- 您现在的位置：买卖IC网 > PDF目录68995 > FSL126HR (FAIRCHILD SEMICONDUCTOR CORP) 1.68 A SWITCHING CONTROLLER, 110 kHz SWITCHING FREQ-MAX, PDIP8 PDF资料下载
参数资料
| 型号： | FSL126HR |
| 厂商： | FAIRCHILD SEMICONDUCTOR CORP |
| 元件分类： | 稳压器 |
| 英文描述： | 1.68 A SWITCHING CONTROLLER, 110 kHz SWITCHING FREQ-MAX, PDIP8 |
| 封装： | MS-001BA, DIP-8 |
| 文件页数： | 13/13页 |
| 文件大小： | 963K |
| 代理商： | FSL126HR |
2011 Fairchild Semiconductor Corporation
www.fairchildsemi.com
FSL126HR Rev. 1.0.0
9
FSL126HR
—
Green
Mode
Fairchild
Power
Switch
(FPS)
Functional Description
Startup
At startup, an internal high-voltage current source
supplies the internal bias and charges the external
capacitor (CA) connected with the VCC pin, as illustrated
in Figure 14. When VCC 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 VCC goes
below the stop voltage of 8V.
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
Feedback Control
FSL126HR 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 RSENSE
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 VFB
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 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 RSENSE 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 (tLEB) after the SenseFET is
turned on.
Protection Circuits
The FPS has several 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, the reliability is improved
without increasing cost. Once a fault condition occurs,
switching is terminated and the SenseFET remains off.
This causes VCC to fall. When VCC reaches the UVLO
stop voltage, VSTOP (8V), the protection is reset and the
internal high-voltage current source charges the VCC
capacitor via the VSTR pin. When VCC reaches the UVLO
start voltage, VSTART (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.
相关PDF资料 |
PDF描述 |
|---|---|
| FSL126MR | 8 A SWITCHING CONTROLLER, 73 kHz SWITCHING FREQ-MAX, PDIP8 |
| FSL136HR | 2.41 A SWITCHING CONTROLLER, 110 kHz SWITCHING FREQ-MAX, PDIP8 |
| FSL136MR | SWITCHING CONTROLLER, PDIP8 |
| FSQ0565RQ | 3.36 A SWITCHING CONTROLLER, 75.8 kHz SWITCHING FREQ-MAX, ZFM6 |
| FSQ0565RS | 2.5 A SWITCHING CONTROLLER, 75.8 kHz SWITCHING FREQ-MAX, ZFM6 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| 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 |
| FSL126MRT | 制造商:FAIRCHILD 制造商全称:Fairchild Semiconductor 功能描述:Green-Mode Fairchild Power Switch (FPSa?￠) |
| FSL126MRTWDTU | 功能描述:电源开关 IC - 配电 6.2Ohms 1mA 50W 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 |
| FSL127H | 制造商:FAIRCHILD 制造商全称:Fairchild Semiconductor 功能描述:Green Mode Fairchild Power Switch |
| FSL127HNY | 功能描述:电源开关 IC - POE / LAN Green Mode Power Switch RoHS:否 制造商:Fairchild Semiconductor 开关数量:Single 开关配置:SPST 开启电阻（最大值）:7.3 Ohms 串话: 带宽: 开启时间（最大值）:13 ns 关闭时间（最大值）:20 ns 切换电压（最大）: 工作电源电压:8 V to 26 V 最大工作温度:+ 125 C 安装风格:Through Hole 封装 / 箱体:TO-220F-6 |
发布紧急采购，3分钟左右您将得到回复。