参数资料
| 型号： | FSDM311A |
| 厂商： | Fairchild Semiconductor |
| 文件页数： | 9/12页 |
| 文件大小： | 0K |
| 描述： | IC FPS PWM/SENSFET 650V 8DIP |
| 标准包装： | 50 |
| 输出隔离： | 隔离 |
| 频率范围： | 61 ~ 73kHz |
| 输入电压： | 7 V ~ 20 V |
| 输出电压： | 650V |
| 功率（瓦特）： | 13W |
| 工作温度： | 25°C ~ 150°C |
| 封装/外壳： | 8-DIP（0.300"，7.62mm） |
| 供应商设备封装： | 8-DIP |
| 包装： | 管件 |
4.1 Overload Protection (OLP): Overload is defined as
the load current exceeding a pre-set level due to an
unexpected event. In this situation, the protection circuit
should be activated to protect the SMPS. However,
even when the SMPS is operating normally, the
overload protection (OLP) circuit can be activated
during the load transition. To avoid this undesired
operation, the OLP circuit is designed to be activated
after a specified time to determine whether it is a
transient situation or an overload situation. If the output
consumes more than the maximum power determined
by I LIM , the output voltage (V O ) decreases below its
rating voltage. This reduces the current through the
opto-coupler LED, which also reduces the opto-coupler
transistor current, thus increasing the feedback voltage
(V FB ). If V FB exceeds 3V, the feedback input diode is
blocked and the 5μA current source (I DELAY ) starts to
charge C FB slowly up to V CC . In this condition, V FB
increases until it reaches 4.5V, when the switching
operation is terminated, as shown in Figure 19. The
shutdown delay time is the time required to charge C FB
from 3V to 4.5V with 5μA current source.
V FB
Over Load Protection
4.5V
3V
t 12 = C FB (V(t 2 )-V(t 1 )) / I DELAY
Figure 20. Internal Soft-Start
6. Burst Operation: To minimize the power dissipation
in standby mode, the FSDM311A enters burst mode
operation. As the load decreases, the feedback voltage
decreases. The device automatically enters burst mode
when the feedback voltage drops below V BURL (0.55V).
At this point, switching stops and the output voltages
start to drop. This causes the feedback voltage to rise.
Once is passes V BURH (0.70V), switching starts again.
The feedback voltage falls and the process repeats.
Burst mode operation alternately enables and disables
switching of the power MOSFET to reduce the switching
loss in standby mode.
t 1
t 2
t
t 12 = C FB
V ( t 2 ) ? V ( t 1 )
I DELAY
;
I DELAY = 5 μ A , V ( t 1 ) = 3 V , V ( t 2 ) = 4 . 5 V
Figure 21.
Burst Operation Block
Figure 19.
Overload Protection (OLP)
Vo
Vo set
4.2 Thermal Shutdown (TSD): The SenseFET and the
control IC are integrated, making it easier for the control
IC to detect the temperature of the SenseFET. When
the temperature exceeds approximately 145 ° C, thermal
shutdown is activated.
V FB
0.7V
0.55V
5. Soft-Start: The FPS has an internal soft-start circuit
that slowly increases the feedback voltage with the
SenseFET current right after it starts up. The typical
soft-start time is 15ms, as shown in Figure 20, where
progressive increment of the SenseFET current is
allowed during the start-up phase. The soft-start circuit
progressively increases current limits to establish
proper working conditions for transformers, inductors,
capacitors, and switching devices. It also helps to
prevent transformer saturation and reduces the stress
Ids
Vds
on the secondary diode.
? 2007 Fairchild Semiconductor Corporation
Figure 22.
t
Burst Operation Function
www.fairchildsemi.com
FSDM311A ? Rev.1.0.2
9
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相关代理商/技术参数 |
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| FSDM311L | 功能描述:电源开关 IC - 配电 SMPS PS for PC TV and Mont Aux Power 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 |
| FSDM3-125M | 制造商:未知厂家 制造商全称:未知厂家 功能描述:Delay Line |
| FSDM3-15M | 制造商:未知厂家 制造商全称:未知厂家 功能描述:Delay Line |
| FSDM3-20M | 制造商:未知厂家 制造商全称:未知厂家 功能描述:Delay Line |
| FSDM3-250M | 制造商:未知厂家 制造商全称:未知厂家 功能描述:Delay Line |
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