TNY280PN
TNY280PN is used as a dedicated power supply ac100v.
We have the development and manufacturing to partner companies.
We sell in the market than last year.
This year, the Zener diode failure of the snubber circuit of the peripheral circuit has occurred 2 pcs.
Total shipments is about 5,000.
The snubber circuit we use a diode and a Zener diode.
Resistance is not used.
Please see attached circuit diagram file.
I would like to see what there is no problem in the circuit basis.
Comments
Thank you for your quick response.
Answer is as below.
1.14W(ac100v,50hz/60hz)
2.800mA(peak)
3.about 170v
4.please attached file.
5.Temperature is 75deg.
It is over 70deg.
Junction temp is 150deg.
How do you decide 70deg to use this IC and ZD?
Please see attache file.
| Attachment | Size |
|---|---|
| document.zip (2.07 MB) | 2.07 MB |
It would seem that based on the data you sent that the zener should be ok. Based on the waveforms that you attached there is ringing on your drain voltage which is due to the leakage inductance. This ringing may cause heating. If I would work on this my next action is to add a series resistor to reduce this ringing. You could start with a 50 ohm resistor.
One thing I forgot to ask is whether the failure occured in the field. If it occured in the field, you might want to check the design's lightning surge susceptibility. Were there other parts which got damaged with the zener?
Hi Matsunaga,
Thank you for choosing Power Integrations.
Could you please provide additional information regarding your design?
1. What is the output voltage, output current and total output power of your power supply?
2. Were you able to measure the maximum drain voltage of your design?
3. What is the reflected voltage across your primary?
4. Could you send your transformer specification or the PIexpert design file?
5. You need to make sure that the power rating of the TVS used is enough to withstand the dissipation. Take thermal measurement of the clamp TVS. The temperature of the TVS at room ambient should not exceed 70degC.