| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a drive circuit for a heat radiation type flow sensor which achieves a strong EMI resistance. <P>SOLUTION: A heater resistance 1 is connected to an emitter terminal of an NPN transistor 2, while a resistance 3 is connected to its collector terminal. An electric potential between the emitter terminal of the NPN transistor 2 and the heater resistance 1 is inputted to an inverting input terminal of an operational amplifier 4, while a constant voltage Vr is inputted to its non-inverting input terminal. An output potential of the operational amplifier 4 is set to be a base voltage of the NPN transistor 2. The drive circuit having the foregoing structure allows the electric potential between the emitter terminal of the NPN transistor 2 and the heater resistance 1 to be inputted to the inverting input terminal of the operational amplifier 4 and allows the constant voltage Vr to be inputted to its non-inverting input terminal. In other words, the drive circuit for the radiation type flow sensor is constructed of a structure having only a negative feedback circuit. This allows the drive circuit for an airflow sensor to stably function and provides the drive circuit with the strong EMI resistance performance. <P>COPYRIGHT: (C)2006,JPO&NCIPI</p> |
