Patent ID: 9024604
Filing Date: 2015-05-05
Classification: H02H,H02M

Abstract:
1. A power circuit comprising: an input terminal configured to input an input current; an input capacitor coupled to the input terminal and configured to accumulate electric charge by the input current; an overvoltage protection circuit coupled to the input terminal and configured to perform clamp operation to clamp a voltage of the input terminal to a clamp voltage; a first switch and a second switch coupled in series between the input terminal and a reference power source; an inductor disposed between a first connection node located between the first switch and the second switch and an output terminal; a main output capacitor coupled to the output terminal; a main output switch disposed between the inductor and the output terminal; a sub-output capacitor coupled to a second connection node located between the inductor and the main output switch through a sub-output switch; and a control circuit coupled to the input terminal and configured to control the first switch, the second switch, the main output switch and the sub-output switch, wherein the control circuit performs: switching operation that repeats on-off and off-on control upon the first switch and the second switch, performed when voltage of the input terminal reaches a first voltage lower than the clamp voltage, until voltage of the second connection node reaches a second voltage, and suspension operation that maintains an off-state of the first switch and the second switch after the voltage of the second connection node reaches the second voltage; the switching operation and the suspension operation on the main output capacitor by switching ON the main output switch; the switching operation on the sub-output capacitor by switching OFF the main output switch and switching ON the sub-output switch, when the input terminal voltage reaches the clamp voltage during a period of the suspension operation on the main output capacitor; and the switching operation or the suspension operation on the main output capacitor and the sub-output capacitor by switching ON the main output switch and the sub-output switch, after the voltage of the second connection node reaches the second voltage by the switching operation on the sub-output capacitor.