摘 要
本文采用电流控制专用芯片NCP1200A，设计恒压，恒流的控制单元电路。在恒压阶段，输出电压通过开关控制进行调节，通过跳过开关周期得以维持。调节使能与禁止周期的比例能维持输出电压的稳定，同时也可以使转换器的效率在整个负载范围内得到优化。在充电过程中产生的温度由温补电路进行调节。恒流控制单元的任务是在负载电阻继续减小的情况下，使输出电流按预定的恒流值保持不变，为此需要使输出电压随着负载电阻的减小而随之降低，在极端情况下，负载电阻阻值降为零（短路状态），输出电压也随之降到零，以保持输出电流的恒定。这些都是恒流部件的功能，在恒流部件工作时，恒压部件亦处于休止状态，它不再干预输出电压的高低。最后运用PROTEL绘图软件设计电路图和PCB板硬件并完成制作、调试。
关键词：NCP1200A、恒流恒压、温补电路
Abstract
An electrical control unit of constant voltage and constant current is designed on base of the current special chip NCP1200A.When In a constant voltage state, output voltage is adjusted and controlled by switch, jumped over the period to maintain. Adjust to and the cycle of proportion to maintain the steady output voltage, and can keep the efficiency of the whole load range was optimized. in the charging circuit by an adjustable temperature temperature compensation circuit. A constant flow of control unit began its task is to lessen the load resistance to the circumstances, the output of the current value as a constant stream remain unchanged. this needs to load output voltage with resistance in decreased and then, in extreme cases, the resistance resistance value is zero （ a short circuit state ）, output voltage also reduced to zero, to maintain the output of the constant current. This is a constant flow of parts, in a constant flow of parts, components are also in a constant pressure on, it is no longer in output voltage. in the end of the use of software design protel drawing circuit diagrams and pcb board hardware and complete fabrication and debug.
Key word：NCP1200A；constant voltage and constant current circuit；Temperature compensation circuit
