| 摘要 |
PURPOSE:To prevent detected temperature from being affected by the offset voltage of a comparator by inhibiting a current due to the offset voltage of the comparator from flowing to a resistance connected between the plus input and minus input of the comparator by a diode when the output of the comparator is inverted. CONSTITUTION:The output of the comparator 11 is inverted when the potential difference between the plus input and minus input reaches a voltage called the offset voltage. Therefore, a variable resistance RA corrects a reference voltage inputted to the minus input of the comparator 11 by the offset voltage so that the output of the comparator 11 is inverted when the ambient temperature of a temperature sensing element RTH reaches, for example, T1 deg.C, namely, when the resistance value of the temperature sensing element RTH reaches RTH. Thus, the variable resistance corrects the reference voltage is corrected by the offset voltage and then a microcomputer 12 when to detect the temperature of the temperature sensing element RTH to the T1 deg.C places only an output terminal 1 in high-voltage voltage and other output terminals 2 and 3 in low-voltage operation to turn on a transistor (TR)Q11 and turn of TRs Q12 and Q13.
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