| 摘要 |
PURPOSE:To provide a power supply circuit whose stepping-up capability with reference to an input voltage is enhanced remarkably and which can achieve a high speed operation. CONSTITUTION:A diode bridge circuit is connected in parallel with an AC power supply. A smoothing capacitor C1 which is composed of, e.g. an electrolytic capacitor or the like is connected across one pair of output ends of the diode bridge circuit. Both ends of the capacitor C1 are connected respectively to power supply lines 36, 37 for a positive electrode and a negative electrode, and a positive voltage Vp and a negative voltage Vn are output. Transistor drive circuits 38, 39 are connected in parallel across the power supply lines 36, 37. The transistor drive circuits 38, 39 respectively output a positive sign DC output Vpp and a negative sign DC output Vnn from output lines L1u, L2u, L1d, L2d. A capacitor Cb is arranged across the transistor drive circuits 38, 39. A part near the output end of the power supply line 38 is connected to a control circuit 11 via a resistance Rf. |
