Switched mode power supply with low ripple - peak detects and filters ripple signal to give additional signal to pulse width modulator

摘要

The pulse width modulating system rectifies the a.c mains supply and passes the smoothed result via a switch to a transformer. The transformer's output is rectified and filtered to give the wanted stabilised output voltage suitable for supplying electronic equipment. The output of the transformer's rectifier is also passed to a peak rectifier whose output is filtered, dc isolated and applied inverted to a summation circuit. The summation circuit adds to it the system's output and a ref. and uses the result to control the width of the pulses that pulse the modulation switch.