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BQ25700A: how should BQ25700A be connected with the BATDRV pin, if the customer do not want to use the function of BATDRV pin?

Nan Zhang
Intellectual 1895 points
Part Number: BQ25700A

Hi team,

    Support need!

    The customer do not want to use the BATDRV pin to cost down. How should the pins of the chip be connected? I get 2 question need to be confirmed.

Q1: How should the pins of the chip be connected? They want to leave the chip pins floating and replace the p-mos with line. Is that connection right?

Q2: Would there be any potential risk without the BATDRV pin used?

YOURS

NAN

  • 0
    TI__Expert 4780 points

    Hi Nan,

    BATDRV can be left open and VSYS should be shorted to SRP.

    Without using the BATFET, the system will not be able to start up with deeply discharged battery, since Battery is connected directly to System. Below are the considerations when not using BATFET:

    When BATFET is removed, the system node VSYS is shorted to SRP. Before the converter starts operation, LDO mode needs to be disabled. The following sequence is required to configure charger without BATFET.

    1. Before adapter plugs in, put the charger into HIZ mode. (either pull pin 6 ILIM_HIZ to ground, or set REG0x32[15] to 1)
    2. Set 0x12[2] to 0 to disable LDO mode.
    3. Set 0x30[0] to 0 to disable auto-wakeup mode.
    4. Check if battery voltage is properly programmed (REG0x15)
    5. Set pre-charge/charge current (REG0x14)
    6. Put the device out of HIZ mode. (Release ILIM_HIZ from ground and set REG0x32[15]=0). In order to prevent any accidental SW mistakes, the host sets low input current limit (a few hundred milliamps) when device is out of HIZ

    Thanks,

    Khalid