There are schottky diodes with a drop of 0.3 V or so.
You can also regulate to something like 4V using an adjustable LDO regulator, and use a regular diodes for the 0.5V drop.
There are schottky diodes with a drop of 0.3 V or so.
You can also regulate to something like 4V using an adjustable LDO regulator, and use a regular diodes for the 0.5V drop.