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Hi All,
We have used the BQ25708 battery management IC in one of the project.
The input to VBUS is from 12V to 24V DC & VSYS is supplied to the entire system including the Host Micro-controller & RF Radio board.
The battery that we are using is a four LiFePO4 cells in series. The maximum charging voltage is 14.6V.
We have used alternate MOSFETs as TI MOSFET parts are not available due to the on going chip shortage. Please review the MOSFETs that we have used.
Below are the parts numbers of the alternate MOSFETs:
a. SIA462DJ-T1-GE3 instead of CSD17551Q3A
b. TSM085P03CV RGG instead of CSD25402Q3A
We have the following questions regarding this IC:
1. What is the proper charging sequence to be followed by the host micro-controller ?
2. We found that if we do not use the battery & do not set the charging current for the battery and try to use the Tx Power Amplifer on RF Radio board, we see that the RF Radio board is going for a power cycle. The minimum system voltage is around 12.30V. So Should we enable the peak power mode when using without the battery ?
3. We have some how set the charging current & voltage to the battery and also the IC is out of Low Power Mode & LDO Mode is disabled. With this configuration flashed on to the host micro-controller & if we do not use the battery, the whole system is shutting down after approximately after 3 seconds with every power cycle. So again, How to program the IC using the host micro-controller when not using the battery ?
I am attaching the schematic for reference.
Thanks & Regards,
Pravardhan U.S
Hi Tiger Zhou,
Waiting for you to get back on the above questions.
Thanks & Regards,
Pravardhan U.S
Hi, Pravardhan,
For the first and third question, I would refer you to our user guide for step by step guidance.
Peak Power mode is also called two-level current limit. You may want to figure out why the charger resets in the first place. If the current limit is too low, then raise the current limit through IIN_HOST register. If the adapter is weak, try a big one. Peak power mode is to utilize the adapter overload capability. You can turn-on the peak power mode without a battery. The peak power mode can trigger on Vsys drop.
Regards,
Tiger