AN INTEGRATED GAS-FLOW SENSOR WITH HIGH-SENSITIVITY, LOW RESPONSE-TIME AND A PULSE-RATE OUTPUT

Silicon integrated flow sensors based on a thermal operating principle are widely known. Major disadvantages of conventional thermal flow se nsors are the low output signal voltages, as well as high response tim e. A sensor based on a constant temperature operating principle, calle d the thermal sigma-delta modulation technique, highly reduces those d rawbacks. 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.