Control bandwidth and transient response of buck converters

Author

Yao, Kaiwei ; Meng, Yu ; Lee, Fred C.

Author_Institution

Bradley Dept. of Electr. Eng., Virginia Polytech. Inst. & State Univ., Blacksburg, VA, USA

Volume

1

fYear

2002

fDate

2002

Firstpage

137

Abstract

A special requirement of the voltage regulator module (VRM) is fast transient response with tight output voltage tolerance. This paper investigates the relationship between the control bandwidth and the transient response in buck converters in both voltage and current mode controls. A critical bandwidth value is discovered, beyond which pushing the bandwidth can no longer reduce the output voltage spike during the transient. This critical bandwidth is determined by the characteristics of the output filter bulk capacitor. In order to reduce the size and improve the transient response of the VRM, better capacitors with low equivalent series resistance (ESR) show that high control bandwidth and high switching frequency are the trends for new designs. Simulation and experimental results prove the theoretical analysis, and a design guideline is proposed for the VRM.

Keywords

DC-DC power convertors; capacitors; electric current control; switching circuits; transient analysis; transient response; voltage control; voltage regulators; buck converters; control bandwidth; critical bandwidth value; current mode controls; fast transient response; high switching frequency; low equivalent series resistance; output filter bulk capacitor; output voltage spike reduction; tight output voltage tolerance; transient; voltage mode controls; voltage regulator module; Bandwidth; Buck converters; Capacitors; Filters; Paramagnetic resonance; Regulators; Size control; Switching frequency; Transient response; Voltage control;

fLanguage

English

Publisher

ieee

Conference_Titel

Power Electronics Specialists Conference, 2002. pesc 02. 2002 IEEE 33rd Annual

Print_ISBN

0-7803-7262-X

Type

conf

DOI

10.1109/PSEC.2002.1023859

Filename

1023859