Title :
On-chip current sensing circuit for current-limited minimum off-time PFM boost converter
Author :
Kim, Yeong-Seuk ; No, Bo-Mi ; Jun-Sik Min ; Al-Sarawi, Said ; Abbott, Derek
Author_Institution :
Sch. of Electr. & Electron. Eng., Univ. of Adelaide, Adelaide, SA, Australia
Abstract :
An on-chip current sensing circuit for current-limited minimum off-time pulse frequency modulation (PFM) boost converter is designed and verified by SPICE simulations. The current mirror pair, power and sensing MOSFETs with size ratio of K, is used in our on-chip current sensing circuit. Very low drain voltages of the current mirror pair should be matched to give accurate current sensing, so a folded-cascode opamp with a PMOS input pair is used in our design. Simulation results show that current sensing is accurate with properly frequency compensated opamp; over-compensation results in inaccuracies in current sensing.
Keywords :
current mirrors; integrated circuit design; operational amplifiers; power MOSFET; power convertors; pulse frequency modulation; PMOS input pair; SPICE simulation; boost converter; current mirror pair; current-limited minimum off-time; folded-cascode operational amplifiers; on-chip current sensing circuit; power MOSFET; pulse frequency modulation; sensing MOSFET; Circuit simulation; Flip-flops; Frequency conversion; Frequency modulation; MOSFETs; Pulse width modulation; Pulse width modulation converters; Strontium; Switching frequency; Voltage; Boost converter; current-limited; current-sensing circuit; minimum off-time; pulse frequency modulation;
Conference_Titel :
SoC Design Conference (ISOCC), 2009 International
Conference_Location :
Busan
Print_ISBN :
978-1-4244-5034-3
Electronic_ISBN :
978-1-4244-5035-0
DOI :
10.1109/SOCDC.2009.5423823
