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參數(shù)資料
| 型號： | FS8S0765RCB |
| 廠商： | Fairchild Semiconductor Corporation |
| 英文描述： | Fairchild Power Switch(FPS) |
| 中文描述： | 飛兆半導體功率開關(guān)（FPS） |
| 文件頁數(shù)： | 11/20頁 |
| 文件大?。?/td> | 1847K |
| 代理商： | FS8S0765RCB |
FS8S0765RCB
11
Functional Description
1.
Start up
: To guarantee stable operation of the
control IC, FS8S0765RCB has UVLO circuit with 6V
hysteresis band. Figure 1 shows the relation between the sup-
ply current (Icc) and the supply voltage (Vcc). Before Vcc
reaches 15V, the FPS consumes only startup current of
80
μ
A, which is usually provided by the DC link through
start-up resistor. When Vcc reaches 15V, the FPS begins
operation and the operating current increases to 15mA as
shown. Once the control IC starts operation, it continues its
normal operation until Vcc goes below the stop voltage of
9V
Figure 1. Strat up with hysteresis
2. Feedback Control
: FS8S0765RCB employs primary side
regulation, which permits elimination of feedback circuit
components in the secondary side such as opto coupler and
TL431. Figure 2 shows the primary side control circuit. The
primary side regulation voltage (Vpsr) is controlled to the
breakdown voltage of zener diode (Dz). Because current
mode control is employed, the drain current of the power
MOSFET is limited by the inverting input of PWM compara-
tor (Vfb*). When MOSFET turns on, usually there exists
high current spike in the MOSFET current caused by pri-
mary-side capacitance and secondary-side rectifier reverse
recovery. In order to prevent premature termination of the
switching pulse due to the current spike, the FPS employs
leading edge blanking (LEB). The leading edge blanking cir-
cuit inhibits the PWM comparator for a short time after the
MOSFET is turned on.
Figure 2. Primary side control circuit
3. Protection function
: FS8S0765RCB has 4 self
protective functions such as abnormal over current protec-
tion (AOCP), over load protection (OLP), over voltage pro-
tection (OVP) and thermal shutdown (TSD). Because these
protection circuits are fully integrated into the IC without
external components, the reliability can be improved without
cost increase. In the event of these fault conditions, the FPS
enters into auto-restart operation. Once the fault condition
occurs, switching operation is terminated and MOSFET
remains off, which forces Vcc to be reduced. When Vcc
reaches 9V, the protection is reset and the supply current
reduces to 80 uA. Then, Vcc begin to increase with the cur-
rent provided through the start-up resistor. When Vcc
reaches 15V, the FPS resumes its normal operation if the
fault condition is removed. In this manner, the auto-restart
alternately enables and disables the switching of the power
MOSFET until the fault condition is eliminated as illustrated
in figure 3.
Figure 3. Auto restart operation after protection
3.1 Abnormal Over Current Protection (AOCP)
: When
the secondary rectifying diodes or the transformer pins are
shorted, a steep current with extremely high di/dt can flow
during the LEB time. Therefore, the abnormal over current
protection (AOCP) block is added to ensure the reliability as
shown in figure 4. It turns off the SenseFET within 300ns
after the abnormal over current condition is sensed.
Figure 4. AOCP block
Vstop=9V
Vstart=
1
5V
80uA
OVP
Vcc
Icc
1
5mA
4
OSC
Vcc
Vref
2uA
0.9mA
V
SD
R
2.5R
FB
Gate
driver
OLP
D1
D2
Vfb*
Vfb
Cfb
D
Z
R
Z
V
psr
time
time
V
V
1
5V
9 V
Vcc
Vds
Protection is activated
(OCP,OLP,OVP or TSD)
Auto restart
V c c
GATE
DRIVER
AOCP COMP.
Vsense : 1V
SenseFET
S Q'
R
OVP
OLP
TSD
UVLO
PWMComp
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相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| FS8S0765RCB_06 | 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:Fairchild Power Switch (FPS⑩) |
| FS8S0765RCBSYDT | 功能描述:IC SWIT PWM CM OVP UVLO HV TO220 RoHS:是 類別:集成電路 (IC) >> PMIC - AC-DC 轉(zhuǎn)換器，離線開關(guān) 系列:- 標準包裝:1 系列:FPS™ 輸出隔離:隔離 頻率范圍:61kHz ~ 73kHz 輸入電壓:8 V ~ 26 V 輸出電壓:650V 功率（瓦特）:12W 工作溫度:-40°C ~ 115°C 封裝/外殼:8-DIP（0.300"，7.62mm） 供應商設(shè)備封裝:8-MDIP 包裝:Digi-Reel® 其它名稱:FSL206MRBNFSDKR |
| FS8S0765RCBTU | 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:Fairchild Power Switch (FPS⑩) |
| FS8S0765RCBYDTU | 功能描述:電源開關(guān) IC - 配電 7a/650V Power Switch Synchronized RoHS:否 制造商:Exar 輸出端數(shù)量:1 開啟電阻（最大值）:85 mOhms 開啟時間（最大值）:400 us 關(guān)閉時間（最大值）:20 us 工作電源電壓:3.2 V to 6.5 V 電源電流（最大值）: 最大工作溫度:+ 85 C 安裝風格:SMD/SMT 封裝 / 箱體:SOT-23-5 |
| FS8S0765RCTU | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:SMPS Controller |
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