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参数资料
| 型号： | FSDL312 |
| 厂商： | FAIRCHILD SEMICONDUCTOR CORP |
| 元件分类： | 稳压器 |
| 英文描述： | 4 A SWITCHING REGULATOR, PDIP8 |
| 封装： | DIP-8 |
| 文件页数： | 4/16页 |
| 文件大小： | 607K |
| 代理商： | FSDL312 |
FSDL312
12
Figure 8. Soft Start Function
6. Burst operation :In order to minimize power dissipation in
standby mode, the FPSTM enters burst mode operation.
Figure 9. Circuit for Burst operation
As the load decreases, the feedback voltage decreases. As shown in
figure 10, the device automatically enters burst mode when the
feedback voltage drops below VBURH(500mV). Switching still con-
tinues but the current limit is set to a fixed limit internally to mini-
mize flux density in the transformer. The fixed current limit is
larger than that defined by Vfb = VBURH and therefore, Vfb is
driven down further.
Switching continues until the feedback
voltage drops below VBURL(300mV). At
this point switching
stops and the output voltages start to drop at a rate dependent
on the standby current load. This causes the feedback volt-
age to rise. Once it passes VBURH(500mV) switching resumes.
The feedback
voltage then falls and the process repeats. Burst
mode operation alternately enables and disables switching of
the power Sense FET thereby reducing switching loss in
Standby mode.
Figure 10. Circuit for Burst Operation
7. Frequency Modulation : EMI reduction can be accom-
plished by modulating the switching frequency of a switched
power supply. Frequency modulation can reduce EMI by
spreading the energy over a wider frequency range than the
band width measured by the EMI test equipment. The
amount of EMI reduction is directly related to the depth of
the reference frequency. As can be seen in Figure 11, the fre-
quency changes from 65KHz to 69KHz in 4mS for the
FSDM0265RN. Frequency modulation allows the use of a
cost effective inductor instead of an AC input mode choke to
satisfy the requirements of world wide EMI limits.
Figure 11. Frequency Modulation Waveform
DR A I N
GN D
Rs e n s e
I_ o v e r
SW IT C H
OF F
5V
3
Vcc
I
delay
I
FB
R
2.5R
FB
0.3/0.5V
PWM
+
-
0.5V
Vcc
I
B_PEAK
Burst
Normal
MOSFET
Current
0.5V
Switching OFF
Current
waveform
Burst Operation
Normal Operation
Feedback
0.3V
Burst Operation
Switching OFF
69kH z
67kH z
65kH z
4kH z
Turn-on
Turn-off
point
Internal
O scillator
D rain to
S ource
voltage
Vds
Waveform
D rain to
S ource
current
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相关代理商/技术参数 |
参数描述 |
|---|---|
| FSDL321 | 功能描述:电源开关 IC - 配电 FPS for DVDP/STB 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 |
| FSDL321L | 功能描述:电源开关 IC - 配电 FPS for DVDP/STB 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 |
| FSDL321L_Q | 功能描述:电源开关 IC - 配电 FPS for DVDP/STB 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 |
| FSDLC01G-S | 制造商:AXIOMTEK 制造商全称:AXIOMTEK 功能描述:Capacity: 128MB to 32GB |
| FSDLC128-S | 制造商:AXIOMTEK 制造商全称:AXIOMTEK 功能描述:Capacity: 128MB to 32GB |
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