An ultra-low power RF interface for biomedical implantable devices

This paper presents an efficient radio frequency (RF) front-end for power and data telemetry in biomedical implantable devices. The fully integrated system includes an amplitude shift keying (ASK) demodulator, a low drop out (LDO) voltage regulator and a charge pump voltage rectifier. This paper presents a rectifier structure based on Dickson charge pump. Simulation results show that this rectifier can provide 1.4 Voltage supply at a PCE of 33.4%. The rectifier consumes 80µW. The demodulator utilizes an ultra- low power envelope amplifier that removes the need for any voltage comparator or Schmitt trigger circuit, With a carrier frequency of 13.56 MHz and 40 Kbps data rate. The proposed ASK demodulator achieves a modulation index range from 38% consuming less than 32µW. The low drop out regulator can provide a maximum current of 2.8 mA and output voltage of 1.2 V and drop out voltage is 200mV. LDO temperature variation is 2.4µV/˚C. The LDO consumes only about 76µW. Designed in a 0.18 µm CMOS process, the system totally consumes 200µW.