US 5,128,676 AGranted

Variable conversion rate analog-to-digital converter

AssigneeBLH Electronics, Inc.

InventorFrank S. Ordway

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Abstract

A high resolution and high speed analog to digital converter for use with a transducer in measuring parameters such as weight, which may stay the same or which may change in the system, the converter having an integrator which integrates for a fixed period the output voltage from the transducer, and subsequently deintegrates a known reference voltage, the deintegration times varying depending upon the magnitude of the transducer output voltage which has been integrated, a comparator comparing the deintegration times of successive conversions and shortening the integration times for the transducer output so as to obtain more conversions per time period to provide a high speed readout when the transducer output is changing, but lengthening the integration times to provide a high resolution readout when the comparison of deintegration times does not reveal any change in the transducer output.

Claims14

Dependent claims

An analog to digital converter circuit for use in measuring systems wherein a parameter or parameters to be measured may be constant or may change and where high resolution is desired where the parameter is constant and high speed conversion is desired where the parameter is changing, comprising:

a means for measuring,
said means for measuring generating an analog output signal having a magnitude which is related to the parameter being measured;
a conversion means for converting the analog output from said means for measuring to a digital signal,
said conversion means including integration means for integrating the signal from said means for measuring, an output of said means for measuring being connected to said integration means;
a comparison means for sensing the output of said means for measuring at a selected time and comparing it with the output of said means for measuring at an earlier selected time to determine an amount of change in the relative magnitudes of the outputs from said means for measuring, and based on that comparison controlling the length of time said integration means integrates subsequent outputs from said means for measuring, whereby when the output is constant, a longer integration time is used for high resolution and when the output is changing by more than a preselected amount, a shorter integration time is used for higher speed.

2 more elements

Dependencies are inferred from the claim text.