Integrated up/down switched capacitor converter with full digital feedback control and output voltage regulation

The paper presents a multi-topology up-down switched-capacitor (SC) converter with a novel full digital control. Load regulation is performed by frequency modulation technique, along with low power feedback control block, providing high conversion average efficiency of 90% for all conversion ratios. The converter achieves 55ns average start-up settling time and 17mV of maximal output ripple over 100mA of load currents. An output voltage regulation circuit is implemented to maintain steady output voltage level over wide range of input battery voltage variations. The converter is designed in 28nm CMOS process using the proposed technique.