A New Charge Control Circuit

With the increasing development of the power electronic technology, the charging management IC (integrated circuit) has been developing towards high integration, high performance-price ratio and high-efficiency. Thin, light and ultra small charging power modules and more efficient green products with less pollution will be favorable in the twenty-first century. Based on the chargable baterry's charaterastic, this paper designed a new type charging control circuit with high stablility, low power consumption, high control ability, sensitivity and reliability by using CMOS technology.The architecture is simple, with high respond speed, high stability and adopts very advanced charging termination methods such as -△V, max voltage, max temptature and temptature change rate so its reliability and safety are very high. Co-operated with the controllable current limiter or constant current source, not only can it be made high quality and low price independent charger, but also in-machine charger. This circuit can realize the fast charge to one or more nickel cadmium or nickel metal hydride batteries. For safe and full charge, after the charging is finished, charger will change into trickle charge process automatically and the trickle charge rate can be chosen according to battery's self discharge amount. So this circuit can be used in the CMOS nickel cadmium or nickel metal hydride batteries charging controller.In this dissertation, the charging battery's development,principle and various charging termination methods are given firstly, then the circuit architecture is designed according to its function requirements. All the sub-blocks circuits are designed and stimulated by Cadence and Hspice. The results indicate the fulfillments of all performance merits.