hello...I would like to get from the DC/DC output a range voltage of 5V to 26V
When I have 12V at the input.
What is the correct way to implement it.
For this requirement you will need a SEPIC topology.
The ADP1621 can support this topology.
You could start with the design tool available on ADI's web site for a 12V in and 12V out example to get an idea of the topology and components needed. You can do a couple of designs at 5V and 26V to see the variation in components needed (Caps and inductors) then select something that may work in all your cases.
You probably will need to simulate your design due to the large variation of operating conditions.
ADP1621 Coupled-SEPIC Design Tool (the design tool is meant to be used with fixed output voltage, so for a variable output voltage you will need to optimize it a bit differently) You may also want to reference text books or app notes on the SEPIC topology if you are not familiar with it.
Here is one to get you started
AN-1106: An Improved Topology for Creating Split Rails from a Single Input Voltage (pdf, 328 kB)
A simulation model is available to run on www.analog.com/ADIsimPE
I hope this helps.
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