TOPSWITCH 265EG Vpin Problem
Hello All,
i have designed the circuit as per the PI-EXPERT Software.
The circuit is working at no load giving Clean output of 27V
But when i am trying to Load say about 100mA, output voltage gets fluctuated continuously and it is not stable.
After Various trial and error, When i pulled down vpin to GND iT WORKED..!!
Now but the circuit is starting very small voltage and i want it to turn on at the 90VAC
Schematics is attached with the post.
I have tried the resistors till 3 mOHM From 4 mOHM but it is not working.
Pls guide where is the problem and how to avoid..??
Regards
Chiku
댓글
Hi,
I have not connected the R12,D4 and VR2 (Overvoltage Protection)
Also X PIN in connected to GND (Disable the Fuction of Current Limit)
But When i am connecting the Vpin with 4 mOHM Resistor with high DC, at no load it gives output but After Putting a 100mA OF Load power supply output voltage oscilates.
When i am connecting HVDC GND to the V pin , it works..
Confused
here i am attaching the Layout.
| 첨부 파일 | 파일 크기 |
|---|---|
| Layout_smps.jpg (346.89 KB) | 346.89 KB |
Hi magicianchiku,
I can't figure out much the layout but it seems there is other ckt connected to Vpin causing impedance variation and trigger UV fault? Do you have additional bjt switch on V pin to control the enable disable function of Vpin? Thanks.
Hi Chiku,
Thank you for your interest of using power integrations part.
Regarding your question, I've seen 2 possible cause of your problem. First is your Xpin threshold. This sets the current limit of the MOSFET. You might set it too high. Try to reduce R6 value until you get your desired maximum power level. Second is your Vpin, your VR2 zener voltage rating might be too low that it easily reach its threshold level. Try to increase zener voltage rating. Hopefully it will help you achieve your desired power supply performance.