Patent ID: 8305084

Claim:
A voltage measuring apparatus for measuring an output voltage of an assembled battery in which a plurality of unit cells are connected in series and are divided into a plurality of blocks, the voltage measuring apparatus comprising: a block voltage detection section which detects a voltage of at least one of the plurality of blocks and provides an analog voltage signal; a reference power supply which generates a reference voltage for A/D conversion; a sampling voltage generation section which generates a sampling voltage based on the reference voltage; a storage for storing voltage data corresponding to the sampling voltage; an A/D conversion section which is arranged in the block voltage detection section and digitizes the analog voltage signal with the reference voltage for A/D conversion and digitizes the sampling voltage with the reference voltage for A/D conversion; a voltage comparing section which compares the digitized sampling voltage with the voltage data stored in the storage; and an abnormality determining section which calculates a difference between the digitized sampling voltage and the voltage data and determines that abnormality occurs in the A/D conversion section when the difference is larger than a threshold.