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TPS5410 - power for audio amp

chethan kp
Expert 1150 points
Other Parts Discussed in Thread: TPS5410, TPS54140

Hi ,

I have an audio amplifier(http://focus.ti.com/lit/ds/slos516c/slos516c.pdf) which requires a supply of 10 to 26 V , and in my system I have micro controller which needs 2.6 to 3.6v. i'm facing problem at the selection of power source  to this audio amplifier and controller

Hence I have selected two TPS5410 one from 20 v to 18 v, 1 A(for audio amp) and other one is for controller(20 to 3 v , 1A) , will this do the help ..?

source to the TPS5410 is from 20v ac to dc adaptor ...

regards

chethan

  • 0
    TI__Guru**** 189401 points

    Hi, Chethan,

    I am going to move your post to the non-isolated dc/dc forum so they can comment on your request.

    -d2

  • 0 in reply to Don Dapkus
    TI__Guru**** 191445 points

    The TPS5410 is not a good choice for 20V to 18 V conversion.  The maximum duty cycle will be exceeded.  You could use it for the 3.3 V rail however.  To make a better assesment, i would need to know details about your ac adapter voltage regulation.

    In general, the TPS5410 is a low cost low performance solution.  the internal compensation limits the type of output filter components you can use.  there are work arounds, but thy require additional design steps that are not available using  the on line design tool swicherpro.  You might want to look at the TPS54140 as an alternative.

     

  • 0
    TI__Guru**** 150930 points

    Chethan,

    With a 20V DC adaptor, the TPS5410 may work for you.  It will certainly work for your 20V to 3V converter.

    The issue with 20V to 18V is that you are above the maximum duty cycle of the TPS5410.  This is specified in the datasheet as a maximum value of 87% minimum.  So, you need to keep your duty cycle below 87% for reliable operation.  Duty cycle in a step-down converter is Vout/Vin, ideally.  When you account for losses, the duty cycle gets higher.  At 1A load, your 20V to 18V converter would likely be trying to run at nearly 100% duty cycle, which is not achievable.

    Would it be possible to use a higher voltage adaptor (at least 22V) or reduce the output voltage to around 16V?  Either of these would give a better solution with the TPS5410.  It might also be possible to power your amp directly from the adaptor without any converter in between.

    You can also order the EVM for the TPS5410 and evaluate it under your conditions.

  • 0 in reply to Chris Glaser
    Expert 1150 points

    Hi,

    I can use ac to dc adaptor maximum up to 25v, 3A, so this would solve the problem.

    I can go with TPS5410 for the two different supply , .. and i'll use the same design which I can get from on-line design ...

    regards

    chethan

  • 0 in reply to chethan kp
    TI__Guru**** 191445 points

    Try those designs in the switcherpro design tool.  Let me know the results.  You may find issues withteh capacitor selection for the 18 V rail as the voltage rating will need to be 25 V.  That will preclude the use onf most low ESR types.