Pulsweitenmodulator

摘要

The invention relates to a pulse width modulator for controlling a semiconductor circuit breaker (S) in a switched-mode power supply unit, comprising: a comparator circuit (VS) for generating control pulses (AI) in accordance with an oscillator signal (OS), whereby the duration of the individual control pulses (AI) depends on a first control signal (RS1) and a second control signal (RS2); a measuring system (MA) for generating a load current signal (LS) dependent on the load current of the circuit breaker (S); and a feedback branch for feeding back the load current signal (LS) to the comparator circuit (VS). The feedback branch comprises a low-pass system (TP), where the load current signal (LS) can be picked up at the input of said system and the second control signal (RS2) at the output.