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BQ24616 sleep current

DavidA
Prodigy 40 points
Other Parts Discussed in Thread: BQ24616

When I connect a 4.2V battery to the BQ24616 EVM, I am measuring Ibat of ~75uA. According to the data sheet, the sleep current for the charger IC should be < 15uA. Do you know where the extra current draw is coming from?

  • 0
    TI__Genius 11480 points

    Hi David,

    If the chip is in sleep mode there are a few places current draw could be coming from:

    • The feedback resistors form a resistive path from battery to ground. This will draw a small amount of current. 
    • a very small amount of current will sink into SRP and SRN
    • The settings and LED indicator portion of the EVM could also be "stealing" some of your battery current.
    • If you have a load at the system, it may be drawing a small amount of current. Even if it is "off" a system load will draw a small amount of current.

  • 0 in reply to David Wiest Jr
    Prodigy 40 points

    Hi David,

    Thanks for the quick response.

    The feedback resistor divider will only add about 4uA to the overall current, the leakage current into SRP and SRN is already included in the total sleep current, and I have no load connected to the EVM.

    The total current still seems unreasonably high, and I need to figure out where it is going.

    Thanks.

  • 0 in reply to DavidA
    TI__Genius 11480 points
    David,

    Can you confirm the settings you are using on the EVM (what jumpers you have on, input/output voltage, etc)? I will try to recreate your set up and see if I can find anything.
  • 0 in reply to David Wiest Jr
    Prodigy 40 points
    The only external connection to the EVM is 4.2V connected to J5-pins 2 & 3 (PGND, BAT).
    Jumper settings:
    JP1 - HI
    JP2 - on
    JP3 - VREF
    JP4 - on
    JP5 - on

    I noticed that if I remove JP4, the total current drops to ~58uA. That's certainly an improvement, but still higher than expected.
  • 0 in reply to DavidA
    TI__Genius 11480 points
    Hi David,

    Sorry for the delay on this. Try and Remove JP2 and JP5, as well and see if that reduces the leakage. There are some paths there that you could have some leakage current.
  • 0 in reply to David Wiest Jr
    Prodigy 40 points

    I tried changing all the jumper positions, and the only one that makes any difference in the total current draw is JP4.

  • 0 in reply to DavidA
    TI__Genius 11480 points

    David,

    How are you measuring your current draw? I would like to make sure we are at least using a similar tool. Also, you have no adapter plugged in, correct?