| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a thermal flow-rate sensor capable of obtaining a digital output, having a high resolution, as well as responding very quickly as a sensor output. <P>SOLUTION: The thermal flow-rate sensor includes a heating resistor 1 heating by a supplied heating current, a temperature detector 2 for a heating element, varying a resistor value thereof, in response to the temperature of the heating resistor 1, and a bridge circuit 100 containing a temperature detector 3 for fluid, varying a resistor value, in response to the temperature of the fluid. The thermal flow rate sensor, further comprises a comparator 81 for digitally outputs the difference between midpoint voltages in a bridge circuit 100; a D/A converter 63 for converting the outputs of the comparator 81 into an analog signal and supplying the analog signal to the heating resistor 1 as a heating current; and an output operator 82 for integrating the outputs of the comparator 81, during a given period and outputting the integration result as a flow rate of the fluid of the object during the given period. <P>COPYRIGHT: (C)2007,JPO&INPIT</p> |
