A Time-Domain CCM/DCM Current-Mode Buck Converter with a PI Compensator Incorporating an Infinite Phase Shift Delay Line

This paper presents a current-mode (CM) buck converter which incorporates two control paths realized in time-domain signal processing. The voltage regulation path (VRP) ensures a high accuracy output voltage (VOUT), while the current feed-forward path (CFFP) simplifies the compensator design. A time-domain proportional-integral (PI) compensator is proposed which incorporates an infinite phase shift delay line (IPSDL) and VCO in cascade. The IPSDL allows the converter to support a wide frequency range with better transient performance. Fabricated in a 180-nm CMOS process, the converter can provide a VOUT from 0.35 V to 2.6 V from a 3.3-V input and supports both CCM and DCM operations. The load regulation is 5.26 mV/A. The load-transient settling time is 15.6 $\mu$s for the output current stepping from 1 A to 50 mA, and is 1.8 $\mu \mathrm{s}$ when transitioning from 50 mA to 1 A. At 1.8-V VOUT, the measured peak efficiency is 95.7%.