A Current-Mode Hysteretic Buck Converter With Multiple-Reset RC-Based Inductor Current Sensor

A current-mode hysteretic buck converter is described in which inductor current is sensed by a resistor-capacitor (RC) network. The inductor current sensing RC network is reset multiple times per switching clock period, which allows it to have time constant much smaller than switching clock period and therefore occupy small silicon area. A frequency regulator ensures the switching frequency to be constant regardless of the operating condition of the buck converter and also integrates comparator delay compensator as its loop filter. The current-mode hysteretic buck converter implemented in a 65 nm complementary metal-oxide-semiconductor (CMOS) process provides 0.6-2.0 V output from 3.3 V input with 1 MHz switching frequency. The maximum load current is 1.5 A and the measured peak power efficiency is 96.3%.