| 摘要 |
PROBLEM TO BE SOLVED: To correctly detect an automatic extinguishment temperature and disconnection of a thermistor by correctly detecting temperatures in a wide range with the use of the thermistor. SOLUTION: A plurality of resistors R1 , R2 , R3 are set to be connected in series with a thermistor TH. The resistors are changed over in accordance with a temperature of the thermistor. A temperature is detected from a divided voltage obtained by the thermistor TH and the resistor connected in series with the thermistor. Resistors R4 , R5 connected at both ends of the thermistor TH are switched in accordance with whether a pulse signal is Hi or Lo, thereby obtaining two kinds of divided voltages at the low temperature side and high temperature side by the thermistor and the resistor connected to the thermistor. The divided voltages are compared with set temperatures at the low temperature side and high temperature side, whereby a temperature is detected. |
