Patent ID: 9350241
Filing Date: 2016-05-24
CPC Classification: H02M,H03K,Y02B

Claim Text:
1. A buck converter, stepping-down an input voltage to an output voltage, comprising: a high-side N-type MOSFET switch, the drain electrode of the high-side N-type MOSFET switch coupled to the input voltage; a low-side N-type MOSFET switch, the drain electrode of the low-side N-type MOSFET switch coupled to the source electrode of the high-side N-type MOSFET switch, the source electrode of the low-side N-type MOSFET switch coupled to a ground, wherein the high-side N-type MOSFET switch and the low-side N-type MOSFET switch have complementary duty cycles; an output filter, coupled to the source electrode of the high-side N-type MOSFET switch and the drain electrode of the low-side N-type MOSFET switch, providing the output voltage; a control circuit, controlling the high-side N-type MOSFET switch and the low-side N-type MOSFET switch; a boot-strap capacitor, a first terminal of the boot-strap capacitor coupled to a regulating voltage, a second terminal of the boot-strap capacitor coupled to the source electrode of the high-side N-type MOSFET switch, the boot-strap capacitor being charged by the regulating voltage, the voltage of the first terminal of the boot-strap capacitor being provided to the control circuit for generating a gate driving signal controlling the high-side N-type MOSFET switch, wherein the voltage of the gate driving signal is larger than the input voltage; and a disabling circuit, coupling to the boot-strap capacitor and the control circuit, the disabling circuit sensing the voltage across the boot-strap capacitor, and generating a control signal to control the control circuit for continuously turning off the high-side N-type MOSFET switch when the voltage crossing the boot-strap capacitor is less than a threshold voltage, and comprising: