Low-Ripple and Dual-Phase Charge Pump Circuit Regulated by Switched-Capacitor-Based Bandgap Reference

Abstract

This paper proposes a low-ripple and dual-phase charge pump circuit regulated by switched-capacitor-based bandgap reference. Due to design of a buffer stage, a system can have better bandwidth and phase margin, and thus, the transient response and driving capability can be improved. Besides, the dual-phase control can reduce the output voltage ripple by means of only one closed-loop regulation in order to improve the power conversion efficiency. Besides, the proposed automatic body switching (ABS) circuit can efficiently drive the bulk of the power p-type MOSFETs to avoid leakage and potential latch-up. Usually, the regulated charge pump circuit needs a bandgap reference circuit to provide a temperature-independent reference voltage. The switched-capacitor-based bandgap reference circuit is utilized to regulate the output voltage. This chip was fabricated by Taiwan Semiconductor Manufacturing Company (TSMC) 0.35 mu m 3.3 V/5V 2P4M CMOS technology. The input voltage range varies from 2.9 to 5.5 V, and the output voltage is regulated at 5 V Experimental results demonstrate that the charge pump can provide 48 mA maximum load current without any oscillation problems.