THERMAL MASS FLOW SENSOR CAPABLE OF OBTAINING PRECISE MEASUREMENT SENSITIVITY WITHIN A WIDE FLOW RATE RANGE

摘要

PURPOSE: A thermal mass flow sensor is provided to vary only a voltage supplied to a heating unit, thereby obtaining precise measurement sensitivity without changing the structure of a basis thermal mass flow sensor.;CONSTITUTION: A thermal mass flow sensor includes a thin film (110), a heating unit (120), first and second thermopiles (131, 132), a control unit (140), and a voltage converter (150). The heating unit is formed on the thin film. The first and second thermopiles connect thermocouples on the upper and lower streams of the heating unit in a row. The control unit varies a heater output of the heating unit, thereby generating heater output controlling signals varying intervals of the first and second thermopiles and the heating unit. The voltage converter varies an output voltage supplied to the heating unit according to the heater output controlling signals generated by the control, thereby supplying to the heating unit.;COPYRIGHT KIPO 2013