Composite structure successive approximation analog-digital converter and quantitative method thereof

Abstract

The present invention provides a composite structure successive approximation analog-digital converter and a quantitative method thereof, belonging to the technical field of analog digital conversion.The composite structure successive approximation analog-digital converter comprises a digital analog conversion module, a comparison module and a successive approximation logic module, the digital analog conversion module comprises a capacitance weight digital analog conversion unit and a serial capacitive digital analog conversion unit, and the successive approximation logic module comprises a capacitance weight successive approximation logic unit and a serial successive approximation logic unit which are respectively used to control the capacitance weight digital analog conversion unit andthe serial capacitive digital analog conversion unit. The composite structure successive approximation analog-digital converter and a quantitative method thereof employ the capacitance weight digitalanalog conversion unit to perform sampling and employ a two-step mode for conversion to achieve quantization of analog input, the comparison module is configured to compare the voltage signals outputby the digital analog conversion module with reference signals, and the obtained comparison result is converted to output codes of a composite structure successive approximation analog-digital converter through the successive approximation logic module. The composite structure successive approximation analog-digital converter and the quantitative method thereof are high in area efficiency, low inpower consumption and fast in conversion speed.

Description

technical field [0001] The invention belongs to the technical field of analog-to-digital conversion, and in particular relates to a compound-structure successive approximation analog-to-digital converter and a quantization method thereof. Background technique [0002] Analog-to-digital converters are widely used in image processing, digital video, and biomedical fields. And for handheld mobile terminal devices (such as image sensors) that are more and more widely used, low power consumption plays a vital role in the service life of the product battery. At the same time, as people have higher requirements for sensory experience such as image quality, and pursue more detailed data information, this requires the analog-to-digital converter system to have faster conversion speed and higher resolution accuracy. [0003] The traditional N-bit binary capacitance weighted successive approximation analog-to-digital converter is as attached figure 1 As shown, it includes binary capa...

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Problems solved by technology

However, the limited common-mode rejection ratio of the comparator causes the input offset of the comparator to be related to the input common-mode level, which deteriorates the overall performance of the analog-to-digital converter.

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