参数资料
型号: FAN7554
厂商: Fairchild Semiconductor
文件页数: 10/22页
文件大小: 0K
描述: IC REG CTRLR FLYBK ISO PWM 8-DIP
标准包装: 50
PWM 型: 电流模式
输出数: 1
频率 - 最大: 500kHz
占空比: 98%
电源电压: 9 V ~ 30 V
降压:
升压:
回扫:
反相:
倍增器:
除法器:
Cuk:
隔离:
工作温度: -25°C ~ 85°C
封装/外壳: 8-DIP(0.300",7.62mm)
包装: 管件
产品目录页面: 1222 (CN2011-ZH PDF)
其它名称: FAN7554_NL
FAN7554_NL-ND
FAN7554
Feedback
As shown in figure16, the internal oscillator clock turns on the MOSFET. The feedback comparator operates to turn it off
again, when the MOSFET current reaches a set value proportional to Vfb. The feedback capacitor Cfb is charged by the inter-
nal current sources , 1mA and 5uA, and is discharged by the secondary side photo-coupler to control the output voltage.
DRIN
OSC
OUT
6
Vfb
2R Vfb/3
S
Q
R
1mA
R
Cfb
5uA 5V
IS
3
Vsense
Vcc
FAN7554
Rs
1
FB
Figure 16. Feedback & PWM Circuit
Delayed Shutdown
During the normal operation, the feedback voltage is between 0~3V. If the output terminal overloads or an error happens to
the feedback loop, the delayed shutdown circuit operates. When the feedback voltage is less than 3V, the feedback capacitor is
charged by current sources, 1mA and 5uA; when the feedback voltage becomes greater than 3V, the capacitor is charged by the
5uA current source because diode D1 turns off. When the feedback voltage is less than 3V, the charge slope becomes an expo-
nential function and, when it is greater than 3V, the charge slope becomes linear. When the feedback voltage reaches almost
6V, the FAN7554 shuts down. The shut down circuit is configured for
auto-restart, so it automatically restarts when Vcc reaches the under voltage 9V.
FB
1
DRIN
5uA
Vcc
2R
OSC
S
Q
OUT
6
Cfb
D1
1mA
5V
R
R
IS
3
Rs
Over Current
Comparator
S
Q
Shutdown
R
6V
10
UVLO - out
Figure 17 - A . Delayed Shutdown & Feedback Circuit
FAN7554
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相关代理商/技术参数
参数描述
FAN7554_03 制造商:FAIRCHILD 制造商全称:Fairchild Semiconductor 功能描述:Versatile PWM Controller
FAN7554D 功能描述:DC/DC 开关控制器 PWM Controller RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK
FAN7554D_Q 功能描述:电流型 PWM 控制器 PWM Controller 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
FAN7554DTF 功能描述:DC/DC 开关控制器 PWM Controller RoHS:否 制造商:Texas Instruments 输入电压:6 V to 100 V 开关频率: 输出电压:1.215 V to 80 V 输出电流:3.5 A 输出端数量:1 最大工作温度:+ 125 C 安装风格: 封装 / 箱体:CPAK
FAN7554DTF_Q 功能描述:电流型 PWM 控制器 PWM Controller 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