Flash type analog to digital converter based on digital front desk correction and analog to digital conversion method

Abstract

The invention discloses a flash type analog to digital converter based on digital front desk correction and an analog to digital conversion method. The flash type analog to digital converter based on the digital front desk correction comprises a voltage-split resistance array, a linear pulse width modulation time-domain comparator, a coding circuit and a digital front desk correction circuit. The linear pulse width modulation time-domain comparator comprises a sampling holding circuit, a discharging current source, a zero judgment circuit and a D trigger. Voltage signals are converted into pulse width signals, and the D trigger is used for finishing comparison. After being simplified, the coding circuit directly enables temperature codes output by the comparator to be converted into binary codes output by the analog to digital converter, thereby omitting the process of improving and comparing of non-monotone tolerance degree of threshold value through complex coding. The algorithm can quickly converge, design requirements for dimensions of a comparator input pipe are reduced, and chip area, power consumption and input load capacitance are reduced. After powered on, the flash type analog to digital converter can finish the correction function in one time and cannot increase additional power consumption.

Description

technical field [0001] The invention relates to a flash analog-to-digital converter and an analog-to-digital conversion method based on digital foreground correction, in particular to a linear pulse width modulation time-domain comparator combined with a digital self-calibration algorithm to eliminate process mismatch errors Comparison of Threshold Shift and Non-Monotonic Flash ADCs. technical background [0002] The flash type is a widely used type of analog-to-digital converter. It can not only be used independently as a single chip, but also an important part of other types of analog-to-digital converters (pipeline type, successive approximation type, etc.). This kind of analog-to-digital converter is suitable for low-precision and high-speed applications. It has the advantages of simple structure, short data delay and high throughput rate, but also has the disadvantages of low power consumption efficiency and large area. [0003] Due to the existence of irreversible pro...

AI Technical Summary

Problems solved by technology

This kind of analog-to-digital converter is suitable for low-precision and high-speed applications. It has the advantages of simple structure, short data delay and high throughput rate, but also has the disadvantages of low power consumption efficiency and large area.

[0003] Due to the existence of irreversible process mismatch errors, it is necessary to increase the size of the comparator to reduce the impact of this non-ideal factor, and the comparator is the main component of the flash analog-to-digital converter, which will further increase the chip area and Power Dissipation and Input Capacitive Load

At the same time, the design of traditional comparators in deep submicron technology is limited by intrinsic gain and signal swing reduction, making it more difficult

[0004] The comparison threshold of the flash analog-to-digital converter is determined by the voltage dividing resistor and the comparator. If it is not monotonous, there will be code words that the encoding circuit cannot process, resulting in a significant decline in overall performance.

Even if the original temperature code output by the comparator is coded with Gray code at the expense of coding speed, it can only tolerate a non-monotonic threshold at most

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