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Browse Prior Art Database

Hot Plug Contact Current Limiting for DC Regulator with Bulk Capacitance

IP.com Disclosure Number: IPCOM000109498D
Original Publication Date: 1992-Sep-01
Included in the Prior Art Database: 2005-Mar-24
Document File: 2 page(s) / 80K

Publishing Venue

IBM

Related People

Brandl, TA: AUTHOR

Abstract

This article describes a circuit that limits the contact mating current associated with hot-plugging a DC regulator into a bulk DC power source.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 60% of the total text.

Hot Plug Contact Current Limiting for DC Regulator with Bulk Capacitance

       This article describes a circuit that limits the contact
mating current associated with hot-plugging a DC regulator into a
bulk DC power source.

      "Distributed Power" is a well-known power distribution scheme
whereby computer cards are designed with their own DC regulators
right on the card.  Among many incentives for a distributed power
system is the "hot-plug" requirement that accompanies continuous
availability systems.  Hot-plug pertains to the ability to plug such
a computer card into a distribution backplane with all power up and
running; subsequently, the plugging response must not disturb any
other card nor should any component parameters be exceeded in the
process.  The circuit presented herein will work for relatively high
card loads, such as a 100-watt card load.

      The on-card DC regulator can typically be designed with a
single open-collector control of its soft-start.  Under soft-start
control, the low to open transition of this open collector signal
will initiate a slow power-up of the DC regulator into the load.

      The drawing shows the circuit of this disclosure.  The key to
this hot-plug scheme is the timing of the "pick" of relay RY1 in
relation to soft-start initiation.  Relays R3 and R4 and diode D1
provide assurance that comparator M1 will start in the "low" state;
thus soft-start is disabled and relay RY1 contacts are open.  Input
capac...