欢迎访问ic37.com |
会员登录 免费注册
发布采购

DER-46 参数 Datasheet PDF下载

DER-46图片预览
型号: DER-46
PDF下载: 下载PDF文件 查看货源
内容描述: 4.5W ( 6Wpk )多路输出DVB -T电源采用TNY264P [4.5W (6Wpk) Multiple Output DVB-T Power Supply using TNY264P]
分类和应用:
文件页数/大小: 22 页 / 1366 K
品牌: POWERINT [ Power Integrations ]
 浏览型号DER-46的Datasheet PDF文件第2页浏览型号DER-46的Datasheet PDF文件第3页浏览型号DER-46的Datasheet PDF文件第4页浏览型号DER-46的Datasheet PDF文件第5页浏览型号DER-46的Datasheet PDF文件第7页浏览型号DER-46的Datasheet PDF文件第8页浏览型号DER-46的Datasheet PDF文件第9页浏览型号DER-46的Datasheet PDF文件第10页  
DER-46  
6 W peak, Multiple output PSU for DVB-T  
April 20, 2005  
4 Circuit Description  
The schematic in Figure 1 shows an off-line flyback converter using the TNY264P. The circuit  
is designed to operate from 195 VAC to 265 VAC input and provides isolated multiple outputs  
(i.e. 2.5V; 3.3V; 5V; 12V; 33V).  
4.1 TinySwitch Primary  
AC input power is rectified by a full bridge, consisting of D1 through D4. The rectified DC is  
then filtered by the bulk storage capacitors C1 and C4. Inductors L1, L2, C1 and C4 form a pi  
(π) filter, which attenuates conducted differential-mode EMI noise.  
The rectified DC rail is applied to one end of the transformer primary, the other end being  
connected to the drain pin of the integrated MOSFET of U1.  
To keep the peak DRAIN voltage acceptably below the BVDSS (700V) of U1, diode D5, C2, R1,  
and R7 form a primary clamp. This network clamps the voltage spike seen on the DRAIN due  
to primary and secondary reflected leakage inductance.  
Capacitor C21 is the decoupling cap for the TOPSwitch.  
R19, R20, R21 and R22 enables the under voltage (UV) line sensing that inhibits U1 to start  
switching below 70VAC during start-up.  
4.2 Output Rectification  
The secondary of T1 has four windings AC stacked together. Each rectified and filtered to  
provide 3.3V, 5V, 12V and 33V DC outputs. While the 2.5V output was derived from 3.3V  
through a voltage dropping diode D12.  
A zener (D9) - resistor (R3) pre load was employed to clamp the 33V from going over voltage  
only when it is lightly loaded while the rest of the outputs are heavily loaded.  
4.3 Output Feedback and control  
The main feedback loop is closed on 3.3V output. DC feedback to the output voltage  
regulator error amplifier (U4) comes from a divider network R9 and R11. The center point is  
tied to the reference input of U4. Capacitor C24 and resistor R8 roll off the high frequency  
gain of U4 while R12 sets the overall gain.  
Power Integrations  
Tel: +1 408 414 9200 Fax: +1 408 414 9201  
Page 6 of 22  
www.powerint.com