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参数资料
| 型号： | FSDM0565RBIWDTU |
| 厂商： | Fairchild Semiconductor |
| 文件页数： | 11/20页 |
| 文件大小： | 0K |
| 描述： | IC SWIT PWM GREEN CM HV I2PAK |
| 标准包装： | 1,000 |
| 输出隔离： | 隔离 |
| 频率范围： | 60 ~ 72kHz |
| 输入电压： | 8 V ~ 20 V |
| 输出电压： | 650V |
| 功率（瓦特）： | 70W |
| 工作温度： | 25°C ~ 150°C |
| 封装/外壳： | TO-262-6 成形引线 |
| 供应商设备封装： | I2-PAK-6L（成形） |
| 包装： | 管件 |
FSDM0565RB
Functional Description
1. Startup : In previous generations of Fairchild Power
Switches (FPS TM ) the Vcc pin had an external start-up
resistor to the DC input voltage line. In this generation the
startup resistor is replaced by an internal high voltage current
source. At startup, an internal high voltage current source
supplies the internal bias and charges the external capacitor
(C vcc ) that is connected to the Vcc pin as illustrated in
Figure 4. When Vcc reaches 12V, the FSDM0565RB begins
switching and the internal high voltage current source is
disabled. Then, the FSDM0565RB continues its normal
switching operation and the power is supplied from the
auxiliary transformer winding unless Vcc goes below the
stop voltage of 8V.
V DC
C Vcc
2.1 Pulse-by-pulse current limit : Because current mode
control is employed, the peak current through the Sense FET
is limited by the inverting input of PWM comparator (Vfb*)
as shown in Figure 5. Assuming that the 0.9mA current
source flows only through the internal resistor (2.5R +R= 2.8
k Ω ), the cathode voltage of diode D2 is about 2.5V. Since D1
is blocked when the feedback voltage (Vfb) exceeds 2.5V,
the maximum voltage of the cathode of D2 is clamped at this
voltage, thus clamping Vfb*. Therefore, the peak value of
the current through the Sense FET is limited.
2.2 Leading edge blanking (LEB) : At the instant the
internal Sense FET is turned on, there usually exists a high
current spike through the Sense FET, caused by primary-side
capacitance and secondary-side rectifier reverse recovery.
Excessive voltage across the Rsense resistor would lead to
incorrect feedback operation in the current mode PWM
control. To counter this effect, the FSDM0565RB employs a
leading edge blanking (LEB) circuit. This circuit inhibits the
PWM comparator for a short time (T LEB ) after the Sense
FET is turned on.
3
Vcc
I start
6
Vstr
Vcc
I delay
Vref
I FB
8V/12V
Vcc good
Vref
Vo
Vfb
H11A817A
C B
4
D1
D2
2.5R
OSC
SenseFET
+
Gate
Internal
Bias
Figure 4. Internal startup circuit
KA431
V SD
V fb *
-
R
OLP
driver
R sense
Figure 5. Pulse width modulation (PWM) circuit
3. Protection Circuit : The FSDM0565RB has several self
2. Feedback Control : FSDM0565RB employs current
mode control, as shown in Figure 5. An opto-coupler (such
as the H11A817A) 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 plus an offset voltage makes it possible to
control the switching duty cycle. When the reference pin
voltage of the KA431 exceeds the internal reference voltage
of 2.5V, the H11A817A LED current increases, thus pulling
down the feedback voltage and reducing the duty cycle. This
event typically happens when the input voltage is increased
or the output load is decreased.
protective functions such as over load protection (OLP), over
voltage protection (OVP) and thermal shutdown (TSD).
Because these protection circuits are fully integrated into the
IC without external components, the reliability can be
improved without increasing cost. Once the fault condition
occurs, switching is terminated and the Sense FET remains
off. This causes Vcc to fall. When Vcc reaches the UVLO
stop voltage, 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,12V, the
FSDM0565RB resumes its normal operation. In this manner,
the auto-restart can alternately enable and disable the
switching of the power Sense FET until the fault condition is
eliminated (see Figure 6).
11
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相关代理商/技术参数 |
参数描述 |
|---|---|
| FSDM0565RBLW | 制造商:Fairchild Semiconductor Corporation 功能描述: |
| FSDM0565RBLWDTU | 功能描述:电源开关 IC - 配电 FPS FOR LCD 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 |
| FSDM0565RBWDTU | 功能描述:电源开关 IC - 配电 SMPS Power Switch Built-in Soft Start 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 |
| FSDM0565RE | 制造商:FAIRCHILD 制造商全称:Fairchild Semiconductor 功能描述:Green-Mode Fairchild Power Switch |
| FSDM0565REIWDTU | 制造商:FAIRCHILD 制造商全称:Fairchild Semiconductor 功能描述:Green Mode Fairchild Power Switch |
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