| 摘要 |
PURPOSE: To provide a voltage stepping-up circuit in which the rising is expedited while reducing the load at the time of rise of a secondary voltage. CONSTITUTION: A voltage stepping-up circuit 10 intermittently supplies a current from a battery 3 to a coil L1 by turning on and off a stepping-up circuit 2, rectifies the stepped-up voltage due to the counterelectromotive force of the coil L1 by a diode D1, and supplies it to a secondary side. The voltage of the secondary side is smoothed by a capacitor C2, and supplies as a drive voltage of an LSI, etc. When the voltage of the capacitor C2 is lowered to a predetermined voltage or less, the capacitor C2 is directly charged by a primary side voltage via an auxiliary charging circuit BC1 inserted with a diode D2 while controlling the charging by the secondary voltage via a resistor R1. When the capacitor C2 is stepped up to a predetermined voltage, the capacitor C2 is charged by the secondary side voltage via the resistor R1. At the time of discharging, the capacitor C2 is discharged via a diode D3. |
