积分商城

最新搜索： STM32上实现FFT 电子元器件快速识别与检测 激光 STC单片机原理 GL3510 QCPL-RB5C
您现在的位置是：首页 > 技术资料 > 如何测试输出纹波和噪声电源
推荐星级：
  • 1
  • 2
  • 3
  • 4
  • 5

如何测试输出纹波和噪声电源

更新时间：2019-12-19 16:20:04 大小：32K 上传用户：yuyw99查看TA发布的资源 标签：电源 下载积分：2分 评价赚积分 （如何评价?） 打赏 收藏 评论(0) 举报

资料介绍

The switching power supplies (either step-down
regulators, or isolated DC-DC converters, or OFFLINE power supplies) have the fundamental advantage of high efficiency i.e. low power dissipation
when compared to linear voltage regulation.
However the switching technique, that is beneficial
to raise the efficiency, has an associated weakness
i.e. the output voltage has always an AC content.
The typical output ripple and noise of a switching
power supply is as shown in fig. 1

部分文件列表

文件名 大小
HOW_TO_TEST_OUTPUT_RIPPLE_AND_NOISE.pdf 32K

【关注视频号领20积分】   【关注公众号立即送20积分】

部分页面预览

（完整内容请下载后查看）
APPLICATION NOTE  
HOW TO TEST OUTPUT RIPPLE AND NOISE OF  
POWER SUPPLIES  
The switching power supplies (either step-down  
However the switching technique, that is beneficial  
to raise the efficiency, has an associated weakness  
i.e. the output voltage has always an AC content.  
The typical output ripple and noise of a switching  
power supply is as shown in fig. 1.  
regulators, or isolated DC-DC converters, or OFF-  
LINE power supplies) have the fundamental advan-  
tage of high efficiency i.e. low power dissipation  
when compared to linear voltage regulation.  
Figure 1. Output ripple and noise of a switching power supply  
Four AC components can be identified:  
The above mentioned parameters are normally  
specified by the peak to peak amplitude so that the  
best method for testing is by an oscilloscope with a  
bandwidth of 20 MHz.  
-
low frequency ripple at 2f being f the AC mains  
frequency  
-
high frequency ripple due to Pulse Width Modu-  
lation (PWM) to obtain the required line and load  
regulation.  
Care must be taken when using the scope probe.  
Fig. 2 shows a wrong method because the ground  
wire of the probe can collect radiated noise and the  
scope display is strongly dependent on the probe  
position.  
-
-
the switching noise that has the same frequency  
of the switching PWM  
the aperiodic random noise that is not related to  
the AC source frequency and/or the switching  
frequency.  
Fig. 3showsa bettermethodbecausethecollection  
of the radiated noise is minimized.  
AN647/0594  
1/3  
How to test the output ripple and noise of power supplies  
Figure 2. Wrong output ripple and noise test  
+
Power supply  
GND  
Figure 3. Correct output ripple and noise test  
+
GND  
Power supply  
The ground ring of the probe is pressed directly  
against the output ground of the power supply and  
the tip is in contact with the output voltage pin.  
A preferred method is shown in fig. 4: the waveform  
displayed on the scope must be multiplied by a  
factor 2.  
Figure 4. Preferred method to test output noise and ripple  
220nF  
Coax cable  
50 Ohm  
+
to AC input  
of scope  
Power supply  
50 Ohm  
GND  
2/3  

相关下载

全部评论(0)

暂无评论
评论赚积分>>

上传资源 上传优质资源有赏金

热门标签

更多>>

最新上传

  • 打赏
  • 30日榜单

热门下载

推荐下载

本站上的所有资源均为源于网上收集或者由用户自行上传，仅供学习和研究使用，无任何商业目的，版权归原作如有侵权，请 来信指出，本站将立即改正。

ICP许可证号：京ICP证070360号     21IC电子网 2000- 版权所有

京ICP备11013301号

京公网安备 11010802024343号