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Multiple Power Sense and Monitoring Circuit for Personal Computer Systems

IP.com Disclosure Number: IPCOM000104251D
Original Publication Date: 1993-Mar-01
Included in the Prior Art Database: 2005-Mar-18
Document File: 1 page(s) / 40K

Publishing Venue

IBM

Related People

Arnold, AF: AUTHOR [+2]

Abstract

Described is a hardware circuit implementation for personal computer (PC) systems to detect and monitor multiple power sources to a device within a system. Devices in or attached to a PC system are often supplied with power from several sources; for example, a D.C. power supply and a battery backup. If either source fails, this circuit will produce a signal indicating a problem while maintaining system operation. The concept described herein provides circuitry to simultane ously detect and monitor device power as supplied from multiple sources to a PC system. The Figure shows the detection and monitoring circuit. If voltage from any of the power supplies, PS#1 through PS#n, is dropped below a specified level, the comparator provides a flag signal to the host indicating that a power source problem exists.

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Multiple Power Sense and Monitoring Circuit for Personal Computer Systems

      Described is a hardware circuit implementation for personal
computer (PC) systems to detect and monitor multiple power sources to
a device within a system.  Devices in or attached to a PC system are
often supplied with power from several sources; for example, a D.C.
power supply and a battery backup.  If either source fails, this
circuit will produce a signal indicating a problem while maintaining
system operation.  The concept described herein provides circuitry to
simultane ously detect and monitor device power as supplied from
multiple sources to a PC system.  The Figure shows the detection and
monitoring circuit.  If voltage from any of the power supplies, PS#1
through PS#n, is dropped below a specified level, the comparator
provides a flag signal to the host indicating that a power source
problem exists.  The values for resistors Ra, Rb, Rc, Rd, ...., Rn
are chosen to ensure that the voltage at the + input of the
comparator is greater than the reference voltage level when any
combination of PS#1 through PS#n drops below a specified voltage
value.  Resistor Rc is of a small value and is used to ensure that
power will be applied to the system regard less of which power source
drops power, assuming that at least one source is still operational.
Resistor Rd is used to ensure that the + input to the comparator goes
below the reference level when the line from a power source is
broken....