Patent ID: 9081069
Filing Date: 2015-07-14
Classification: G01R

Abstract:
1. 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 a 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 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, and includes a plurality of first transistors, each of which drain is connected to a terminal connected to one end of the cell groups through a resistor, each of which source is connected to a terminal connected to another end of the cell groups through a current generator, and each of which gate is connected to the connection point of the plurality of cells of the cell groups and an end of the cell groups, the first transistor causes a drain current to be decreased, the drain current being decreased by a voltage drop or a current decrement in the plurality of connection points of the cell groups and an end of the cell groups, a plurality of second transistors which are arranged in series between the terminals connected to the both ends of the cell groups, each of which gate is connected to the drains of the first transistors, and which is turned off due to the decrement of the drain current, and a second logical circuit which generates the second alarm signal by turning off at least one of the plurality of second transistors.