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DC-DC转换器芯片的技术参数一个优秀电源电路是电子产品的可靠性保障，什么样的电源电路才算是优秀的电源呢？一些有经验的工程师使用稳压器电源时，都会考虑如何减小稳压器的纹波，降低功耗，提高电源转换效率，产品尺寸等问题，因为这些问题都是衡量电源好坏的关键。
随着半导体技术的发展，电源稳压器的纹波越来越小，转换效率越来越高，输入电压越来越低，输出电压范围越来越广，功能日趋强大，其应用范围覆盖仪表、通信、安防及消费类电子等诸多领域，下面以DC-DC转换器芯片的技术参数进行说明。
输入、输出与效率DC-DC转换器的输入电压要求在特定的范围里，输入电压太低，无法提供足够的能量，输入电压太高，芯片无法承受。
LDO工作效率随着输入电压增加而减少，而DC-DC芯片效率与输入电压关系不大，这是DC-DC最大的优点之一。
输出电流能力是内含FET的DC-DC转换器的的最重要的参数，ON的DC-DC器件NCP3102能输出高达10A的电流，可满足您对电源的苛刻要求。
效率定义为输出功率除以输入功率，而更高的效率意味着高效的电源管理，ON的DC-DC器件NCP1595效率高达95%。
软启动硬启动电路刚开始工作时，由于输出电容上并没有积蓄能量，因此电压很低，电路的反馈回路检测到低电压值时，将会采用最宽的PWM来尽快使输出电压上升，但是此过程由于反馈回路反应很快，因此容易造成电流过冲，损坏电路元件。
应用软启动技术，优点在于：输出电压上升的速度减慢，启动电流得到控制，从而保护了负载；大大降低了对前级电源瞬输出态功率的要求；ON大部分的器件支持软启动技术。
上下电顺序控制建立和维持合适的电源环境对系统的正常运行至关重要，特别是FPGA、DSP、ARM等处理器的设计中，为了避免闩锁、浪涌电流或I/O争用等问题，可能需要多达4到5路或更多个电源按照规定的顺序和斜率进行上下电。
此外，许多应用还要求上电顺序和缓上电斜率可调节，以适应各种不同的情况。
三相电源检测系统设计三相电源检测系统设计摘 要本设计采用AT89C51单片机实现三相电压与电流的检测。
该设计可检测三相交流电压（AC220V×3）及三相交流电流（A、B、C 线电流0～5A）。
本系统的变压器、放大器、A/D 转换和计算产生的综合误差满足5%的精度要求。
输出采用128×64 LCD 方式显示，单片机电源部分直接由AC220V 交流电经整流、滤波、稳压供电。
系统采用数字时钟芯片和8kB 的RAM 进行存储器的扩展。
关键词关键词：：三相交流电 AD 转换 变压器 LCD 显示 8KB RAM1.引言当前电力电子装置和非线性设备的广泛应用，使得电网中的电压、电流波形发生严重畸变，电能质量受到严重的影响和威胁；同时，各种高性能家用电器、办公设备、精密试验仪器、精密生产过程的自动控制设备等对供电质量敏感的用电设备不断普及对电力系统供电质量的要求越来越高，电能质量问题成为各方面关注的焦点，电能质量检测是当前的一个研究热点，有必要对三相电信号进行采样，便于进一步分析控制。
目前，精度要求不高的交流数字电压表大多采用平均值原理，只能测量不失真时的正弦信号有效值，因此受到波形失真的限制而影响测量精度和应用范围。
真有效值数字仪表可以测量在任何复杂波形而不必考虑波形种类和失真度的特点以及测量精确度高、频带范围宽、响应速度快的特点而得到广泛应用。
提高系统的测量精度、稳定性特性是设计中的关键。
真有效值的数字电压数字电压表和以往的仪表有所不同的是可以检测波形复杂的三相交流电压电流。
这些都是以单片机为基础的智能化仪表，同时充分表明单片机是一个应用于对象体系的智能化工具。
本设计用单片机进行三相电压与电流的硬件检测系统。
该系统检测三相交流电压（AC220V×3）及三相交流电流（A、B、C线电流0～5A）。
本系统的变压器、放大器、A/D转换和计算产生的综合精度满足5%要求。
输出显示采用128×64点阵的LCD，单片机电源由AC220V交流供电通过变压与整流稳压电路实现。
电子设计应用2003年第5期摘要：本文首先介绍了真有效值数字电压表的基本原理,然后阐述LTC1966 TRMS／DC转换器工作原理,最后给出由LTC1966构成的多量程真有效值数字电压表电路。
关键词：真有效值;TRMS／DC转换器;D-S调制器;数字电压表真有效值数字电压表的基本原理利用真有效值(TRMS)数字仪表,可以准确、实时地测量各种波形的有效值电压,满足现代电子测量之需要。
交流电压有效值是按下式定义的：(1)其近似公式为：(2)分析式(2)可知,借助于电路对输入电压u进行“平方→ 取平均值→开平方”运算,就能获得交流电压的有效值。
因这是由有效值定义式求出的,故称之为真有效值。
目前生产的真有效值/直流转换器(如美国ADI公司的AD636、AD736,美国LT公司的LTC1966等),都是采用这种原理而设计的。
真有效值电压表和平均值电压表测量典型波形的误差比较见表1。
表中波峰因数(KP)定义为峰值电压(UP)与有效值电压(URMS)之比。
图1 LTC1966管脚排列及内部框图LTC1966工作原理LTC1966是美国凌特公司(LT)于2002年最新推出的真有效值RMS/DC转换器,与其他RMS/DC产品相比较,它在完成乘法／除法运算时,未采用通常的对数-反对数的计算方法,而是采用了全新的D-S计算技术。
LTC1966具有简单电路接法(只有一个外接平均CAVE)、灵活的输入／输出结构(差分或单端)、灵活的供电方式(2.7V~5.5V单电源,最大范围为±5.5V双电源)、高准确度(50Hz~1kHz的误差只有0.25%)、良好的线性(小于0.02%)、很宽的动态电流范围、易于校准等特性。
LTC1966采用MSOP-8封装,管脚排列及内部框图如图1所示,各引脚功能如下：GND—地;UIN1、UIN2—差分输入端1和2;USS—负电源端,对地接-5.5V电源或直接接地;UOUT—电压输出端。
三相电源检测系统设计三相电源检测系统设计摘 要本设计采用AT89C51单片机实现三相电压与电流的检测。
该设计可检测三相交流电压（AC220V×3）及三相交流电流（A、B、C 线电流0～5A）。
本系统的变压器、放大器、A/D 转换和计算产生的综合误差满足5%的精度要求。
输出采用128×64 LCD 方式显示，单片机电源部分直接由AC220V 交流电经整流、滤波、稳压供电。
系统采用数字时钟芯片和8kB 的RAM 进行存储器的扩展。
关键词关键词：：三相交流电 AD 转换 变压器 LCD 显示 8KB RAM1.引言当前电力电子装置和非线性设备的广泛应用，使得电网中的电压、电流波形发生严重畸变，电能质量受到严重的影响和威胁；同时，各种高性能家用电器、办公设备、精密试验仪器、精密生产过程的自动控制设备等对供电质量敏感的用电设备不断普及对电力系统供电质量的要求越来越高，电能质量问题成为各方面关注的焦点，电能质量检测是当前的一个研究热点，有必要对三相电信号进行采样，便于进一步分析控制。
目前，精度要求不高的交流数字电压表大多采用平均值原理，只能测量不失真时的正弦信号有效值，因此受到波形失真的限制而影响测量精度和应用范围。
真有效值数字仪表可以测量在任何复杂波形而不必考虑波形种类和失真度的特点以及测量精确度高、频带范围宽、响应速度快的特点而得到广泛应用。
提高系统的测量精度、稳定性特性是设计中的关键。
真有效值的数字电压数字电压表和以往的仪表有所不同的是可以检测波形复杂的三相交流电压电流。
这些都是以单片机为基础的智能化仪表，同时充分表明单片机是一个应用于对象体系的智能化工具。
本设计用单片机进行三相电压与电流的硬件检测系统。
该系统检测三相交流电压（AC220V×3）及三相交流电流（A、B、C线电流0～5A）。
本系统的变压器、放大器、A/D转换和计算产生的综合精度满足5%要求。
输出显示采用128×64点阵的LCD，单片机电源由AC220V交流供电通过变压与整流稳压电路实现。
基于状态机的LTC1196串并转换学号：1211082133姓名：向薛成1、设计要求利用状态机等设计将LTC1196(ADC)的穿行输出数据转换成并行数据的转换电路，ADC的时钟由转换电路提供，CS信号由转换电路处理后提供给ADC，以保证LTC1196的时序要求。
2、概念和芯片介绍1、状态机状态机(FSM)是数字系统设计中最重要的设计内容之一，通过状态转换图设计手段可以将复杂的控制时序图形化表示，分解为状态之间的转换关系，将问题简化。
状态机主要分为两大类：第一类，若输出只和状态有关而与输入无关，则称为Moore状态机：第二类，输出不仅和状态有关而且和输入有关系，则称为Mealy状态机。
状态机的基本结果如图1所示。
图1：状态机基本机构2、LTC1196(ADC)芯片该芯片采用SO-8塑料封装，高采样频率：1MHz，低成本。
单电源3V和5V规格，低功耗：10mW（采用3V电源）50mW（采用5V电源），±1/2LSB总为调整误差（在整个温度范围内），三线式串行I/O，1v至5V舒服跨度范围，把1Mhz输入转为7个有效值，差分输入。
其引脚图如图2所示。
图2：LTC1196引脚图图3：LTC1196时序图上图是LTC1196的时序图，从图可以看出在CS为高电平及变为低电平的第1个时钟周期的时候，输出为高阻。
在第3个时钟周期才输出数据，到底11个周期数据传输完毕，然后CS又变成高电平。
所以，LTC1196每12个时钟周期输出8位串行数据。
了解TLC1196的时序后，便能很好的编写VHDL程序。
3、状态机的状态图图3：状态转换图从时序图可以知道，在CS变为低电平后第三个时钟周期的下降沿将有数据输出，接着8个周期输出LTC1196的8位转换数据。
S0设置为并行数据输出状态，控制位为OP=1时输出，并且CS=1；S1设置为CS=0后内部计数，当计数器COUNT=10时转换状态。
4、源程序LIBRARY IEEE;USE IEEE.STD_LOGIC_1164.ALL;USE IEEE.STD_LOGIC_UNSIGNED.ALL;USE IEEE.STD_LOGIC_ARITH.ALL;ENTITY DCFQ IS --D触发器PORT(D,CLK:IN STD_LOGIC;Q:OUT STD_LOGIC);END DCFQ;ARCHITECTURE BHV OF DCFQ ISBEGINPROCESS(CLK)BEGINIF CLK 'EVENT AND CLK='0' THEN Q<=D;END IF;END PROCESS;END BHV;————————————————————————————————LIBRARY IEEE;USE IEEE.STD_LOGIC_1164.ALL;ENTITY YIWEI IS --移位寄存器PORT(D,EN,CLK:IN STD_LOGIC;DOUT:BUFFER STD_LOGIC_VECTOR(7 DOWNTO 0));END YIWEI;ARCHITECTURE BHV OF YIWEI ISCOMPONENT DCFQPORT(D,CLK:IN STD_LOGIC;Q:OUT STD_LOGIC);END COMPONENT DCFQ;SIGNAL DD:STD_LOGIC_VECTOR(8 DOWNTO 0);BEGINDD(0)<=D;G1:FOR N IN 0 TO 7 GENERATEFX:DCFQ PORT MAP(DD(N),CLK,DD(N+1));END GENERATE;PROCESS(EN)BEGIN--IF CLK 'EVENT AND CLK='0' THENIF EN='1' THEN DOUT<=DD(8 DOWNTO 1);ELSE DOUT<="ZZZZZZZZ";-- END IF;END IF;END PROCESS;END BHV;————————————————————————————————LIBRARY IEEE;USE IEEE.STD_LOGIC_1164.ALL;USE IEEE.STD_LOGIC_UNSIGNED.ALL;ENTITY LTC1196 IS --串并转换PORT(CLK,LTCOUT:IN STD_LOGIC;Q:OUT STD_LOGIC_VECTOR(7 DOWNTO 0);CS:BUFFER STD_LOGIC);END LTC1196;ARCHITECTURE BHV OF LTC1196 ISTYPE STATE IS(S0,S1);SIGNAL CURRENT_STATE,NEXT_STATE:STATE;SIGNAL OP:STD_LOGIC;SIGNAL COUNT:INTEGER RANGE 0 TO 11;SIGNAL YIN:STD_LOGIC;COMPONENT YIWEIPORT(D,EN,CLK:IN STD_LOGIC;DOUT:BUFFER STD_LOGIC_VECTOR(7 DOWNTO 0));END COMPONENT;BEGINCOM:PROCESS(CURRENT_STATE)BEGINCASE CURRENT_STATE ISWHEN S0=>CS<='1';OP<='1';NEXT_STATE<=S1;WHEN S1=>CS<='0';IF COUNT=10 THENOP<='0';NEXT_STATE<=S0;ELSE OP<='0';NEXT_STATE<=S1;END IF;END CASE;END PROCESS;REG:PROCESS(CLK)BEGINIF CLK 'EVENT AND CLK='0' THENIF CS='0'THENCOUNT<=COUNT+1;ELSE COUNT<=0;END IF;YIN<=LTCOUT;CURRENT_STATE<=NEXT_STATE;END IF;END PROCESS;U1:YIWEI PORT MAP(YIN,OP,CLK,Q); END BHV;5、仿真结果图4：仿真结果1图5：仿真结果2在图4中输入端的输入序列为'000011110000'，并行输出端Q为'01111000'，即在CS=0后的COUNT=2到COUNT=10的8位数据。
交流检测真有效值芯片原理介绍及实用电路1、真有效值数字电压表的基本原理利用真有效值(TRMS)数字仪表,可以准确、实时地测量各种波形的有效值电压,满足现代电子测量之需要。
,借助于电路对输入电压u进行“平方→ 取平均值→开平方”运算,就能获得交流电压的有效值。
因这是由有效值定义而求出的,故称之为真有效值。
目前生产的真有效值/直流转换器(如美国ADI公司的AD636、AD736,美国LT公司的LTC1966等),都是采用这种原理而设计的。
真有效值电压表比平均值电压表测量典型波形的误差更小。
下面来介绍工程上常用的LTC1966的原理及使用。
2、LTC1966工作原理LTC1966是美国凌特公司(LT)于2002年最新推出的真有效值RMS/DC转换器,与其他RMS/DC产品相比较,它在完成乘法／除法运算时,未采用通常的对数-反对数的计算方法,而是采用了全新的D-S计算技术。
LTC1966具有简单电路接法(只有一个外接平均CAVE)、灵活的输入／输出结构(差分或单端)、灵活的供电方式(2.7V~5.5V单电源,最大范围为±5.5V双电源)、高准确度(50Hz~1kHz的误差只有0.25%)、良好的线性(小于0.02%)、很宽的动态电流范围、易于校准等特性。
图1 LTC1966管脚排列及内部框图LTC1966采用MSOP-8封装,管脚排列及内部框图如图1所示,各引脚功能如下：GND—地;UIN1、UIN2—差分输入端1和2;USS—负电源端,对地接-5.5V电源或直接接地;UOUT—电压输出端。
RMS平均值是通过此引脚与COM引脚之间的平均值电容CAVE来实现转换。
COM—输出电压返回端。
输出电压的产生和该引脚的电压有关。
一般COM端接地,在AC+DC输入情况下,UOUT与COM引脚之间不平衡,该引脚应对地接一小电阻;UDD—正电源端。
电压范围为2.7V~5.5V;EN—使能控制端,低电平有效。
LTC1966内部主要包括4部分电路：D-S调制器、极性转换开关、低通滤波器(LPF)和关断控制电路。
第 21 卷 第 7 期2023 年 7 月太赫兹科学与电子信息学报Journal of Terahertz Science and Electronic Information TechnologyVol.21，No.7Jul.，2023一种真有效值测量方案设计与验证刘宁庄1，段富才1，文迪雅1，许龙2(1.西安科技大学电气与控制工程学院，陕西西安710600；2.中国计量大学理学院，浙江杭州310018)摘要：针对目前国内真有效值(RMS)测量芯片依赖进口的问题，提出了一种基于现场可编程门阵列(FPGA)的数字式高精确度的真有效值测量方案。
首先利用FPGA设计有限长单位冲击响应滤波器(FIR)对AD采样后的数据进行滤波，然后采用改进的有效值计算式计算信号的真有效值，最后取连续8个周期真有效值的平均值作为最终的测量结果。
通过设计串行的开方运算、除法运算的算法，降低FPGA的使用资源。
经过样机实际测试表明，测量结果与信号真值的相对误差低于0.5%。
该方案测量精确度高，一致性好，使用资源少，对于真有效值数字测量芯片的设计和真有效值测量具有一定的参考价值。
关键词：数字测量；真有效值；现场可编程门阵列；冲击响应滤波器；开方运算；除法运算中图分类号：TM932 文献标志码：A doi：10.11805/TKYDA2020738Design and verification of a true root mean square measurement schemeLIU Ningzhuang1，DUAN Fucai1，WEN Diya1，XU Long2(1.School of Electric and Control Engineering，Xi'an University of Science and Technology，Xi'an Shaanxi 710600；2.College of Science，China Jiliang University，Hangzhou Zhejiang 310018)AbstractAbstract：：A high-precision and digital true root mean square measurement method based on Field Programmable Gate Array(FPGA) is presented. Firstly, FPGA is employed to design Finite ImpulseResponse(FIR) filter to filter the AD sampled data. Furthermore, the improved RMS formula is adopted tocalculate the true RMS of the signal. The mean value of the true RMS value of eight consecutive cycles istaken as the final measurement result. By designing the algorithms of serial extraction and divisionoperations, the use of FPGA resources is reduced. The actual test of the prototype shows that the relativeerror between the measurement results and the true value of the signal is less than 0.5%. The solutionhas high measurement accuracy, good consistency, and less resources, which has certain reference valuefor the design of the true RMS digital measurement chip.KeywordsKeywords：：digital measurement；true root mean square；Field Programmable Gate Array；Finite Impulse Response filter；square root operation；division operation测量交流信号的真有效值对分析信号的功率以及其他参数都有重要意义[1-4]。
PYBJ15-Q24-S5-Mdate 06/24/2019page1 of 9SERIES: PYBJ15 │ DESCRIPTION: DC-DC CONVERTERFEATURES• up to 15 W isolated output• ultra wide 4:1 input voltage range • single regulated output• output short circuit, over current, over voltage protection • efficiency up to 89%• DIP and SMT mounting styles • available with or without case• 1500 Vdc isolationMODELinput voltageoutput voltageoutput currentoutput powerripple & noise 1efficiency 2typ (Vdc)range (Vdc)(Vdc)min (mA)max (mA)max (W)max (mVp-p)typ (%)PYBJ15-Q24-S3249~36 3.30450014.8510088PYBJ15-Q24-S5249~365030001510088PYBJ15-Q24-S12249~3612012501510089PYBJ15-Q24-S15249~3615010001510089PYBJ15-Q48-S34818~75 3.30450014.8510088PYBJ15-Q48-S54818~755030001510088PYBJ15-Q48-S124818~7512012501510089PYBJ15-Q48-S154818~751510001510089Notes: 1. From 5~100% load, nominal input, 20 MHz bandwidth oscilloscope, with 10 µF tantalum and 1 µF ceramic capacitors on the output. From 0~5% load, ripple and noise is <5% Vo.2. Measured at nominal input voltage, full load.3. All specifications are measured at T a=25°C, humidity < 75%, nominal input voltage, and rated output load unless otherwise specified.PART NUMBER KEYBase NumberPYBJ15 - Q XX - S XX - X XInput VoltageOutput VoltageCase:“blank” = with case O = no caseMounting Style:D = DIPM = SMTdate 06/24/2019 │page 2 of 9 CUI Inc │ SERIES: PYBJ15 │DESCRIPTION: DC-DC CONVERTERINPUTparameter conditions/description min typ max unitsoperating input voltage24 Vdc input models48 Vdc input models 91824483675VdcVdcstart-up voltage24 Vdc input models48 Vdc input models 918VdcVdcsurge voltage24 Vdc input models for 1 second max48 Vdc input models for 1 second max -0.7-0.750100VdcVdcunder voltage shutdown24 Vdc input models48 Vdc input models 5.5126.515.5VdcVdccurrent 24 Vdc input models3, 5 Vdc output models12, 15 Vdc output models727718mAmA48 Vdc input models 3.3 Vdc output models5 Vdc output models363360mAmAstart-up current24 Vdc input models48 Vdc input models 3,0001,500mAmAremote on/off (CTRL)4turn on (CTRL pin pulled low to GND (0~1.2 Vdc))turn off (CTRL pin open or pulled high (3.5~12 Vdc))input current when switched off615mAalarm indication (ALM)Valm (relative to GND), when under voltage protection isgoing to happen, and during the over voltage protectionworking status.0.2 1.2Vdc Valm (relative to GND), other working status 3.59Vdcfilter Pi filterno load power consumption0.36W Notes: 4. The voltage of the CTRL pin is referenced to input GND pin.OUTPUTparameter conditions/description min typ max unitsmaximum capacitive load53.3, 5 Vdc output models12 Vdc output models15 Vdc output models4,7001,000820μFμFμFvoltage accuracy from 0% to full load±1±2% line regulation from low line to high line, full load±0.2±0.5% load regulation6from 5% to full load±0.5±1% switching frequency7PWM mode300kHz transient recovery time25% load step change, nominal input voltage300500μstransient response deviation 25% load step change, nominal input voltage3.3, 5 Vdc output modelsall other output models±3±3±8±5%%temperature coefficient at full load±0.03%/°C Note: 5. Tested at input voltage range and full load.6. At 0~100% load, the max load regulation is ±3%.7. Value is based on full load. At loads <50%, the switching frequency decreases with decreasing load for efficiency improvement.date 06/24/2019 │ page 3 of 9CUI Inc │ SERIES: PYBJ15 │ DESCRIPTION: DC-DC CONVERTER PROTECTIONSparameterconditions/description min typmax units over voltage protection output shut down 110160%over current protection hiccup, auto recovery110180230%short circuit protectionhiccup, continuous, auto recoverySAFETY AND COMPLIANCEparameter conditions/descriptionmin typ max units isolation voltageinput to output for 1 minute at 1 mA input to case 8 for 1 minute at 1 mA output to case 8 for 1 minute at 1 mA 1,500500500Vdc Vdc Vdc isolation resistance input to output at 500 Vdc input to case 8 at 500 Vdc output to case 8 at 500 Vdc 100100100MΩMΩMΩisolation capacitance input to output, 100 kHz / 0.1 V 1,000pFsafety approvals IEC 62368-1, EN 62368-1conducted emissions CISPR32/EN55032, class B (external circuit required, see Figure 2-a) radiated emissions CISPR32/EN55032, class B (external circuit required, see Figure 2-a)ESDIEC/EN61000-4-2, contact ±6 kV , class B radiated immunity IEC/EN61000-4-3, 10 V/m, class AEFT/burst IEC/EN61000-4-4, ±2 kV , class B (external circuit required, see Figure 2-b)surgeIEC/EN61000-4-5, line-line ±2 kV , class B (external circuit required, see Figure Figure 2-b)conducted immunity IEC/EN61000-4-6, 3 Vr .m.s, class A MTBF as per MIL-HDBK-217F , 25°C 1,000,000hoursRoHSyesNote:8. Only applies to versions with case.ENVIRONMENTALparameterconditions/description min typmax units operating temperature see derating curves-4085°C storage temperature -55125°C storage humidity non-condensing595%vibration10~150 Hz, for 60 minutes on each axis 5GDERATING CURVESO u t p u t L o a d (%)60801004020120 0Temperature Derating Curve(Output Load vs. Ambient Tempearature3.3, 5 Vdc output models)O u t p u t L o a d (%)60801004020120 070Temperature Derating Curve(Output Load vs. Ambient Tempearature12, 15 Vdc output models)date 06/24/2019 │ page 4 of 9CUI Inc │ SERIES: PYBJ15 │ DESCRIPTION: DC-DC CONVERTER MECHANICALparameterconditions/descriptionmintypmaxunits dimensionsDIP without case:3.3, 5 Vdc output models: 38.70 x 27.20 x 6.20 [1.524 x 1.071 x 0.244 inch]12, 15 Vdc output models: 38.70 x 27.20 x 5.80 [1.524 x 1.071 x 0.228 inch]mm mm DIP with case:3.3, 5 Vdc output models: 39.10 x 29.50 x 6.80 [1.539 x 1.161 x 0.268 inch]12, 15 Vdc output models: 39.10 x 29.50 x 6.40 [1.539 x 1.161 x 0.252 inch]mm mm SMT without case:3.3, 5 Vdc output models: 38.70 x 27.20 x 6.20 [1.524 x 1.071 x 0.244 inch]12, 15 Vdc output models: 38.70 x 27.20 x 5.80 [1.524 x 1.071 x 0.228 inch]mm mm SMT with case:3.3, 5 Vdc output models: 39.10 x 29.50 x 6.80 [1.539 x 1.161 x 0.268 inch]12, 15 Vdc output models: 39.10 x 29.50 x 6.40 [1.539 x 1.161 x 0.252 inch]mm mm case material aluminum alloyweightwithout case 3.3, 5 Vdc output models without case 12, 15 Vdc output models with case 3.3, 5 Vdc output models with case 12, 15 Vdc output models11.08.813.811.5g g g g10 Sec. Max.Wave Soldering Time4 Sec. Max.Peak Temp. 260°C Max.Time (sec.)T e m p e r a t u r e (°C )25020015010050SOLDERABILITYparameter conditions/descriptionmin typ max units hand soldering 1.5 mm from case for 10 seconds 300°C wave soldering 9see wave soldering profile260°C reflow soldering 10see reflow soldering profileMaximum duration >217°C is 60 seconds.For actual application, refer to IPC/JEDEC J-STD-020D.1245°CNote: 9. For DIP models only. 10. For SMT models only.50100150200250245217T e m p e r a t u r e (°C )Time (sec.)60 sec max (>217°C)Peak Temp 245°CWave Soldering Proflile(DIP models)Reflow Soldering Profile(SMT models)date 06/24/2019 │ page 5 of 9CUI Inc │ SERIES: PYBJ15 │ DESCRIPTION:DC-DC CONVERTER units: mm [inch]tolerance: ±0.50[±0.020]pin section tolerance: ±0.10[±0.004]Recommended PCB LayoutTop Viewunits: mm [inch]tolerance: ±0.50[±0.020]pin section tolerance: ±0.10[±0.004]MECHANICAL DRAWING (DIP WITH CASE )Recommended PCB LayoutTop ViewMECHANICAL DRAWING (DIP WITHOUT CASE )PIN CONNECTIONS PIN Function 1+Vo 2+Vo 3+Vo 40V 50V 6NC 7ALM 8CTRL 9NC 10+Vin 11+Vin 12GND 13GND PIN CONNECTIONS PIN Function 1+Vo 2+Vo 3+Vo 40V 50V 6NC 7ALM 8CTRL 9NC 10+Vin 11+Vin 12GND 13GND 14NCNote: NC = no connectdate 06/24/2019 │ page 6 of 9CUI Inc │ SERIES: PYBJ15 │ DESCRIPTION: DC-DC CONVERTER units: mm [inch]tolerance: ±0.50[±0.020]pin section tolerance: ±0.10[±0.004]MECHANICAL DRAWING (SMT WITHOUT CASE )Recommended PCB LayoutTop Viewunits: mm [inch]tolerance: ±0.50[±0.020]pin section tolerance: ±0.10[±0.004]MECHANICAL DRAWING (SMT WITH CASE )PIN CONNECTIONS PIN Function 1+Vo 2+Vo 3+Vo 40V 50V 6NC 7NC 8ALM 9CTRL 10NC 11+Vin 12+Vin 13GND 14GND Recommended PCB LayoutTop ViewPIN CONNECTIONS PIN Function 1+Vo 2+Vo 3+Vo 40V 50V 6NC 7NC 8ALM 9CTRL 10NC 11+Vin 12+Vin 13GND 14GND 15NCNote: NC = no connectdate 06/24/2019 │page 7 of 9 CUI Inc │ SERIES: PYBJ15 │DESCRIPTION: DC-DC CONVERTERAPPLICATION CIRCUITFigure 1 Table 1Vin+Vo0V Vout(Vdc)Cin(μF)Cout(μF)3.3/5/12/1510010This series has been tested according to the following recommended circuit (Figure 1) before leaving the factory. If you want to further reduce the input and output ripple, you can increase the input and output capacitors or select capacitors of low equivalent impedance provided that the capacitance is less than the maximum capacitive load of the model.EMC RECOMMENDED CIRCUITTable 2Figure 2Recommended External Circuit ComponentsVin (Vdc)2448FUSE choose according to actual input currentC0470 µF / 50 V680 µF / 100 VC1, C2 4.7 µF / 50 V 4.7 µF / 100 VC3refer to the Cout in T able 1C4330 µF / 50 V330 µF / 100 VLCM1 4.7 µHCY1, CY22000 pF /2 kVdate 06/24/2019 │page 8 of 9 CUI Inc │ SERIES: PYBJ15 │DESCRIPTION: DC-DC CONVERTERPACKAGINGunits: mmInner Carton Size: 280 x 196 x 63 mmOuter Carton Size: 600 x 285 x 225 mmOuter Carton QTY: 288 pcsdate 06/24/2019 │ page 9 of 9CUI Inc │ SERIES: PYBJ15 │ DESCRIPTION: DC-DC CONVERTER CUI offers a two (2) year limited warranty. Complete warranty information is listed on our website.Headquarters20050 SW 112th Ave.Tualatin, OR 97062800.275.4899Fax 503.612.2383cui .com*******************rev.description date 1.0initial release06/24/2019The revision history provided is for informational purposes only and is believed to be accurate.REVISION HISTORYPYBJ15-Q24-S5-M。
C919试飞测试设备供电系统多重保护技术薛建良;葛红娟;徐于松;张璐【摘要】针对C919试飞测试设备供电系统的高可靠性要求,在采用三通道分级供电和冗余供电的基础上,提出该系统的多重保护方案,设计并研制了包含输入过欠压保护、输出过欠压和过流保护、过温保护、输出电压纹波保护及冷却风扇失速保护等多重保护电路,详细分析了基于无限增益多路负反馈二阶高通滤波技术的纹波保护电路和基于可预置同步/异步二进制减法计数芯片CD40103的冷却风扇失速保护电路.仿真和实验测试表明:当实际输入电压、输出电压及过载能力等超出设计范围时,系统实现了保护功能,且与预期设计指标相吻合.【期刊名称】《中国民航大学学报》【年(卷),期】2019(037)001【总页数】5页(P12-16)【关键词】C919供电系统;多重保护技术;纹波保护;冷却风扇失速保护【作者】薛建良;葛红娟;徐于松;张璐【作者单位】南京航空航天大学民航学院,南京 211106;南京航空航天大学民航学院,南京 211106;南京航空航天大学民航学院,南京 211106;南京航空航天大学民航学院,南京 211106【正文语种】中文【中图分类】V242.2C919试飞测试设备供电系统[1]是指通过抽引飞机本体115 V的交流电转换成28 V直流电，并以航空蓄电池组为备用电源，经控制保护切换电路，为各类试飞测试设备进行供电管理的电气系统。
测试供电系统的工作状态将直接影响试飞测试设备的正常工作和飞机的飞行安全，因此，监测和保护该供电系统，对于机载系统设备的安全性尤为重要。
传统的机载电源系统保护方案[2-4]主要包括过欠压保护和过流保护，保护形式单一且器件较多。
近几年的研究多集中在提高器件集成度、优化电路设计等方面，如利用LTC4364浪涌抑制器进行限压限流[5]、利用单片机C8051F120实现智能监测和控制[6]等。
由于该系统存在AC/DC变换单元，经整流滤波后输出的直流电压中含有一定的交流分量，为确保交流分量有效值在技术指标的允许范围内，需要对输出电路的纹波电压进行监测。
交流输入电压、电流监测电路设计引言电子设备只有在额定电压、电流下才能长期稳定工作，因此需要设计相应的监测、保护电路，防止外部输入电压或者负载出现异常时造成设备损毁。
工频交流电压、电流的大小，通常是利用它的有效值来度量的。
有效值的常用测量方法是先进行整流滤波，得出信号的平均值，然后再采用测量直流信号的方法来检测，最后折算成有效值。
但是由于供电主回路中存在大量的非线性电力、电子设备，如变压器、变频器、电机、UPS、开关电源等，这些设备工作时会产生谐波等干扰。
大型电动设备启动、负载突然变化、局部短路、雷电等异常情况出现时，供电主回路中会出现浪涌。
当这些情况发生时，供电线路上已不是理想的正弦波，采用平均值测量电路将会产生明显的测量误差。
利用真有效值数字测量电路，可以准确、实时地测量各种波形的电压、电流有效值。
下面介绍的监测电路安装于配电箱中，与外围保护电路一起实现对电子设备保护的功能。
真有效值数字测量的基本原理电流和电压的有效值采集电路原理基本相同，下面以电压真有效值为例进行原理分析。
所谓真有效值亦称真均方根值(TRMS)。
众所周知，交流电压有效值是按下式定义的：分析式(1)可知，电路对输入电压u进行“平方→取平均值→开平方”运算，就能获得交流电压的有效值。
因这是由有效值定义式求出的，故称之为真有效值。
若将式(1)两边平方，且令，还可以得到真有效值另一表达式URMS=式(3)中，Avg表示取平均值。
这表明，对u依次进行“取绝对值→平方/除法→取平均值”运算，也能得到交流电压有效值。
式(3)比式(2)更具有实用价值。
由于同时完成两步计算，与分步运算相比，运算器的动态范围大为减小，既便于设计电路，又保证了准确度指标。
美国模拟器件公司(ADI)的AD536、AD637、AD737系列单片真有效值/直流转换器，即采用此原理设计而成。
而凌力尔特公司的单片真有效值/直流转换器LT1966、LT1967、LT1968在RMS-DC的转换过程中采用一个∆∑调制器作除法器，一个简单的极性开关作乘法器。
什么是DC-DC转换？该内容转载自EDC电驱未来DC-DC转换器是一种电气系统（设备），它将直流（DC）源从一个电压电平转换为另一个电压电平。
换句话说，DC-DC转换器将直流输入电压作为输入，并输出不同的直流电压。
输出的直流电压可以高于或低于直流输入电压。
顾名思义，DC-DC转换器仅适用于直流（DC）源，而不适用于替代电流（AC）源。
DC-DC转换器也称为DC-DC电源转换器或电压调节器。
图片：DC-DC转换器的工作原理如果我们有两个电气系统，在不同的电压水平下工作，一个高电平（140 V），另一个低电平（14 V），DC-DC转换器可以将它们之间的电压从高转换为低或从低到高。
从一个电压电平到另一个电压杠杆的转换是在一些功率损耗的情况下完成的。
根据DC-DC转换器的工作点（电压和电流）和转换器的类型，效率可以在75%至95%或更高之间。
电池电动汽车（BEV）中的DC-DC转换器用于将高电池电压（例如400 V）转换为低直流电压（例如12 V），用于传统的12 V负载（灯，多媒体，电动车窗等）。
DC-DC转换器是一种功率转换器，它通过暂时存储输入能量，然后将该能量释放到不同电压的输出，将直流电源（DC）从一个电压电平转换为另一个电压电平。
电能的存储可以在磁场存储组件（电感器，变压器）或电场存储组件（电容器）中完成。
直流-直流转换器的效率电功率P [W]是电压U [V]和电流I [A]之间的乘积。
P=U⋅I例如，如果输入电压Uin= 120 V，最大电流Iin= 5 A，这将给出输入功率：Pin=120⋅5=600 W由于电功率是守恒的（Pout=Pin），并且我们假设DC-DC转换器没有损耗（100%效率），对于输出电压Uout= 14 V，我们可以计算输出电流如下：实际上，转换将产生一些损耗，最大输出电流将小于100%效率计算的电流。
DC-DC转换器的效率计算公式为：η [%]=PoutPin⋅100有几种类型的DC-DC转换器。
DC/DC ConverterUL60950-1 certifiedCSA/CAN C22.2 60950-1-07 certified UL62368-1 certifiedCSA/CAN C22.2 62368-1 certified CSA/CAN C22.2 60601-01 certified ANSI/AAMI ES60601-1 certified EN55011 certified CB reportY E A Rwa r r a n ty52MOPP 250VACE314885RoHS 2+compliant10 from 1020 Watt4:1 Input1.6“ x 1“Single and DualOutputREM20-W Selection GuidePart Input Output Output Efficiency Max. CapacitiveNumber Voltage Range Voltage Current typ. (1) Load(2)[VDC] [VDC] [mA] [%] [µF]REM20-2405SW (3)9-36 5 4000 87 5000REM20-2412SW (3) 9-36 12 1667 88.5 850REM20-2415SW (3) 9-36 15 1333 88 700REM20-2424SW (3) 9-36 24 833 88 220REM20-4805SW (3) 18-75 5 4000 89.5 2500REM20-4812SW (3)18-75 12 1667 88 500REM20-4815SW (3)18-75 15 1333 88 350REM20-4824SW (3) 18-75 24 833 88.5 5000REM20-2405DW (3) 9-36 ±5 ±2000 86 ±850REM20-2412DW (3) 9-36 ±12 ±833 88 ±700REM20-2415DW (3) 9-36 ±15 ±667 88 ±220REM20-4805DW (3) 18-75 ±5 ±2000 86 ±2500REM20-4812DW (3)18-75 ±12 ±833 88.5 ±500REM20-4815DW (3)18-75±15 ±667 88±350Notes:Note1: Efficiency is tested at nominal input and full load at +25°C ambient Note2: Max Cap Load is tested at nominal input and full resistive loadDescriptionThe REM20-W series of medical grade regulated DC/DC converters features reinforced 5kVAC/1 minute isolation with low 2µA leakage (B, BF and CF compatible) and are 60601-1 3rd Ed. certified for 250VAC continuous working voltage isolation. The industry standard 1.6”x1” package offers tightly regulated single and dual outputs, with low output ripple and zero-load operation. The outputs are also short circuit and overload protected. The converters are certified to CB, IEC/EN and ANSI/AAMI standards and carry the UL mark.“CTRL pin option (positive logic)”W ide Input Voltage Range (4:1)S ingle or D ualOutput Power nom. Input Voltage nom. Output VoltageREM20- __ __ _ W/PModel NumberingNotes:Note3: standard is with suffix …/P“ (CTRL pin with positive logic) without suffix is without CTRL pin (no pin) please refer to “Dimension Drawing (mm)”Ordering Examples:REM20-2412SW/P = 4:1 Input, 9-36Vin, 12Vout, with control pin positive logic REM20-4815DW = 4:1 Input, 18-75Vin, ±15Vout, without control pinSpecifications (measured @ Ta= 25°C, nominal input voltage. full load and after warm-up)Specifications (measured @ Ta= 25°C, nominal input voltage, full load and after warm-up)Specifications (measured @ Ta= 25°C, nominal input voltage, full load and after warm-up)Trim up12345678910[%]Vout set =12.1212.2412.3612.4812.6012.7212.8412.9613.0813.20[VDC]R up (E96) ≈205k 100k 64k947k536k529k424k920k117k915k8[W ]Trim up12345678910[%]Vout set = 5.05 5.10 5.15 5.20 5.25 5.30 5.35 5.40 5.45 5.50[VDC]R up (E96) ≈255k 127k 82k561k948k740k234k830k126k123k7[W ]REM20-xx12SW(/P)REM20-xx05SW(/P)Trim down12345678910[%]Vout set =11.8811.7611.6411.5211.4011.2811.1611.0410.9210.80[VDC]R down (E96) ≈ 768k383k249k182k143k118k97k684k573k263k4[W ]Trim down12345678910[%]Vout set =4.95 4.90 4.85 4.80 4.75 4.70 4.65 4.60 4.55 4.50[VDC]R down (E96) ≈ 249k121k78k756k244k235k729k424k921k18k2[W ]Trim up12345678910[%]Vout set =15.1515.3015.4515.6015.7515.9016.0516.2016.3516.50[VDC]R up (E96) ≈162k 78k749k936k528k 22k618k715k813k311k5[W ]Trim up11121314151617181920[%]Vout set =16.6516.8016.9517.1017.2517.4017.5517.7017.8518.00[VDC]R up (E96) ≈10k 8k87k66k86k 5k34k64k13k63k2[W ]REM20-xx15SW(/P)Trim down12345678910[%]Vout set =14.8514.7014.5514.4014.2514.1013.9513.8013.6513.50[VDC]R down (E96) ≈825K402k261k191k150k124k105k88k776k868k1[W ]Trim CalculationVout nom R 1R 2k u V ref5VDC 5k1W 2k W 2.5 2.5VDC 12VDC 10k W 5k1W 9.515VDC 10k W 5k1W 12.524VDC56k W13k W21.5Practical Example REM20-1212SW +10% / -10%:Calculation:Vout nom = nominal output voltage [VDC]Vout set = trimmed output voltage [VDC]V ref = reference voltage [VDC]R up = trim up resistor [W ]R down = trim down resistor [W ]R 1 & R 2 = internal resistors [W ]k u = trim up factor[ ]R up =10k x 2.5- 5k1 =15k7W13.2 - 2.5 - 9.5R up according to E96 ≈ 15k8WR down according to E96 ≈ 64k3WR down =(10.8 - 2.5) x 10k- 5k1 =64k1W12 - 10.8R down =(Vout set - V ref ) x R 1- R 2Vout nom - Vout setR up =R 1 x V ref - R 2Vout set - V ref - k uSpecifications (measured @ Ta= 25°C, nominal input voltage, full load and after warm-up)PROTECTIONSParameterCondition ValueShort Circuit Protection (SCP) (6)continuous, auto-recovery Over Load Protection (OLP)% of Iout ratedhiccup mode, 150% - 185%Output Over Voltage Protection (OVP)Zener diode clamp5Vout 12Vout 15Vout 24Vout 6.2VDC typ.15VDC typ.20VDC typ.30VDC typ.Over Temperature Protection (OTP)at tc point (refer to “Dimension Drawing (mm)”)+115°C typ.Isolation Voltage (5)I/P to O/P working voltagetested for 1 minute continuous5kVAC 250VAC Isolation Resistance 2G W min.Isolation Capacitance 20pF max.Leakage Current 240VAC, 60Hz 2µA typ. / 2.5µA max.Insulation Grade reinforcedMeans of Protection 2MOPPMedical Device Classification built-in power supplyClearance/Creepage>8.0mmTrim up12345678910[%]Vout set =24.2424.4824.7224.9625.2025.4425.6825.9226.1626.40[VDC]R up (E96) ≈576k 280k 182k 133k 105k 84k569k895k352k345k3[W ]Trim up11121314151617181920[%]Vout set =26.6426.8827.1227.3627.6027.8428.0828.3228.5628.80[VDC]R up (E96) ≈40k235k731k628k726k123k721k519k617k916k2[W ]REM20-xx24SW(/P)Trim down12345678910[%]Vout set =23.7623.5223.2823.0422.8022.5622.3222.0821.8421.60[VDC]R down (E96) ≈4M992M431M621M18931k768k649k562k487k432k[W ]Notes: Note5: For repeat Hi-Pot testing, reduce the time and/or the test voltageNote6: Refer to local safety regulations if input over-current protection is also required. Recommended fuse: slow blow typeREGULATIONSParameterCondition ValueOutput Accuracy ±1.0% max. Line Regulation low line to high line Single Output ±0.2% max.Dual Output ±0.5% max.Load Regulation no load to full loadSingle Output 0.2% max.Dual Output 1.0% max.Cross Regulation assymetrical load 25% / 100% full loadonly Dual Output±5.0% max.Transient Responserecovery time25% load step change100µs typ. / 250µs max.Specifications (measured @ Ta= 25°C, nominal input voltage, full load and after warm-up)SAFETY AND CERTIFICATIONSCertificate Type (Safety)Report / File Number StandardInformation Technology Equipment, General Requirements forSafetyE196683UL60950-1, 2nd Edition, 2014 CAN/CSA-C22.2 No. 60950-1-07, 2nd Edition, 2014Audio/video, information and communication technology equip-ment. Safety requirementsUL62368-1 CAN/CSA-C22.2 No. 62368-1Medical Electric Equipment, General Requirements for Safety and Essential Performance E314885ANSI/AAMI ES60601-1 (2005/R2012 + A1:2012), 2012CAN/CSA-C22.2 No. 60601-1:14, 3rd Edition, 2014-03Medical Electric Equipment, General Requirements for Safety andEssential Performance (CB Scheme)180505201IEC60601-1:2005, 3rd Edition + AM1:2012 RoHS2+RoHs 2011/65/EU + AM2015/863Specifications (measured @ Ta= 25°C, nominal input voltage. full load and after warm-up)DIMENSION and PHYSICAL CHARACTERISTICSParameter Type ValueMaterialcasebaseplatepottingnon-conductive black plastic (UL94-V0)non-conductive black plastic (UL94-V0)silicone (UL94-V0)Dimension (LxWxH)40.6 x 25.4 x 10.2mm Weight24g typ.The product information and specifications may be subject to changes even without prior written notice.The product has been designed for various applications; its suitability lies in the responsibility of each customer. The products are not authorized for use in safety-critical applications without RECOM’s explicit written consent. A safety-critical application is an application where a failure may reasonably be expected to endanger or cause PACKAGING INFORMATIONParameterTypeValuePackaging Dimension (LxWxH) tube290.0 x 43.5 x 19.7mmPackaging Quantity 10 pcsStorage Temperature Range -55°C to +125°C Stoarge Humiditynon-condensing5% to 95% RH max.。
DC/DC Convert erIEC/EN60950-1 certified1-2 AmpSIP12Vertical & REACHcompliantRoHS 2+compliant10 from 10Y E A Rwa r r a n ty3FeaturesSwitching Regulator• Non-isolated• Adjustable output voltage• 1-2AMP adjustable positive step down integrated switching regulator • Internal short circuit protection • ON/OFF control (ground off)• Efficiency up to 97%• Positive to negative converterDescriptionThe R-6xxx series is a high performance 1.5V to 15V (18V), 1.1 Amp to 2Amp, 12-Pin SIP (single in-line package) switching regulator. The Synchronous rectification yields excellent efficiencies up to 97%. Short circuit protection reduces the short circuit input current to under 50mA.R-6xxxP_DNote1: Vin-Vout ≥ 1.5V if adjust function is usedNote2: please refer to basic characteristics on page I-2Notes:Note3: x can be …P“ = vertical through hole x can be …D“ = bent for horizontal through hole mountingModel NumberingOrdering Examples:R-612.5P Iout= 1000mA nom. Vout= 2.5VDC P= vertical through holeR-623.3D Iout= 2000mA nom. Vout= 3.3VDCD= bent for horizontal through hole mountingPinning (3)Output Current (A)nom. Output VoltageR-6_ __ xSpecifications (refer to standard application circuit, Ta= 25°C)Specifications (refer to standard application circuit, Ta= 25°C)Specifications (refer to standard application circuit, Ta= 25°C)Trim Tables or Calculation2ADC R-611.8P/D R-612.5P/D R-613.3P/D R-615.0P/D R-619.0P/D R-6112P/D3ADC R-621.8P/D R-622.5P/D R-623.3P/D R-625.0P/D R-629.0P/D R-6212P/DVout nom. 1.8VDC 2.5VDC 3.3VDC 5.0VDC9.0VDC12VDCVout adj.R down R up R down R up R down R up R down R up R down R up R down R up3.3 1.7kΩ 5.9kΩ9.7kΩ0Ω0Ω3.6 1.2kΩ 3.9kΩ18kΩ14kΩ 1.5kΩ560Ω3.9 2.8kΩ9.1kΩ20kΩ 3.3kΩ 1.2kΩ4.5 1.6kΩ 3.9kΩ60kΩ7.5kΩ 2.1kΩ5.0 2.4kΩ11kΩ 4.0kΩ5.1 2.2kΩ60kΩ12kΩ 4.3kΩ5.5 1.6kΩ15kΩ17kΩ 5.6kΩ6.0 1.1kΩ7.2kΩ24kΩ7.5kΩ7.0 2.8kΩ51kΩ12kΩ8.0 1.5kΩ130kΩ19kΩ9.0880Ω31kΩ10450Ω36kΩ55kΩ11180Ω15kΩ125kΩ128.2kΩ13 4.7kΩ11kΩ14 2.7kΩ 4.0kΩ15 1.3kΩ 1.6kΩPROTECTIONSParameter Condition Value Short Circuit Protection (SCP)continuous, automatic recovery Short Circuit Input Current Vin > 12VDC20mA typ. / 100mA max.Specifications (refer to standard application circuit, Ta= 25°C)ENVIRONMENTALParameterConditionValueOperating Temperature Range *************************************/s-40°C to +85°CMaximum Case Temperature +110°C Thermal Impedance @ natural convection 0.1m/s25°C/W Operating Humidity non-condensing95% RH max.Operating Altitude 2000m Pollution Degree PD2MTBFaccording to MIL-HDBK 217F, G.B.+25°C +71°C563 x 103 hours 117 x 103 hoursDIMENSION AND PHYSICAL CHARACTERISTICSParameterTypeValueMaterial case pottingnon-conducive black plastic, (UL94 V-0)epoxy, (UL94 V-0)Dimension (LxWxH)32.2 x 9.1 x 15.0mmWeight9g typ.SAFETY AND CERTIFICATIONSCertificate Type (Safety)Report / File NumberStandard Information Technology Equipment, General Requirements for Safety 1605077-12IEC60950-1:2005, 2nd Edition + AM2:2013EN60950-1:2006 + AM2:2013EAC RU-AT.49.09571TP TC 004/2011RoHS 2+RoHS-2011/65/EU + AM-2015/863Specifications (refer to standard application circuit, Ta= 25°C)Specifications (refer to standard application circuit, Ta= 25°C)PACKAGING INFORMATIONParameter Type ValuePackaging Dimensions (LxWxH)R-6xxxDR-6xxxP520.0 x 20.0 x 19.0mm530.0 x 23.0 x 19.0mmPackaging Quantity tube15pcs Storage Temperature Range-40°C to +125°CThe product information and specifications may be subject to changes even without prior written notice.The product has been designed for various applications; its suitability lies in the responsibility of each customer. The products are not authorized for use in safety-critical applications without RECOM’s explicit written consent. A safety-critical application is an application where a failure may reasonably be expected to endanger or cause。
DC-DC变换器原理DC/DC Converter Principle太阳电池输出的是直流电，是不是可直接作为直流电源使用呢，对于对电压没有准确要求的微、小型用电设备是可以的，如计算器、玩具等。
太阳电池输出电压取决于光伏器件的连接方式与数量，并与负载大小与光照强度直接有关，不能直接作为正规电源使用。
通过DC-DC变换器可以把太阳电池输出的直流电转换成稳定的不同电压的直流电输出。
DC-DC变换器就是直流——直流变换器，是太阳能光伏发电系统的重要组成部分，下面就其原理作简单介绍。
DC-DC变换基本原理直流变换电路主要工作方式是脉宽调制(PWM)工作方式，基本原理是通过开关管把直流电斩成方波（脉冲波），通过调节方波的占空比（脉冲宽度与脉冲周期之比）来改变电压。
降压斩波电路直流斩波电路简单，是使用广泛的直流变换电路。
图1左上部是一个斩波基本电路，Ud是输入的直流电压，V是开关管，UR是负载R上的电压，开关管V把输入的Ud斩成方波输出到R上，图1右上部绿线为斩波后的输出波形，方波的周期为T，在V导通时输出电压等于Ud，导通时间为ton，在V关断时输出电压等于0，关断时间为toff，占空比D=ton/T，方波电压的平均值与占空比成正比。
图1下部绿线为连续输出波形，其平均电压如红线所示。
改变脉冲宽度即可改变输出电压，在时间t1 前脉冲较宽、间隔窄，平均电压（UR1）较高；在时间t1 后脉冲变窄，平均电压（UR2）降低。
固定方波周期T不变，改变占空比调节输出电压就是(PWM)法，也称为定频调宽法。
由于输出电压比输入电压低，称之为降压斩波电路或Buck变换器。
图1 DC-DC变换基本原理方波脉冲不能算直流电源，实际使用要加上滤波电路，图2是加有LC滤波的电路，L是滤波电感、C2是滤波电容、D是续流二极管。
当V导通时，L与C2蓄能，向负载R输电；当V关断时，C2向负载R输电，L通过D向负载R输电。
输出方波选用的频率较高，一般是数千赫兹至几十千赫兹，故电感体积很小，输出波纹也不大。
1SYMBOL PARAMETER CONDITIONSBOARD SUFFIXVALUE V IN Input Voltage Range A & B 3.5V to 12.5V C 5.0V to 12.5V V OUTOutput VoltageLTC1265A 2.5V ±0.06V LTC1265-3.3B 3.3V ±0.10V LTC1265-5C 5.0V ±0.2VI Q Typical Supply Current I OUT = 0mA at 12.5V Input ALL 160µA In Shutdown at 12.5V InputALL 15µA I OUT Maximum Output Current ALL 1.0A V RIPPLETypical Output RippleBurst Mode Operation, I OUT= 100mA ALL 70mV P-P Continuous Mode Operation, I OUT = 1A ALL30mVP-PStep-Down DC/DC ConverterDESCRIPTIOUThis demonstration circuit is a step-down (buck) regulator using the LTC ®1265/LTC1265-3.3/LTC1265-5. Exclusive use of surface mount components results in a highly efficient application in a small board space. This demo board highlights the capabilities of the LTC1265 which uses a current mode, constant off-time architecture to switch an internal P-channel power MOSFET. This results in a power supply that has low ripple and fast transient response. At low load currents the LTC1265 automatically switches to Burst Mode TM operation to reduce switching losses and maintain high operating efficiencies. In drop-out, the internal P-channel MOSFET is turned on continu-ously (100% duty cycle) providing low dropout operation with V OUT ≅ V IN . The part can also be shut down, drawing less than 15µA, making this part ideal for current sensitive applications. An on-board low-battery detector allows the user to monitor the input supply through an external resistive divider. This divided voltage is compared with an internal 1.25V reference voltage. Gerber files for this circuit board are available. Call the LTC factory.TYPICAL PERFOR A CE CHARACTERISTICS A D BOARD PHOTOU UW LOAD CURRENT (A)0.0170E F F I C I E N C Y (%)758085901000.11DC074A • TA0195Efficiency vs Load CurrentBurst Mode is a trademark of Linear Technology Corporation.PERFOR A CE SU ARYU W WW2DEMO MANUAL DC074ASYMBOL PARAMETERCONDITIONSBOARD SUFFIXVALUE ∆V OUTTypical Load Regulation0mA < I OUT < 1A, V IN = 10V A 30mV 0mA < I OUT < 1A, V IN = 10V B 50mV 0mA < I OUT < 1A, V IN = 10VC 70mV V IH Shutdown Pin High Minimum Voltage at Pin 10 for Device to Be in Shutdown ALL 1.2V V IL Shutdown Pin Low Maximum Voltage at Pin 10 for Device to Be in ActiveALL 0.6V I QLow-Battery Trip PointALL1.25 ±0.1VPERFOR A CE SU ARYU W WWS PACKAGE14-LEAD PLASTIC SOIC *ADJ OUTPUT VERSIONSPWR V IN V IN LB OUT LB IN C T I TH SENSE –SW PWR V IN PGND SGND SHDN NC (V FB *) SENSE +LTC1265CS LTC1265CS-3.3LTC1265CS-5V OUT µF LTC1265 LTC1265-3.3 LTC1265-5PACKAGE A D SCHE ATIC DIAGRA SU W WPARTS LISTREFERENCE DESIGNATOR QUANTITYPART NUMBER DESCRIPTIONVENDOR TELEPHONE C11VJ1206A392KXAT Cap, Mono Chip, 3900pF, 50V, 10%Vitramon (203) 268-6261C21VJ1206U103MXAT Cap, Mono Chip, 0.01µF, 25V, 10%Vitramon C31VJ1206U104MXXAT Cap, Mono Chip, 0.1µF, 25V, 10%Vitramon C41VJ1206A101KXAT Cap, Mono Chip, 100pF, 50V, 10%Vitramon C51VJ1206A181JXAT Cap, Mono Chip, 180pF, 50V, 5%: Board AVitramon VJ1206A151JXAT Cap, Mono Chip, 150pF, 50V, 5% : Board B & C C61593D686X0020E2W Tantalum Cap, 68µF, 20V, 20%Sprague (207) 324-4140C71593D107X0010D2W Tantalum Cap, 100µF, 10V, 20%Sprague D11MBRS130LT3Schottky DiodeMotorola (602) 244-3558L11LPT4545-200Inductor, 20µH : Board A & B Dale(605) 665-9301LPT4545-330Inductor, 33µH : Board CFigure 1.3DEMO MANUAL DC074APARTS LISTREFERENCE DESIGNATOR QUANTITY PART NUMBER DESCRIPTION VENDOR TELEPHONE R1 1WSL2010-0.10.1Ω 1% 0.5W Resistor Dale (605) 665-9301R2 1CRCW1206499J 499Ω 5% Chip Resistor Dale R3 1CRCW1206223J 22k 5% Chip Resistor Dale RFB1, RFB2 1CRCW1206343J 34k 5% Chip Resistor: Board A Dale U11LTC1265CS Board A IC LTC(408) 432-1900LTC1265CS-3.3Board B IC LTC1265CS-5Board C ICQUICK START GUIDEThis demonstration board is easy to set up to evaluate the performance of the LTC1265. Please follow the procedure outline below for proper operation.•Connect the input power supply to the V IN and GND terminals.•The LB OUT pin is a current sinking pin. When the LB IN pin goes below 1.25V the LB OUT pin will sink 1mA of current.•The LB IN pin is the low battery detector input pin.Normally, its input comes from the input voltagethrough a resistive divider network (see LOW BAT-TERY DETECTOR).•Connect the load between the V OUT and GND terminals.•Refer to Figure 4 for proper arrangement of measure-ment equipment setup•The SHDN pin is pulled down to ground by R3. To put the part in shutdown, connect a voltage greater than 1.2V to this pin.OPERATIOUcurrent limit and excellent line and load regulation. The constant off-time adds to this list simplicity (neither an oscillator nor ramp compensation are required), inherent 100% duty cycle in dropout, and constant inductor ripple current.Because the off-time is constant, the operating frequency changes with input voltage. For example, in an LTC1265-3.3 application the frequency will double when V IN is increased from 4.7V to 8V with V OUT at 3.3V. To maximize the efficiency over a wide current range, loss reducing circuit techniques must be carefully applied. Because of the MOSFET gate charge, switching the gate from V IN to ground ends up as additional input current from V IN ,decreasing efficiency. At low output currents this loss term dominates. This is the principal reason that the LTC1265 changes to Burst Mode operation as the output current drops.The circuit shown in Figure 1 operates from input voltages of 3.5V to 12.5V. For Board A, the output voltage is set to 2.5V by the resistive dividers, RFB1 and RFB2. For Board A and Board B, the circuit is optimized at input voltage of 5V while Board C is optimized at a 9V input voltage. For all boards, the LTC1265 is operating at a frequency of 200kHz when at their respective optimized input voltage and the LTC1265 is operating in continuous mode.This demonstration unit is intended for the evaluation of the LTC1265 switching regulator IC and was not designed for any other purposes.OPERATIONThe LTC1265 switching regulator uses the constant off-time, current mode architecture shown in Figure 2.Current mode operation was judged to be mandatory for its well-known advantages of clean start-up, accurate4DEMO MANUAL DC074AOPERATIOUThe continuous mode operation is as follows: the internal P-channel MOSFET switch is turned on at the end of the off-time and turned off when the inductor current has ramped up to the current comparator threshold. During the off-time the catch diode D1 turns on. At the end of the constant off-time, the P-channel MOSFET is again turned on and the cycle repeats.LTC1265 Burst Mode is automatically invoked when the current required by the load is less than the minimum current supplied by the continuous operation. During Burst Mode operation the output voltage is regulated via a hysteretic comparator which, when tripped, shuts down the MOSFET driver and much of the control circuitry to conserve DC supply current. From the time the compara-tor trips until the lower comparator threshold is reached,the load current is completely supplied by a charge stored in the output capacitor. When the output capacitor dis-charges to the lower threshold, the main loop again briefly turns on at a low current level to recharge the capacitor.This cycle repeats at a progressively slower rate as the output current is reduced.LOW-BATTERY DETECTORThe low-battery indicator senses the input voltage through an external resistive divider. This divided voltage connects to the (–) input of a voltage comparator (Pin 4) which is compared with a 1.25V reference voltage. With the current going into pin 4 being negligible, the following expression is used for setting the trip limit:V LB_TRIP = 1.251 +R4R3))Figure 2. LTC1265 Block DiagramFigure 3. Low-Battery ComparatorV FBADJUSTABLE VERSIONV DC074A • F035DEMO MANUAL DC074AOPERATIOUHOW TO MEASURE VOLTAGE REGULATIONWhen trying to measure voltage regulation remember that all measurements must be taken at the point of regulation. This point is where the LTC1265’s control loop looks for the information to keep the output voltage constant. This information occurs between Pin 7 and Pin 11 of the LTC1265. These points correspond to the output terminals of the demonstration board. Test leads should be attached to these terminals. Measurements should not be taken at the end of test leads at the load . Refer to Figure 4 for proper monitoring equipment configuration.This applies to line regulation (input to output voltage regulation) as well as load regulation tests. In doing line regulation tests always look at the input voltage across the input terminals.For the purposes of these tests the demonstration circuit should be fed from a regulated DC bench supply, so additional variation on the DC input does not add an error to the regulation measurements.The technique used to measure the ripple is also impor-tant. Here is a list of things to do and not to do when using a scope probe:1.DO NOT USE THE GROUND LEADS/CLIPS THAT ARE ATTACHED TO THE SCOPE PROBE!2.DO ATTACH THE SHIELD OF THE PROBE BODY TO THE NEGATIVE SIDE OF THE OUTPUT CAPACITOR!DO NOT USE WIRE!3.DO PUT THE TIP OF THE SCOPE PROBE DIRECTLY ON THE POSITIVE TERMINAL OF THE OUTPUT CAPACITOR.4.DO NOT USE A PROBE WHOSE BODY IS NOT COMPLETELY SHIELDED.Any unshielded lead, such as a ground lead on a scope probe, acts as an antenna for the switching noise in the supply. Therefore any use of a ground lead will invalidate the measurement.Be extremely careful to ensure that other sources of noise do not invalidate the measurement. Noise from the 60Hz power line that feeds the bench power supply poweringDC074A • F04RIPPLE MEASUREMENTFor the purpose of measuring output ripple it is best to measure directly across the output terminals.As in the regulation tests the supply must be fed from a regulated DC source so that ripple on the input to the circuit under test does not add to the output ripple,causing errors in the measurement.Figure 4. Proper Measurement Setupthe LTC1265 demonstration board can cause errors in the measurement. This noise (especially spikes) can propa-gate through the bench supply and appear on the groundFigure 5. Scope Probe and Typical Measurement SetupDEMO MANUAL DC074Aof the demonstration unit. If this is a problem, a battery canbe used to power the unit for ripple tests.Also be wary of ground loops. The input DC supply shouldfloat and the only ground should be that of the scopeprobe. Never float the oscilloscope as it may present asafety hazard.An alternate technique is to take a 50Ω or 75Ω piece ofcoax and solder the leads directly to the output capacitor.Keep the shield over the center conductor for as great adistance as possible. The center conductor can pick up stray radiation when it is not shielded, so minimize thelength of exposed center conductor. The other end of thecoax should have a BNC connector for attaching to theoscilloscope.CHECKING TRANSIENT RESPONSESwitching regulators take several cycles to respond to astep in DC (resistive) load current. When a load stepoccurs, V OUT shifts by an amount equal to ∆I LOAD× ESR, where ESR is the effective series resistance of C OUT.∆I LOAD also begins to charge or discharge C OUT until the regulator loop adapts to the current change and returnsV OUT to its steady-state value. During this recovery time V OUT can be monitored for overshoot or ringing which would indicate a stability problem. The external compo-nents shown in the Figure 1 circuit will prove adequate for most applications.A second, more severe transient is caused by switching inloads with large (>1µF) supply bypass capacitors. Thedischarged bypass capacitors are effectively put in parallelwith C OUT, causing a rapid drop in V OUT. No regulator can deliver enough current to prevent this problem if the load switch resistance is low and it is driven quickly. The only solution is to limit the rise time of the switch drive so that the load rise time is limited to approximately 25 × C LOAD. Thus a 10µF capacitor would require a 250µs rise time, limiting the charging current to about 200mA.COMPONENTSComponents selection can be very critical in switching power supply applications. This section discusses some of the guidelines with selecting the different components. The LTC1265 data sheet details more specific selection criteria for most of the external components surrounding the IC. Be sure to refer to the data sheet if changes to this demo circuit are anticipated.CapacitorsThe most common component uncertainty with switching power supplies involves capacitors. In this circuit (refer to Figure 1) C6 and C7 are all specially developed low ESR, high ripple-current tantalum capacitors specifically designed for use in switching power supplies. ESR or Equivalent Series Resistance is the parasitic series resis-tance in the capacitor. Very often this resistance is the limiting element in reducing ripple at the output or input of the supply. Standard wet electrolytics may cause the feedback loop to be unstable (this means your power supply becomes an oscillator). They may also cause poor transient response or have a limited operating life. Standard parts normally do not have an ESR specification at high frequencies (100kHz) so, although you may find a part that works to your satisfaction in a prototype, the same part may not work consistently in production. Furthermore, surface mount versions of wet electrolytics are not space efficient, and they may have high ESR and limited lifetimes.Normal tantalums are not recommended for use in these applications (most notably the low cost ones) as they do not have the ability to take the large peak currents that are required for the application. Tantalums have a failure mechanism whereby they become a low value resistance or short. Wet electrolytics rarely short; they usually fail by going high impedance if over-stressed. Very few tantalum manufacturers have the ability to make capacitors for power applications.There are some tantalums, such as those used in this design, that are specifically designed for switching power supplies. They are much smaller than wet electro-lytic capacitors and are surface mountable but they do cost more.One other choice that fits between wet electrolytics and tantalums is organic semiconductor type capacitors (OS-CON) that are specifically made for power supply applications. They are very low ESR and are ≈1/2 the size of an equivalent wet electrolytic.OPERATIOU67DEMO MANUAL DC074AInformation furnished by Linear Technology Corporation is believed to be accurate and reliable.However, no responsibility is assumed for its use. Linear Technology Corporation makes no represen-tation that the interconnection of its circuits as described herein will not infringe on existing patent rights.InductorTo most engineers, inductors are the least familiar compo-nent in a switching power supply. This is unfortunate because the most flexible component in the system is the inductor. The size, shape, efficiency, form factor and cost are variables that can be traded off against one another.The only fixed requirement of the inductor used with the LTC1265 is that it must be able to support the output DC current and still maintain its inductance value.Although the inductor used in the demo board is from Dale, there are a wide variety of inductors available from other manufacturers. Sumida’s CDR 74B, CD75, CDR105B and CDR125 series are suitable for this demo board.In addition, Coilcraft’s DO3316 series and Coiltronics CTX series are also suitable in this demo board. However,re-characterizing the circuit for efficiency is necessary if any of the alternate inductors are used in place of the existing one.There are many inductors that will work in this circuit. Each inductor design will have a different physical size, different loss characteristics as well as different stray field patterns.All of these items must be considered to optimize a design.Because of the aforementioned variations in design and cost of inductor, we suggest you contact some of the inductor manufacturers in Table 1 and discuss your needs with them. Very often, a standard low cost solution which will meet your needs is on the shelf.Sense ResistorThe current sense resistor specified in the component list is manufactured by Dale. Alternate resistor sources include International Resistive Company and the SL, SP series by KRL/Bantry.Schottky DiodeThe catch diode carries load current during the off-time.The average diode current is therefore dependent on the P-channel switch duty cycle. At high input voltages the diode conducts most of the time. As V IN approaches V OUT the diode conducts only a small fraction of the time. The most stressful condition for the diode is when the output is short-circuited. Under this condition the diode must safely handle I PEAK at close to 100% duty cycle. A fastOPERATIOUswitching diode must also be used to optimize efficiency.Schottky diodes are a good choice for low forward drop and fast switching times. Most LTC1265 circuits will be well served by a MBRS130LT3 Schottky ponent ManufacturersBesides those components that are used on the demon-stration board, other components may also be used.Below is a partial list of the manufacturers whose compo-nents you can use for the switching regulator. Using components, other than the ones on the demonstration board, requires re-characterizing the circuit for efficiency.Table 1. Inductor ManufacturerMANUFACTURER PART NUMBERS CoilcraftD03316 Series1102 Silver Lake Road Cary, Illinois(Phone) 708-639-6400(Fax) 708-639-1469Coiltronics InternationalEcono-Pac 6000 Park of Commerce Blvd.Octa-PacBoca Raton, FL 33487(Phone) 407-241-7876(Fax) 407-241-9339Dale Electronics Inc.LPT4545E. Highway 50P.O. Box 180Yankton, SD 57078-0180(Phone) 605-665-9301(Fax) 605-665-1627Sumida Electric Co. Ltd.CD 74B Series 5999 New Wilke Rd., Suite #110CD 75 Series Rolling Meadows, IL 60008CDR105B(Phone) 708-956-0666(Fax) 708-956-0702Table 2. Capacitor ManufacturersMANUFACTURER PART NUMBERS AVX Corporation TPS SeriesP.O. Box 887Myrtle Beach, S.C. 29578(Phone) 803-448-9411(Fax) 803-448-1943Sanyo Video Components OS-CON Series2001 Sanyo Avenue San Diego, CA 92071(Phone) 619-661-6322(Fax) 619-661-1055Sprague593D Series678 Main Street Sanford, ME 04073(Phone) 207-324-4140(Fax) 207-324-72238DEMO MANUAL DC074A Linear Technology Corporation1630 McCarthy Blvd., Milpitas, CA 95035-7487(408) 432-1900 qFAX : (408) 434-0507 qTELEX : 499-3977© PCB LAYOUT A D FIL WUComponent Side Solder MaskSolder Side Solder MaskPC FAB DRAWI GUSYMBOLA B DIAMETER 0.094 0.018 NUMBEROF HOLES7 4 11TOTAL HOLES DC074A • PCB01Component SideSolder SideComponent Side Silkscreen。
