A CMOS Low Drop out Voltage Regulator

This work presents the implementation of a CMOS Linear Voltage Regulator (LVR) used to power up bio-implanted systems. The topology is based on a classical structure of a Low Dropout Regulator (LDO) and receives his activation energy from a RF link characterizing a passive RFID tag. The LVR was designed to achieve important features like low power consumption, and a small silicon area without the need for any external discrete components. The low power operation represents an essential condition to avoid a high energy RF link, thus minimizing the power of the transmitter and the thermal effects on the patient tissues. The project was implemented in a 0.35μm CMOS process and a prototype was tested to validate the overall performance. The LVR output is regulated at 1V and supplies a maximum load current of 0.5mA @ 37°C. The load regulation is 13mV/mA and the line regulation is 39mV/V. The LVR total power consumption is 1.2mW.