Tool/software:
Hi
We are looking to use LP8868Z/W in a LED lamp application.
We are driving two high brightness LEDs from a 2S or 3S Lithium battery pack.
The cell voltage for the 2S pack will be about 6V in a close to discharged state. The LED Vf will be about 5.75V, so there will not be much headroom in this case.
My first question is how to use the UVP input in this case.
I guess the voltage headroom will be to small (less then 1,2V stated in DS to trig fault condition).
We do not need the fault protection features in our design.
Can we leave UVP unconnected or do we need to connect directly to Vin or Vcc?
The second question is regarding the FSET and COMP design.
Is there any equations or design calculators to help choosing the components.
The FSET has a table in DS stating different fixed switching frequencys and the corresponding resistor value. But I guess there is an equation to determine the Fsw based on arbitrary resistor values?
The COMP design is only stated in the DS with some generic recommendation for the example design, but no further information regarding any adjustments to a custom design.
Best regards
/Johan
