- Topology : push-pull converter ; primary with center tap, secondary with center tap
- 2 switches on primary (in phase shift), 2 diodes on secondary
- Frequency : 150KHz(Mosfet frequency)
- Input DC voltage : 12 to 48V
- Output DC voltage : 24V +/-10%
- Output current : 1.2 A Max
- Max duty cycle on each primary winding: 0.5
- Isolation voltage primary/secondary (not for safety purposes) Let's say 500V DC
我的设计是:磁芯-3C94/N87 EP13,初级-6T/绕组,AWG32#,次级-15T/绕组,AWG34#.
但在客户测试时出现如下问题:
Vin = 12V DC
Iin = 1.85A
Pin = 22.2W
F=150 KHz
DutyCycle = 43% for each push-pull arm -Seems OK at this voltage
Ipeak on each MOSFET : 3.2A (Linear ramp, seems OK too)
Vout = 25.2V
Pout = 19.1W
Overall efficiency = 86% - OK
除输出功率没达到,其他OK.
但当Vin>15V时,初级电流急剧上升,效率急剧下降.
请各位大虾帮忙分析问题所在.
