| 摘要 |
PROBLEM TO BE SOLVED: To provide a method and a circuit for sensing a current wherein a current passed through an exciting switch can be accurately detected even at a high resonance frequency and a current resonance type DC-DC converter provided therewith. SOLUTION: The current resonance type DC-DC converter 10A has a current resonance type DC-DC converter section 12 including: the exciting switch SW1 that is turned on/off in response to a drive control signal VGH; a resonance inductor Lr one end of which is connected to the exciting switch; and a resonance capacitor Cr one end of which is connected to the other end of the resonance inductor. A control circuit 30 includes a CR series circuit 31 that is connected in parallel with the exciting switch SW1 and constructed of a capacitor C1 and a resistor R1. Based on a voltage V(C1) across the capacitor, the control circuit generates a drive control signal VGH so as to turn off the exciting switch when the current I<SB>SW1</SB>passed through the exciting switch is substantially zeroed. COPYRIGHT: (C)2007,JPO&INPIT
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