so as to control the duration of outputting the driving signal, the detection signal and the boost level having a maximum voltage difference to determine a continuous rise of the voltage of the input power to exceed the boost level and providing the modulation voltage to compensate the reference voltage or the detection signal to control the voltage difference smaller than the maximum voltage difference.