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[TWL6032A2B4YFF] The charging LED is blinking when battery near full

We encountered one issue. The charging LED is always blinking when battery near full.

If I changed VOREG from 4.1V to 4.2V, the blinking issue is gone after few miniutes.

We have some question that list below.

1. Is it caused by VBAT have big change when charging current terminates?

2. If the 120 mV hysteresis in chapter 4.9.3.6(SWCS057H) can be programmable or not.

  • Hi Francis,

    1. It is most likely cause by the VBAT voltage changing by 120 mV as you identified. Have you been able to take a scope shot of the VBAT voltage where it is measured by the PMIC (CHRG_VBAT input)? One additional item to check is the resistance on the charging path to VSYS. If there is a large resistance, the change in current direction across this resistance can trigger the hysteresis. For example, if system is drawing 1A and charging battery at 100 mA and measuring 4.1V, and then charger turns off and battery is now supplying the 1A, then the 2.1A change can trigger a 120 mV difference with just 57 mohm.

    2. It is not.

  • in my case charging current 500mA, the termination(VTERM=50mA), R2=20mohm, we use TI's EVB reference design, we solving the blink issue by change VOREG from 4.1V to 4.2V for 1 battery, but when we change to another battery the charging LED blink for more than 12 hours, how solve this battery depended issue?
  • Hi Charlie,

    Have you checked the LINEAR_CHRG_STS register? If there is an issue, it could show up here. You probably will still need to take a scope shot of the CHRG_VBAT input as it is not clear whether the battery voltage is not staying high or if it is a function of the settings.
  • if we want to use SW to take over the EOC(END of Charge) control, EOC interrupt will disable the charger and use VBUS to Supply VSYS.
    after VBAT drop to a rrogram Voltage(assume 3.95V), then generate a interrupt to restart the Charging , How to generate this interrupt? Query the VBAT seem to be not efficient
  • Hi Charlie,

    I am not seeing a better method for detecting battery threshold crossing. Alternatively you could just re-enable the charger periodically independent of battery voltage.
  • e2e.ti.com/.../351201
    after apply the SW fix for change VSYSREG, the problem disappear