Title :
Design of high output current, high switching frequency current mode buck DC-DC regulator in WLCSP for portable applications
Author :
Bin Shao ; Liu, Bill
Author_Institution :
State Key Lab. of ASIC & Syst., Fudan Univ., Shanghai, China
Abstract :
The paper introduces a high output current and high switching frequency buck DC-DC regulator with gate scaling function to improve the efficiency at light load together with reduced output voltage ripple and noise. External FET driver is also implemented as an option to move the excessive heat from inside the chip for thermal sensitive applications. A fast current sensing loop method is used to minimize the limitation of minimum on time of the conventional current mode buck converter. A guardring strategy for power MOSFET to prevent the latch up and minority carrier injection is also discussed. It is fabricated in TSMC 0.35 um CMOS process with dual-poly and quad-metal. The WLCSP (Wafer Level Chip Scale Package) is used to minimize the parasitic, as well as to reduce the board size in application. The measurement result reaches nearly 85% efficiency at 2A load current when input voltage is 3.6V and output voltage is 1.1V.
Keywords :
CMOS integrated circuits; DC-DC power convertors; chip scale packaging; current-mode circuits; driver circuits; field effect transistors; wafer level packaging; CMOS process; WLCSP; current 2 A; current mode buck DC-DC regulator; current sensing loop method; external FET driver; gate scaling function; guardring strategy; minority carrier injection; size 0.35 mum; switching frequency; voltage 1.1 V; voltage 3.6 V; voltage ripple; wafer level chip scale package; Driver circuits; FETs; Logic gates; Power MOSFET; Regulators; Sensors;
Conference_Titel :
Solid State Circuits Conference (A-SSCC), 2010 IEEE Asian
Conference_Location :
Beijing
Print_ISBN :
978-1-4244-8300-6
DOI :
10.1109/ASSCC.2010.5716560
