Theory of Operation 4-5
implement power savings features. From the CMOS setup routine, an automatic power
down mode can be selected which enables the drive to turn off its motor after a specified
period of inactivity. Additional Sleep modes can direct additional power savings during
inactive periods by powering down the control circuitry.

4.2.7 Floppy Disk Drive Subsystem

The Extensa 60x and 65x Series notebooks contain provisions for supporting a Floppy
Disk Drive installed internally or externally connected to the parallel port. The Floppy
Disk Drive Subsystem consists of a Floppy Controller and the Floppy Disk Drive located
either in the media bay or external to the notebook (not both).
The 3.5-inch floppy disk drive can read/write standard 3.5-inch disks (either1.44 MB
or 2 MB capacity). The drive can also read a 720 KB disk (for interchange of data with
other computers).
The data transfer rate for the floppy disk drive is 500 Kbits per second for high-density
disks and 250 Kbits per second for double-density disks.

4.2.8 Power Subsystem

The notebook is equipped with a software/hardware monitored/controlled Power
Subsystem that minimizes battery usage for prolonged battery operation and
automatically recharges the batteries when the notebook is used with an AC adapter.

4.2.8.1 AC Power Adapter

The computer is equipped with a universal AC power adapter that converts AC voltage
into DC voltage (approx. 46 Watts of power) used to operate the notebook and charge
the batteries. The specifications for the AC adapter include:
♦Input Voltage: 100 to 250 VAC
♦Input Current: Approximately 1.5 Amps
♦Input Frequency: 50 to 60 Hz
4.3 Detailed Circuit Theory
The remainder of this section provides chip-level circuit description for the Extensa
Series Notebooks.