Protection ic and method of monitoring a battery voltage

A protection IC which is connected to cell groups of a secondary battery assembly formed by connecting a plurality of cell groups, in which a plurality of cells of a secondary battery are connected in series, and monitors battery voltages of the plurality of cells in the cell groups, the protection IC comprising:

• a plurality of terminals which are connected to connection points of the plurality of cells in the cell groups and both ends of the cell groups;
• a first alarm generating portion which detects an overvoltage by comparing voltages of the plurality of cells of the cell groups on both ends of the plurality of cells and generates the first alarm signal;
• and
• a second alarm generating portion which detects disconnection in connection points of the plurality of cells of the cell groups and disconnection between the connection points of the plurality of cells of the cell groups and the both ends of the cell groups and the plurality of terminals by detecting a voltage drop or a current decrement at the connection points of the plurality of cells of the cell groups and at one end of the cell groups in the plurality of cells of the cell groups, and generates a second alarm signal.