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参数资料
| 型号： | FA5515P |
| 厂商： | FUJI ELECTRIC CO LTD |
| 元件分类： | 稳压器 |
| 英文描述： | 1.5 A SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, PDIP8 |
| 封装： | DIP-8 |
| 文件页数： | 4/22页 |
| 文件大小： | 260K |
| 代理商： | FA5515P |
FA551X
12
4. Overcurrent limiting circuit
The overcurrent limiting circuit detects the peak value of every
drain current pulse (pulse by pulse method) of the main
switching MOSFET to limit the overcurrent. The detection
threshold voltage is +0.24V for FA5510/11 or –0.17V for
FA5514/15 with respect to the ground as shown in Figure 13
and Figure 14. The drain current of the MOSFET is converted
to voltage by resistor Rs and fed to the IS pin of the IC. If the
voltage exceeds the reference voltage +0.24V (FA5510/11) or
–0.17V (FA5514/15) of comparator C4, comparator C4 works to
set flip-flop output Q to high. The output is immediately turned
off to shut off the current. Flip-flop output Q is reset on the next
cycle to turn on the output again. This operation is repeated to
limit the overcurrent.
If the overcurrent limiting circuit malfunctions due to noise,
place an RC filter between the IS pin and MOSFET as shown in
Figure 13 and Figure 14. (See item 12 in “Design advice.”)
Figure 15 is a timing chart that illustrates overcurrent-limiting
operations.
5. Vcc overvoltage protection circuit
The IC contains a Vcc overvoltage protection circuit to protect
the IC from damage by overvoltage. Figure 16 shows the
overvoltage protection circuit. Figure 17 is a timing chart that
illustrates overvoltage protection operations. Overvoltage is
detected if the supply voltage Vcc rises to 31.8V (Icc=14mA) or
more and current flows in the built-in zener diode. The output of
comparator C5 then goes high and the constant current source
(0.95mA) raises the CS pin voltage. When the CS pin voltage
exceeds 8.5V, the output of comparator C2 goes high to turn off
the 5V REF circuit. The IC then enters the latched mode and
the IC output is put in the off (low voltage) state. When latched
mode, the IC current consumption is 45A (typ) (Vcc=10V).
This current must be supplied through the startup resistor.
The overvoltage shutdown operation can be reset by lowering
the supply voltage to below 9.0V or forcing the CS pin voltage
below 7.9V. (When you want to enable Vcc overvoltage
shutdown at a desired voltage, see item 6 in “Design advice.”)
Fig. 13
Overcurrent limiting circuit (FA5510/11)
Fig. 14
Overcurrent limiting circuit (FA5514/15)
Fig. 15
Overcurrent timing chart
Fig. 16
Overvoltage shutdown circuit
Fig. 17
Overvoltage shutdown timing chart
3
4
CS pin
FB pin
Oscillator
0.24V
O.C.P.
C4
F.F
PWM
OSC UVLO
R
S
Q
Output
circuit
IS(+)
GND
C
R
Rs
OUT
pin
FA5510/11
3
4
CS pin
FB pin
Oscillator
-0.17V
O.C.P.
C4
F.F
PWM
OSC UVLO
R
S
Q
Output
circuit
IS(-)
GND
C
R
Rs
OUT
pin
FA5514/15
CS pin voltage
DT voltage
FB pin voltage
Oscillator output
OUT pin output
Comparator C4
reference voltage
FA5510/11:+0.24V
FA5514/15:-0.17V
IS pin voltage
REF pin voltage ON
OFF
H
L
(4V)
Overcurrent limiting
PWM
Output
circuit
UVLO
REF
RT
CS
FB
VCC
OSC
5V
VCC
ENB
5V REF
4V
0.8/0.68V
8.5/7.9V
DMAX
Cs
C3
3.5V
8
6
1
2
7
C1
C2
0.95mA
C5
0.8V
15.5V
~
+
-
Vin
Comparator C2
reference voltage
(8.5V)
CS pin voltage
DT voltage
Osillator output
OUT pin voltage
REF pin voltage
FB pin voltage
(4V)
(9.5V)
H
L
ON
OFF
Overvoltage
detection
Shutdown
(0V)
相关PDF资料 |
PDF描述 |
|---|---|
| FA5514N | 1.5 A SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, PDSO8 |
| FA5515N | 1.5 A SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, PDSO8 |
| FA5510N | 1.5 A SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, PDSO8 |
| FA5511P | 1.5 A SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, PDIP8 |
| FA5514P | 1.5 A SWITCHING CONTROLLER, 500 kHz SWITCHING FREQ-MAX, PDIP8 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| FA5515P-D1 | 制造商:Fuji Electric 功能描述: |
| FA551X | 制造商:未知厂家 制造商全称:未知厂家 功能描述:CMOS IC For Switching Power Supply Control |
| FA5526 | 制造商:FUJI 制造商全称:Fuji Electric 功能描述:Fuji Switching Power Control IC |
| FA5527 | 制造商:FUJI 制造商全称:Fuji Electric 功能描述:Fuji Switching Power Control IC |
| FA5527P-A2 | 制造商:Fuji Electric 功能描述: |
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