High-accuracy low-power three-segment type TDC circuit used for array system

Abstract

The invention discloses a high-accuracy low-power three-segment type TDC circuit used for an array system. A high-segment TDC part employs a linear feedback shift register circuit to perform the measurement in wide dynamic ranges. A middle-segment TDC part employs signals generated by a low-segment voltage-controlled ring oscillator circuit as control signals, and records the middle-segment quantification time through an asynchronous subtraction counting circuit. A low-segment ring oscillator TDC part performs the measurement having smaller quantification errors, and determines the resolution. Quantification results of the three segments are stored through a latch circuit. When the data is read, the quantification results are serially output in a binary system form through the high-segment linear feedback shift register circuit in order. On the premise that the high-segment counting clock frequency of a conventional two-segment type TDC circuit is identical to that of the three-segment type TDC circuit, the three-segment type TDC circuit can achieve higher resolution and can output data with higher accuracy. On the premise that the low-segment ring oscillator frequency is not changed, the high-segment counting clock frequency of the three-segment type TDC circuit is decreased, and the power consumption of the circuit can be obviously reduced.

Description

technical field [0001] The invention relates to a novel high-precision and low-power three-stage time-to-digital conversion (TDC) circuit that can be applied to an array system. The circuit effectively saves area and reduces power consumption, so it can be better applied to pixel array time measurement system. Background technique [0002] A time-to-digital converter (TimeDigitalConverter, TDC) is a common digital-analog hybrid circuit for time measurement, which can quantify time intervals and form high-precision digital values, and realize digital output. ROIC (Readout Circuit) is a key module in the infrared detection system, and the time-to-digital converter, as a time measurement circuit, can convert the measured time analog quantity into a digital signal, which is the core module of ROIC. Improving the measurement accuracy in a specific measurement range is very critical to the array TDC, where the measurement accuracy is positively related to the circuit area. Howev...

AI Technical Summary

Problems solved by technology

However, the application conditions of the pixel array, the limitations of area and power consumption have greatly increased the technical difficulty of TDC quantization performance. Under the premise of ensuring a certain measurement range, the current array TDC still has the situation that the accuracy cannot be further reduced.

[0003] Due to the more detailed error extraction and quantification process of the general three-stage structure, if there is a deviation in the phase at the initial moment of the measured time, simultaneous detection cannot be achieved; in addition, the middle-stage time margin of the three-stage TDC structure in a large array needs to be Refinement, which requires the use of a parallel structure, power consumption and resources are also a problem

Therefore, the single-pixel high-precision three-segment TDC structure is difficult to use in large arrays

At present, the array TDC suitable for large arrays is mainly concentrated on the two-stage structure, and due to the limitation of the circuit area, the complex two-stage TDC structure is not suitable, and the simple two-stage TDC structure is due to the wide range constraints, limiting the reduction in accuracy

Therefore, it is difficult to further improve the accuracy of the array TDC, and it is urgent to design a new structure suitable for the use of the array to break through the restriction of accuracy.

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