Simple dc/dc converter increases available power in dual-voltage system
The schematic in Figure 1 shows a way to increase the power available from a current-limited 5V supply by adding power from a –5V supply. The dc/dc converter generates a single 12V, 150-mA (1.8W) output from two regulated and current-limited input sources at 5V, 300 mA (1.5W) and –5V, 300 mA (1.5W). Because the input uses different-polarity voltage sources, the design uses a flyback dc/dc converter to avoid a system-grounding problem. Level-shifted feedback sensing using a pnp transistor, Q1, references the feedback signal to the negative input voltage. You calculate the feedback-resistor divider by using the formula R1=R4(VOUT–VBE)/VREF, where R1connects to the emitter of Q1, R4 connects to the collector of Q1, VBE is the base-emitter voltage of Q1, and VREF is the feedback reference voltage of the switching regulator.
To simplify the circuit, the flyback converter in Figure 1 uses an LT1946 monolithic switching regulator. The voltage rating of the monolithic regulator has to be greater than the maximum switching voltage of the flyback converter, calculated by [(VIN1+|–VIN2|)MAX+VOUT(MAX)/(T1 turns ratio)]+VSPIKE. The maximum switching voltage is approximately 25V for the circuit in Figure 1. Note also that the input capacitor and dc/dc regulator input must be able to handle a maximum input voltage of 10V, resulting from the calculation +VIN1(MAX)+|–VIN2(MAX)|. In an event of fault-current conditions, such as shorted input or output, a zener diode, D2, creates the undervoltage-lockout threshold to turn off the LT1946 whenever either input source is in current limit or the input voltage (+VIN1+|–VIN2|) drops below 6V to help the input supply recover when the fault condition is removed. In a system with two available current-limited power supplies, you can convert the two supplies into a single supply that has more power-handling capability than either of the two inputs. A flyback topology based on an LT1946 monolithic converter offers a simple approach to the grounding problem and the feedback-sensing problem inherent in a dual-input power supply. Sharing the power between two input sources not only adds output-power capability, but also increases the overall flexibility of the system.
Simple dc/dc converter increases available power in dual-voltage system的更多相关文章
- PID DC/DC Converter Controller Using a PICmicro Microcontroller
http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1824&appnote=en011794 ...
- LT1946A-- Transformerless dc/dc converter produces bipolar outputs
Dual-polarity supply provides ±12V from one IC VC (Pin 1): Error Amplifier Output Pin. Tie external ...
- Practice safe dc/dc converter
Short-circuit protection is an obvious requirement for a power supply, especially when its load conn ...
- Add margining capability to a dc/dc converter
You can easily add margining capability—that is, the ability to digitally adjust the output voltage— ...
- [专业名词·硬件] 2、DC\DC、LDO电源稳压基本常识(包含基本原理、高效率模块设计、常见问题、基于nRF51822电源管理模块分析等)·长文
综述先看这里 第一节的1.1简单介绍了DC/DC是什么: 第二节是关于DC/DC的常见的疑问答疑,非常实用: 第三节是针对nRF51822这款芯片电源管理部分的DC/DC.LDO.1.8的详细分析,对 ...
- DC/DC与LDO的差别
转自:http://bbs.eetop.cn/thread-459121-1-1.html 在平时的学习中,我们都有接触LDO和DC/DC这一类的电源产品,但作为学生的我们队这些东西可能了解不够深刻, ...
- DC DC降壓變換器ic 工作原理
目前DC/DC轉化器大致可分為:升壓型dc dc變化器.降壓型dc dc變化器及可升壓又可降壓dc dc變換器.我們今天主要提一下降壓型dc dc變換器的原理: 見下圖降壓變換器原理圖如圖1所示, 當 ...
- DC DC電路電感的選擇
注:只有充分理解電感在DC/DC電路中發揮的作用,才能更優的設計DC/DC電路.本文還包括對同步DC/DC及異步DC/DC概念的解釋. DCDC電路電感的選擇 簡介 在開關電源的設計中電感的設計為 ...
- (笔记)电路设计(十一)之DC/DC电源转换方案设计应用
十大 法则之一:搞懂什么是DC/DC电源以及DC/DC转换电路分类 DC/DC电源电路又称为DC/DC转换电路,其主要功能就是进行输入输出电压转换.一般我们把输入电源电压在72V以内的电压变换过程称为 ...
随机推荐
- 报错:/application/zabbix/sbin/zabbix_server: error while loading shared libraries: libmysqlclient.so.18: cannot open shared object file: No such file or directory
启动zabbix_server时报错: /application/zabbix/sbin/zabbix_server: error while loading shared libraries: li ...
- 设计模式--工厂模式 caffe_layer注册
来源:http://www.cnblogs.com/zhouqiang/archive/2012/07/20/2601365.html 来源:http://blog.luoyetx.com/2016/ ...
- CGIC函数说明
CGIC函数说明 参考cgic函数说明_Embedded Resources Library Online (C)郝博士 cgiFormResultType cgiFormString( char * ...
- 【转】Python OCR识别图片验证码
转载自:博客 对于某些网站登录的时候,往往需要输入验证码才能实现登录.如果要爬虫这类网站,往往总会比这个验证码导致无法爬取数据.以下介绍一种比较折中的方法,也是比较可行的方法: 实现思想: 1.通过截 ...
- 新版Java为什么要修改substring的实现
Java字符串的截取操作可以通过substring来完成.有意思的是,这个方法从jdk1.0开始,一直到1.6都没有变化,但到了1.7实现方式却发生了改变.你可能会认为之所以要对一个成熟且稳定的方法做 ...
- NIO-4pipe
import java.io.IOException; import java.nio.ByteBuffer; import java.nio.channels.Pipe; import org.ju ...
- bzoj 1864
思路:随便dp一下 #include<bits/stdc++.h> #define LL long long #define fi first #define se second #def ...
- Wannafly挑战赛7 C - 小Q与氪金游戏
题目描述 “为世界上所有的美好而战!”小Q同学最近沉迷“稳固3”,为了从最新的蛋池中抽出自己喜欢的角色卡,不惜氪下重金.在这个游戏中,氪一单可以得到x个宝石,而抽一次卡需要花费y个宝石,由于游戏策划十 ...
- 洛谷P3444 [POI2006]ORK-Ploughing [枚举,贪心]
题目传送门 ork 格式难调,题面就不放了. 分析: 一道偏难的贪心和枚举题.考试的时候是弃疗了...yyb巨佬已经讲的很详细了,推荐他的博客.这里小蒟蒻就只放代码了. Code: #include& ...
- 抓包分析LVS-NAT中出现的SYN_RECV
CIP:192.168.10.193 VIP:192.168.10.152:8000 DIP:100.10.8.152:8000 RIP:100.10.8.101:8000 和 100.10.8.10 ...