Analog-to-digital converter (ADC) and method

Abstract

An analog-to-digital converter (ADC) and a method are disclosed. The ADC includes a dithering circuit system. The dithering circuit system includes a signal level detector, a dithering amplitude controller, a random code generator, and a dithering digital-to-analog converter (DAC). The signal level detector receives the analog input signal and provides amplitude level information associated with the analog input signal. The dithering amplitude controller receives the amplitude level information from the signal level detector, and provides a control signal. The dithering amplitude controller varies the control signal based on the amplitude level information. The dithering DAC receives the control signal from the dithering amplitude controller and a pseudo-noise (PN) signal from the random code generator, and provides the dithering signal based on the control signal. The dithering signal varies based on an amplitude level of the analog input signal.

Description

technical field [0001] The present disclosure relates generally to data conversion between analog and digital forms, and more particularly to dither control of signal amplitudes based on data conversion circuits. Background technique [0002] High-performance automotive radar sensors require data conversion circuits, such as analog-to-digital converters (ADCs) or digital-to-analog converters (DACs), to have ultra-low spurious levels to avoid false positives and / or missed detections with small radar cross-sections. Target. However, mismatch of circuit components in an ADC, such as a successive approximation register (SAR) ADC, may prevent the ADC from achieving the desired low spurious levels. In radar systems, for example, ADCs can have non-ideal transfer functions due to signal-related offsets, component mismatches, and memory effects, which can prevent achieving low spurious levels when necessary. [0003] Dithering is a technique to improve the linearity of an ADC so th...

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However, the dither signal must be large enough to be effective

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