A DIGITAL CONTROLLER FOR DC-DC SWITCHING CONVERTERS FOR OPERATION AT ULTRA-HIGH CONSTANT SWITCHING FREQUENCIES

摘要

A digital controller for low-power DC-DC switch mode power supplies (SMPS) suitable for on-chip implementation and use in portable battery-powered systems is provided. The digital controller allows operation at ultra high constant switching frequencies and can be implemented with a simple low-power digital hardware. The digital controller includes a digital pulse width modulator (DPWM), based on a multi­bit 2nd orders sigma-delta (Σ-Δ) principle, and a dual-sampling mode PID compensator. The output voltage is either sampled at a frequency lower than the switching frequency (undersampled) or sampled at the switching rate. In steady-state, undersampling results in reduced power consumption, while during transients, sampling at the switching rate provides fast transient response. Another aspect of the present invention is a dual sampling/clocking scheme, which is relied on by the DPWM described. A method is also provided for controlling low power DC-DC switch mode power supplies operating at high constant switching frequencies.