Abstract
With the rapid development of portable electronic products, the development of low-power circuit to extend battery lifetime has become a major issue today. At the same time, in order to effectively use the limited battery energy distribution, power management system definitely plays a vital role. For system-on-chip（SoC）power management IC, it must be able to provide back-end needed for each sub-circuit of different voltage and load current. Low dropout linear regulator, based on its advantage of simple structure, low noise, and fast response time, becomes a very important and widely used unit. Conventional low dropout linear regulators use certain compensation that is with an external capacitor connecting a parasitic resistor in series. However, the gain and dominant pole location will change with the loading so this technique is manifestly complicated for compensation. Secondly, a capacitor of a few □F occupies large circuit area so that it can not be physically integrated on the chip. Researching a capacitor-free LDO, therefore, will help the purpose of implementing fully SoC power management. This study proposes the employment of a current feedback compensation design to eliminate the need of external capacitors for low dropout linear voltage regulators. And the design will be applied for low-power sensor interface ICs with 1.2V to 3.3V supply voltage. The regulator provides an output voltage of 1V as well as a maximum output current of 50mA. Finally, the circuit is implemented in TSMC 0.35μm 2P4M CMOS process.