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| 型号： | FSQ0370RNA |
| 厂商： | Fairchild Semiconductor |
| 文件页数： | 11/17页 |
| 文件大小： | 0K |
| 描述： | IC SWIT PWM GREEN OVP UVLO 8DIP |
| 产品变化通告： | Passivation Layer Change 07/Dec/2007 |
| 标准包装： | 50 |
| 输出隔离： | 隔离 |
| 频率范围： | 92kHz ~ 108kHz |
| 输入电压： | 9 V ~ 20 V |
| 输出电压： | 700V |
| 功率（瓦特）： | 27W |
| 工作温度： | 25°C ~ 140°C |
| 封装/外壳： | 8-DIP（0.300"，7.62mm） |
| 供应商设备封装： | 8-DIP |
| 包装： | 管件 |
| 产品目录页面： | 1222 (CN2011-ZH PDF) |
Application Information
Methods of Reducing Audible Noise
Switching-mode power converters have electronic and
magnetic components, which generate audible noise
when the operating frequency is in the range of
20~20,000Hz. Even though they operate above 20KHz,
they can make noise, depending on the load condition.
The following sections discuss methods to reduce noise.
Glue or Varnish
The most common method of reducing noise involves
using glue or varnish to tighten magnetic components.
The motion of core, bobbin, and coil and the chattering
or magnetostriction of core can cause the transformer to
produce audible noise. The use of rigid glue and varnish
helps reduce the transformer noise. Glue or varnish can
also can crack the core because sudden changes in the
ambient temperature cause the core and the glue to
expand or shrink in a different ratio.
Ceramic Capacitor
Using a film capacitor instead of a ceramic capacitor as a
snubber capacitor is another noise reduction solution.
Some dielectric materials show a piezoelectric effect,
depending on the electric field intensity. Hence, a
snubber capacitor becomes one of the most significant
sources of audible noise. Another possibility is to use a
Zener clamp circuit instead of an RCD snubber for
higher efficiency as well as lower audible noise.
Adjusting Sound Frequency
Moving the fundamental frequency of noise out of the
2~4kHz range is the third method. Generally, humans
are more sensitive to noise in the range of 2~4kHz.
When the fundamental frequency of noise is located in
this range, the noise sounds louder although the noise
intensity level is identical (see Figure 19).
When the FPS acts in burst mode and the burst
operation is suspected to be a source of noise, this
method may be helpful. If the frequency of burst mode
operation lies in the range of 2~4kHz, adjusting the
feedback loop can shift the burst operation frequency. To
reduce the burst operation frequency, increase a
feedback gain capacitor (C F ), opto-coupler supply
resistor (R D ); and feedback capacitor (C B ), and decrease
a feedback gain resistor (R F ), as shown in Figure 20.
? 2006 Fairchild Semiconductor Corporation
FSQ0170RNA, FSQ0270RNA Rev. 1.0.5
11
Figure 19. Equal Loudness Curves
Figure 20. Typical Feedback Network of FPS
Other Reference Materials
AN-4134: Design Guidelines for Off-line Forward
Converters Using Fairchild Power Switch (FPS?)
AN-4137: Design Guidelines for Off-line Flyback
Converters Using Fairchild Power Switch (FPS?)
AN-4140: Transformer Design Consideration for Off-line
Flyback Converters using Fairchild Power Switch (FPS?)
AN-4141: Troubleshooting and Design Tips for Fairchild
Power Switch (FPS?) Flyback Applications
AN-4147: Design Guidelines for RCD Snubber of
Flyback
AN-4148: Audible Noise Reduction Techniques for
FPS? Applications
www.fairchildsemi.com
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相关代理商/技术参数 |
参数描述 |
|---|---|
| FSQ0370RNA_12 | 制造商:FAIRCHILD 制造商全称:Fairchild Semiconductor 功能描述:Green Mode Fairchild Power Switch (FPSa?￠) |
| FSQ0465RB | 制造商:FAIRCHILD 制造商全称:Fairchild Semiconductor 功能描述:Green-Mode Fairchild Power Switch (FPS) for Quasi-Resonant Operation - Low EMI and High Efficiency |
| FSQ0465RBLDTU | 功能描述:电源开关 IC - 配电 SMPS Power switch (QRC) 4A 650V RoHS:否 制造商:Exar 输出端数量:1 开启电阻（最大值）:85 mOhms 开启时间（最大值）:400 us 关闭时间（最大值）:20 us 工作电源电压:3.2 V to 6.5 V 电源电流（最大值）: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:SOT-23-5 |
| FSQ0465RBWDTU | 功能描述:电源开关 IC - 配电 SMPS Power switch (QRC) 4A 650V RoHS:否 制造商:Exar 输出端数量:1 开启电阻（最大值）:85 mOhms 开启时间（最大值）:400 us 关闭时间（最大值）:20 us 工作电源电压:3.2 V to 6.5 V 电源电流（最大值）: 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:SOT-23-5 |
| FSQ0465RS | 制造商:FAIRCHILD 制造商全称:Fairchild Semiconductor 功能描述:Green-Mode Fairchild Power Switch (FPS) for Quasi-Resonant Operation - Low EMI and High Efficiency |
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