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# 实验报告:DPS内部挡位无法输出>10V电压
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## 基本信息
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| 项目 | 内容 |
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|--------------|-----------------------|
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| 实验日期 | `2025-08-05` |
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| 操作人 | `沈浴阳、庞博` |
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| 报告版本 | `V1.0` |
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| 板卡编号 | `JC124M060_A2` |
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---
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## 一、实验背景
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- 对于DPS,在5uA, 20uA, 200uA, 2mA, 60mA下,若需要输出>9V电压,需将DPS板卡上运放供电从\~9V抬升至\~14V
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- 据推测,这一限制是由于运放与光耦电路对电压输出造成了影响
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---
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## 二、实验目的
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<!-- 清晰描述实验要验证的关键问题 -->
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1. 目标1:验证运放与光耦对电压输出造成限制
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2. 目标2:尝试修改光耦与运放部分电路解决这一限制
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---
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## 三、实验环境
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- **硬件配置**
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- PPMU2.0 板卡一套:
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- PMU: JC124M014_A7
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- DPS: JC124M060_A1 * 2
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- MOLEX: JC124M038_A8
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- K7_w/_NOR: JC124M049_A1 * 2
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- **软件环境**
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- v1.4.0.1154-7817866b4-debug
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---
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## 四、实验步骤
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### 1. 准备工作
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<!-- 分步骤描述准备过程 -->
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1) 组装板卡
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2) 板卡上电并连接电脑
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3) 准备示波器、万用表
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### 2. 测试流程
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<!-- 按顺序记录关键操作 -->
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1. 使用DPS通道1、3进行测试,其余通道作为对比组不做修改:
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1. 1、3通道移除1A档所用光耦
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2. 对DPS进行初始化(获取初始值,Offset=8000)
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3. 在FVMV模式下,分别在5uA,20uA,200uA,2mA档下,全通道Force 13V
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4. 获取全通道DPS Measure读数
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2. 修改1通道光耦电路,
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1. 将并联输入,公共脚输出修改为单输入,单输出,公共脚悬空
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2. 重复第2步中的ii~iv
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---
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## 五、实验结果
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### 关键数据记录
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步骤2:
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| 挡位 | 测试组 | 对照组(1&3) | 偏差值
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|--------|--------|------|------|
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| 5uA | 9.388 | 13.000 |-3.612|
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| 20uA | 9.470 | 12.999 |-3.529|
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| 200uA | 9.714 | 13.001 |-3.287|
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| 2mA | 11.787 | 13.000 | -1.213 |
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步骤3:
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| 挡位 | 测试组(1) | 对照组(3) | 对照组(11) |
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|--------|--------|------|------|
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| 5uA | 12.991 | 13.000 | 9.388 |
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| 20uA | 12.992 | 12.999 | 9.470 |
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| 200uA | 12.992 | 13.001 | 9.714 |
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| 2mA | 12.992 | 13.000 | 11.787|
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---
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## 六、问题分析
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<!-- 使用故障树等结构化方法 -->
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```{mermaid}
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flowchart TD
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n1["光耦"] --> n2["Pin5->Pin4存在二极管"]
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n3["DPS小档位无法输出大电压"] --> n1 & n4["运放"]
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n4 --> n6["In+/In-电压范围为Vdd~Vss,超出范围则会被内部二极管钳位"] & n12["Vout不超过Vdd"]
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n6 --> n7@{ label: "<span style=\"background-color:\">In+通过1K电阻连至光耦1@Pin4</span>" }
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n7 --> n8@{ label: "Force/MeasH->IN+<br style=\"--tw-scale-x:\">Pin5->Pin4" }
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n10["Vout+串联肖特基二极管至光耦2@Pin4"] --> n9@{ label: "Force/MeasH->Vout<br style=\"--tw-scale-x:\">Pin5->Pin4" }
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n2 --> n11@{ label: "<span style=\"background-color:\">如果Pin5电压>Pin4电压</span>" }
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n11 --> n5["二极管导通,存在电流通路"]
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n12 --> n10
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n8 --> n13["小档位Force 13V"]
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n9 --> n13
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n13 --> n14@{ label: "Force=13<br style=\"--tw-scale-x:\">Vout=9.6V" } & n15@{ label: "Force=13<br style=\"--tw-scale-x:\">IN+ = 9V<br>" }
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n15 --> n11
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n14 --> n11
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n5 --> n18["ForceV ClampI"]
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n18 --> n20["电流通过1K电阻"] & n21["肖特基二极管反向导通"]
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n20 -- "<span style=background-color:>5uA/20uA/200uA Clamp</span>" --> n24["Force电压小于期望值"]
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n21 -- "<span style=background-color: rgb(255, 255, 255);>2mA Clamp</span>" --> n24
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n1@{ shape: rounded}
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n3@{ shape: rounded}
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n4@{ shape: rounded}
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n6@{ shape: rect}
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n12@{ shape: rect}
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n7@{ shape: rect}
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n8@{ shape: rect}
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n10@{ shape: rect}
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n9@{ shape: rect}
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n11@{ shape: diam}
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n5@{ shape: rounded}
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n13@{ shape: rounded}
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n14@{ shape: rect}
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n15@{ shape: rect}
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n20@{ shape: rounded}
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n21@{ shape: rounded}
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```
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---
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## 七、结论与建议
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✅ **实验结论**
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1. 光耦中存在二极管,当正向存在压降时,二极管导通,运放输入端电阻上出现压降,存在电流
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2. 运放Vout后连接一肖特基二极管,其反向漏电流达到~100uA级别,存在漏电流
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3. 当Force电压时Clamp电流,当Force,ExtForce,MeasureH,ExtMeasure间存在通路时,可能触发ClampI,导致观察到输出电压小于期望电压
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⚠️ **改进建议**
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- [ ] 建议1:修改光耦输入输出端连接方式 (需注意此接法时光耦负载能力)
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- [ ] 建议2:加大运放输入端电阻阻值
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---
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## 附件
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1. 电路原理图
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1. 运放输入电阻
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1. 光耦连接方式(建议方案A)
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")
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1. 光耦负载能力
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@@ -0,0 +1,10 @@
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##############################
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PPMU2.0 Lab Reports
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##############################
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.. toctree::
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:maxdepth: 1
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:caption: Contents:
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:glob:
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*
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