Fast-transient DC-DC converter with hysteresis prediction voltage control

This study presents a hysteresis prediction voltage control (HPVC) technique based on a predictive control method with early actions to solve ringing circumstances and to alleviate transient ripples. A dc-dc converter switches from a voltage-controlled pulse width modulation mode to the proposed HPVC mode during transient. Hence, the dc-dc converter has a fast transient response when its load current varies. The converter also keeps constant switching frequency during the steady state. The ringing, recovery time and transient ripples can be effectively reduced without paying a price of increasing the output capacitor of the power converter. A prototype chip with the proposed HPVC technique was implemented in a 0.35-μm CMOS technology. The experimental results show that the recovery time is less than 10 μs for a 400-mA load current change.