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參數資料
| 型號： | FAN7544N |
| 廠商： | FAIRCHILD SEMICONDUCTOR CORP |
| 元件分類： | 穩壓器 |
| 英文描述： | Terminal Block; RoHS Compliant:Yes RoHS Compliant: Yes |
| 中文描述： | 0.6 A FLUORESCENT LIGHT CONTROLLER, 54.5 kHz SWITCHING FREQ-MAX, PDIP8 |
| 封裝： | DIP-8 |
| 文件頁數： | 7/14頁 |
| 文件大小： | 1185K |
| 代理商： | FAN7544N |
FAN7544
7
Application Information
Start-up Circuit
The start-up current is supplied to the IC through the start up resistor (Rst). In order to reduce the power dissipation in Rst, the
Rst is connected to the full wave rectified output voltage.
The following equations can be used to calculate the size of Rst
The size of supply capacitor (Cs) is normally decided in
terms of the start up time and operating current built up
by auxiliary operating current source.
The turn off snubber capacitor (CQ) and two diodes
(D1, D2) constitute the auxiliary operating current
source for the IC. The charging current through the CQ
flows into the IC and also charges the supply capacitor.
If the size of CQ is increased, the V
CC
voltage on the
Cs is also increased.
Under Voltage Lock Out(UVLO)
UVLO mode of the FAN7544 is designed to maintain
an ultra low supply current of less than 140uA, and to
guarantee that the IC is fully functional before two out-
put drivers are activated.
Oscillator
The gate drive output frequency is as half as that of the triangular waveform on timing capacitor (CT) at pin #2. In normal
operating mode, the timing capacitor charging current is 4
×
Irt(=Vref/RT). The discharging current is 5.25 times of the charg-
ing current (5.25
×4×Ι
rt). The charging period of the timing capacitor is the on time of the MOSFET. During the discharging
period, both of the MOSFETs are off.
Rst
-------------------------------------–
Ist max
,
<
----------------------–
×
3
–
0.2
10
539k
=
=
P
RSt
---------------------------------------------------–
(
)
2
R
St
0.5W
≤
=
R
St
2
Vin ac_max
)
2
Vcc
–
(
)
2
×
≥
R
St
260K
≥
260K
R
St
539K
≤
≤
∴
DC 400V
Rectifier
Output
Cs
Rst
G1
G2
Vcc
M1
M2
CQ
D1
D2
ZD1
Figure 10. Start-up Circuit
Figure 11. CT & Output Waveforms
VCT
OUT1
OUT2
Charging
Period(
T
CH
)
I
CH
Discharging
Period(
T
DIS
)
I
DIS
=6.25*I
CH
3.7V
Vref
I
CH
I
DIS
CT
Dead Time
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相關代理商/技術參數 |
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|---|---|
| FAN7546MX | 制造商:Fairchild Semiconductor Corporation 功能描述: |
| FAN7547A | 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:LCD Backlight Inverter Drive IC |
| FAN7547AM | 功能描述:LCD 驅動器 CCFL BACK LIGHT IC RoHS:否 制造商:Maxim Integrated 數位數量:4.5 片段數量:30 最大時鐘頻率:19 KHz 工作電源電壓:3 V to 3.6 V 最大工作溫度:+ 85 C 最小工作溫度:- 20 C 封裝 / 箱體:PDIP-40 封裝:Tube |
| FAN7547AMX | 功能描述:LCD 驅動器 CCFL BACK LIGHT IC RoHS:否 制造商:Maxim Integrated 數位數量:4.5 片段數量:30 最大時鐘頻率:19 KHz 工作電源電壓:3 V to 3.6 V 最大工作溫度:+ 85 C 最小工作溫度:- 20 C 封裝 / 箱體:PDIP-40 封裝:Tube |
| FAN7547AMXC | 制造商:FAIRCHILD 制造商全稱:Fairchild Semiconductor 功能描述:LCD Backlight Inverter Drive IC |
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