Patent attributes
There is provided an abnormality detection apparatus for a secondary battery device having n secondary batteries (where n is 2 or more) connected in series for obtaining a high battery voltage. The apparatus includes n voltage detecting circuits which outputs high-level signals at a normal voltage between both terminals of each of the n secondary batteries, n N-channel field effect transistors having gates to which outputs of the n voltage detecting circuits are respectively supplied, and n P-channel field effect transistors having gates to which drain voltages of the n N-channel field effect transistors are respectively supplied. In the n P-channel field effect transistors, a drain of a P-channel field effect transistor is connected to a source of the next P-channel field effect transistor successively, thus detecting an abnormality by a voltage obtained at a drain of the n-th P-channel field effect transistor.
