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bq24190 - Change input current limit, then return to DEFAULT mode?

Jonathan Bender
Expert 7895 points
Other Parts Discussed in Thread: BQ24190, BQ24192

Hello,

The default input current limit for bq24190 is 1.5A, but it's being used in an application that needs it to be 3A. There is a host MCU in the system, but it is not available for 'hosting' duties - it just needs to be able to write the 3A setting into REG00[2:0], and then have the charger operate autonomously (DEFAULT mode).

Is it possible to change the input current limit register setting, and then return the device to DEFAULT mode?

Figure 25 would seem to indicate that doing this would cause the registers to reset (and thus set the input current limit back to 1.5A).

If that's the case, would bq24192 be the correct replacement (functionally similar, aside from the USB D+/D- and PG addition, but with a default input current limit of 3A)?

Thanks,

Jonathan

  • 0
    TI__Guru 57541 points
    You may use bq24192 instead if the 192 default settings and pin functions meet the application specs. If still using 190, the host can change the input current limit to 3A, then disable watchdog time by setting REG05[5:4] = 00, 190 will continue operating under the same register settings just like working in default mode but with different register settings. Thanks!
  • 0 in reply to Ning T
    TI__Expert 7895 points
    Thanks for the reply and suggestion on disabling the watchdog.

    If using the bq24190 in host mode, after disabling the watchdog, are there any other automatic behaviors that the device expects the host to manage?

    Section 9.4.1.1 describes how the host would need to manage the HIZ state for a USB100mA charge source, but that seems like a very specific case that shouldn't affect the end application here. It would be good to know of any other situations like this when operating in host mode.

    Thanks,

    Jonathan
  • 0 in reply to Jonathan Bender
    TI__Guru 57541 points

    1) No. If host has no further comments, the device will keep running under the same register settings.

    2) That is input source detection when a DC source is plugged in. If your source is not USB100mA charge source, you do not need to worry about it.

     

    Thanks!

  • 0 in reply to Ning T
    TI__Expert 7895 points
    Many thanks for the help!

    Jonathan