[FAQ] BQ25700A: How soon could the host write to the buck-boost charger after power on?

When an input source plugs in, the charger checks the input source voltage to turn on LDO and all the bias circuits. It sets the input current limit before the converter starts.

The power-up sequence from DC source is as follows:

1. 50 ms after VBUS above V_{VBUS_CONVEN}, enable 6 V LDO and CHRG_OK goes HIGH
2. Input voltage and current limit setup
3. Battery CELL configuration
4. 150 ms after VBUS above V_{VBUS_CONVEN}, converter powers up.

Suggest waiting for 200ms, before sending a new register value to the charger.