摘要:该设计系统以STC89C54单片机为控制器，控制自动分流比例和过流保护，并通过液晶屏幕，显示出电流的分流比例和分流数值。该系统采用开关电源芯片LM2576为电源芯片，以LM317为辅助电源芯片，以AD620为电流采样芯片，以TLC549芯片为A/D转换器。通过单片机STC89C54控制恒流源的介入来达到自动分流比例和均流的要求，单片机控制继电器来控制LM2576的ON/OFF端的开断，从而控制DC-DC开关电源电压的输出。操作方便简单。两路电源能够在外接负载变化的情况下自动均流，整个系统具有电路简单，输出电流范围大，精度高，稳定可靠的特点，并具有过流﹑短路保护及自动恢复功能，很好的达到了题目的各项要求。本系统实现了两个额定输出功率均为16W 的8V DC-DC 模块构成的并联供电系统，供电系统的效率超过60% ，完全满足题目基本和发挥部分的要求。

关键词：开关电源；并联供电；单片机STC89C54；自动分流比例； LED1602

Abstract:The design system based on STC89C54single-chip microcomputer as the controller, control automatic shunt ratio and overcurrent protection, and through the LCD screen, showing the shunt current shunt ratio and numerical. The system adopts the switch power supply chip LM2576power chip, LM317chip AD620 as auxiliary power, current sampling chip，Based on the TLC549 chip A/D converter. SCM control through the current sampling circuit to achieve the automatic shunt ratio and mean flow requirements, SCM control LM2576ON/OFF end breaking, so as to control the DC-DC switching power supply output voltage. Easy to operate. Two power to external load changes in the case of automatic current sharing, the whole system has the advantages of simple circuit, the output current range, high precision, stable and reliable characteristics, and has over-current, short circuit protection and automatic restoration of function, very good to achieve the requirements. This system realized the two rated output power is 16W8V DC-DC module consisting of parallel power supply system, power supply system efficiency over 60%, fully meet the subject of basic and the requirements to play a part.

Key words: Switching power supply; parallel power supply; the microcontroller STC89C54; automatically divert proportion; LED1602