"The monolithically formed battery charger includes at least one step-down converter having a given duty ratio coupled to a battery-terminal interface that provides a stepped-down output voltage and current that may be used to charge a rechargeable battery."

FWIW...

This is a step down circuit cast on silicon(monolithic). They broadened it up a bit...the underlined signifies they wish it to be for more than just trickling a battery charge. It's but one piece where other circuit factors would be necessitated, such as sensing issues and the controlling of them.

The circuit I emphasized that e.Digital implements (couples and de-couples as needed) is a step up circuit.....taking the 3 volt battery and converting it to 5v to be directed to the micro-controller when in battery mode. This is a sensed operation having other circuit factors involved and controlled.

It's how circuits are coupled and decoupled that e.Digital has a keen interest in, no matter what the circuit. As well as circuits it has contrived, such as, the step up circuit redirected back to the micro-controller among many other circuit orchestrations, such as those need for voice recording and data management. When a deliberate or sensed function is commanded....all the pieces software/hardware needed, couple for the function to come into play and execute....de-couple when completed.

Manipulating the console(buttons, touch screen , whatever) can implement multiple functions where by all necessary circuit coupling -decoupling take place. It's what happens under the user input or sensed input bring things together that is important.

doni