Switched‐capacitor sequential‐flash data converters

Abstract

Sequential‐flash data converters using switched‐capacitor circuits are developed for realizing a given conversion speed with a minimum number of components. Repeating n‐bit flash conversion m times, each converter accomplishes (m x n)‐bit digital‐to‐analog or analog‐to‐digital conversion in m cycles of a clock frequency. An accurate conversion is also possible because each converter is configured such that the offset voltages of op‐amps and parasitic capacitances have no effect on the conversion process. Error analysis shows that a conversion accuracy higher than 8 bits can be expected from each converter if integrated using present MOS technologies. Prototype converters built using discrete components are also given to confirm the principles of operation.