We are finishing the design of a solar light using the SPV1040.
Reading the datasheets, application notes and testing the evaluation board STEVAL-ISV006V2, we had a general vision regarding circuit performance.
Anyway there is two critical questions that we didn’t find an answer in documentation.
We designed all circuit following AN3319 and in page 14 chapter 6 the topic ‘Input Voltage Partitioning’ suggest a resistor from Vmpp-set to PV+ with 1 K ohm (R3 in circuit of page 12).
Why use a low value like 1 Kohm that will sink to much current from solar panel ?
Can we use at least 10K in such resistor ?
What current needs Vmpp-set pin to operate correctly ?
Is same topic is not detailed what the relation between solar panel Vmp and the voltage in Vmpp-pin.
Is mentioned that to SPV1040 start operation needs >=0.3V in Vmpp-set pin.
That is the voltage in the Vmpp-set pin when the solar panel reach the Vmp voltage ?
In another words we should start SPV1040 at solar panel Vmp or at a lower voltage ?
If we should start SPV1040 at a lower voltage, than Solar Panel Vmp, what the relation between Solar panel Vmp and SPV1040 start voltage.
To be more clear, if the solar panel have a 2.5V Vmp voltage, we should calculate the both resistors in Vmpp-set pin to have >= 0.3V when solar panel reach 2.5V or before that ?
An answer to the above questions will be helpful to set-up the final values and finish the design.
Thanks in advance.