Patent ID: 9748789
Date: 2017-08-29
CPC Classifications: H02H,H02J

Claim:
1. A charging/discharging control circuit comprising: a control circuit that detects a voltage and abnormality of a secondary cell; and an over-current detection circuit that detects an over-current with a voltage of an over-current detection terminal, wherein the over-current detection circuit includes: a reference voltage circuit that includes a constant current circuit, a first resistor, a switch between the constant current circuit and the first resistor, and a transistor having a resistance value that varies with a voltage of the secondary cell, the reference voltage circuit outputting a voltage that is generated due to the flowing of a current of the constant current circuit to the resistor and the transistor, the over-current detection circuit further including a first comparator circuit that compares the voltage of the over-current detection terminal with the voltage of the reference voltage circuit and having an output connected to the control circuit, and a second comparator connected to the over-current detection terminal and to a second reference voltage circuit and having an output connected to the switch, wherein the second comparator is configured to output a signal from the over-current detection terminal to turn on the switch when a potential difference between the secondary cell and the over-current detection terminal is greater than a voltage of the second reference voltage circuit.