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TPS65217: Best PMIC to use with a home-brew android tablet with 11" display?

Dylan Maisel
Prodigy 20 points
Part Number: TPS65217

We would like to power a custom portable computer with a lithium battery and PMIC capable of driving a 20 Watt display and an additional 5 Watts of digital devices. The more integrated the solution is, the better.
Are there limitations here with the TPS65217XX family? If so, what is the best PMIC to use to take in 3.7V li-po power, and generate voltages for an LED display as well as the embedded systems? The battery pack is rated at 2A current maximum.

  • 0
    TI__Genius 10200 points

    Hi,

    I have assigned your post to our expert for this device, Brian Berner. He should get back to you by Monday.

    Thanks,

    Gerard

  • 0
    TI__Mastermind 30260 points

    Will your system be based on the Sitara AM335x processor?

    The potential limitations of using the TPS65217x PMIC for the application is that the display sounds very large/power hungry. 20 Watts is more than the entire PMIC can use, given that IACLMT (current limit through AC pin) has a maximum value of 2A (5V*2A = 10W).

    Also, I would be surprised if a single-cell Lithium Ion battery (1S1P, or even 1S2P) could power your system for a considerable amount of time.

    I would first create a detailed power budget: how fast do you want to charge the battery? How many additional rails are needed? What is the voltage and load current for each? Then it would be easier to recommend a PMIC.

  • 0 in reply to Brian Berner
    Prodigy 10 points

    Hi Brian, thanks for the reply!

    Yeah I had a feeling the TPS65217 was not "quite" the right part for the job, but I was hoping there was something out there that could drive the big display.

    If it wasn't for the display, powering this system would be easy because everything else is lower-power digital devices. We are using a SOM for the Android core with an integrated PMIC, which can take 5V and generates the other voltages needed for the chipset. Total power of all of that stuff is 6 Watts (full-load, worst case).

    As far as the battery pack goes, we can specify the topology. Currently we are using a 33 Watt-hour 1S3P battery pack, but I fear 3V is just too low of a voltage and the current numbers needed by a 12V or greater boost circuit are looking silly at those voltage levels. It is feeling like I am reinventing the wheel and this problem has been solved by every laptop and tablet manufacturer. 

    Given this additional information, what would you recommend? Is the solution to move to a 4S battery pack? We can do that if we have to, but I'll need to redesign the charger(have any parts that can charge/manage a 4 cell series Li-po pack in that case?). I am already in dialogue with our display vendor but they are overseas and a bit slow to respond to my technical questions.

  • 0 in reply to Dylan Maisel1
    TI__Mastermind 30260 points

    Dylan,

    Yes, if you have a SoM/CoM (motherboard) that accepts 5V as the input and generates all the other voltages for the SoC/Processor, then you probably don't need a PMIC in your system.

    Realistically, there aren't a lot of chips that integrate the functionality you are describing because they are very different functions: 

    It might be best to settle on the desired battery topology, then go through and pick the parts you want to use from each of these 3 categories. Finally, you will need to start a new e2e thread to confirm with the experts of each device family that you have selected an appropriate part.

    Unfortunately, my expertise is limited to multi-rail PMIC devices like the TPS65217, which I don't think is a good fit here.