INN3678C-H606 failure in case of short circuit on output
Hi to all,
I'm testing a power supply with PFC pre-regulator, that mantain the DC-bus at 400 V. The output are a 24V, 1.8 A and a 15V, 0.5 A. I'm not using a SR rectifier, but a SIC diode on the 24 V output.. All seems okay, except for two things.
One is the audible noise with light load, coming from the transformer. This is because the switching frequency of the Innoswitch3 is around 16 KHz. Increasing the load, the frequency too increase and the audible noise disappear. I'm trying to reduce the magnetizing inductance increasing the transformer's air gap to increase the frequency at light load. Do you have any other suggestion?
The second, more important, is that with a short circuit on the 24 V output (coming when the power supply is already powered ON) most of times the Innoswitch get damaged (the RFWD resistor becomes very hot). What could be the reason? A voltage overstress in this condition? What do you suggest to protect the Innoswitch?
Thank you.
Comments
Hi,
Could I share those informations by mail? They are confidential.
Regards
Hi E.A,
I would recommend raising issue a new ticket in our online support. This way you can send the design files privately.
Please raise ticket at this link.
Regards,
PI-Nanoe
Short-circuit output failures in the INN3678C-H606 can often result from insufficient thermal management or incorrect circuit design. Verifying component ratings and ensuring proper layout for current flow can help prevent recurrence. For detailed specifications and design guidelines, consult the INN3678C-H606 datasheet to optimize your application.
Hi Emily,
We are glad to welcome you here at PI. If you have any question, feel free to create a new post or raise an online request ticket in this link.
Regards,Gavin
Hi E.A,
Can you provide us the transformer construction and design files of your design (schematic and layout). Also, if you can provide us the PIExpert/Xls files would be great.
Normally, the FWD voltage may damage when voltage peak reaches above the maximum voltage which is 150V. Can you capture the waveform across the anode-cathode of 24V output diode. The overstress voltage may be reduced by optimizing the snubber or transformer construction.
Regards,
PI-Nanoe