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TPS54360B: Design Help

Ray Vincent Aranzaso
Mastermind 18180 points
Part Number: TPS54360B
Other Parts Discussed in Thread: TPS54360

Hi,

Good Day. I have a customer who is working with TPS54360B. Please see below his query for your reference. Thank you very much.

Applying the scheme indicated in the TPS54360 manual and in the AN to create a power supply with dual voltages +/-12V , I observe that as the load increases the value of the two voltages diverges, especially if the load is not balanced on the two branches. With this type of circuit it is more or less normal but the most serious problem is that not all the boards have the same behavior. Some cards diverge by a few tenths of a volt, others go up to 2 volts with a load of 100mA. what assumptions can be made to explain this difference?

Best Regards,

Ray Vincent

  • 0
    TI__Guru 73615 points

    Hello

    It would be best if you can supply your specific schematic for our review.

    Also, the input voltage and maximum loads.

    I will assume you are using a fly-buck similar to figure 33 in the data sheet.

    As you mentioned it is difficult to get good regulation from the secondary side.

    I think that the differences you are experiencing may be due to the differences in leakage 

    inductance of the transformer.  You may want to measure the leakage inductance on a small sample

    and see if there are any major differences.  Of course, you would always strive for the lowest possible

    leakage inductance with a fly-buck type of topology.

    Thanks

  • 0 in reply to Frank De Stasi
    TI__Mastermind 18180 points

    Hi Frank,

    Good Day. Please see below the response of our expert to your query. Thank you very much.

    Yes, the schematic is absolutely the same as suggested in fig.33, with 24V for input voltage and +12V/-12V for output voltage with 200mA maximum load. I supposed the problem was in the transformer, now I am wondering if and how it is possible to reduce this effect of the dispersion inductance.

    Best Regards,

    Ray Vincent

  • 0 in reply to Ray Vincent Aranzaso
    TI__Guru 73615 points

    Hello

    I think you may need to consult your transformer manufacturer to see if anything can be done 

    to reduce your leakage inductance or make it more predictable.  Also, be sure that you are using

    a Schottky diode or an ultra fast diode with low Trr.

    I have attached a page of resources that you may find helpful.

    Thanks