A new transponder architecture for long range telemetry applications

This report presents a new architecture that can achieve long range wireless power and high data rate data telemetry. The architecture described in the report achieves long range operation with a fully CMOS compatible integrated circuit, unlike current state-of-the-art methods, and can be used in various applications such as long range passive RFID device, wirelessly power sensors and sensor networks. An RF-to-DC converter rectifies the incident RF signal and stores it on a storage capacitor. The voltage stored on the capacitor is used as the supply for the rest of the system blocks. The RF-to-DC converter generates DC output voltages much higher than the incident RF signal amplitude. The converter needs -12.3 dBm of incident RF power to generate a 3VDC supply voltage. This corresponds to an operational range of more than 18.3 meters.; A low power mode selector circuit constantly monitors the voltage stored on the storage capacitor and generates an enable signal when there is enough voltage stored to operate the system blocks. The system is enabled when the voltage on the capacitor exceeds a high threshold and is disabled when it drops below a lower threshold.; A new system clock generation scheme is proposed in this architecture. A fully integrated LC oscillator injection locked to the incident RF signal is used to extract a system clock in synchronization with the base station. The LC oscillator generates high purity system clock with low power consumption.; Three prototypes have been designed based on this architecture. All devices are fabricated in TSMC 0.25mum mixed-mode process. The first one is a long range RFID device that transmits an 8-bit ID on an AM modulated 900 MHz carrier at 56 Mbits/sec. The second one is a wireless temperature sensor, which transmits the ambient temperature information as a shift of the 2.3 GHz carrier. The sensor has 126ppm/°C sensitivity with 0.983 linearity. The third prototype is a long range telemetry device with an integrated ADC. It transmits a combination of the output of a 5-bit ADC and a 3-bit ID word on a BPSK modulated 900 MHz carrier at 8Mbits/sec.