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Browse Prior Art Database

Continuous Roll Processing of High Performance Dielectrics

IP.com Disclosure Number: IPCOM000117294D
Original Publication Date: 1996-Jan-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 66K

Publishing Venue

IBM

Related People

Hitchcock, LJ: AUTHOR

Abstract

When a DC/DC converter with a capacitive input is suddenly plugged (hot plugged) into a DC buss, the high inrush current can: 1. damage the connector pins 2. stress the input diodes or capacitors 3. cause a transient on the buss which could affect other buss users

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This is the abbreviated version, containing approximately 52% of the total text.

Continuous Roll Processing of High Performance Dielectrics

      When a DC/DC converter with a capacitive input is suddenly
plugged (hot plugged) into a DC buss, the high inrush current can:
  1.  damage the connector pins
  2.  stress the input diodes or capacitors
  3.  cause a transient on the buss which could affect other buss
users

When a DC/DC converter experiences an internal failure which causes a
high buss current, it can cause:
  1.  a transient on the buss which could affect other users
  2.  the buss overcurrent protection to trip and shut everything
down
  3.  fire and smoke since the buss overcurrent protection is set too
       high to protect individual converters

If the bulk rises too fast, sensitive control and diagnostic
circuitry can latch up.

      In a redundant system, there should be as few single points of
failure as possible.  If one supply fails due to an internal short,
it must not cause much of a disturbance to the input buss.  A fuse is
too slow and provides no current limiting when hot plugging.  The
circuit in Fig. 1 solves all the above problems.  It provides a
controlled rise of output voltage, limits the inrush current, and
limits the current during a fault and then latches off.

      Assume Vbuss is hot plugged.  A voltage is applied to the
source of Q1 and Vsg slowly charges toward the turn-on threshold.
The time is dependent on R4 and C1.  If Q2 remains off, Q1 will
conduct with a current limited by Vsg while C3 is charging.  Vc3 will
increase in a controlled manner.  If a more linear ramp is need...