Patent ID: 8493039

Claim:
A cascade-connected boost circuit, comprising a first-stage boost circuit, an output terminal and a regulation filtering capacitor, one end of the regulation filtering capacitor grounded, and another end thereof coupled to the output terminal, the first-stage boost circuit comprising an input terminal, a PWM generator, a first inductor, a first diode and a first switch, one end of the first inductor coupled to the input terminal, and another end thereof coupled to an anode of the first diode, a controlling terminal of the first switch coupled to the PWM generator, a first conductive terminal thereof grounded, and a second conductive terminal thereof coupled to the anode of the first diode, characterized in that the cascade-connected boost circuit further comprises a second-stage boost circuit, the second-stage boost circuit comprising a second inductor, a second switch, a first serial diode and a first parallel diode, one end of the second inductor coupled to a cathode of the first diode, and an another end thereof coupled to an anode of the first serial diode, a cathode of the first serial diode coupled to the output terminal, a controlling terminal of the second switch coupled to the PWM generator, a first conductive terminal thereof coupled to a second conductive terminal of the first switch, and a second conductive terminal of the second switch coupled to the anode of the first serial diode, a anode of the first parallel diode coupled to the input terminal, and a cathode thereof coupled to the cathode of the first diode.