Browse Prior Art Database

Detection Method for Non-supported AC adapter

IP.com Disclosure Number: IPCOM000123278D
Original Publication Date: 1998-Aug-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Odaohara, S: AUTHOR [+2]

Abstract

Disclosed is a method and circuit which detects non-supported AC adapter. Most of electrical devices have an AC adapter as a power source. The DC jack of AC adapter is very similar among the devices. And, non-supported AC adapter may be connected to some device. This method shows how to detect and treat non-supported AC adapter when it is attached by accident.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 77% of the total text.

Detection Method for Non-supported AC adapter

   Disclosed is a method and circuit which detects
non-supported AC adapter.  Most of electrical devices have an AC
adapter as a power source.  The DC jack of AC adapter is very similar
among the devices.  And, non-supported AC adapter may be connected to
some device.  This method shows how to detect and treat non-supported
AC adapter when it is attached by accident.

   The figure shows a circuit which enables this
method.  BLOCK 1 is a circuit which detects the maximum allowable
voltage of the device.

   BLOCK 2 is a circuit which detects the minimum allowable
voltage of the device.  If voltage of the AC adapter is between the
maximum and minimum allowable voltage, the voltage meets system
requirement.  But, in case the voltage is out of the range,
transistor FET1 should be turned off so that the AC adapter is
detached from the device electrically.  BLOCK 3 is a sort of
protection circuit.  Detection current is set to a value which is a
little bit larger than the maximum current of supported AC adapter.
When supported AC adapter is attached, the circuit never detects the
current value even in abnormal condition.  This circuit works only
when non-supported AC adapter, which has ability to supply larger
current, is attached and abnormal condition such as short circuit
happens.  If BLOCK 3 works, the non-supported AC adapter is detached
electrically.  In case non-supported AC adapter is connected and its
supply cu...