Patent ID: 8248744
Filing Date: 2012-08-21
Classification: G01R

Abstract:
1. A voltage detecting apparatus comprising: a direct-current power source insulated from a ground electric potential; a flying capacitor storing an electric charge from the direct-current power source; an input device constituted of a first input device and a second input device, the first input device being disposed between one terminal of the flying capacitor and a positive electrode of the direct-current power source, and the second input device being disposed between the other terminal of the flying capacitor and a negative electrode of the direct-current power source; a voltage divider dividing a voltage across the flying capacitor; a voltage detecting device connected to a ground electric potential and detecting the voltage across the flying capacitor divided by the voltage divider, an output device constituted of a first output device and a second output device, the first output device being disposed between one terminal of the flying capacitor and a positive electrode of the voltage detecting device, and the second output device being disposed between the other terminal of the flying capacitor and a negative electrode of the voltage detecting device wherein the input device has a current limiting device for preventing more than a prescribed current from flowing into the input device, wherein the voltage divider is constituted of a first resistor (R wherein a first protective device is arranged between a positive electrode of the direct-current power source and the ground electric potential to prevent more than a prescribed voltage from applying to the first resistor and the voltage detecting device, wherein a second protective device is arranged between a negative electrode of the direct-current power source and the ground electric potential to prevent more than a prescribed voltage from applying to the second resistor, wherein the first protective device and the second protective device are placed after the first output device and the second output device, and wherein the first protective device is arranged in parallel with the first resistor of the voltage divider, and the second protective device is arranged in parallel with the second resistor of the voltage divider.