Patent ID: 6377429
Filing Date: 2002-04-23
Classification: H02J

Abstract:
A protective circuit for protecting a rechargeable battery through which a charge or discharge current can flow, this protective circuit including:measuring means adapted to be connected in series with said battery and to provide a measuring voltage representative of said current, said measuring voltage being able to have a first temperature dependence; detection and comparison means adapted to receive said measuring voltage and a reference voltage and to generate a control signal in response to a comparison of said reference and measuring voltages, said reference voltage being able to have a second temperature dependence; and interruption means adapted to control the flow of said current through said battery in response to said control signal, wherein said detection and comparison means include adjustment means for compensating said first temperature dependence of the measuring voltage and/or said second temperature dependence of the reference voltage, said detection and comparison means including: means for generating first, second, third, fourth and fifth diode voltages, and calculating means including capacitive elements and switching elements to connect selectively and sequentially, during a first and a second phase, said capacitive elements to said means for generating said diode voltages and to terminals to which are applied said measuring voltage and said reference voltage, so that said calculating means generate said control signal during said second phase, said adjustment means generating a compensation value defined from the sum: of the product of the difference between said first and second diode voltages by a first determined coefficient, and of the product, by a second determined coefficient, of the sum of said third diode voltage and the product of the difference between said fourth and fifth diode voltages by a third determined coefficient, said control signal being representative of the sum of the difference between said reference voltage and said measuring voltage, and of said compensation value.