Offset compensation in flash ADCs using floating-gate circuits

Traditionally, high speed analog to digital converters (ADC) are built using various forms of the flash converter architecture. However, all of these structures suffer from one major flaw, offsets. Whether these offsets are introduced from the resistive biasing network, mismatches in the comparators, or from other sources, extensive care must be taken to compensate for them. There are several methods used to correct for these offsets, but many of these methods require complicated compensation circuitry or greatly increase the cost and area of the ADC. This paper presents an alternative to these methods, implementing the high speed data converters using floating-gate circuits. The floating-gate circuits provide a method of accurately programming the reference voltages of the flash converter, instead of obtaining them from a resistive biasing network. As a result, any form of offset that is introduced can be compensated for by adjusting the reference voltage.