Hello,
I have some doubts regarding how does the battery detection in the BQ27425-G2 work. We are designing a system powered always by a battery that will never be removed, so we will always have the battery connected. In that specific case, I am not sure about the behaviour of the BQ27425-G2.
In the datasheet I have read that there are 2 methods to detect battery insertion (but we don't want to detect this as battery will be always connected). The methods described are (pag.12 of the datasheet):
1. DETECTING INSERTION WITH BIN PIN: "When OpConfig[BIE]] is set, [BAT_DET] is set by detecting a logic high to low transition at BIN pin."
2. SENDING COMMANDS WITH AN EXTERNAL HOST: "When OpConfig[BIE]] is low, [BAT_DET] is set when host issues BAT_INSERT subcommand and clear when host issues BAT_REMOVE subcommand."
The doubt is:
- If we set to "1" the OpConfig[BIE] and we fix BIN pin to GND (without causing transition), but forcing the pin to logic "0", will the BQ27425 understand that a battery is inserted or will it remain forever in the "initialization" state shown inf figure 2 of pag.23 of datasheet? Does the BQ27425 really expect a transition or a logic "0" will be enough?
- In the other case (OpConfig[BIE]=0), if we send the BAT_INSERT subcommand in order to set [BAT_DET], is this value stored forever? When the system is powered off and on again, what is the value of BAT_DET?. Is it necessary to send the BAT_INSERT command again?
If it is possible, we don't want to use an external host to control the BQ27425 (the BQ27425 should work in stand-alone mode), we only need an optical led connected to the GPOUT pin, that will switch ON when battery is low.
Thanks for your help!