A self-oscillating pulse-width modulator comprises an input, an output and a control loop. The control loop comprises a forward branch and a feedback loop. The forward branch is connected between the input and the output and comprises a comparator and a delay element. The feedback loop loops back to the input a feedback signal which depends on an output signal present at the output. The phase shift of the open control loop is 180° at the frequency of an oscillation to be generated by the modulator. At least a part of the phase shift is realized in the forward branch by means of the at least one delay element.