数控直流电流源毕业的设计.docVIP

毕业设计报告(论文) 题目：数控直流电流源 所 属 系 电子工程系 专 业 自 动 化 学 号 姓　　名 指导教师 吴 春 红 起讫日期 2012.2 --- 2012.5 设计地点 东南大学成贤学院 东南大学成贤学院毕业设计报告（论文） 诚 信 承 诺 本人承诺所呈交的毕业设计报告（论文）及取得的成果是在导师指导下完成，引用他人成果的部分均已列出参考文献。如论文涉及任何知识产权纠纷，本人将承担一切责任。 学生签名： 日　　期： 数控直流电流源 摘 要 本系统是以直流恒流源为核心，STC12C5A16AD单片机为系统主控制器，通过键盘来步进调整电流源的输出电流，该电流源具有电流可预置，1mA步进，步进电流≤10mA，由数码管直观显示输出电流值，电流输出范围为100mA～300mA。该系统由主控制器输出数字量，经过TLC5615数模转换之后，输出模拟电压，经过运算放大器隔离放大之后，控制TIP122功率管的基极电压，随着功率管基极电压的变化而输出不同的电流。另外，单片机还同时对输出电流进行实时监控。电流源的输出电流经过热稳定较好的采样电阻后，完成了电流/电压转换。采样电阻上的电压经过同相放大之后，通过单片机完成模/数转换分析处理。通过该反馈环节，可以使电流源的输出电流更加稳定，以形成稳定的压控电流源。 关键词：STC12C5A16AD；TLC5615；TIP122; 恒流源 Numerical Controlled Constant-Current Source Abstract In the system the DC current source is the centre, and STC12C5A16AD version single chip microcomputer is main controller. Output current of DC power can be set by the keyboard，the current source has the current preset, 1 mA step and step into the current than 10 mA, by digital tube visual display output current value, current output for 100 mA ~ 300 mA. The digitally programmable signal is made by the central controller, which converted to the analog voltage after the Digital-to-Analog of TLC5615. Then the analog voltage which is isolated and amplified by operational amplifiers, is sent to the base electrode of TIP122, and the current of the emitter varies with the change of the base’s voltage. Otherwise, the output current can be monitored by the MCU real-timely. The current-to-voltage conversion is completed when the current pass through the sampling resistor whose thermal stability is very well. At the same time, the DAC is achieved by the TLC5615 after the phase amplification of the voltage on sampling resistor. And then the MCU will analyse and process the data. The output current can be more stable by the feedback loop so that a stable voltage-controlled constant current power is designed. Keywo