Tool/software:
Hi, I am designing a system where a 3-cells battery can be recharged by either a photovoltaic panel or the F50-12V microturbine, depending on which input provides the appropriate power. I would like to know if the BQ25798 chip is suitable for this purpose. Additionally, I am providing the schematic and layout for you to verify its correctness. Thank you in advance.
HI Alberto,
Regarding using the microturbine, I am assuming it has a HiZ output, so is considered an energy harvesting power source? If so, the host software can manually write to the VINDPM to find its MPP. I do not think the auto MPP, which is optimized for solar panels, will find the MPP.
Regarding the schematic, what is the voltage rating of the capacitors? Ceramic capacitors' capacitance derate with applied voltage. The capacitance after derating needs to meet the minimum required values below:
Other than that, I see no obvious issues on the schematic.
Regarding the layout, the recommended layout is shown below. The PMID and SYS 0.1uF and at least one 10uF capacitor must be placed on top of the IC connecting their pins and GND without vias. That means the SWx traces must route under the IC and then use vias to reach the inductor.
Regards,
Jeff
Hi Jeff,
The voltage rating of all capacitors is 25V.
Regarding the layout, do you mean something like this?
I forgot to answer about the microturbine. It is a three-phase motor with a rectifier and some zener diodes for regulating the output.
This is a schematic I found online about the 5V version of the microturbine.
