Browse Prior Art Database

Two-Phase Card Pin for "Hot" Card Insertion

IP.com Disclosure Number: IPCOM000104216D
Original Publication Date: 1993-Mar-01
Included in the Prior Art Database: 2005-Mar-18
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Ouchi, NK: AUTHOR

Abstract

Disclosed is a mechanism that use electronic card pins that have a resistive phase to permit low current charging of card circuits and full conductive phase for operation. This will permit insertion into active circuits with minimum impact to the other elements in the circuit.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 71% of the total text.

Two-Phase Card Pin for "Hot" Card Insertion

      Disclosed is a mechanism that use electronic card pins that
have a resistive phase to permit low current charging of card
circuits and full conductive phase for operation.  This will permit
insertion into active circuits with minimum impact to the other
elements in the circuit.

      In high availability systems, parts must be changed while the
system is operational.  Many systems permit cards to be
inserted/removed while power is on the board.  Card pins of varying
length have been used to insure that power and signal sequencing are
correct as the card is inserted.  However, the decoupling capacitors
and the signal input lines draw significant current when the pins are
inserted.  This causes a problem to the power supplies and to the
signal drivers.  CMOS logic exacerbates this problem in that the
inputs look very capacitive and the outputs have very low current
drive capability.

      Disclosed is the use of a two phase card pin where the portion
that is inserted first has a resistive property and the portion that
is used in the final position has high conductivity.  A schematic of
the pin is shown in Fig. 1a and the relationship of the pin and board
contacts as it is inserted is shown in Fig. 1b.  Fig. 2a illustrates
how the pins are used in inserting cards into a live circuit.  The
card is inserted into the initial position where the resistive part
of the pins make contact.  The capacitive loads c...