VOLTAGE REGULATOR FOR CHARGING GENERATOR

PURPOSE:To smooth a ripple having continuously varying frequency and to monolithically provide it by detecting the rotating speed of a charging generator for an automobile for outputting a signal from an armature winding, and varying the frequency of an oscillator for turning ON, OFF a switch element in response to the speed. CONSTITUTION:A field current flowing to a field winding 1b of a generator 1 is so regulated by exciting current control means 3 that the output of a generator 1 becomes a value responsive to a command voltage VBC from voltage detecting means 4. The means 4 removes the ripple component contained in the voltage waveform of a storage battery 5 to suppress the voltage drop. The means 4 detects the rotating speed of the generator 1 by a signal of an armature winding 1a to vary the oscillation frequency of a variable frequency oscillator 4e in response to the speed of the generator 1. Thus, switching frequencies of switch elements 4a, 4b are controlled to optimum values to maintain a ripple smoothing rate constant.