Abstract: A flash-type analog-to-digital converter (ADC) uses only 2.sup.n-m comparators coupled to the analog input line to generate a n-bit digital output signal. Each pair of these actual comparators are coupled, in parallel, to 2.sup.m pseudocomparators which provide values representing comparisons of the input signal value to respective reference values between the reference values used by the actual comparators. The output signals of each pair of actual comparators are combined in respectively different proportions at each of the pseudocomparators. In this manner, the output signals of the actual comparators are averaged to produce the interstitial comparison values. In one embodiment of the invention, the ADC is implemented in BiCMOS technology with a bipolar differential input stage and a CMOS latching comparator. Signals are distributed from the actual comparators to the pseudocomparators via a pair of resistive ladder networks.
Type:
Grant
Filed:
May 29, 1992
Date of Patent:
March 1, 1994
Assignees:
David Sarnoff Research Center Inc., Industrial Technology Research Institute, Electronics Research & Service Org.