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 allows a controlled power up/down sequencing of the display. The output voltage can be increased or decreased in digital steps by applying a logic signal to the CTRL pin. The output voltage range, as well as the output voltage step size, can be programmed with the feedback divider network. With a high switching frequency of up to 1 MHz, the TPS61045 allows the use of small external components and together, with the small 8-pin QFN package, a minimum system solution size is achieved.

  • Input Voltage Range . . .1.8 V to 6 V
  • Output voltage of up to 28V possible
  • Up to 85% Efficiency
  • Digitally Adjustable Output Voltage Control
  • Disconnects Output From Input During Shutdown
  • Switching Frequency . . . Up to 1 MHz
  • No Load Quiescent Current . . . 40 µA Typ
  • Thermal Shutdown Mode
  • Shutdown Current . . . 0.1 µA Typ
  • Available in Small 3mm × 3mm QFN package
  • APPLICATIONS
    • LCD Bias Supply For Small to Medium LCD Displays
    • OLED Display Power Supply
      • PDA, Pocket PC, Smart Phones
      • Handheld Devices
      • Cellular Phones

DAC = 0V : Vo = 1.233 * ( 2200 / 390 ) + 1.233 * ( 1 + 2200/180 ) = 6.95V + 16.303V = 23.253V

DAC = 1.233V : V0 = 1.233 * ( 1 + 2200/180 ) = 16.303V

SETTING THE OUTPUT VOLTAGE (see Figure 1)


When the converter is programmed to the minimum output voltage,
the DAC output (DO) equals the reference voltage of 1.233 V (typ).

Therefore, only the feedback resistor network (R1) and (R2) determines the output voltage under these conditions.
This gives the minimum output voltage possible and can be calculated as:

The maximum output voltage is determined as the DAC output (DO) is set to 0 V:

the DAC output DO (pin 3) one-step where one step is typically 19.6 mV. ( 0..63 : 6 Bit DAC )

The DAC output pin (DO) drives an external resistor (R3) connected to the external feedback
divider. The DO output has a typical output voltage range from 0 V to Vref (1.233V). If the DO output voltage is
set to 0 V, the external resistor (R3) is more or less in parallel to the lower feedback resistor (R2) giving the
highest output voltage. Programming the DO output to Vref gives the lowest output voltage. Internally, a 6-bit DAC
is used with 64-steps and 0 as the first step. This gives a typical voltage step of 19.6 mV which is calculated as:

A voltage step on DO of 19.6mV (typ) changes the output voltage by one step and is calculated as:

The possible output voltage range is determined by selecting R1, R2 and R3.

A possible larger output voltage range gives a larger output voltage step size.

The smaller the possible output voltage range, the smaller the output voltage step size.

DIGITAL INTERFACE (CTRL)

When the CTRL pin is pulled high the device starts up with softstart
and the DAC output voltage (DO) sets to its center voltage with a typical output voltage of 607 mV.

The output voltage can be programmed by pulling the CTRL pin low for a certain period of time.

Depending on this time period the internal DAC voltage increases or decreases one digital step,
as outlined in Table 2 and Figure 16.

Programming the DAC output V(DO) to 0 V places R3 in parallel to R2, which gives the maximum output voltage.

If the DAC is programmed to its maximum output voltage equal to the internal reference voltage, typically V(DO) = 1.233 V,

then the output has its minimum output voltage.

数控、0.5%精度、更安全的APD偏置电源

MAX1932为光学接受器中的雪崩光电二极管(APD)产生一个低噪声、高电压输出。通过一个恒定频率的、脉宽调制(PWM) boost拓扑及一个独特的结构――该结构在反馈回路中加入可选择的RC或者LC后滤波器仍可保持稳定调压,得以达到非常低的输出纹波和噪声。一个精确的参考和误差放大器可以保持0.5%输出电压准确度。

MAX1932可以保护贵重的APD,抵制不利的工作条件,同时提供最优的偏压。传统的boost转换器通过测量开关电流来进行保护,而MAX1932集成了精确的高端限流特性来保护雪崩条件下的APD。一个限流标志位指示精确的雪崩击穿点以方便APD工作点的校准。MAX1932控制方式防止输出过冲和欠冲,可使APD安全工作而不发生数据丢失。

输出电压可以通过外部电阻器、内部8位DAC、外部DAC或者其他电压源来进行精确的调节。

输出范围和偏移都是可通过外部电阻器独立调节的。这可在要求一个受限制电压范围的应用中充分利用DAC的分辨率,

如输出4.5V至15V、4.5V至45V、20V至60V或40V至90V。

  • 电路板面积小
  • 电路高度<2mm
  • 2.7V至5.5V输入电压
  • 4.5V至90V输出电压范围
  • 无过冲
  • 精确的高端限流
  • 雪崩指示标记
  • 8位SPI兼容DAC
  • 和外部DAC兼容
  • 0.5%输出电压精度
  • 低输出电压纹波(< 1mV)
  • 小尺寸的12引脚,4mm x 4mm微型QFN封装

Output Control DAC

DACOUT = DAC code x (1.25V/256) + 1.25V/256.

An internal digital-to-analog converter can be used to control the output voltage of the DC-DC converter (Figure 2).

The DAC output is changed through an SPI™ serial interface using an 8-bit control byte.

On power-up, the DAC defaults to FF hex (1.25V), which corresponds to a minimum boost converter output voltage.
DAC Code = 0xFF : 0xFF * 1.25 / 256 + 1.25 / 256 = 1.25V

Alternately, the output voltage can be set with external resistors, an external DAC, or a voltage source.

Output span and offset are independently settable with externnal resistors.

See the Applications Information section for output control equations.

Output and DAC Adjustments Range

Many biasing applications require an adjustable output voltage,
which is easily obtained using the MAX1932’s DAC output (Figure 2).

The DAC output voltage is given by the following equation:

On power-up, DACOUT defaults to FF hex or 1.25V,
which corresponds to the minimum VOUT output voltage.

The voltage generated at DACOUT is coupled to FB through R6.
DACOUT can sink only 50µA so:

R6 >= 1.25V / 50uA = 25K

Select the minimum output voltage (VOUTFF),
and the maximum output voltage (VOUT01)
for the desired adjustment range.

R5 sets the adjustment span using the following equation:

R5 = (VOUTFF - VOUT01) * (R6/1.25V)

R8 sets the minimum output of the adjustment range with the following equation:

R8 = (1.25V ✕ R5)/(VOUTFF)

Setting the Output Voltage without  the DAC

Adjust the output voltage by connecting a voltagedivider from the output (VOUT) to FB
(Figure 2 with R6 omitted).

Select R8 between 10kΩ to 50kΩ. Calculate R5 with the following equation:

R5 = R8 * ( VOUT / 1.25V - 1 ) ::: VOUT = 1.25V * ( 1 + R5/R8 )

BOOST Converter Analog/Digital Adjusted Output Voltage TPS61045 MAX1932的更多相关文章

  1. Boost Converter

    Single Inductor Buck-Boost Converter in Tiny WCSP The TPS63036 is a non inverting buck-boost convert ...

  2. Digital Adjustment of DC-DC Converter Output Voltage in Portable Applications

    http://pdfserv.maximintegrated.com/en/an/AN818.pdf http://www.maximintegrated.com/app-notes/index.mv ...

  3. Use a microcontroller to design a boost converter

    Boost converters, like other switchers, have traditionally received their control signals from a ded ...

  4. Changing the Output Voltage of a Switching Regulator on the Fly

    http://www.powerguru.org/changing-the-output-voltage-of-a-switching-regulator-on-the-fly/ There are ...

  5. External components provide true shutdown for boost converter

    The step-up switching-converter circuit in Figure 1 presents a familiar problem: If you shut down bo ...

  6. Tracking Boost Regulator TYPICAL 5V REGULATION WITH BOOST CONVERTER AND LDO

    Cs5171: Tracking Boost Regulator Adding a current mirror circuit to a typical boost circuit allows t ...

  7. AX5511 Boost Converter

    GENERAL DESCRIPTION    The AX5511 is a current mode step up converter intended for small, low powera ...

  8. Digital Adjustment of DC-DC Converter Output Voltage 电阻选择

  9. Analog/digital converter (ADC)

    1.ADC1 and ADC2 are 10-bit successive approximation Anolog to Digital Converters. 所谓successive appro ...

随机推荐

  1. openstack环境下的虚拟机通过浮动IP访问后能ping通外网IP不能ping通域名

    1.环境简介 openstack环境下构造Ubuntu系统的VM,VM配置受管子网和自管子网,同时绑定浮动IP 2.通过浮动IP访问VM后,ping www.baidu.com失败,但是通过IP地址p ...

  2. Homestead在windows7 下的搭建

    遇到的问题有 1.Homestead 的版本问题,教程git版本是 v5,最新是v7的,如果用最新,就要求vagrant的版本是 2.0的: 2.启动homestead后,出现 No input fi ...

  3. JavaScript 兼容性总结

     请实现鼠标点击任意标签,alert该标签的名称(注意兼容性) function elementName(evt){ evt = evt|| window.event; var selected = ...

  4. 开源IDS系列--snorby 进程正常,但是worker无法启动 The Snorby worker is not currently running

    设置页面报错:   The Snorby worker is not currently running. It's imperative you start the worker immediate ...

  5. Codeforces Round #345 (Div. 1) D - Zip-line 带单点修改的LIS 主席树 | 离线树状数组

    D - Zip-line #include<bits/stdc++.h> #define LL long long #define fi first #define se second # ...

  6. Oracle 子查询和组函数练习

    SELECT * FROM emp; SELECT * FROM dept; 1.查询公司员工工资的最大值,最小值,平均值和总和. SELECT MAX(sal) AS 工资最大值, MIN(sal) ...

  7. JQuery插件ajaxFileUpload 异步上传文件(PHP版)

    太久没写博客了,真的是太忙了.善于总结,进步才会更快啊.不多说,直接进入主题. 前几天想在手机端做个异步上传图片的功能,平时用的比较多的JQuery图片上传插件是Uploadify这个插件,效果很不错 ...

  8. js获取URL中指定的值

    function getSearchString(key) { // 获取URL中?之后的字符 var str = location.search; str = str.substring(1,str ...

  9. 牛客网 牛客练习赛43 C.Tachibana Kanade Loves Review-最小生成树(并查集+Kruskal)+建虚点+读入挂

    链接:https://ac.nowcoder.com/acm/contest/548/C来源:牛客网 Tachibana Kanade Loves Review 时间限制:C/C++ 2秒,其他语言4 ...

  10. 2017-2018-1 20179202《Linux内核原理与分析》第二周作业

    本周着重学习了汇编指令,并通过反汇编C程序了解栈帧变化. 实践 看了孟老师的演示视频后,我重新写了C程序,如下: int main() { int a=1,b=2; return g(a,b); } ...