Fast-transient integrated digital DC-DC converter with predictive and feedforward control
Foong, Huey Chian
Tan, Yen Kheng
Tan, Meng Tong
Date of Issue2012
School of Electrical and Electronic Engineering
This paper introduces a dual-mode digital dc-dc converter combining the predictive and feedforward control with the conventional PID controller to achieve fast transient response and low overshoot. An additional predictive or jerk component is added to the conventional PID controller to speed up the transient response and reduce the settling time by approximately 50%. This predictive term is based on the second derivative of the error signal and introduces zero to the loop response which leads to increased bandwidth and improved phase margin. In addition, a feedforward control is also employed to further improve the transient by evaluating the change in the inductor current during the on and off time of the power transistors. Theoretical analysis and simulations were carried out to analyze the proposed design and algorithm. The proposed design is verified on silicon with a prototype of a digital dc-dc converter fabricated in CMOS 0.18 μ m process. The digital dc-dc converter achieved a settling time of 4 μs and an overshoot of 15 mV for a step-load transient of 450 mA, which are improved significantly as compared to the prior arts.
DRNTU::Engineering::Electrical and electronic engineering
IEEE transactions on circuits and systems I : regular papers
© 2012 IEEE.