| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve the quietness and energy saving of a fan by sensitively controlling the driving of the fan corresponding to temperature. <P>SOLUTION: The fan driving control circuit 1 is constituted of a temperature detecting circuit 2 having a thermistor Rt with which a resistance value changes corresponding to ambient temperature, and outputting the temperature-corresponding voltage Vt of the thermistor Rt, an analog voltage circuit 3 for outputting an analog voltage Vref, and an amplification circuit 4 for comparing the temperature corresponding voltage Vt with the analog voltage Vref, and supplies the output of the amplification circuit 4 to the fan. The amplification circuit 4 includes an operational amplifier U1, a transistor Q1, a feedback circuit 4a, and a diode D1 connected so that a direction returning to the feedback circuit 4a is forward. Thus, when the ambient temperature is lower than a predetermined temperature, the fan is stopped, and when the ambient temperature is the predetermined temperature or higher, the fan is driven and the rotational speed of the fan can be controlled in proportion to the ambient temperature. <P>COPYRIGHT: (C)2004,JPO |
