Capacitance diagnosing circuit for capacitor

Abstract

Abstract PURPOSE:To enable an easy detection of capacitance without separating a capacitor from a power source circuit by detecting a circuit voltage in a charging resistance of a backup power source circuit after the closing of a power source switch to be compared with the reference voltage waveform. CONSTITUTION:A voltage withdrawing circuit 8 is connected to the connection point 9 on the negative pole side of a backup capacitor 3 to extract changes in the terminal voltage of a charging resistance 4. On the other hand, a reference voltage generation circuit 15 is connected to the output terminal O point the same with a voltage detection circuit 14 and the voltage equal to the circuit 14 is applied to be charged into the capacitor 3. A CR constant is set on the circuit 15 in conformity to a charge curve of the capacitor 3 and a diminishing waveform is outputted. Therefore, when output value of the circuit 14 is smaller than the output value of the circuit 15, namely, the capacitance of the capacitor 3 is smaller, a comparator 25 produces an output at the output terminal R and outputs a signal U to an alarm through a buffer circuit 28. Thus, the detetion of catapcitance can be done easily with the capacitor left on the power source circuit.

Inventors

• 👤 Osamu Ono
• 👤 治 小野

Bibliographic Details