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參數資料
| 型號： | TOP248F |
| 英文描述： | SMPS Controller |
| 中文描述： | 開關電源控制器 |
| 文件頁數： | 21/52頁 |
| 文件大小： | 457K |
| 代理商： | TOP248F |
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TOP242-250
21
H
9/02
Figure 41. 30 W Power Supply using External Current Limit Programming and Line Sensing for UV and OV.
Application Examples
A High Efficiency, 30 W, Universal Input Power Supply
The circuit shown in Figure 41 takes advantage of several of
the
TOPSwitch-GX
features to reduce system cost and power
supply size and to improve efficiency. This design delivers
30 W at 12 V, from an 85 to 265 VAC input, at an ambient of
50
°
C, in an open frame configuration. A nominal efficiency
of 80% at full load is achieved using TOP244Y.
The current limit is externally set by resistors R1 and R2 to a
value just above the low line operating peak DRAIN current
of approximately 70% of the default current limit. This allows
use of a smaller transformer core size and/or higher transformer
primary inductance for a given output power, reducing
TOPSwitch-GX
power dissipation, while at the same time
avoiding transformer core saturation during startup and output
transient conditions. The resistors R1 & R2 provide a signal
that reduces the current limit with increasing line voltage, which
in turn limits the maximum overload power at high input line
voltage. This function in combination with the built-in soft-
start feature of
TOPSwitch-GX
, allows the use of a low cost
RCD clamp (R3, C3 and D1) with a higher reflected voltage,
by safely limiting the
TOPSwitch-GX
drain voltage, with
adequate margin under worst case conditions. Resistor R4
provides line sensing, setting UV at 100 VDC and OV at
450 VDC. The extended maximum duty cycle feature of
TOPSwitch-GX
(guaranteed minimum value of 75% vs. 64%
for
TOPSwitch-II
) allows the use of a smaller input capacitor
(C1). The extended maximum duty cycle and the higher
reflected voltage possible with the RCD clamp also permit the
use of a higher primary to secondary turns ratio for T1 which
reduces the peak reverse voltage experienced by the secondary
rectifier D8. As a result a 60 V Schottky rectifier can be used
for up to 15 V outputs, which greatly improves power supply
efficiency. The frequency reduction feature of the
TOPSwitch-GX
eliminates the need for any dummy loading
for regulation at no load and reduces the no load/standby
consumption of the power supply. Frequency jitter provides
improved margin for conducted EMI meeting the CISPR 22
(FCC B) specification.
Output regulation is achieved by using a simple Zener sense
circuit for low cost. The output voltage is determined by the
Zener diode (VR2) voltage and the voltage drops across the
optocoupler (U2) LED and resistor R6. Resistor R8 provides
bias current to Zener VR2 for typical regulation of
±
5% at the
12 V output level, over line and load and component
variations.
12 V
@ 2.5 A
D2
1N4148
T1
C5
47
μ
F
10 V
U2
LTV817A
VR2
1N5240C
10 V, 2%
R6
150
R15
150
C14
1 nF
D1
UF4005
R3
68 k
2 W
C3
4.7 nF
1 kV
CY1
2.2 nF
U1
TOP244Y
D
L
S
X
F
C
R8
150
C1
68
μ
F
400 V
C6
0.1
μ
F
D8
MBR1060
C10
560
μ
F
35 V
C12
220
μ
F
35 V
C11
560
μ
F
35 V
RTN
R5
6.8
R1
4.7 M
1/2 W
R4
2 M
1/2 W
R2
9.09 k
PI-2657-040501
L3
3.3
μ
H
BR1
600 V
2A
F1
3.15 A
J1
L1
20 mH
L
N
CX1
100 nF
250 VAC
CONTROL
TOPSwitch-GX
PERFORMANCE SUMMARY
Output Power:
Regulation:
Efficiency:
Ripple:
30 W
±
4%
≥
79%
≤
50 mV pk-pk
8
相關PDF資料 |
PDF描述 |
|---|---|
| TOP248R-TL | SMPS Controller |
| TOP249F | SMPS Controller |
| TOP249R-TL | SMPS Controller |
| TOP243R-TL | SMPS Controller |
| TOP244F | SMPS Controller |
相關代理商/技術參數 |
參數描述 |
|---|---|
| TOP248F- | 制造商:POWERINT 制造商全稱:Power Integrations, Inc. 功能描述:TOPSwitch-GX Family Extended Power, Design Flexible, EcoSmart, Integrated Off-line Switcher |
| TOP248FN | 功能描述:交流/直流開關轉換器 155 W 85-265 VAC 205 W 230 VAC RoHS:否 制造商:STMicroelectronics 輸出電壓:800 V 輸入/電源電壓（最大值）:23.5 V 輸入/電源電壓（最小值）:11.5 V 開關頻率:115 kHz 電源電流:1.6 mA 工作溫度范圍:- 40 C to + 150 C 安裝風格:SMD/SMT 封裝 / 箱體:SSO-10 封裝:Reel |
| TOP248FN- | 制造商:POWERINT 制造商全稱:Power Integrations, Inc. 功能描述:TOPSwitch-GX Family Extended Power, Design Flexible, EcoSmart, Integrated Off-line Switcher |
| TOP248FN-TL | 制造商:POWERINT 制造商全稱:Power Integrations, Inc. 功能描述:TOPSwitch-GX Family Extended Power, Design Flexible, EcoSmart, Integrated Off-line Switcher |
| TOP248F-TL | 制造商:POWERINT 制造商全稱:Power Integrations, Inc. 功能描述:TOPSwitch-GX Family Extended Power, Design Flexible, EcoSmart, Integrated Off-line Switcher |
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