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BQ25723: How does VINDPM work

Lily Huang
Prodigy 40 points
Part Number: BQ25723

Tool/software:

Hi, 

I have questions about VINDPM, which I can't find the answer in datasheet. 

1. Can we disable it like we disable IINDPM? 

2. In our design, REG0x0A is default value = 3.2V, with USBC PSU, we always see REG0x21[4] = 0 which means Charger is never in VINDPM. I don't quite understand what the proper value for REG0x0A would be and how it would affect VINDPM. 

3. When charger in VINDPM, what does it exactly mean?   

Thanks

LL

  • +1
    TI__Mastermind 31751 points

    Hello Lilly,

    Lily Huang said:
    1. Can we disable it like we disable IINDPM? 

    No, You can't disable, but you can set it to the min value of 3.2V

    Lily Huang said:
    2. In our design, REG0x0A is default value = 3.2V, with USBC PSU, we always see REG0x21[4] = 0 which means Charger is never in VINDPM. I don't quite understand what the proper value for REG0x0A would be and how it would affect VINDPM. 
    Lily Huang said:
    3. When charger in VINDPM, what does it exactly mean?   

    Please refer to section 9.3.18 Input Source Dynamic Power Mangement for more details. Basically if the System load demands more power than the adapter can provide, the input voltage can ended up falling to the set value REG0x0A. The Adapter  will try to maintain this input voltage by reducing charge current. If the system load demands even more power, the device will shut off the converter and the system will crash.

    Best Regards,

    Christian.

  • 0 in reply to Christian Moyer
    Prodigy 40 points

    Now I kind of understand it. 

    So, when we set REG0x0A to the min value, 3.2V, it basically turns off VINDPM given that my adapter output voltage would never drop to this low voltage.

    Is it right? 

  • +1 in reply to Lily Huang
    TI__Mastermind 31751 points

    Hello Lily,

    Yes, If you set REG0x0A to the min value, it's basically turned off. This is what we typically recommend for customers who want to disable VINDPM.

    Best Regards,

    Christian.