I came across the LTM8020 dc-dc buck converter and thought it would be ideal for charging the Mark V bike light Li-ion battery.
The 4 to 36V input range is great, and it has an adjustable 1.25 to 5V output – suitable for my preferred 4.0V charging voltage.
There is an application circuit for charging batteries.
The 200mA current limit suits my purpose.
And the inductor and switches are on the chip – or at least in the package.
Alas and alack, the package is a 6x6mm pad grid array and therefore completely beyond my limited soldering skills.
Respond below, or to alice@electronicsweekly.