An integrated 10MHz 3 States Buck converter for fast transient response in 180nm CMOS

This paper presents a three-state buck converter using a "bypass" state which role is to reduce the amount of energy in the inductor by cutting it off the circuit. The addition of that state makes the converter behave as an order 1 system and thus achieves automatic and seamless loop transition during load transient to achieve small voltage under/overshoot and short recovery time. The proposed chip has been implemented in CMOS 0.18 um and uses 2.25 mm
²
area. A 88 % peak efficiency is achieved over 0 to 1A range of load at 1.2 V output voltage. It responds to a 1A load transient in 300 ns while switching at 10 MHz, with a 20mV overshoot.