Successive approximation register adc with a window predictive function

Abstract

A successive approximation register (SAR) analog-to-digital converter (ADC) is disclosed. A first and second capacitor DACs receive a first and second input signals respectively. A first coarse comparator compares an output of the first capacitor DAC with a window reference voltage, a second coarse comparator compares an output of the second capacitor DAC with the window reference voltage, and a fine comparator compares the output of the first capacitor DAC with the output of the second capacitor DAC. A SAR controller receives outputs of the first and second coarse comparators to determine whether the outputs of the first and second capacitor DACs are within a predictive window determined by the window reference voltage. The SAR controller bypasses at least one phase of analog-to-digital conversion of the SAR ADC when the outputs of the first capacitor DAC and the second capacitor DAC are determined to be within the predictive window. The SAR controller decodes the outputs of the first and second coarse comparators and the fine comparator to obtain a converted output of the SAR ADC.