Boost converters, like other switchers, have traditionally received their control signals from a dedicated circuit. However, a recent trend is to integrate simple switching-power-supply building blocks into generic devices, such as microcontrollers.…

The step-up switching-converter circuit in Figure 1 presents a familiar problem: If you shut down boost converter IC1 by pulling its  input low, external inductor L1 and forward-biased Schottky diode D1 allow the load to continue drawing current. For…

Single Inductor Buck-Boost Converter in Tiny WCSP The TPS63036 is a non inverting buck-boost converter able to provide a regulated output voltage from an input supply that can be higher or lower than the output voltage. The buck-boost converter is ba…

DIGITALLY ADJUSTABLE BOOST CONVERTER The TPS61045 is a high frequency boost converter with digitally programmable output voltage and true shutdown. During shutdown, the output is disconnected from the input by opening the internal input switch. This…

Cs5171: Tracking Boost Regulator Adding a current mirror circuit to a typical boost circuit allows the user to select the amount of boost voltage and ensure a constant difference between input and output voltage.   This is useful for high side drive…

GENERAL DESCRIPTION    The AX5511 is a current mode step up converter intended for small, low powerapplications. The converter input voltage ranging from 2.6V to 5.5V. The Output voltage can be set up to 27V. The frequency is 1.2MHz allows the use of…

http://learn.adafruit.com/ice-tube-clock-kit/design Tubes such as VFDs, Nixies, Decatrons, etc require high voltage to light the gas in the tube. For nixies, this iabout 170VDC. VFDs aren't as bad they only need about 30-50VDC. In order to reduce cos…

It's a Buck; It's a Boost, No! It's a Switcher! Sanjaya Maniktala, National Semiconductor Corp., Santa Clara, CA We like to give everything a name or label very quickly. We probably feel we can then easily identify the object in the future, and also…

Targeting use in portable-system applications that require raising a battery's voltage to a higher level, IC boost regulators often include output transistors that can drive storage inductors. However, most boost regulators' absolute-maximum input-vo…

http://www.romanblack.com/smps/conv.htm What is it?  This is a simple smps voltage converter, it makes an output voltage of +13.3v from a "standard" +5v supply as used with logic chips. I was contacted by hobby PIC programmer legend Myke Predko …

http://electronicdesign.com/power/simple-addition-permits-voltage-control-dc-dc-converters-output In a standard dc-dc converter, a resistor divider typically defines a fixed output voltage. However, applications like programmable output voltage power…

2.3 Boost 变换器实例 图2.13(a)所示的Boost变换器器是另一个众所周知的开关模式变换器,其能够产生幅值大于直流输入电压的直流输出电压.图2.13(b)给出了使用MOSFET和二极管的开关的实际实现.让我们应用小纹波近似以及电感伏秒平衡和电容电荷平衡的原理来找到该变换器的稳态输出电压和电感电流. Fig 2.13 Boost converter example 将开关置于位置1时,电感器的右侧接地,从而形成图2.14(a)的电路.此子间隔的电感电压和电容电流为: \[v_{L}=…

3.5 示例:Boost变换器中包含的半导体传导损耗 作为最后一个示例,让我们考虑对图3.22所示的Boost变换器中的半导体传导损耗进行建模.功率损耗的另一个主要来源是半导体器件的正向电压降引起的传导损耗.金属氧化物场效应晶体管(MOSFET)或双极结型晶体管(BJT)的导通压降可以以合理建模为导通电阻\(R_{on}\).如果是二极管,绝缘栅双极型晶体管(IGBT)或晶闸管,则电压源加上导通电阻会得到精度非常高的模型:如果在单个工作点对变换器建模,则可以省略导通电阻. Fig 3.22 Bo…

5.3 Boost变换器实例 作为第二个示例,考虑图5.12的Boost变换器.让我们来确定不同模式的边界并且求解DCM下的电压变换比.此前在2.3节中分析了在CCM工作的Boost变换器的特性,并确定了电感电流直流分量\(I\)和纹波峰值幅度\(\Delta i_{L}\)的表达式. Fig 5.12 Boost converter example 当二极管导通时,其电流等于电感电流\(i_{L}(t)\),从图2.18可以看出,电感电流的最小值在二极管导通间隔期间,\(DT_{s}<t<T…

http://sourceforge.net/projects/openprogrammer/?source=navbar Open Programmer http://openprog.altervista.org/OP_eng.html#Quick Open Programmer v0.8.x Quick facts Completely free and Open Source (including firmware) Programs PIC10-12-16-18-24, dsPIC30…

http://en.wikipedia.org/wiki/Intel_cpus List of Intel Atom microprocessors List of Intel Xeon microprocessors List of Intel Itanium microprocessors List of Intel Celeron microprocessors List of Intel Pentium microprocessors List of Intel Pentium Pro…

http://uzzors2k.4hv.org/index.php?page=usbpicprog My Tait Serial programmer works alright, but not every computer has a parallel port, and these days they're almost extinct. Most laptop don't even have a serial port! Thinking ahead a USB programmer s…

The LM27313 switching regulator is a current-mode boost converter with a fixed operating frequency of 1.6 MHz. The use of the SOT-23 package, made possible by the minimal losses of the 800 mA switch, and small inductors and capacitors result in extre…

7.5 状态空间平均 现有文献中已经出现了很多变换器交流建模的方法,其中包括电流注入法,电路平均和状态空间平均法.尽管某种特定方法的支持者可能更愿意使用该方法去建模,但所有方法的最终结果都是等效的.并且所有人都具有这样的共识:平均和小信号的线性化是对PWM变换器建模的关键步骤. 本节将介绍文献中提到的状态空间平均法(S.´Cuk, Modeling, Analysis, and Design of Switching Converters, Ph.D. thesis, California In…

This is a tutorial on how to program the Serial Ports on your Linux box.Serial Ports are nice little interfaces on the PC which helps you to interface your embedded system projects using a minimum number of wires.In this tutorial we will write a smal…

http://dangerousprototypes.com/forum/viewtopic.php?t=170 It looks like the PICKIT2 uses a small boost converter. http://www.oshonsoft.com/picprogprousb.html USB Pro PIC-PIC18-PIC16-AVR Programmer USB Pro AVR Programmer Serial Port Pro PIC-PIC18-PIC16…

一.PFM模式 为什么升压中用的多呢(http://bbs.eetop.cn/thread-357181-1-1.html) 1.PFM 对于Boost Converter来说可以把PWM固有的右半平面零点搬移到高频.环路补偿较易 2.PFM环路是数字非线性控制,不需要补偿.没有升压用PFM控制方式多的说法,如果对效率要求高同时对纹波要求不高,可以用这种控制方式. 3.PFM的纹波大 二. PFM 的DC DC buck 需要另外设计补偿电路吗? (http://bbs.eetop.cn/thr…

In certain dc/dc-converter applications, on-chip, cycle-by-cycle current limit may be insufficient protection to prevent a failure during a short circuit. A nonsynchronous boost converter provides a direct path from the input to the short circuit thr…

http://www.ti.com/lit/an/slva299a/slva299a.pdf Many boost converters have an external rectifier diode. The input voltage of the TPS61170 main boost converter is connected to the output voltage when the device is disabled. Due to the direct pass from…

1.1 功率处理概论 电力电子领域关注的是利用电子设备对电力进行处理[1–7].如图1.1所示,其中关键部件就是开关变换器.通常,开关变换器包含电源输入和控制输入端口以及电源输出端口.原始输入功率按控制输入指定的方式进行处理,产生相应的条件输出功率.其可以执行以下几个基本功能之一[2].在DC-DC变换器中,直流输入电压被转换为具有更大或更小幅值的直流输出电压,也可能具有相反的极性,或者具有输入和输出参考地的隔离.在AC-DC整流器中,交流输入电压被整流,产生直流输出电压.可以控制直流输出电压和…

3.2 考虑电感铜损 可以拓展图3.3的直流变压器模型,来对变换器的其他属性进行建模.通过添加电阻可以模拟如功率损耗的非理想因素.在后面的章节,我们将通过在等效电路中添加电感和电容来模拟变换器动态. Fig 3.3 DC transformer 让我们来考虑下Boost电路中电感的铜损.实际电感器会表现出两种功率损耗:(1)由导线电阻导致的铜损:(2)由磁芯中的磁滞和涡流导致的磁芯损耗.图3.5给出了使用电感器与电阻\(R_{L}\)串联的结构描述了适合电感器铜损的模型.所以实际电感就是包含理想…

6.1 电路演化 第一章使用基本原理构建了buck变换器(图6.1).开关可以降低电压直流分量,低通滤波器可消除开关纹波.在CCM下,buck变换器的变换比为\(M=D\).buck变换器是最简单的,最基础的电路,我们将从这个电路得出其他电路. Fig 6.1 The basic buck converter 6.1.1 源荷反转 让我们首先考虑一下,如果将变换器的电源输入端口和电源输出端口互换会出现什么情况.在图6.2(a)的buck变换器中,电压\(V_{1}\)施加在端口1,电压\(V_{…

6.3 变压器隔离 在许多应用场合中,期望将变压器结合到开关变换器中,从而在变换器的输入输出之间形成直流隔离.例如,在离线(off-line)应用中(变换器输入连接到交流公用系统),根据监管部门要求,需要隔离.在这些情况下,只需要在变换器的交流输入端连接一个50Hz或者60Hz的变压器即可获得隔离.但由于变压器的尺寸和重量随频率成反比,因此通过将变压器并入变换器中恶意实现显著的改进, 使得变压器以数十或者百KHz频率工作. 当需要较大的升压或者降压变换比时,使用变压器可以优化变换器.通过合适的变…

7.2 基本交流建模方法 在本节中,PWM变换器的交流小信号模型导出步骤将被推导和解释.关键步骤是:(a)利用小纹波近似的动态版本,建立了与电感和电容波形的低频平均值相关的方程式,(b)平均方程的扰动和线性化,(c)交流等效电路模型的构建. 以图7.7所示的buck-boost变换器为例.按照以往相同的方式,分析以确定电感和电容的电压电流波形开始.当开关处于位置1时,可以获得图7.8(a)所示的电路.电感电压和电容电流为: \[v_{L}(t)=L \frac{di(t)}{dt}=v_{g}(…

7.4 规范电路模型 在讨论了推导开关变换器交流等效电路模型的几种方法后,让我们先停下来,说明下这些结果.所有的在 CCM下以PWM工作的DC-DC变换器都具有相似的基本功能.首先,他们在理想情况下,以100%效率对电压或者电流等级进行转换.其次,他们包含对波形的低通滤波器.尽管必须滤除高频开关纹波,但这种滤波也会影响到低频电压和电流的变化.第三,可以通过占空比的变化来控制变换器的波形. 我们期望具有相似物理特性的变换器具有相似的等效电路结构.因此,我们可以定义一个规范电路模型,来正确说明所有这…