Tool/software:
Using the 4-phase synchronous buck configuration,
Please find the schematic and quickstart design below.
LM5143A-Q1 Quickstart Design.pdf
we observed the following:
- At Vin = 25 V, Vout = 15 V, the output current can reach 70 A.
- At Vin = 40 V, Vout = 15 V, we are able to test up to 60 A, but at 70 Athe overcurrent protection is triggered and the output voltage cannot be maintained.
- At Vin = 50 V and Vout = 15 V with no load, we observed an abnormal temperature rise on Phase 3 exceeding 100 °C. We measured the Vgs of the Phase 3 down-side MOSFET as shown in the figure below. For comparison, the Vgs of the Phase 2 down-side MOSFET shows a normal duty variation, while the Vgs of the Phase 3 down-side MOSFET exhibits abnormal duty behavior. We are not sure why this variation occurs. Or are there other possible causes?
Could you please advise how we can improve this?
Best regards,
YUMING