A method and apparatus for analog-to-digital conversion. An Analog-to-Digital Converter (ADC) includes M ADC.sub.j, j=1, 2, . . . , M. Each ADC.sub.j comprises a number of cells each of which comprises a first switch, a second switch, a current sink and an inverter. An inverter of a cell in an ADC.sub.j changes state in response to a current associate with an input signal of the ADC.sub.j exceeding a threshold, thus switching on the next cell. Each ADC.sub.j is enabled to perform analog-to-digital conversion on a residual current of a previous ADC.sub.j-1 after the previous ADC.sub.j-1 has completed its analog-to-digital conversion and has been disabled.
STATEMENT OF GOVERNMENT LICENSE RIGHTS
The present invention was made with government support under contract number DE-AC02-98CH10886, awarded by the U.S. Department of Energy. The Government has certain rights in this invention.