A 50MHz Digitally Controlled Integrated Voltage Regulator with 92.8% Peak Efficiency

This paper presents a digitally-controlled four-phase high-frequency buck converter operating at 50-MHz switching frequency. The proposed voltage regulator achieves a peak efficiency of 92.88% during 1.8V-to-1V conversion under 4A load conditions. The digital control system incorporates several innovative techniques: a windowed flash ADC operating at 200MHz oversampling frequency for power optimization, digital trimming enabling comparator calibration within 1/2 LSB for enhanced precision, and a hybrid DPWM architecture combining counter and delay-line techniques with dual-edge modulation. The delay line implementation achieves 20ps resolution by leveraging the minimum delay of the process. Experimental results show satisfactory transient response, with undershoot limited to 105mV during load transitions between 4A and 16A, while maintaining significant improvements in circuit simplicity and control latency reduction.