- 您现在的位置：买卖IC网 > PDF目录67412 > FA7704V (FUJI ELECTRIC CO LTD) 0.4 A DUAL SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO16 PDF资料下载
参数资料
| 型号： | FA7704V |
| 厂商： | FUJI ELECTRIC CO LTD |
| 元件分类： | 稳压器 |
| 英文描述： | 0.4 A DUAL SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO16 |
| 封装： | 1.10 MM, TSSOP-16 |
| 文件页数： | 6/21页 |
| 文件大小： | 242K |
| 代理商： | FA7704V |
14
Quality is our message
FA7703/04
(4)PWM comparator
PWM comparator of FA7703/04 has 4 input
terminals. (Fig. 4) The oscillator output 2 is
compared with the CS terminal voltage 1, the
DT terminal voltage3, and the Error Amplifier
output 4.
Among those 3 inputs of 1, 3, and
4, the one with the lowest voltage is chosen and
given priority. While the value of the chosen
voltage is lower than the value of the waveform
of oscillator output, PWM comparator output is
set to LOW. Similarly, while the value of the
chosen voltage is higher than the waveform of
oscillator output, PWM comparator output is set
to HIGH. (Fig. 5)
When FA7703/04 are turning ON, the soft start
function starts according to the CS terminal
voltage 1, then the output pulses begin to widen
gradually. The maximum pulse width is adjusted
by changing the DT terminal voltage. In steady
operation, the pulse width is determined with the
condition of the Error Amplifier output 4, and
then the output voltage of DC-DC converter is
stabilized. The operation flow chart of PWM
comparator and OUT terminal is shown in Fig. 5.
The output polarity of OUT1 terminal changes
according to the condition of SEL1 terminal. The
polarity of OUT 2 terminal is different between
FA7703 and FA7704; accordingly, select the type
for your desired circuit design.
(5)Soft start function
As described in Fig. 6, a capacitor CCS is
connected to CS terminal. When the power
supply of FA7703/04 starts and the undervoltage
lockout protection circuit (UVLO) is cancelled,
the capacitor CCS is charged by the internal
current source (2.2
A. typ.), and the voltage of
CS terminal rises gradually. Since the voltage of
CS terminal is connected to PWM comparator,
the output pulses begin to widen gradually, and
then the soft start function starts as a result. (Fig.
5)
(6)Timer latch short-circuit protection circuit
The short-circuit protection circuit of FA7703/04
consists
of
two
comparators.
(S.C.
DET
comparator, S.C.P comparator)
In steady
operation, the output of Error Amplifier is
approximately 1V, accordingly, the output of
S.C.DET comparator is set to High, and the
voltage of CS terminal is clamped at 1.27V. If the
output voltage drops due to a short-circuit or the
like, the output voltage of Error Amplifiers rises.
When the output voltage of Error Amplifiers
exceeds 1.5V(typ.), the output of S.C.DET
comparator is set to Low, and the clamp action
at the CS terminal voltage of 1.27V is cancelled,
then the voltage of CS terminal rises up to the
VREG voltage. When the voltage of CS terminal
exceeds
2.0V(typ.),
the
output
of
S.C.P
comparator is set to High, accordingly, the
output of FA7703/04 is shut off. In this case,
FA7703/04 operate in OFF latch mode and the
current consumption in this mode is 1.3mA(typ.).
The operating waveform of the voltage of CS
terminal is shown in Fig. 7.
The
approximate
time
(tp)
between
the
occurrence of a short-circuit in the output and
the triggering of the short-circuit protection
+
-
+
Oscillation voltage
CS term inal voltage
DT term inal voltage
Error Am plifier output
PW M output
1
2
3
4
Fig.4
+
-
1.5V
2.0V
1.27V
S.C.DE T
S.C.P
FB
UV LO
output off
2
2.2 A
C CS
CS
VC C
Fig.6
Fig.5
PW M
output
OUT1
Nch driv en
(SEL1:REG )
OUT1
Pch driv en
(SEL1:G ND)
OUT2
FA7703
OUT2
FA7704
Oscillation voltage
CS term inal voltage
DT term inal voltage
Error Am plifier output
4
3
1
2
相关PDF资料 |
PDF描述 |
|---|---|
| FA7703V | 0.4 A DUAL SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO16 |
| FA7704M | 0.4 A DUAL SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO16 |
| FA7703M | 0.4 A DUAL SWITCHING CONTROLLER, 1000 kHz SWITCHING FREQ-MAX, PDSO16 |
| FA7738N | 5.5 A SWITCHING REGULATOR, 400 kHz SWITCHING FREQ-MAX, PDSO8 |
| FA7738P | 5.5 A SWITCHING REGULATOR, 400 kHz SWITCHING FREQ-MAX, PDIP8 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| FA771 | 制造商:Black Box Corporation 功能描述:DB25 TO RJ45,8 WIRE,F MOD THUMBSCREW ADPTR KIT |
| FA7711V | 制造商:FUJI 制造商全称:Fuji Electric 功能描述:FUJI Power Supply Control IC |
| FA7726 | 制造商:FUJI 制造商全称:Fuji Electric 功能描述:45V Input Buck Converter 3ch/2ch IC with Power MOSFET |
| FA7730 | 制造商:FUJI 制造商全称:Fuji Electric 功能描述:45V Input Buck Converter 3ch/2ch IC with Power MOSFET |
| FA7764 | 制造商:FUJI 制造商全称:Fuji Electric 功能描述:FUJI Power Supply Control IC |
发布紧急采购，3分钟左右您将得到回复。