# SY8205同步降压可调DCDC电源模块（原理图和PCB）

**URL:** <https://bbs.eeclub.top/t/topic/118>\
**Category:** 个人项目分享 / Personal Project Sharing\
**Tags:** Power, DCDC, Hardware, Silergy, Open-Source\
**Created:** [2025 年10 月 30 日 15:58 UTC](https://bbs.eeclub.top/t/topic/118 "2025-10-30T15:58:10Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

作者： ![zeruns](https://bbs.eeclub.top/user_avatar/bbs.eeclub.top/zeruns/32/7_2.png) [@zeruns](https://bbs.eeclub.top/u/zeruns)\
发布日期： [2025 年10 月 30 日 15:58 UTC](https://bbs.eeclub.top/t/topic/118/1 "2025-10-30T15:58:11Z")

</div>

**SY8205同步buck降压电源模块，输入电压4.5-30V，输出电压0.6-30V可调，效率90%以上，最大连续输出电流5A，峰值电流6A。**

开源链接：[https://url.zeruns.com/obGu3](https://url.zeruns.com/obGu3)

SY8025数据手册下载地址：[https://url.zeruns.com/0SYO7](https://url.zeruns.com/0SYO7) 提取码：5l5x

- 画了个 MSP430F149的最小系统板 开源出来了：[https://blog.zeruns.com/archives/713.html](https://blog.zeruns.com/archives/713.html)
- STM32F030C8T6最小系统板和流水灯（原理图和PCB）：[https://blog.zeruns.com/archives/715.html](https://blog.zeruns.com/archives/715.html)

电子/单片机技术交流群：[2169025065](https://qm.qq.com/q/ZmTfBbFM4Y)

## 简介

SY8205是矽力杰推出的一款内置开关管的同步buck降压芯片，开关频率为500kHz，输入电压4.5-30V，最大连续输出电流为5A，峰值电流6A，FB引脚的基准电源为0.6V 1.5%精度，电流折返式输出短路保护，热关断保护，自动恢复功能，有输出使能引脚（高电平开启，低电平关闭），有软启动。

实际测试输出4A电流时发热巨大，必须加散热，不加任何散热可长时间运行的输出电流在3A左右。

**下面测试数据是将两个100μF的固态电容换成了220μF的高频电解电容后测得的，感觉100微法的电容小了点。**

学生党作品，请各位大佬指点一下。

## 效率测试

| 输入电压 | 输入电流 | 输入功率 | 输出电压 | 输出电流 | 输出功率 | 效率 |
| --- | --- | --- | --- | --- | --- | --- |
| 15V | 0.868A | 13.02W | 11.95V | 1A | 11.95W | 91.8% |
| 15V | 2.48A | 37.2W | 11.87V | 2.99A | 35.49W | 95.4% |
| 25V | 2.595A | 64.88w | 12.19V | 4.98A | 60.71W | 93.6% |
| 15V | 0.35A | 5.25W | 5.01V | 1A | 5.01W | 95.4% |
| 15V | 1.46A | 21.9W | 5.02V | 3.98A | 19.98W | 91.2% |

## 纹波测试

下面测纹波的方法有点不太恰当，接地回路太长了，测得纹波可能大一点。  
输入18V，输出12V时的空载纹波，6.8Hz左右，峰峰值500mV左右。  
输入18V，输出12V，接20Ω水泥电阻做负载，纹波4kHz左右，峰峰值670mV左右。  
纹波偏大，感觉是滤波电容小了，建议将滤波电容改成470μF的，PCB还需要调整优化一下。

 ![](https://s3.eeclub.top/original/1X/71ca8445266892d6326cfdf2ff378ad7cad65051.jpeg)  
 ![](https://s3.eeclub.top/original/1X/be89364eba446e5c2d716e85a7ebec1a946e4319.jpeg)

2023.6.15重新测了一下纹波，这次选用电流大点，纹波确实变小了很多，上面测试结果是因为电流小的时候是PFM模式。实测电流低于1.4A左右时会进入PFM模式。

输入25V，输出5V2A时的纹波峰峰值72mV左右。

 ![](https://s3.eeclub.top/original/1X/7e72d5e848c53956b521ffe9cd9599298ec95521.jpeg)

输入25V，输出12V3A时的纹波峰峰值130mV左右。

 ![](https://s3.eeclub.top/original/1X/721fa358d05da05cd148a849d2397ee87f962ab7.jpeg)

## 实物图

 ![](https://s3.eeclub.top/original/1X/7e24a0f4e79bfa9aba8611fb08e80ab961123d1c.jpeg)  
 ![](https://s3.eeclub.top/original/1X/53db0cdbed1f9f6990572aa6d781256919f5741d.jpeg)  
 ![](https://s3.eeclub.top/original/1X/718252ea8102b774f92c202dab5180310d3b3e4f.jpeg)

## 元件购买地址

- 0805电阻样品本：[https://s.click.taobao.com/oWjIgGu](https://s.click.taobao.com/t?e=m%3D2%26s%3DGnf5xK8vQF9w4vFB6t2Z2ueEDrYVVa64LKpWJ%2Bin0XLjf2vlNIV67oUqJBc%2FkNNCr8hK%2FDw%2Bbm1%2FmzaS0s2vXCsmIF0UHtujBkxkgN7jKg%2BiJaQjFxYBevWfPAv4x3d%2FOlGkMkr%2BSUUYmUGuVZn0uVMZHCs3Xen4dp2lWP3iSWYLZMqoQW%2BfuKGzo1lVxIioJvhmaiPv%2F5vOv8XvY6GYXRqmMYYi3EPKgtpr14tiADQK7UqMCBUriG0QFbctzqdyQsSSpN50Tf30oRXWDqY30GHQ7dFzkf%2BmfWsUjZoD5RBFvIJeoWZli5YPtEev%2BpcacSpj5qSCmbA%3D&union_lens=lensId%3APUB%401684662328%4021336a72_0af0_1883db31d26_d233%4001%40eyJmbG9vcklkIjo2MTM1NCwiic3BtQiiI6Il9wb3J0YWxfdjJfcGFnZXNfcHJvbW9fZ29vZHNfaW5kZXhfaHRtIn0ie)
- 0805电容样品本：[https://s.click.taobao.com/r9ea1Hu](https://s.click.taobao.com/t?e=m%3D2%26s%3DHUOwk6IKUTtw4vFB6t2Z2ueEDrYVVa64K7Vc7tFgwiHjf2vlNIV67nYY5qxgQ5pjPkWZNjOK2CN%2FmzaS0s2vXCsmIF0UHtujBkxkgN7jKg%2BiJaQjFxYBevWfPAv4x3d%2FOlGkMkr%2BSUUYmUGuVZn0uUeNaL1L6rWLYVnYE523ghoLZMqoQW%2BfuKGzo1lVxIioZ7PkP5ESYSK2NOnbQ%2FlO5lq7XGYat254ig%2BQiDe6c7IoHdw48Y5g2fSnJ6rHNSCOQsSSpN50Tf30oRXWDqY30GHQ7dFzkf%2BmfWsUjZoD5RDF6ZM%2FmwxRREDCgZ8VT1oiIYULNg46oBA%3D&union_lens=lensId%3APUB%401684662439%402104be69_0b37_1883db4cf32_7cce%4001%40eyJmbG9vcklkIjo2MTM1NCwiic3BtQiiI6Il9wb3J0YWxfdjJfcGFnZXNfcHJvbW9fZ29vZHNfaW5kZXhfaHRtIn0ie)
- SY8205芯片：[https://s.click.taobao.com/klaXQGu](https://s.click.taobao.com/t?e=m%3D2%26s%3DA2Nkl4N%2B5gJw4vFB6t2Z2ueEDrYVVa64LKpWJ%2Bin0XLjf2vlNIV67p305xKga2A1mSMhGfkQJ75%2FmzaS0s2vXCsmIF0UHtujBkxkgN7jKg%2BiJaQjFxYBevWfPAv4x3d%2FOlGkMkr%2BSUUYmUGuVZn0uRDBbf95h6seTxpmwkkouzqi1jMNxDhLMnotgd7NXRy%2F3OppJwt5etiBFtNlHKT36y3JPz%2BLVah%2BLRhN%2B4hd%2FHMyS0Q3lJVkOpLOmraasad3y52VBIY1a8OjO9AJYjY8CXJ%2BwEVkOqHFdIW9JNkz7%2FhuShzkDg9djg2UTTL%2B0QqkjYeyvAuvyy%2FGJe8N%2FwNpGw%3D%3D&union_lens=lensId%3APUB%401685024294%4021054b1f_0c0f_188534644f6_72d3%4001%40eyJmbG9vcklkIjo2MTM1NCwiic3BtQiiI6Il9wb3J0YWxfdjJfcGFnZXNfcHJvbW9fZ29vZHNfaW5kZXhfaHRtIn0ie)
- 电解电容：[https://s.click.taobao.com/r6CWQGu](https://s.click.taobao.com/t?e=m%3D2%26s%3DgIyBfTUHh2Nw4vFB6t2Z2ueEDrYVVa64K7Vc7tFgwiHjf2vlNIV67r84V7NtsKuSZW7hPg9Hazh%2FmzaS0s2vXCsmIF0UHtujBkxkgN7jKg%2BiJaQjFxYBevWfPAv4x3d%2FOlGkMkr%2BSUUYmUGuVZn0uUiVxHzNh4HOQTrT%2Fc8OcPai1jMNxDhLMmuCMDETpg3i5A6eMwLbECxehNHRxlPw9qZYtFBWgEhZpsyFWVn1rldu3vVl75UWxz3sIfVdOCpFtM7yFVcfj3Nv%2BdQcxB3rX8YJSha3z5pM4JOed0Rxa6OB8Lw4RtREmZs8U%2B4l3nuuxgxdTc00KD8%3D&union_lens=lensId%3APUB%401685024343%4021049f66_0b6a_18853470624_819e%4001%40eyJmbG9vcklkIjo2MTM1NCwiic3BtQiiI6Il9wb3J0YWxfdjJfcGFnZXNfcHJvbW9fZ29vZHNfaW5kZXhfaHRtIn0ie)
- 可调电阻：[https://s.click.taobao.com/eTaBmGu](https://s.click.taobao.com/t?e=m%3D2%26s%3D59J3fkK4O9Fw4vFB6t2Z2ueEDrYVVa64K7Vc7tFgwiHjf2vlNIV67s8i8cYadAVxu6Vvho8Zh8B%2FmzaS0s2vXCsmIF0UHtujBkxkgN7jKg%2BiJaQjFxYBevWfPAv4x3d%2FOlGkMkr%2BSUUYmUGuVZn0uUeNaL1L6rWLYVnYE523ghoLZMqoQW%2BfuKGzo1lVxIioGU8Er%2F5hqyFETgCEXvCh0Jc1cxCpGUapib9TtJ5a0D1CSbN7RLbNA8morVYn0YnDQsSSpN50Tf30oRXWDqY30GHQ7dFzkf%2BmfWsUjZoD5RDJEWjj16xFWrPuePArBxH3IYULNg46oBA%3D&union_lens=lensId%3APUB%401685024407%4021070d42_0b50_18853480055_744f%4001%40eyJmbG9vcklkIjo2MTM1NCwiic3BtQiiI6Il9wb3J0YWxfdjJfcGFnZXNfcHJvbW9fZ29vZHNfaW5kZXhfaHRtIn0ie)

元器件购买推荐立创商城，优惠注册链接：[https://activity.szlcsc.com/invite/D03E5B9CEAAE70A4.html](https://activity.szlcsc.com/invite/D03E5B9CEAAE70A4.html)

## 原理图

 ![](https://s3.eeclub.top/original/1X/189e9364178d6d0dc796268ae8fe05cb29f3481a.png)

## PCB

 ![](https://s3.eeclub.top/original/1X/7873b350ff1aadb0f8058f08abb5294b992aea1b.png)  
 ![](https://s3.eeclub.top/original/1X/704c33adbba5f6927301c5571b4d9bc58a3251a9.png)

## 推荐阅读

- **高性价比和便宜的VPS/云服务器推荐:** [https://blog.vpszj.cn/archives/41.html](https://blog.vpszj.cn/archives/41.html)
- 怎样搭建个人博客：[https://blog.zeruns.com/archives/218.html](https://blog.zeruns.com/archives/218.html)
- 我的世界服务器搭建教程：[https://blog.zeruns.com/tag/mc/](https://blog.zeruns.com/tag/mc/)
- STM32读取SHT3x系列温湿度传感器：[https://blog.zeruns.com/archives/700.html](https://blog.zeruns.com/archives/700.html)
- 使用VSCode代替Keil实现STM32和51单片机的开发：[https://blog.zeruns.com/archives/690.html](https://blog.zeruns.com/archives/690.html)