Abstract: A signal generator controls power output on the basis of the output from a &Dgr;-&Sgr; modulator or oscillator. That output may be generated in real time by the modulator or oscillator and fed to a switch control logic unit which controls a power switching stage to output switchably switched power from a power supply to an output, preferably via a filter. Alternatively the output of a &Dgr;-&Sgr; oscillator or modulator may be stored in a switchable memory to be retrieved when needed. A further alternative is to control the power switching stage by a processor with a program which reproduces the control effect of the &Dgr;-&Sgr; oscillator/modulator Feedback from the output may be used to control the &Dgr;-&Sgr; modulator/oscillator and/or the power supply.