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.

  • TI Thinks Resolved

BQ78350-R1: How is the precharge of bq78350-r1 prohibited?

Intellectual 320 points

Replies: 1

Views: 278

Part Number: BQ78350-R1

Hi,

How is the precharge of bq78350-r1 prohibited?The register PCHG_EN of FET Options has been configured for the bq783350-r1 never USES PRECHG.

At the same time, we see the data manual describing Setting the Precharge Start Voltage and Charging Voltage Low = 0 mVdisables the Precharge function.

But in actual use, even if we put Precharge Start Voltage and Charging Voltage Low = 0, and PCHG_EN 0, we find that the pre-charging section still has action.

  best regards,

  • Hi Jason,
    The part has a pre-charge mode as shown in the figure in the technical reference manual section 5.1. It will always have an action as described in section 5.2.
    If you don't want to enter pre-charge mode you could move the 2 thresholds so that pre-charge mode is not entered, see section 5.2.
    If you want to use the charge FET for pre-charge, clear the PCHG_EN bit, (see page 15, the table on page 47 is incorrect).
    The Pre-Charging Current has the same range as Fast Charging Current (see page 47), so you could allow the gauge to enter pre-charge mode but the current reported to the charger would be the same.
    If you want to prevent the battery from pre-charging and the charger will follow the current from the ChargingCurrent, set Pre-Charging Current = 0 mA. If the charger will not follow the ChargingCurrent value, you can prevent pre-charge by enabling the pre-charge FET and not implementing a current path.
    Also when changing parameters, it is a good practice to reset the gauge to be sure the parameter is used, either cycle power or send a reset.

    TI provides design resources and design advice (including technical, schematic, code and/or system review) “as is” and with all faults.  All information in this or related correspondence is provided subject to TI’s Important Notice (http://www.ti.com/corp/docs/legal/important-notice.shtml).

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.