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TPS65135: spec check

GARETH OU
Guru 10335 points
Part Number: TPS65135
Other Parts Discussed in Thread: TPS65132

Hi

The customer of this chip supplies power to the MIPI display and sets the output to 5.5V and -5.4V. When no load is applied, the voltage is 5.5V and -5.4V. After the display is connected, the voltage rises to 6V and -6.3V. When the load is added, the voltage rises. It's high, is it normal?

  • 0
    TI__Mastermind 29990 points

    Hi GARETH,

    May I know what are the load current added on AVDD and AVEE?

    BR

    Patrick

  • 0 in reply to Patrick Yao
    Guru 10335 points

    Hi Patrick

    The screen manufacturer replied that the currents of the two voltages AVDD and AVEE are different and there is a mismatch, as follows

    VSP:

    1. Black screen =-0.051A

    2.White screen=-0.051A

    3.RGB screen=-0.068A

    VSN:

    1. Black screen =0.05A

    2.White screen=0.006A

    3.RGB screen=0.022A

    The customer did an experiment and found that if AVEE is not loaded, the voltage of AVDD will increase if the load exceeds 13mA;

    Is there any way to prevent the voltage from rising due to current mismatch between AVDD and AVEE? Thanks!

  • 0 in reply to GARETH OU
    TI__Mastermind 29990 points

    Hi GARETH,

    TPS65135 is recommended to add same load current on AVDD and AVEE, and the current mismatch within 50% is also accepted. But seems the mismatch of RGB screen is ~3 times higher.

    BTW, may I know if customer will consider other solutions? From my side, TPS65132 is a good choice here as well.

    BR

    Patrick

  • 0 in reply to Patrick Yao
    Guru 10335 points

    Hi Patrick

    Thank you for your reply and suggestions

    So adjusting the TPS65135 schematic will not improve the voltage rise problem. It is because the product does not match the screen, right?

    What is the difference between TPS65132 and TPS65135?

    Does the voltage of TPS65132 not increase when the positive and negative currents do not match (more than 50%)?

    SPEC-FX10006-B(1).pdf

  • 0 in reply to GARETH OU
    TI__Mastermind 29990 points

    Hi GARETH,

    TPS65132 generates the AVDD and AVEE with different circuit, so both circuits can work separately and no need to worry about the load current mismatch.

    BR

    Patrick