How to I sync two SPV1040 solar charger ICs connected in parallel so that both of them have the exact voltage set point?

[PTher.1]

I am using 2 SPV1040 that are controlling 1 solar panel per chip. With that said, I am using a super cap with no battery and when the super cap is discharged the two ICs work in unison to charge the Super cap to the voltage set point. Once that is complete, it seems that one of the ICs becomes the master as it will source all of the current from the load with the other IC not sourcing any current. With that known, is there anything else I can do other than making sure the two Voltage Control resistors are coherent throughout? FYI the Voltage output is set to 5V.

Thank You

[Andrew Lohmann]

There probably is no benefit in doing what you suggest but you can move the output voltage dividers (R1 R2) from Vbatt to Vout. The current sense resistors will tend to also cause the current to be shared between the two ICs as the voltage approaches the desired 5V. That is at light current one IC will still be doing all the work (which is good and most efficient) but the other IC will not turn on/off at moderate current but will reduce and increase smoothly towards 0% and 50% of the power output.

This is the same technique used when many power BJT's are connected in parallel to share the current and prevent thermal runaway - that is fit emitter resistors.

I tried to use SPV1050 some years ago I added extra capacitors as a precaution against EMI but they probably stopped it working properly. Some of the demo boards also added extra capacitors so I am not sure how well SPV1040 or SPV1050 work? It sounds like what you have works.

[Andrew Lohmann]

I don't know if the two MPPT circuits will interaction prevent optimum power transfer to occur but that might depend on the value of the two output capacitors?