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PMP40379: 500-W, Single Stage LLC Power Supply Reference Design for Audio Amplifier

Part Number: PMP40379

Hello

I have a major question in refrence to the above refrence design.

When loading one rail of the SMPS output as below, what is the resulting voltages?

Example 1:

Loading the +42V rail with 6A (+ & 0) not loading the -42V rail, what is the voltage at the both rails?

Loading the -42V rail with 6A (- & 0) not loading the +42V rail, what is the voltage at the both rails?

They will remain +-42VDC in such load conditions?

Any answer is really appreciated.

  • Hello Micro,

    I am checking with the designer to see if we have cross regulation data.

    In general for a design like this where only one of the outputs is regulated, you can expect 5-10% variation on the rail that is not regulated.

    Thus, the +42V rail will always be close to that value and the -42V rail could vary from -38V to -46V just as an example.  I don't have the exact numbers for this design.

    Please give us sometime and we will respond.

  • 1680.Schematic Prints.pdf

    Hello Robert,

    I am not sure if the variation is going to be 10% maximum,

    I have serious cross regulation problem with my current L6599 prototype, with around 38% variation on the rail when loading one rail, everything is OK when loading the +- rails.

    I am attaching the regulation circuit I am using in the L6599 design for your reference, it is set to +-34VDC you may spot something.

    I know this is a different problem, but PMP40379 is very similar in principle, and if it works well I will build it.

    are there any designs to regulate both rails ?

    Thanks for your attention.

  • Hi Micro,

    The cross regulation data of PMP40379 shows on the table below, the output voltage variations are within -4%~6%.

    Best Regards

    Oliver