参数资料
| 型号： | FSL146MRBN |
| 厂商： | Fairchild Semiconductor |
| 文件页数： | 9/16页 |
| 文件大小： | 0K |
| 描述： | IC FPS POWER SWITCH 8-MDIP |
| 标准包装： | 1 |
| 系列： | FPS™ |
| 输出隔离： | 隔离 |
| 频率范围： | 61kHz ~ 73kHz |
| 输入电压： | 8 V ~ 26 V |
| 输出电压： | 650V |
| 功率（瓦特）： | 35W |
| 工作温度： | -40°C ~ 125°C |
| 封装/外壳： | 8-DIP（0.300"，7.62mm） |
| 供应商设备封装： | 8-MDIP |
| 包装： | 标准包装 |
| 其它名称： | FSL146MRBNFSDKR |
Functional Description
1. Startup: At startup, an internal high-voltage current
source supplies the internal bias and charges the
external capacitor (C Vcc ) connected to the V CC pin, as
illustrated in Figure 17. When V CC reaches 12V, the
FSL146MRBN begins switching and the internal high-
voltage current source is disabled. The FSL146MRBN
continues normal switching operation and the power is
supplied from the auxiliary transformer winding unless
V CC goes below the stop voltage of 7.5V.
Figure 17. Startup Block
2. Soft-Start : The internal soft-start circuit increases
PWM comparator inverting input voltage, together with
the SenseFET current, slowly after it starts. The typical
soft-start time is 15ms. The pulse width to the power
switching device is progressively increased to establish
the correct working conditions for transformers,
inductors, and capacitors. The voltage on the output
capacitors is progressively increased to smoothly
3. Feedback Control : This device employs Current-
Mode control, as shown in Figure 18. An opto-coupler
(such as the FOD817) and shunt regulator (such as the
KA431) are typically used to implement the feedback
network. Comparing the feedback voltage with the
voltage across the R SENSE resistor makes it possible to
control the switching duty cycle. When the reference pin
voltage of the shunt regulator exceeds the internal
reference voltage of 2.5V, the opto-coupler LED current
increases, pulling down the feedback voltage and
reducing drain current. This typically occurs when the
input voltage is increased or the output load is decreased.
3.1 Pulse-by-Pulse Current Limit : Because Current-
Mode control is employed, the peak current through
the SenseFET is limited by the inverting input of the
PWM comparator (V FB *), as shown in Figure 18.
Assuming that the 90 μ A current source flows only
through the internal resistor (3R + R =27k ? ), the
cathode voltage of diode D2 is about 2.5V. Since D1
is blocked when the feedback voltage (V FB ) exceeds
2.5V, the maximum voltage of the cathode of D2 is
clamped at this voltage. Therefore, the peak value of
the current through the SenseFET is limited.
3.2 Leading-Edge Blanking (LEB) : At the instant the
internal SenseFET is turned on, a high-current spike
usually occurs through the SenseFET, caused by
primary-side capacitance and secondary-side rectifier
reverse recovery. Excessive voltage across the R SENSE
resistor leads to incorrect feedback operation in the
Current-Mode PWM control. To counter this effect, the
leading-edge blanking (LEB) circuit inhibits the PWM
comparator for t LEB (300ns) after the SenseFET is
turned on.
establish the required output voltage. This helps prevent
transformer saturation and reduces stress on the
secondary diode during startup.
Figure 18. Pulse Width Modulation Circuit
? 2012 Fairchild Semiconductor Corporation
FSL146MRBN ? Rev. 1.0.0
9
www.fairchildsemi.com
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相关代理商/技术参数 |
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| FSL156MRBN | 功能描述:电源开关 IC - 配电 Green-Mode FPS 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 |
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| FSL176MRT | 制造商:FAIRCHILD 制造商全称:Fairchild Semiconductor 功能描述:Green-Mode Fairchild Power Switch (FPSa?￠) |
| FSL176MRTUDTU | 功能描述:电流型 PWM 控制器 GRN Mode PowerSwitch RoHS:否 制造商:Texas Instruments 开关频率:27 KHz 上升时间: 下降时间: 工作电源电压:6 V to 15 V 工作电源电流:1.5 mA 输出端数量:1 最大工作温度:+ 105 C 安装风格:SMD/SMT 封装 / 箱体:TSSOP-14 |
| FSL2 | 制造商:Cooper Crouse-Hinds 功能描述: |
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