A Low Voltage-High Efficiency CMOS Rectifier For Low Power Battery-Less System

With the rapid development of microelectronics, high performance lowpower battery-less devices such as biomedical implant devices play a moreand more important role in modern medical treatments and internet of thingssuch as measurement of internal blood pressure, monitoring of organs, cardiacpacemaker transplant, field building detection. These kinds of devices must besmall in size which should meet the requirement of medical implant.Meanwhile, low voltage and low power are also important factors to extendthe devices'service life.All those devices should translate AC voltages to DC voltage to power theloading system. In this conversion process, rectification is the most importantpart on which the whole system's efficiency and supply voltage depend. Inbattery-less system, the supply voltage is commonly at a low level.Traditional diode rectifier cannot work in these low voltage systems. Thus,the development of low voltage rectifier is significant to the whole industry.This thesis presents a low voltage CMOS full-wave rectifier fortranscutaneous power transmission in low power battery-less system. Byusing a simple comparator-controlled switch which needs a small supplyvoltage, the lowest input voltage amplitude can be reduced to 0.7V with astandard CMOS 0.18um process. With only one comparator, the proposeddesign dramatically reduces the the power loss and the production cost. Incombination with current offset which minimize the reverse current of therectifier under different input amplitudes, the proposed rectifier can achieve amaximum peak voltage conversion efficiency of more than 93% and a power efficiency of approximately 87%. The chip area is only 0.21mm2. All theseaspects are better than previous researches.