Patent ID: 6014098
Filing Date: 2000-01-11
Classification: H03M

Abstract:
An analog to digital converter comprising:a plurality of differential amplifiers each having first and second input terminals,a voltage input for providing for the introduction of an input voltage to the first one of the input terminals in each of the differential amplifiers,a progressive fraction reference for providing for the production of progressive fractions of a reference voltage,a reference input for providing for the introduction of an individual one of the progressive fractions of the reference voltage to each of the second input terminals,each of the differential amplifiers being constructed to provide a first output when the input voltage on the first terminal of such differential amplifier exceeds the voltage on the second terminal of the differential amplifier and to provide a second output when the voltage on the second terminal of the differential amplifier exceeds the voltage on the first terminal of the differential amplifier,a low impedance providing a low impedance value and connecting corresponding terminals in successive ones of the differential amplifiers to provide, in such differential amplifiers through such low impedance, load-bearing currents affecting the relative values of the first and second outputs, thereby to reduce the effects of cell mismatches on said output signals, anda high impedance connected in each of the differential amplifiers and providing a high impedance value in each of the differential amplifiers relative to the impedance value of such low impedance to provide for the flow of the load bearing currents through such low impedance,the differential amplifiers in the plurality being divided into sub-sets, the terminals in corresponding differential amplifiers in the different sub-sets having common connections to the low impedance.