Browse Prior Art Database

Low Power Alternate Current/Direct Current Adapter

IP.com Disclosure Number: IPCOM000118928D
Original Publication Date: 1997-Sep-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 40K

Publishing Venue

IBM

Related People

Horikoshi, H: AUTHOR

Abstract

Disclosed is an Alternate Current/Direct Current (AC/DC) adapter for reducing power consumption.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

Low Power Alternate Current/Direct Current Adapter

      Disclosed is an Alternate Current/Direct Current (AC/DC)
adapter for reducing power consumption.

      The AC/DC adapter can minimize the power dissipation when it is
not connected to the devices, such as a notebook Personal Computer
(PC).  The Gate Feedback signal from notebook PC to AC/DC adapter
turns on/off the Gate of the FET.  When the Gate of the FET is turned
off, the internal circuit of the AC/DC adapter is turned off.  As a
result, there is no power dissipation inside the AC/DC adapter.
Also, there is no user interface change because of this method.

      Fig. 1 shows the AC/DC adapter where the DC output is connected
to the DC input of the notebook PC.  The Gate Feedback signal is
connected to the FG, which turns on the Gate of the p-channel FET.
Therefore, the AC/DC adapter outputs the DC to the notebook PC.

      Fig. 2 shows the AC/DC adapter where the DC output is not
connected to the DC input of the notebook PC.  The Gate Feedback
signal is not connected to the FG, which turns off the Gate of the
p-channel FET.  Consequently, the internal circuit of the AC/DC
adapter is turned off to save power consumption.