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I have a question regarding a power supply setup I was presented with. I don't know how it should work.

I have a device with these electrical characteristics:

  • VDC = 48 V ± 1%
  • Continues DC current <= 425 A
  • Peak current 628 A for 1ms

I have been offered a solution with 4 power supplies, "tx500048" (see the tx500048 data sheet).

I don't really understand how 4 power supplies could support the peak current of the device. What parameters determine that the power supplies are capable of such currents?

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    \$\begingroup\$ How non-linear or reactive is your load? It seems to be rather harsh or unrealistic to demand 48V+/-1% with an Req of 0.1 ohm and a load regulation expectation of est1% demands a Zout of 1% of 0.1 = 1 mOhm which is better suited to a LiPo battery pack with a simple regulated float charger rather than a massive complex regulator with critical timing in nanoseconds with demands of the lowest practical impedance on earth for bulk capacitors in the smallest size package. Please share the wisdom behind this spec! Did you ask the "presenter" to explain how it should under all adverse conditions? \$\endgroup\$
    – D.A.S.
    Commented Nov 24, 2016 at 6:59

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If they do not support active current sharing but suppport passive current sharing with adjustment then it may be possible.

Passsive current sharing requires that there is some diode internal to output so it is back-drive protected for power-up, transient and power glitch situations.

You need to specify your load for these conditions. Latched shutoff? e.g. requiring operator intervention, or autonomous.

It depends on your step,load specs for voltage error tolerance.

You may also have power on surge current limits as these are 30Aac each and you may enquire if this can be reduced with ZCS triac on input with bypass timer relay.

Lambda do make good supplies but cooling must be examined and a full design spec verification of your system under all foreseen circumstances for environment and power quality exceptions.

The best design is only based on your best stated requirements and DVT plan. I have done this before with Lambda and others, so feel free to inquire how.

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The PDF datasheet available from the page you linked shows that the output current limiter can be set to 110A. So it's possible that four in parallel could supply up to 440A for a short period.

I'm not sure I'd recommend it, though.

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