Wireless power transfer and a Dual-Slope ADC design for Battery-less TPMS

A 13.56MHz 3w RF power was transferred up to 43cm for Battery-less-Tire Pressure Monitoring System (TPMS) with CMOS technologies. The diameter of transmitting antenna coil for the 3W 13.56MHz Power Transmitter is 40cm, and the receiving antenna coil for the Monitoring Module is of the same size and installed inside tire. The power recovery circuit converts received RF power to DC power of 2.88V continuous output voltage with a periodic 9.6mA output current which lasts 18.3ms per 95ms, which driving the Infineon SP30 including modules such as Pressure Sensor, A/D, MCU and 433MHz Data Transmitter. A Dual-Slope ADC is designed for transforming the analog signal from pressure sensor to digital signal. Simulation results show that the analog part of the ADC operates normally at a typical output of the sensor.