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About LDO temp/load compensation

yang qiang
Prodigy 40 points

Using the TPS7A4501, when it working with a 1A load, and environment temperature of 80 degree, it will has a voltage loss of about 50-100mV.

But our purpose is to maintain the output voltage to +/- 10mV.

We can use the software to compensate this voltage loss, however, it takes lost of time to do this.

So, is there any way to do this compensation with HARDWARE circuit? Some kind of AVC circuit?

  • 0
    TI__Prodigy 600 points

    Hi Yang,

    We don't have such external hardware solution can perform AVC function. This output voltage drop is appropriate for this part and 10mV tolerance is too tight for almost common LDO IC. I thought the software compensation you did should be the best way to reach your goal.

    Regards,

    Hughie Lu

  • 0 in reply to Hughie Lu
    TI__Prodigy 570 points

    Perhaps you can try to have your resistive network very, very close to the place you would like to have this very tight load regulation spec (this is to compensate for any resistive loses).

    Remember to keep your Cout and Cff (between fb and out) very close to the LDO.

     

    Also, remember that although the device is rated from -40C to 125C, the temperature parameter is Tj (juction temperature) not Ta (ambient temperature); at 1A load this condition may not be met due to the power dissipated by the device itself.