TI中文支持网Part Number:UC3843Other Parts Discussed in Thread: UC3825
Hi ，Have a good day.
we got a special power requirement that we hope to complete a flyback power supply with a wide voltage output to achieve adjustable output from 0V-250V, and the maximum power is 120W.
In order to achieve a very small ripple voltage, we hope to avoid entering burst mode on all output voltages,and we chose the UC3843 and we designed the Demo board.
To meet more precise voltage and current control，we put the IC on the second side realized by photoelectric driver and current transformerto .
And we found some questions may need your professional support:
1，Can UC3843 meet our needs not to enter Burst mode? Are there other TI ICs that can be supported?
2，I found that the other companies have implemented this requirement by a flyback with UC3825. Is there any special difference between UC3825 and UC3843 for Burst mode?
3，We found that our demo board has irregular driving problems. What are the reasons for this problem? We posted the schematic.
4，How should the transformer be designed for this requirement, could you send me your opinion?
Thanks a lot.Flyback.pdf
Johnsin Tao：
Hi
你的输入电压是多少？
UC3843没有Burst mode，只有DCM/CCM模式，UC3825是双驱动，和UC3843完全不同，你可以对比这两datasheet。
我在TI的参考设计中看到了一个0~100V的设计： https://www.ti.com.cn/tool/cn/TIDA-01592
当然和你的参数肯定不一样，但是你可以参考它的控制方式，特别是反馈。
