Browse Prior Art Database

Common Master and Slave Power Supplies

IP.com Disclosure Number: IPCOM000122617D
Original Publication Date: 1991-Dec-01
Included in the Prior Art Database: 2005-Apr-04
Document File: 2 page(s) / 73K

Publishing Venue

IBM

Related People

Egan, PK: AUTHOR [+2]

Abstract

A common technique used to control or balance loading between parallel power supplies is to design one unit as a master, and the others as slaves. When operating power supplies in parallel using a master/slave configuration, there is an error amp in the master unit which will drive the control circuit sections in the master and all of the slave units. This makes the design of the slave units different from the master unit and nonfunctional without the master unit's error amp voltage. This article describes a method that allows a single hardware design (or part number) to function either as a master or slave depending on how it is wired into the system.

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Common Master and Slave Power Supplies

      A common technique used to control or balance loading
between parallel power supplies is to design one unit as a master,
and the others as slaves.  When operating power supplies in parallel
using a master/slave configuration, there is an error amp in the
master unit which will drive the control circuit sections in the
master and all of the slave units.  This makes the design of the
slave units different from the master unit and nonfunctional without
the master unit's error amp voltage.  This article describes a method
that allows a single hardware design (or part number) to function
either as a master or slave depending on how it is wired into the
system.

      The figure shows a block diagram of a system which has common
hardware for both master and slaves.  This system is possible due to
the addition of Rs and bringing both sides of Rs to the outside of
the power unit where the system cabling can be used to select which
unit is the master.

      As shown in the figure, unit 1 is the master supply and all
other supplies are slaves.  Rs has a resistance high enough so that
it will not appreciably load the error voltage coming from the master
unit (Rs >> ERROR AMP Zo) and small enough so that in a single unit
with no master/slave wiring, it will not appreciably lower the error
voltage to the control section (Rs << CONTROL Zin).  Rs is required
in this system so that the power units can be tested individually an...