Tool/software:
Hi,
We are currently evaluating the UCC256613DDBR, but we are facing an issue where the V5P output stops functioning. Please find the summary of our observations below:
Phenomenon:
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In some cases, only V5P fails. For certain devices, applying an external 5 V allows normal operation.
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Hi/Lo MOSFETs are almost never damaged.
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From waveform observation, it seems that shoot-through between Hi/Lo MOSFETs may be generating short-circuit noise, which might be coupled into the V5P path.
Countermeasures Tried:
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Added TVS diodes to VCC, HO, LO, and V5P.
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Supplied VCC from an external DC power source.
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None of the above improved the situation.
Test Environment:
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The evaluation is based on an existing product designed with UCC256403A.
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Only the controller IC and its peripheral components have been changed to UCC256613.
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The main resonant circuit (transformer, resonant inductor/capacitor, etc.) remains unchanged.
Questions:
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What could be the possible root causes of V5P output failure?
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Are there any known failure mechanisms or critical design considerations we should pay attention to?
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Could you suggest any recommended countermeasures or design guidelines to avoid this failure?
We have prepared the relevant schematics, waveforms, and calculation sheets, but since these contain confidential information, we cannot share them on a public forum. Would it be possible to share such materials with you through a private channel?
We would greatly appreciate your guidance on this matter.
Best regards,
Conor
