A low-power successive approximation analog-to-digital converter and its conversion method

Abstract

The invention discloses a low power consumption successive approximation type analog-digital converter and a converting method of the low power consumption successive approximation type analog-digital converter. A switched capacitor network comprises a capacitor pair which is one less in number when compared with output binary coding, timing sequence of switches is arranged anew, common mode electrical level Vcm is introduced during the comparison process, compensation capacitor in traditional successive approximation type analog-digital converter switched capacitor networks, and the effect of achieving N bit resolution ratio of N-1 capacitor is achieved. Compared with traditional successive approximation type analog-digital converters, two capacitor pairs of a highest order and a second highest order are cut down, and accordingly the whole total capacitance is reduced by 75%. Along with reduction of capacitance, charging and discharging target is correspondingly reduced, accordingly overall power consumption is lowered, chip area is reduced, and economic benefit is improved. During conversion process, compared with traditional structures, common mode voltage change quantity of an input end of a comparator is little in common mode shaking only.

Description

technical field [0001] The invention belongs to the technical field of integrated circuits, in particular to a successive approximation analog-to-digital converter and a conversion method thereof. Background technique [0002] The successive approximation analog-to-digital converter is an analog-to-digital converter structure with medium and high precision, medium speed and ultra-low power consumption. For applications such as wireless sensor networks and portable devices, analog-to-digital converters are required to operate at low supply voltages. However, as the power supply voltage decreases, the gain of the circuit is limited, and the structure of the successive approximation analog-to-digital converter only includes a comparator, a digital-to-analog converter and a successive approximation register, and does not need a circuit that provides gain. The power consumption of digital circuits will continue to decrease as the process size shrinks, while the power consumption...

AI Technical Summary

Problems solved by technology

However, as the power supply voltage decreases, the gain of the circuit is limited, and the structure of the successive approximation analog-to-digital converter only includes a comparator, a digital-to-analog converter, and a successive approximation register, and does not require a gain-providing circuit.

The power consumption of digital circuits will continue to decrease as the process size shrinks, while the power consumption of analog circuits is difficult to reduce synchronously with the progress of the process

Capacitive successive approximation analog-to-digital converters need to use large capacitors in the case of high resolution, which not only consumes a lot of charge and discharge power, but also wastes chip area by making large capacitors, and the economic benefit is not high

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