A High Efficiency FLL-Assisted Current-Controlled DC-DC Converter Over Light-Loaded Range

作者：Lan Po Hsiang^*; Huang Po Chiun

来源：IEEE Transactions on Circuits and Systems I-Regular Papers, 2012, 59(10): 2468-2476.

DOI：10.1109/TCSI.2012.2188937

• Current-mode controlled DC-DC converter
• frequency-locked loop (FLL)
• off-time modulation
• on-chip current-sensing circuit

Current mode control is widely used in the switching power supply designs because of its fast response and less stability concern. However its performance at light load condition is limited by the precision of current sensing. In this work, instead of using high speed current sensor, a frequency-locked loop (FLL) is incorporated to extend the operation range with high power efficiency using a single controller. The 1.8-V output DC-DC converter has been fabricated with a standard 0.35-mu m CMOS process and supplied from 2.7 to 4.3 V. Experimental results show that this switching converter operates from 100 to 600 kHz with the efficiency higher than 90% for the load current between 25 and 450 mA. The output voltage ripple is smaller than 30 mV with a 4.7-mu H inductor and a 4.7-mu F capacitor.

• 出版日期2012-10
• 单位清华大学