A CMOS Linear power supply for a Wireless Biomedical Sensor

This paper describes a CMOS Linear Voltage Regulator (LVR) of an implanted physiological signal system (biosensor) that is used to monitor blood pressure. This system is part of a Wireless Biomedical Sensor (WBS). The LVR topology is based on a classical structure of a Low Dropout Regulator (LDO). The energy is received from a RF link, thus operating as 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's tissues. It was implemented in a 0.35 μm CMOS process and the prototypes were tested to validate the overall performance.