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DI-29 参数 Datasheet PDF下载

DI-29图片预览
型号: DI-29
PDF下载: 下载PDF文件 查看货源
内容描述: 25W的反激式DC -DC转换器 [25 W Flyback DC-DC Converter]
分类和应用: 转换器
文件页数/大小: 2 页 / 66 K
品牌: POWERINT [ Power Integrations ]
 浏览型号DI-29的Datasheet PDF文件第2页  
®
Design Idea DI-29  
®
DPA-Switch  
25 W Flyback DC-DC Converter  
Topology  
Flyback  
Device  
Power Output  
Input Voltage  
Output Voltage  
Application  
DC-DC Converter  
25 W  
36 - 75 VDC  
DPA425R  
7 V  
Design Highlights  
Resistor R3 programs the internal current limit of the  
DPA425R to 50% of nominal. The larger DPA-Switch  
selectionreducesconductionlosses,raisingefficiencywithout  
circuit changes or increased overload power.  
• Extremely low component count  
• High efficiency – 85% using Schottky rectifiers  
• No current sense resistor or transformer required  
• Accurate input under/over voltage meets ETSI standards  
• Operates to zero load with no pre-load required  
• Output overload, open loop and thermally protected  
• 400 kHz operation minimizes size of magnetics  
Zener VR1 clamps leakage inductance spikes, keeping the  
DRAIN voltage below BVDSS. The bias supply for U1 is  
provided from an auxiliary flyback transformer winding.  
On the secondary, a snubber across D2 (C9, R5 and R13)  
limits the secondary leakage inductance spikes generated by  
diode reverse recovery. Inductor L2, C13 and C14 form a  
post-filter to reduce high frequency output switching ripple.  
A soft-finish network, C18, D3 and R7, eliminates output  
turn-onovershoot.Theremainingcomponentsprovideoutput  
voltage regulation and loop compensation.  
Operation  
DPA-Switchgreatlysimplifiesthedesigncomparedtoadiscrete  
implementation. Resistor R1 programs the input under/over  
voltages to 33 V and 86 V, respectively. Including tolerances  
these thresholds guarantee the converter is operational between  
36 V and 75 V, without the cost of additional line sense  
components.  
R5  
6.8  
C9  
2.2 nF  
50 V  
R13  
6.8 Ω  
C7 1 nF  
R14  
1.5 kV  
10 Ω  
L2  
300 nH  
6 A  
C10  
100 µF 100 µF 100 µF  
10 V 10 V 10 V  
C11  
C12  
C13  
C14  
+ V  
L1  
36-75 VDC 1 µH 2.5 A  
IN  
C15  
100 µF 100 µF  
1 µF 7 V, 3.57 A  
10 V 10 V  
T1  
7,8  
1
D2 MBRB2545CT  
D1 BAV19WS  
RTN  
5,6  
FL  
2
3
C23  
4.7 µF  
20 V  
4
R1  
619 kΩ  
1%  
R10  
18.2 kΩ  
1%  
U2  
R7  
10 kΩ  
U2  
C1  
1 µF  
100 V  
C2  
1 µF  
100 V  
C3  
1 µF  
100 V  
DPA-Switch  
C16  
100 nF  
U1  
D3  
BAV19WS  
DPA425R  
R6  
R12  
D
S
L
150 Ω  
5.1 Ω  
CONTROL  
C
C17  
R9  
1 µF  
220 Ω  
C18  
10 µF  
10 V  
R4  
X
F
R3  
1.0 Ω  
VR1  
15 kΩ  
C5  
220 nF  
SMBJ  
130  
1%  
U3  
C6  
68 µF  
10 V  
R11  
LM431AIM3  
10.0 kΩ  
-V  
IN  
1%  
PI-3012-120902  
Figure 1. DPA-Switch Flyback DC-DC Converter Schematic.  
December 2002  
DI-29  
www.powerint.com