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Controlling a Number of Predetermined Currents

IP.com Disclosure Number: IPCOM000093145D
Original Publication Date: 1967-Jun-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 47K

Publishing Venue

IBM

Related People

Rullgard, A: AUTHOR

Abstract

The system provides analog output signals to three outputs A, B, and C. Three nonprecision digital-to-analog converters 10, 20, and 30 are provided. Precision digital-to-analog converter 5 and precision analog comparison circuit 6 are also provided. Switching circuits 7A, 7B, and 7C are provided so that converter 5 can be connected to any output A, B, and C. Switches 8A, 8B, and 8C are provided so that any converter 10, 20 or 30 can be connected as an input of comparison circuit 6.

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Controlling a Number of Predetermined Currents

The system provides analog output signals to three outputs A, B, and C. Three nonprecision digital-to-analog converters 10, 20, and 30 are provided. Precision digital-to-analog converter 5 and precision analog comparison circuit 6 are also provided. Switching circuits 7A, 7B, and 7C are provided so that converter 5 can be connected to any output A, B, and C. Switches 8A, 8B, and 8C are provided so that any converter 10, 20 or 30 can be connected as an input of comparison circuit 6.

Each converter 10, 20, and 30 includes a plurality of resistors R that interconnect voltage source 3 to the output of a particular converter. The magnitudes of resistors R are discussed below.

When it is desired to establish a particular analog voltage at one output, for example, at output A, switch 7A connects output A to converter 5 and the latter generates the desired voltage. While switch 7A has output A connected to converter 5, switch 8A connects converter 10 to comparison circuit 6. Switches 10a...10n in converter 10 are then manipulated until comparison circuit 6 indicates that the output of converter I0 equals the output of converter 5. When these two outputs are equal, switches 7A and 8A are changed so that the output from converter 10 is gated to output A.

The ratio between the magnitude of the various resistors in each converter 10, 20, and 30 is designated as L. L has a value such as L > 1 and L < 2/(1 + P). The quantity P is...