MPM82504 x4 parallel for 400A design

DC-DC Power Converters
1

When we use the 4x MPM82504 in paralle for 400A.
After CTRL enable. votlage rise to target voltage then drop around 68mV after ~8ms.

MPM
MPM841×638 59.7 KB

  • Ramp setting, we try 27mV, voltage drop disapear but ripple is 100mV
  • Ramp setting, 68mV/41mV both has drop situation

Is there anything we can do to mitigate this symptom?

2

Hi @flint , thank you for posting on the MPS Technical Forum.

Table 5 from the datasheet may be of help:

image
image1056×993 166 KB

Is this start-up waveform showing output voltage while under 400A load?

Best, Will

3

Thanks for the reply.

We initially set up according to this table. Afterwards, we tried many different settings and found that the issue does not occur when the ramp value is small (8.6 mV). In addition, although we designed for 400 A, the final application does not require such a high current. The waveform reflects the no-load condition.

4

Understood.

Is ripple in spec with 8.6mV ramp?

5

We don’t observe any significant high ripple in it
but we just don’t understand why the ramp value setting impact vout at beginning like this.