This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

UCC256402: HV Pin

Part Number: UCC256402
Other Parts Discussed in Thread: UCC25640

I am reaching out to seek clarification regarding the operation of the High Voltage Startup (HV) pin on the UCC25640(2/4) LLC Resonant Controller. Specifically, I am inquiring about the minimum voltage required for proper functionality of the HV pin I did not find anything in the datasheet, did not provide specific guidance regarding the required minimum voltage or current for proper operation of the HV pin, only suggested a 5k resistor value.

 I only found some minor information in this forum:

(UCC256402: HV to VCC to VREG concerns and other questions - Power management forum - Power management - TI E2E support forums)

 ["Hi Texas Instruments,

My questions are:

Not directly related. Can I power this chip with Vin=80VDC through HV pin.


Hi Ronald,

Yes, 80V should be enough. We normally recommend at least 40V on HV to successfully charge VCC up to 26V. Please note the 10mA number to size the HV resistor string resistance accordingly so the HV pin is >40V when the HV startup is taking place."]

Could you please provide clarification on the minimum voltage required for proper operation of the HV pin on the UCC25640(2/4) series controllers? Additionally, any guidance or recommendations you could provide regarding the HV pin voltage, including the required voltage or current for proper operation and more information about the suggested resistor, would be greatly appreciated.

Thank you for your attention to this matter. I look forward to your response.


Best regards,