| 摘要 |
PROBLEM TO BE SOLVED: To provide a capacitance detecting device and a deterioration detecting device that can diagnose with high precision the deteriorated state of a capacitor from the variation of its capacitance value from the initial capacitance of the capacitor.SOLUTION: A capacitance detecting device is equipped with a Schmitt trigger circuit 21 to which a voltage on the high potential side of a capacitor 10 is inputted, an integrator 22 that integrates the output of the Schmitt trigger circuit, a comparator 23 that compares the output of the integrator with a reference voltage, an oscillator 25 that outputs a pulse of a prescribed duty ratio, an RS flip flop 26 that receives the output of the comparator 23 as its reset input and the output of the oscillator 25 as its set input, an OR gate 27 to which the output of the RS flip flop and the output of the oscillator 25 are inputted, and a resistor 28 connected between the output side of the OR gate and the high potential side of the capacitor 10. The detecting device causes the OR gate 27 to output a pulse of a width proportional to the capacitance value of the capacitor 10 by making the amplitude of the output voltage of the OR gate 27 slightly smaller than the high potential side threshold of the Schmitt trigger circuit 21.SELECTED DRAWING: Figure 1 |
