摘 要
本文采用電流控制專用芯片NCP1200A，設計恒壓，恒流的控制單元電路。在恒壓階段，輸出電壓通過開關控制進行調節，通過跳過開關周期得以維持。調節使能與禁止周期的比例能維持輸出電壓的穩定，同時也可以使轉換器的效率在整個負載范圍內得到優化。在充電過程中產生的溫度由溫補電路進行調節。恒流控制單元的任務是在負載電阻繼續減小的情況下，使輸出電流按預定的恒流值保持不變，為此需要使輸出電壓隨著負載電阻的減小而隨之降低，在極端情況下，負載電阻阻值降為零（短路狀態），輸出電壓也隨之降到零，以保持輸出電流的恒定。這些都是恒流部件的功能，在恒流部件工作時，恒壓部件亦處于休止狀態，它不再干預輸出電壓的高低。最后運用PROTEL繪圖軟件設計電路圖和PCB板硬件并完成制作、調試。
關鍵詞：NCP1200A、恒流恒壓、溫補電路
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
