A Low Current Power-up Algorithm and Circuits for Charge Pump under Harsh Wireless Power Transfer Systems using Adaptive Ramp Control

In this paper, we present a low current power-up algorithm and circuits for charge pump under harsh wireless power transfer system using adaptive ramp control. In order to reduce peak current consumption, adaptive power-up ramp control (APRC) is suggested with variable pumping clock control. In addition to an ADC for output voltage sensing and quantization, a low-current timer oscillator and state machine are used to prevent power-up fail under unstable wireless power transfer environment. With these improvement, output voltage of 10V is secured with a peak current as low as 0.17mA in the entire charge pump operation. The proposed charge pump is designed and confirmed using $0.18 \mu \mathrm{m}$ CMOS technology. It occupies 085mm
²
, and shows 15.3% of power efficiency with supply voltage of 3.3V