Design of a delta-sigma modulated switching power supply

An alternative control solution for a switching power supply using a delta-sigma (/spl Delta//spl Sigma/) modulator in place of a PWM controller is presented. The /spl Delta//spl Sigma/ modulator controller does not exhibit the spikes in the noise spectrum characteristic of the PWM controller. A multi-bit /spl Delta//spl Sigma/ modulator controller reduces the output noise floor below the conventional PWM controller noise floor. While the PWM is shown to have better power transfer efficiency, possible alternatives are suggested to increase the /spl Delta//spl Sigma/ modulator controller efficiency.