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BQ25895: QC3.0 Both at input and output

Gluonn R&I
Prodigy 235 points
Part Number: BQ25895
Other Parts Discussed in Thread: BQ25898D, BQ25890H, BQ25703A, BQ25703, BQ25890

Hi

I am designing a circuit that supports QC3.0 both at input side for charging the battery and at the output side to supply power to supported mobile phones. I am confused on which part to select at input side and want to know how to supply 9V/12V at output side and how to do a handshake with the mobile phone that supports QC3.0. Here are my questions:

1. I see that TI is recommending BQ25890H/BQ25898D instead on BQ25895 for QC3.0. What's the reason for the same? Can BQ25895not support QC3.0? I see that one PowerBank manufacturer uses BQ25895 to enable quick charge. Here is the teardown of the product that uses BQ25895. Link

2. One of the TI Engineers recommended BQ25703A in this E2E thread. I also need Fuel Gauge in my design, which is inbuilt in BQ25703. Which part do you recommend on using? BQ25703 or BQ25890H or BQ25895?

3. I do not know how to enable QC3.0 on the output side(To phones). It'd be great if you can tell me how to do the handshake with mobile and how to support multiple voltages: 5V,9V,12V, etc., Does TI has any part to do this? Or do I have to use multiple boost converters?

Thanks in advance.

Teja

  • 0
    TI__Guru**** 165766 points

    Hi Teja,

    The bq25895 D+/D- voltage are not controllable by the user but the bq25890H/898D are controllable and therefore capable of performing the handshaking with various HVDCP adapters.  See http://www.ti.com/lit/an/slua786/slua786.pdf for instructions on how to write your host code to do this.

    The bq25890 family can only charge single cell LiIon battery and can only provide 5V in OTG boost mode.  To use this IC and provide >5V in OTG boost mode would require an additional boost converter circuit. 

    The bq2570x family can charge multiple LiIon batteries and can provide up to 20V in OTG boost mode.  However, the bq2570x does not have integrated D+/D- and so an external IC will be needed to interface with the USB bus.

  • 0 in reply to Jeff F
    Prodigy 235 points
    Hello Jeff,

    Thank you for responding.

    1. Understood. I shall use BQ25890H/898D.

    2. Do I need an MCU to monitor voltage levels on D+ and D- lines on output side and switch boost converter(s) accordingly? Or does TI have any part that does this for us?

    3. Can you please tell if TI has any IC to interace with USB Bus?

    Thanks
    Teja
  • 0 in reply to Gluonn R&I
    TI__Guru**** 165766 points

    Hi Teja,

    You will need a MCU to control the voltage levels of the bq25890H/898D D+/D- pins. 

    I am not familiar with TI's USB portfolio.  I suggest searching at http://www.ti.com/interface/usb/overview.html.  TI will not have a QC3.0 chip as QC is a proprietary protocol.