Analog-to-Digital Converters Using Not Multi-level But Multi-bit Feedback Paths

Conventional analog-to-digital converters (ADCs) with medium or high bit-resolution have a feedback path that connects a tentative digital output with the analog input to obtain a final digital output. Digital-to-analog converters (DACs) are used in the feedback path to generate the multi-level analog signal that is needed to process the feedback signal with the input signal in the analog domain. In this paper, Nyquist and oversampling ADCs using no DACs are presented, and their operations are proved by a behavior-model simulation. To remove the DACs from the feedback path and to replace the multi-level signal with the multi-bit one, a Hopfield artificial neural network is used with delta-sigma modulators as neurons. This new ADC architecture results in a circuit configuration more compact than that of conventional ADCs using the DAC.