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BQ25790: Dual BQ25790 design and general questions

Charles (KAT) Zhang
Intellectual 1405 points
Part Number: BQ25790

Tool/software:

Dear team,

Lenovo tablet team is evaluating BQ25790 but have following concerns which I didn't find the D/S.

1. Does BQ25790 support dual charger design? One as primary and one as secondary to support higher input power.  Do have I reference design for that? They are interested in BATP/BATN connection for second BQ25790.

2. Does BQ25790 support BC1.2 detection in HIZ mode?

3. Does BQ25790 support QC charging? if yes, is it qualified by QC or is just compatible.

4. Can we tie unused TS pin 10K to GND?

Thank you,

Charles.

  • 0
    TI__Mastermind 20930 points

    Hello Charles,

    Charles (KAT) Zhang said:
    1. Does BQ25790 support dual charger design? One as primary and one as secondary to support higher input power.  Do have I reference design for that? They are interested in BATP/BATN connection for second BQ25790.

    No, We do not have a reference design. Can you explain more what is the reason for the dual chargers?

    Charles (KAT) Zhang said:
    2. Does BQ25790 support BC1.2 detection in HIZ mode?

    The EN_HIZ bit is cleared automatically when the adapter is plugged in. BC1.2 dection only occurs when the adapter is first plugged in, So there should not be any issue with BC1.2 detection and HIZ mode.

    Charles (KAT) Zhang said:
    3. Does BQ25790 support QC charging? if yes, is it qualified by QC or is just compatible.

    The device should be capable of supporting the power input of the QC charging. Since the charger does not have CC1/2 lines, a USB PD communication chip or port controller will be necessary

    Charles (KAT) Zhang said:
    4. Can we tie unused TS pin 10K to GND?

    I don't see any obvious issue with doing this, I also recommend enabling TS_IGNORE also. REG0x18[0]=1

    Best Regards,

    Christian

  • 0 in reply to Christian Moyer
    TI__Intellectual 1405 points

    Hi Christian,

    Charles (KAT) Zhang said:
    1. Does BQ25790 support dual charger design? One as primary and one as secondary to support higher input power.  Do have I reference design for that? They are interested in BATP/BATN connection for second BQ25790.

    No, We do not have a reference design. Can you explain more what is the reason for the dual chargers?

    -> Because they want more charge power.  Their current design want 7A charging power, where one BQ25790 can only support 5.  Is dual charger design achievable? 
    Charles (KAT) Zhang said:
    3. Does BQ25790 support QC charging? if yes, is it qualified by QC or is just compatible.

    The device should be capable of supporting the power input of the QC charging. Since the charger does not have CC1/2 lines, a USB PD communication chip or port controller will be necessary

    -> So BQ25790 cannot 'detect/communicate'  with QC standard device right? it is just able to withstand the power

    Charles (KAT) Zhang said:
    4. Can we tie unused TS pin 10K to GND?

    I don't see any obvious issue with doing this, I also recommend enabling TS_IGNORE also. REG0x18[0]=1

    -> They are just want to know how to deal with unused TS pin.  I see we need to enable TS_IGNORE, but for hardware what should we do with the PIN? GND or float.

    Thank you

    Best Regards,

    Charles

  • 0 in reply to Charles (KAT) Zhang
    TI__Mastermind 20930 points

    Hello Charles,

    Charles (KAT) Zhang said:
    -> Because they want more charge power.  Their current design want 7A charging power, where one BQ25790 can only support 5.  Is dual charger design achievable? 

    This might be possible, however we have not tested this solution before so we can not guarantee this will work. I recommend testing this on an EVM.

    Charles (KAT) Zhang said:
    -> So BQ25790 cannot 'detect/communicate'  with QC standard device right? it is just able to withstand the power

    Yes, This is correct.

    Charles (KAT) Zhang said:
    -> They are just want to know how to deal with unused TS pin.  I see we need to enable TS_IGNORE, but for hardware what should we do with the PIN? GND or float.

    Since the value on this pin is being ignored, this pin can be left floating or tied to GND

    Best Regards,

    Christian.