参数资料
型号: FSL116HR
厂商: Fairchild Semiconductor
文件页数: 9/13页
文件大小: 0K
描述: IC FPS SWITCH PWM/SENSEFET 8MDIP
标准包装: 50
系列: FPS™
输出隔离: 隔离
频率范围: 90kHz ~ 110kHz
输入电压: 9 V ~ 26 V
输出电压: 650V
功率(瓦特): 16W
工作温度: -40°C ~ 105°C
封装/外壳: 8-DIP(0.300",7.62mm)
供应商设备封装: 8-MDIP
包装: 管件
Functional Description
Startup
At startup, an internal high-voltage current source
supplies the internal bias and charges the external
capacitor (C A ) connected with the V CC pin, as illustrated
in Figure 14. When V CC reaches the start voltage of 12V,
the FPS? begins switching and the internal high-
voltage current source is disabled. The FPS continues
normal switching operation and the power is provided
from the auxiliary transformer winding unless V CC goes
below the stop voltage of 8V.
Feedback Control
FSL116HR employs Current-Mode control, as shown in
Figure 16. An opto-coupler (such as the FOD817A) 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 shunt regulator reference pin voltage
exceeds the internal reference voltage of 2.5V, the opto-
coupler LED current increases, the feedback voltage V FB
is pulled down, and the duty cycle is reduced. This
typically occurs when the input voltage is increased or
the output load is decreased.
Figure 14. Startup Circuit
Oscillator Block
The oscillator frequency is set internally and the FPS
has a random frequency fluctuation function. Fluctuation
of the switching frequency of a switched power supply
can reduce EMI by spreading the energy over a wider
frequency range than the bandwidth measured by the
EMI test equipment. The amount of EMI reduction is
directly related to the range of the frequency variation.
The range of frequency variation is fixed internally;
however, its selection is randomly chosen by the
combination of external feedback voltage and internal
free-running oscillator. This randomly chosen switching
frequency effectively spreads the EMI noise nearby
switching frequency and allows the use of a cost-
effective inductor instead of an AC input line filter to
satisfy the world-wide EMI requirements.
Figure 15. Frequency Fluctuation Waveform
? 2010 Fairchild Semiconductor Corporation
FSL116HR ? Rev. 1.0.1
9
Figure 16. Pulse-Width-Modulation Circuit
Leading-Edge Blanking (LEB)
At the instant the internal SenseFET is turned on, the
primary-side capacitance and secondary-side rectifier
diode reverse recovery typically cause a high-current
spike through the SenseFET. Excessive voltage across
the R SENSE resistor leads to incorrect feedback operation
in the Current-Mode PWM control. To counter this
effect, the FPS employs a leading-edge blanking (LEB)
circuit ( see the Figure 16 ). This circuit inhibits the PWM
comparator for a short time (t LEB ) after the SenseFET is
turned on.
Protection Circuits
The FPS has protective functions such as overload
protection (OLP), over-voltage protection (OVP), output-
short protection (OSP), under-voltage lockout (UVLO),
abnormal over-current protection (AOCP), and thermal
shutdown (TSD). Because these various protection
circuits are fully integrated in the IC without external
components, reliability is improved without increasing
cost. If a fault condition occurs, switching is terminated
and the SenseFET remains off. This causes V CC to fall.
When V CC reaches the UVLO stop voltage, V STOP (8V),
the protection is reset and the internal high-voltage
current source charges the V CC capacitor via the V STR
pin. When V CC reaches the UVLO start voltage, V START
(12V), the FPS resumes normal operation. In this
manner, the auto-restart can alternately enable and
disable the switching of the power SenseFET until the
fault condition is eliminated.
www.fairchildsemi.com
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相关代理商/技术参数
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FSL117HLNY 制造商:Fairchild Semiconductor Corporation 功能描述:
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FSL126HR 功能描述:电流型 PWM 控制器 Green Mode Fairchild Power Switch (FPS) 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
FSL126MR 功能描述:电流型 PWM 控制器 FPS FOR LOW POWER 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