• State
  • Locked Locked
  • Replies 2 replies
  • Subscribers 62 subscribers
  • Views 109 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

BQ25172: Output connected to TPS62840DLCR Step-Down Converter (without battery input)

Akhil Kalariya
Prodigy 30 points
Part Number: BQ25172
Other Parts Discussed in Thread: BQ24040,

Hi,

I've designed PCB where I'm charging battery using BQ25172DSGR (IC3) IC. I'm using TPS62840DLCR (IC5) IC to Step-Down Converter to power my MCU and other components.

Please find attached image of schematic.

When I don't connect battery at J8 connector, IC3 is not supplying proper output. due to this IC5 is not giving 3.3V output.

My application require to operate device if battery is not inserted and supply is coming directly from USB input.

Any solution for this which I can do in currret designed PCB.

Please suggest.

  • 0
    TI__Guru 67866 points

    Hi Akhil

    The BQ25172 does not a power supply mode similar to the BQ24040 TTDM mode..  It will cycle between over voltage and recharge. 

    But BQ24040 is Li-Ion not NiMH.  

    Sorry but do not have a good way to operate with no battery.

  • 0 in reply to Bill Johns
    Prodigy 30 points

    Hi,

    Thank you for update.

    I've added two diodes D1 & D5 to bypass charging IC whenever there is input supply present. replaced R20 with diode D1 to protect battery from direct charging.

    willl test this soon in curret design circuit.