Browse Prior Art Database

Power Fault Wave Shape Storage

IP.com Disclosure Number: IPCOM000085872D
Original Publication Date: 1976-Jun-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 3 page(s) / 55K

Publishing Venue

IBM

Related People

Freisitzer, N: AUTHOR [+3]

Abstract

The probable cause of a power fault in a computer DC power system is determined by storing the voltage and current wave-shapes digitally for later reconstruction.

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Power Fault Wave Shape Storage

The probable cause of a power fault in a computer DC power system is determined by storing the voltage and current wave-shapes digitally for later reconstruction.

The system consists of an analog-to-digital (A/D) converter 10, a digital memory system 12, a digital-to-analog (D/A) converter 14 and the necessary control circuitry 16, 18. The A/D converter 10 is connected so that the output voltage and current of a power supply (regulator) 20 are the inputs through analog multiplexer 22 to the A/D converter 10. If the system has more than one power supply as is usually the case, the other supplies are connected through additional inputs to the analog multiplexer 22.

Fig. 1 shows a schematic representation of a simple system with one regulator 20. In normal operation, the regulator amplifier and control circuits 24 keep the output voltage at the sense points within 1/2 or 1 percent of its set value. The current requirement by the load 26 will remain within some known limits.

In the event of a malfunction in either the regulator 20 or load 26, the current and/or voltage will go outside its normal limits. Signals proportional to both the regulators output voltage and current (as provided by the voltage drop across current-sensing register R) are fed to both the analog multiplexer 22 and the A/D control circuits 16.

The A/D control circuits 16 are set so that a small variation in these values start the circuit operation. Once the limit is exceeded, the analog multiplexer 22 is used to select alternately between the voltage signal and the current signal. As each value is selected, the A/D converter 10 converts the analog signal into a digital representation and at the completion of the conversion, the digital value is stored in a location in the digital memory 12.

The timing is such that each conversion is equally spaced in time and that such spacing is close enough to get the important information in the fault wave- shape. Corrective action can be taken either by internal circuits in the regulator 20, i.e., simply turning off the regulator, or by additional circuits in the A/D control circuits 16, so...