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TPS25942A: Seamless transition with priority

Alexander Alioshyn
Prodigy 170 points
Part Number: TPS25942A

Hello,

I have a portable device with an embedded non-rechargable battery and an external power source.

The battery voltage can vary from 9 to 3 volts. The voltage range of the external power source can be between 5 and 17.

My load is a custom computer module. Its peak current at the startup is about 3A and then it draws only about 0.5A continuously.


I want to create a system with the seamless transition between both power sources with the priority of the external power source.

Is it possible with the TPS25942A?

I can not let the external power source to charge the internal battery and visa versa.

The power consumption of the whole solution is critical and as far as I understand the DIODE mode won't suit me because of the power dissipation.

Other critical factors are: reverse polarity protection for both of the power inputs and an ability to turn off both of the switches with the help oth the external pushbutton controller.

  • 0
    TI__Guru* 95911 points
    Hi Alexander,

    Thanks for reaching us on E2E.
    You can consider TPS25942A device in Priority Power Multiplexing configuration as per Figure 79. Set the power good threshold and Enable threshold for the external power source at ~5V.
    DIODE mode configuration is suitable for systems with almost equal power rails. Not possible to use for your system.
    For Reverse Polarity Protection -> refer Figure 86 -> signal diode in the GND terminal path ensures that device is not functional during reverse polarity conditions and internal FET blocks the reverse path.

    Best Regards,
    Rakesh