| 摘要 |
PURPOSE:To detect the abnormality of a temp. sensor without degrading its temp. detecting resolving power by providing an amplifier which amplifies the output voltage of the temp. sensor, and detecting the abnormality of the temp. sensor from the input voltage of this amplifier. CONSTITUTION:A voltage amplifier 3 is inputted with the detecting voltage VA at the connection point (a) of a thermistor 1 and a resistance 2, amplifies this and outputs output voltage VB. On the other hand, the detected voltage VA for abnormality of the sensor 1 is taken from the input side of the amplifier 3. The resistance value of the sensor 1 does not go to 0OMEGA in a practicable measurement temp. range, and outputting of VCC does not occur when the voltage VA is normal. Hence, abnormality is easily detected from the attainment of VCC by the voltage VA only when the sensor 1 is shorting. In case the sensor 1 is disconnected, the detected voltage goes to 0V. In this case, the case when the maximal voltage is generated is decided as a shortcircuit, and the case when the minimal voltage is generated as a disconnection. The resolving power and control characteristics of temp. measurement are improved by taking the practicalbe range relatively narrow. |
