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DI-56 参数 Datasheet PDF下载

DI-56图片预览
型号: DI-56
PDF下载: 下载PDF文件 查看货源
内容描述: 19.2 W¯¯ DC- DC转换器 [19.2 W DC-DC Converter]
分类和应用: 转换器
文件页数/大小: 2 页 / 371 K
品牌: POWERINT [ Power Integrations ]
 浏览型号DI-56的Datasheet PDF文件第1页  
DI-56  
• Good layout practices  
Key Design Points  
- For length of +12 V secondary current loop from  
transformer pin 8, diode D30 and capacitors C30, C31  
and back to pin 7 of the transformer: ensure identical  
path length for C30 and C31 to guarantee they equally  
share the ripple current.  
• For the nominal under-voltage set point VUV:  
R1 = (VUV – 2.35) / 50 µA  
VOV = (R1 x 135 µA) + 2.5 V  
• For highest efficiency designs: use continuous conduction  
mode operation designed at approximately 0.4 KRP;  
minimize turns in the transformer and at this (19 W) power  
level keep AC flux density (BM) <1500 Gauss; fully fill a  
single layer for each winding to minimize leakage  
inductance and maximize copper fill factor; if possible use  
Schottky rectifying diodes (D20 and D30) with a low-  
forward drop.  
• The transformer primary is split in order to minimize  
leakageinductanceandthusobtainbettercross-regulation.  
Note:minimizingprimaryleakageinductancewillimprove  
output cross-regulation at load extremes.  
• The -12 V output is not directly sensed as part of the  
regulation loop. Cross-regulation may be improved by  
adding a second sense resistor to work in conjunction with  
R10. Both resistors R10 and the second sense resistor  
would be changed to 76 keach.  
- The same is also true for the layout of the -12 V output.  
• Choosing a larger DPA-Switch will increase efficiency at  
low and medium input voltages.  
TRANSFORMER PARAMETERS  
Core Material  
Bobbin  
Epcos P/N: P 14x8 N87, ungapped  
8-pin P 14x8 surface mount bobbin  
Primary 7T + 7T, 2 x 29 AWG  
Bias 5T, 1 x 36 AWG  
Winding Details  
+12 V 5T, 2 x 29 AWG  
-12 V 5T, 2 x 29 AWG  
Primary-1 (4-NC), -12 V (6-5), Bias (2-3),  
+12 V (8-7), Primary-2 (NC-1)  
Winding Order &  
Pin Numbers  
• Set resonant frequency of post-filter (L2, C22 or L3, C32)  
beyond crossover frequency (typically 5% to 10% of  
switching frequency).  
Primary Inductance  
22 µH ±25% (at 400 kHz)  
3.8 MHz (minimum)  
0.75 µH (maximum)  
Primary Resonant  
Frequency  
Leakage Inductance  
Table 1. Transformer Design Parameters.  
A
9/03  
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