| 摘要 |
PURPOSE:To reduce the capacity of a capacitor by correcting the input of a stepup chopper controller by the input current of a stepup chopper, thereby reducing the ripple current of an input stage capacitor. CONSTITUTION:The transistor (Tr) T1 of a stepup chopper 22 is controlled by a chopper controller 32 having a comparator 30 and a base amplifier 31. The controller 32 compares by a differential amplifier 34 the output of the chopper 22 with the reference voltage of a reference voltage setter 33, controls the TrT1 with the output of a triangular wave signal generator 35 to maintain the chopper output constant. A current detector CT1 detects an input current i1 and inputs it to a differential amplifier 38. Thus, the variation signal of the current i8 is subtracted by the output voltage of the amplifier 34 to be corrected to obtain a signal voltage having small ripple, thereby controlling the chopper. Accordingly, the stepup chopper current i2 becomes a continuous current waveform having small ripple. |
