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參數資料
| 型號： | FA7622CPE |
| 廠商： | FUJI ELECTRIC HOLDINGS CO., LTD. |
| 元件分類： | 基準電壓源/電流源 |
| 英文描述： | Bipolar IC For Switching Power Supply Control |
| 中文描述： | 雙極集成電路開關電源控制 |
| 文件頁數： | 6/8頁 |
| 文件大小： | 67K |
| 代理商： | FA7622CPE |
FA7622CP(E)
6
4. Timer and latch circuit for overload protection
Figure 9 shows the timer and latch circuit for overload
protection and Fig. 10 shows its timing during an overload.
If the power supply output decreases due to an overload, the
error amplifier output decreases. If the voltage decreases to
less than 0.3V, the switch that clamps the CP pin voltage to
the ground disconnects. This charges capacitor Cp from the
REF pin through the resistor Rcp and the CP pin voltage
increases. When the voltage reaches 1.25V, OUT1 (OUT2)
voltage is clamped to ground.
The N-channel MOSFET (or NPN transistor) connected to the
OUT1 (or OUT2) is turned OFF and cuts off the power supply.
The time t
L
from when the circuit is overloaded until the power
supply is cut off can be determined as follows:
(9)
.................
t
L
(m
S
) = 0.67C
P
(
μ
F) R
CP
(k
)
5. Overcurrent limiting circuit
This is a pulse-by-pulse overcurrent limiting circuit which
detects and limits the peak of each drain current pulse from the
main switching transistor (MOSFET).
Figure 11 shows the overcurrent limiting circuit and Fig. 12
shows its timing.
This circuit detects a drain current with a voltage sampling
resistor Rs. If a voltage lower than the V
CC1
pin voltage by
210mV or more is input to OCL1 (OCL2), the OUT1 (OUT2) is
clamped to ground. At the same time, DT1 (DT2) is raised to
the reference voltage V
REF
. (This reduces the duty-cycle to
0%)
This circuit has hysteresis to prevent noise from causing
malfunction.
The R
S
voltage which is propotional to drain current is limited
to 210mV (typ.) and released at 170mV (typ).
Fig. 9
Fig. 10
Fig. 11
Fig. 12
2
OUT1
(OUT2)
OCL1
(OCL2)
VCC1
-0.21V
REF
DT1
(DT2)
VCC1
D
I
1
Rs
OUT1
(OUT2)
Time
VCC1
VCC1
-0.2V
OCL1
(OCL2)
(Similar to I
D
)
Voltage waveforms
PWM output
FB1(FB2)
DT1(DT2)
Time
CP
CT
1.25V
(Threshold voltage
of CP pin)
Voltage waveforms
20
1
2
1
2
1.25V
C
P
S1
REF
OUT1
(OUT2)
R
CP
FB1
(FB2)
0.3V
CP
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相關代理商/技術參數 |
參數描述 |
|---|---|
| FA7622P | 制造商:未知廠家 制造商全稱:未知廠家 功能描述: |
| FA7630CE | 制造商:未知廠家 制造商全稱:未知廠家 功能描述:Analog IC |
| FA7630CP | 制造商:FUJI 制造商全稱:Fuji Electric 功能描述:Bipolar IC For Switching Power Supply Control |
| FA7630CPE | 制造商:FUJI 制造商全稱:Fuji Electric 功能描述:Bipolar IC For Switching Power Supply Control |
| FA765 | 制造商:Black Box Corporation 功能描述:MMJ Modular Adapter Kit, DB9 to MMJ, Male |
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