Programmed Adjustable Power
Programmed Adjustable Power
I just explored an easy scheme to design a high precision programmed adjustable power.
In this scheme, there is no needs to make a complex PWM circult,
just a liner or switcher adjustable voltage regulator and a resister network, a DAC, and a MCU.
Resister network change DAC output voltage into feedback voltage
and let adjustable voltage regulator regulate output voltage itself.
Outputting an fixed voltage by using resister to control regulator may be easy,
but there is a little challenge to output adjustable voltage.
My mates used to use digital potentiometer to adjust output voltage, but digital potentiometer is too instable.
Lucky, DAC with a resister network works better, and they can provide high precision output witch depends the resolution of DAC.
In this figure, voltage of the node feedback is fixed by the Vref (OR Vsense) of regulator.
LM2576 is 1.23V, TPS5432 is 0.808V.
When there is voltage difference between Vout of DAC and Vref of regulator, the difference sets up an current in R2.
Then the current through R1 to the ground.
This adjustable current could change the resistance because voltage between Vref and GND is fixed
and no current will go into Vref pin duo to the virtual short and virtual open of the error amplifier inside of the regulator chip.
Now it's time to value R3, R2, R1.
Make sure that the output range of this regulator (Vout) and DAC (Vdac) , and Vref by checking the datasheet of part.
Then, list two equation.
(Vdac.max-Vref)/R2+(Vout.min-Vref)/R3=Vref/R1
(Vdac.min-Vref)/R2+(Vout.max-Vref)/R3=Vref/R1
Three unknown resistance, but two equation, we must assume the value of R3. 10K is very common.
Then check the Idac.max to make sure that DAC will not overloaded.
[Update 2014/Tue/22] PS:
Three terminal regulator, such as LM317 is not available to this equation because the 1.25V is between Ref pin and out pin.
We use TI's TLC5615, 10-BIT DIGITAL-TO-ANALOG CONVERTERS as our DAC.
This chip has 3-Wire Serial Interface, so we can use Arduino to control it.
Arduino is an open-source physical computing platform based on the AVR MCU.
Now give the Arduino program.
//Arduino project http://arduino.cc
//by Mini Dragon at http://minidr.com/archives/687
//This program is licensed under a Creative Commons Attribution-ShareAlike 3.0 License.
#define CS 2 //chip enable
#define CLOCK 3
#define DATA 4 #define HALF_CLOCK_PERIOD 2 //2 uS of clock period
float j=;
void setup()
{
pinMode(DATA, OUTPUT);
pinMode(CLOCK,OUTPUT);
pinMode(CS,OUTPUT);
digitalWrite(CS,HIGH);
digitalWrite(DATA,LOW);
digitalWrite(CLOCK,LOW);
} void writeValue(uint16_t value)
{
digitalWrite(CS,LOW);//start of 12 bit data sequence
digitalWrite(CLOCK,LOW);
data = data << ; //Add 2 0 at the end of the data. A 10-bit data word should add 2 0 at the LSB bit (sub-LSB) since the DAC input latch is 12 bits wide.(SEE TLC5615C DATASHEET)
for(int i=; i>=; i--)//send the 12 bit sample data
{
digitalWrite(DATA, (value & ( << i) ) >> i );//DATA ready
delayMicroseconds(HALF_CLOCK_PERIOD);
digitalWrite(CLOCK,HIGH);//DAC get DATA at positive edge
delayMicroseconds(HALF_CLOCK_PERIOD);
digitalWrite(CLOCK,LOW);
}
digitalWrite(CS,HIGH);//end 12 bit data sequence
} void loop()
{
j=; //in here, 567 is a example. DAC OUT=j*Vref/1024
writeValue(floor(j));
}
Each DAC output voltage maps a main Vout.
Long day for me to update my blog. I even don't know my blog was blocked by our Great Fire Wall.
Yesterday I passed my first time of GRE test.
That's a f**k test.
But during the day of preparing the GRE, I got a chance to attend our University's electronic design contest.
In the contest, I fixed some problems of my power and add some now function into it.
This is the top layer of the power.
You can see a black PCB which plug into the main board.
That's a current detection module.
I using TI's INA200A to detecting the current of power's output.
Then using Arduino's ADC to check out the current if the current exceeds the threshold value.
This threshold value could change during the runtime.
If the power is overloaded, the relay (yellow thing) will cut off the output to protect the buck chip until manual reset the system.
The 1602 LCD could display the output voltage, output current and cut off thrshold current value.
Using Arduino to control the LCD is very simple like using printf() function in C language.
This the bottom layer of the power. I using the surface mount package part to keep the system small.
This is the out put waveforms.
About 15mV ripple voltage in 1A load, 10V output.
Fantastic result by using Nichicon HD aluminium electrolytic capacitor.
That's all of the
This project is open-sourced, under the licence of BY-NC-SA.
If you want the SCH, PCB file and Arduino file, leave the comment and I will mail you ASAP.
Thanks to Texas Instruments for offering me so many kind of chips free.
dfd
Programmed Adjustable Power的更多相关文章
- 22.I/O特性
IO资源 IO是与外界沟通和控制的通道,fpga提供了丰富的IO和一些实用的特性. 本文简要的将主要的特性摘录下来做设计参考用.具体参数参考handbook. 第一部分:IO特性概述 -----通过软 ...
- 15.Cyclone II的IO资源学习
IO资源 IO是与外界沟通和控制的通道,fpga提供了丰富的IO和一些实用的特性. 本文简要的将主要的特性摘录下来做设计参考用.具体参数参考handbook. 第一部分:IO特性概述 -----通过软 ...
- Power aware dynamic scheduling in multiprocessor system employing voltage islands
Minimizing the overall power conservation in a symmetric multiprocessor system disposed in a system- ...
- Programmable current source requires no power supply
Engineering labs are usually equipped with various power supplies, voltmeters, function generators, ...
- 一起学微软Power BI系列-使用技巧(5)自定义PowerBI时间日期表
1.日期函数表作用 经常使用Excel或者PowerBI,Power Pivot做报表,时间日期是一个重要的纬度,加上做一些钻取,时间日期函数表不可避免.所以今天就给大家分享一个自定义的做日期表的方法 ...
- 一起学微软Power BI系列-使用技巧(4)Power BI中国版企业环境搭建和帐号问题
千呼万唤的Power BI中国版终于落地了,相信12月初的微软技术大会之后已经铺天盖地的新闻出现了,不错,Power BI中国版真的来了,但还有些遗憾,国际版的一些重量级服务如power bi emb ...
- 一起学微软Power BI系列-使用技巧(3)Power BI安卓手机版安装与体验
Power BI有手机版,目前支持安卓,苹果和WP,不过没有WP手机,苹果在国内还不能用,要FQ和用就不测试了.安卓的我也也是费了九牛二虎之力才把app下载下来,把方法分享给大家. FQ太麻烦,所以建 ...
- Power BI官方视频(3) Power BI Desktop 8月份更新功能概述
Power BI Desktop 8月24日发布了更新版本.现将更新内容翻译整理如下,可以根据后面提供的链接下载最新版本使用. 1.主要功能更新 1.1 数据钻取支持在线版 以前的desktop中进行 ...
- 一起学微软Power BI系列-使用技巧(1)连接Oracle与Mysql数据库
说起Oracle数据库,以前没用过Oracle不知道,但是这1年用Oracle后,发现真的是想狂吐槽,特别是那个.NET驱动和链接字符串,特别奇葩.总归是和其他数据库不一样,标新立异,不知道为何.另外 ...
随机推荐
- iOS编码规范参考
目录 注释 1.1 多行注释 1.2 单行注释 1.3 函数的注释 命名 2.1 常量的命名 2.2 函数的命名 2.3 变量的命名 2.3.1 成员变量 2.3.2 公 ...
- iOS8 自定义navigationItem.titleView
navigationBar其实有三个子视图,leftBarButtonItem,rightBarButtonItem,以及titleView.前两种的自定义请参考http://www.cnblogs. ...
- SQLSTATE[42000]
SQLSTATE[42000]: Syntax error or access violation: 1140 Mixing of GROUP columns (MIN(),MAX(),COUNT() ...
- A*算法改进——Any-Angle Path Planning的Theta*算法与Lazy Theta*算法
本文是该篇文章的归纳http://aigamedev.com/open/tutorial/lazy-theta-star/#Nash:07 . 传统的A*算法中,寻找出来的路径只能是沿着给出的模型(比 ...
- 洛谷 P4128: bzoj 1815: [SHOI2006]有色图
题目传送门:洛谷 P4128. 计数好题,原来是 13 年前就出现了经典套路啊.这题在当年应该很难吧. 题意简述: \(n\) 个点的完全图,点没有颜色,边有 \(m\) 种颜色,问本质不同的图的数量 ...
- C语言清空输入缓冲区的N种方法对比【转】
转自:http://www.cnblogs.com/codingmylife/archive/2010/04/18/1714954.html C语言中有几个基本输入函数: //获取字符系列 int f ...
- MVC 控制器中传递dynamic(对象) 给视图
有时候不想重新定义一个实体,则使用 dynamic 来定义匿名类型. //匿名类型 传递到前台 Model dynamic viewModel = new { UserID = 5016 }; ret ...
- Linux配置Selenium+Chrome+Java实现自动化测试
1.安装chrome sudo apt-get install libxss1 libappindicator1 libindicator7 wget https://dl.google.com/li ...
- Go语言规格说明书 之 词汇元素(Lexical elements)
go version go1.11 windows/amd64 本文为阅读Go语言中文官网的规则说明书(https://golang.google.cn/ref/spec)而做的笔记,完整的介绍Go语 ...
- 字符串(string.cpp)
字符串(string.cpp) 神TM字符串DP 题目描述: 小林和亮亮正在做一个游戏.小林随意的写出一个字符串,字符串仅由大写字母组成,然后指定一个非负整数m,亮亮可以进行至多m次操作.每次操作为交 ...