The circuit includes a lithium backup battery for powering the 3.3 V RAMs when neither ac source nor other battery source is present but this backup battery is never allowed to power the 3.3 V MAIN output.
(The circuit; includes; a lithium backup battery for powering the 3.3 V RAMs) (neither ac source nor other battery source; is; present but this backup battery is never allowed to power the 3.3 V MAIN output) (this backup battery; is never allowed; ) (this backup battery; to power; the 3.3 V MAIN output)
The circuit neither ac source nor other battery source this backup battery this backup battery
includes is is never allowed to power
a lithium backup battery for powering the 3.3 V RAMs
present but this backup battery is never allowed to power the 3.3 V MAIN output
the 3.3 V MAIN output