Low power low-dropout voltage regulator (LDO) with fast load transient response

Abstract

With the recent explosion of devices driving “smart technologies” such as tablets, phones, all the portable and hand-held electronic devices such as cellular phones, PDA, MP3 players, GPS and other multi-media entertainments. The target for the portable battery operated product is towards reducing the number of battery cells, in order to decrease the cost and size. All these battery operated devices need power management circuits to work efficiently and extend the battery life, thus power regulation and power management have become one of the fastest growing sectors in the industry.The goal of this project is to design and implement a low power fully integrated CMOS low-dropout voltage regulator (LDO) based on quick response (QR) circuit to improve the load transient response. A 2.5V, 150mA with proposed high speed response circuit has been implemented in 0.25µm TSMC CMOS technology. The low-voltage operation ability, high current efficiency and low-voltage transient response performance can be achieved. With the small on-chip decoupling capacitor, the LDO with proposed QR circuit can achieve a fast load transient response with less transient overshoot or undershoot when instantaneous load fluctuation. By using the PMOS pass gate in the output stage we achieved a small regulator area and minimum dropout voltage for 100~150mA of output current. The proposed high speed response circuit included Memory circuit, PD_Charge and PD_Discharge circuit, Comparator and Vout_Discharge circuit.