Digital Pulse-Frequency/Pulse-Amplitude Modulator for Improving Efficiency of SMPS Operating Under Light Loads

In this paper we show a novel digital control method for improving efficiency of SMPS operating at light loads and demonstrate its hardware implementation. In discontinuous conduction mode (DCM) it simultaneously performs a change of switching frequency and peak amplitude of the inductor current in order to achieve better efficiency than conventional pulse-frequency modulator solutions. Supporting analysis, simulations, and experimental results verify advantages of this control method