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Browse Prior Art Database

Latch-Up Protection Method for MicroChannel Docking Station

IP.com Disclosure Number: IPCOM000104539D
Original Publication Date: 1993-May-01
Included in the Prior Art Database: 2005-Mar-19
Document File: 4 page(s) / 110K

Publishing Venue

IBM

Related People

Kamijoh, K: AUTHOR [+3]

Abstract

Disclosed is a Latch-up protection method when a MicroChannel* architecture system PC is connected to an expansion unit, in which MicroChannel signals are directly connected to each box's LSIs. As a most popular power control method, when the PC is connected to the MicroChannel expansion unit or box, a DC power (Vcc) of both sides are supplied from one side, that is the system PC or the expansion box, to avoid LSI latch-up. According to the conventional method, the one side has to have large power supply unit to cover DC of the both sides and this causes great cost up. According to this invention, the system PC and the MicroChannel expansion box is required only to have a power supply unit that can supply only its power consumption respectively.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Latch-Up Protection Method for MicroChannel Docking Station

      Disclosed is a Latch-up protection method when a MicroChannel*
architecture system PC is connected to an expansion unit, in which
MicroChannel signals are directly connected to each box's LSIs.  As a
most popular power control method, when the PC is connected to the
MicroChannel expansion unit or box, a DC power (Vcc) of both sides
are supplied from one side, that is the system PC or the expansion
box, to avoid LSI latch-up.  According to the conventional method,
the one side has to have large power supply unit to cover DC of the
both sides and this causes great cost up.  According to this
invention, the system PC and the MicroChannel expansion box is
required only to have a power supply unit that can supply only its
power consumption respectively.  So, the system PC power supply can
be designed without the expansion box's power consumption and so is
the expansion box.  Fig. 1 shows the power supply configuration.

      The system PC has a main switch to power on/off both of the PC
and the expansion box.

o   The MicroChannel signals are connected between the system PC and
    expansion box via an expansion connector.

o   Additional 2 signals (PWR_ON,PWR_ON_RTN) are through the
    expansion connector.  PWR_ON signal is activated by Main Switch
    ON.  When this signal is activated, Expansion Box DC power is
    activated.  PWR_ON_RTN signal is controlled by Expansion unit's
    power supply.  When this signal is activated, System PC DC power
    is activated.

      According to this configuration, following are the invention to
prevent Latch-up, that is Power On/Off sequence and MicroChannel
signals' Termination value formula.  Fig. 2 shows the power on/off
sequence of this invention.  Signals with * mark is controlled by the
expansion box power supply.

      In Fig. 2, between 2.  and 5.  both of the Vcc's are activated.
The latch-up never occurs as far as formula 1) is satisfied.

      ]VccE-VccP]  < Vla + Vdelta                                 (1)

      where: Vdelta = min(Vcc-Vsig) while Vcc is activated.
  ...