2023-11-10 03:05 AM
Hi All,
I'd like to create a PCB for my school project that captures energy from a small solar panel using SP1040. The harvested energy will then be used to charge a LiFePO4 battery (3.6~3.7V) through the LD6924 battery charger. Additionally, the voltage will be regulated to supply power to the MCU VDD. My ultimate goal is to construct a completely autonomous outdoor wireless module powered by solar energy. I've consulted various reference designs and product datasheets to develop the following schematics. I would greatly appreciate it if you could review it and provide feedback on potential improvements or identify any mistakes in the implementation.
Best regards,
Levan
Solved! Go to Solution.
2023-11-10 07:03 AM
Yes, L6924D can charge LiPo, whereby the LiPo is charged to 100% with the current setting of 4.2V. If you want to fully utilise its possible lifetime (which also charges the battery to slightly below 100%), you should set the battery-saving voltage of 4.1V.
With the LD39050 and your application you will burn a maximum of 900mV (800mV at 4.1V), which can still be some power loss depending on the battery capacity and the output power of the PV panel. As a rule, however, you should be able to manage with thermal vias, as they are also included in the STEVAL-ISV012V1, because the maximum current in the LD39050 is limited anyway.
Good luck!
/Peter
2023-11-10 04:49 AM
Quick cross-check:
Unfortunately, I cannot currently recommend a LiFePO4 charger.
Hope this helps anyway?
Regards
/Peter
2023-11-10 05:39 AM
Thank you for your feedback and guidance. If I substitute LiFePo4 with LiPo in this schematic, would it be fine? Regarding the dropout on LD39050 from 4.2V to 3.3V, should thermal vias be enough or i will need some heat sinks?
Thanks
2023-11-10 07:03 AM
Yes, L6924D can charge LiPo, whereby the LiPo is charged to 100% with the current setting of 4.2V. If you want to fully utilise its possible lifetime (which also charges the battery to slightly below 100%), you should set the battery-saving voltage of 4.1V.
With the LD39050 and your application you will burn a maximum of 900mV (800mV at 4.1V), which can still be some power loss depending on the battery capacity and the output power of the PV panel. As a rule, however, you should be able to manage with thermal vias, as they are also included in the STEVAL-ISV012V1, because the maximum current in the LD39050 is limited anyway.
Good luck!
/Peter