A Time-Domain Current-Mode Buck Converter With a PI Compensator Incorporating an Infinite Phase Shift Delay Line

This article presents a current-mode buck converter that incorporates two control paths implemented using time-domain (TD) signal processing. The voltage regulation path (VRP) ensures high-accuracy output voltage, while the current feed-forward path (CFFP) simplifies the compensator design. A TD proportional-integral (PI) compensator is proposed, which consists of an infinite phase shift delay line (IPSDL) and a voltage-controlled oscillator (VCO) in cascade. The IPSDL enables the converter to support a wide frequency range with improved transient performance. The converter is fabricated using a 180-nm CMOS process and can provide <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$V_{\text {OUT}}$ </tex-math></inline-formula> ranging from 0.4 to 2.3 V from a 3.3-V input, supporting both continuous-conduction mode and discontinuous-conduction mode (DCM) operations. The load regulation (LR) is 5.26 mV/A. The load-transient settling time is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$8.4~{\mu }$ </tex-math></inline-formula>s when the output current steps from 1 A to 50 mA and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3~{\mu }$ </tex-math></inline-formula>s when transitioning from 50 mA to 1 A. At <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$V_{\text {OUT}}$ </tex-math></inline-formula> of 1.8 V, the measured peak efficiency is 95.7%.