Temperature sensor based on relativity between self-oscillation in FPGA and temperature

Temperature is an important parameter that needs to be monitored in IMU and other navigation devices. Thermocouple or digital temperature sensor (such as DS18B20) is usually used in temperature detecting, so a highly integrated and low-cost temperature detecting design in FPGA is important. In this paper, the self-oscillation signal was generated by ring oscillator set up in FPGA and its period had positive relativity with the FPGA's temperature, so the temperature could be gotten by detecting the period of self-oscillation signal. In the end, a temperature sensor using FPGA as both sensing part and processing part was designed. Experiments on the FPGA chip of series Virtex-2 from Xilinx show that the resolution is better than 0.1°C and the accuracy is better than 0.5°C within -40°C~+60°C, which can satisfy the general requirement in monitoring temperature. The temperature sensor is low-cost, highly integrated and highly reliable.