Research on an ultra-low power thermoelectric-type anemometer

Beyond the conventional hot-wire sensor, a new thermoelectric sensor with ultra-low power consumption without heating is proposed. Using the TSMC 0.35 um CMOS-MEMS process, the thermoelectric sensor is fabricated with 32 pair of central-symmetrical thermocouples positioned. When the fluid passes through the thermopile, the fluid will take away the heat, so that a temperature difference is generated between the cold end and hot end of the thermocouples. The temperature sensor is calibrated and senses the drop of temperature at the center of membrane during the measurement. For different flow velocities, it is interesting to find that the drop of temperature is verified by the output voltage of sensing circuit from thermopile and the same for temperature sensor which behaves as a function of flow velocity. The new approach for the anemometer of sensing flow velocity is realized by our proposed thermopile which is proved to be a practical technique with ultra-low power consumption.