An integrated gas flow sensor with high sensitivity, low response time and a pulse-rate output

Abstract Silicon integrated flow sensors based on a thermal operating principle are widely known. Major disadvantages of conventional thermal flow sensors are the low output signal voltages, as well as high response time. A sensor based on a constant temperature operating principle, called the thermal sigma-delta modulation technique, highly reduces those drawbacks. The output signal of the presented smart thermal flow sensor is a TTL-compatible pulse-rate modulated voltage. A 10-bit resolution can be obtained within 20 ms.