Nonuniform A/D Quantization for ImprovedDynamic Responses of Digitally ControlledDC–DC Converters

This paper presents an approach to improve dynamic responses of digitally controlled DC-DC converters using nonuniform analog-to-digital (A/D) quantization of the output voltage error. The nonuniform A/D quantizer parameters are selected to achieve improved step-load transient responses without compromising stability margins. The implementation, which includes a programmable A/D quantizer and a look-up table based discrete-time compensator, is simple and well suited for practical high-frequency digital pulsewidth modulation controllers. Simulation and experimental results are presented for a proof-of-concept point-of-load 5 V-to-1.3 V digitally controlled synchronous buck converter.