Effective extraction method for triple errors in foreground calibration of TI‐ADCs

Abstract

This paper presents a novel procedure for detecting offset, gain, and timing skew errors in foreground calibration of time-interleaved analog-to-digital converters (TI-ADCs). An efficient peak detection scheme has been introduced, which is successfully employed to extract timing skew error. The designed method has also been extended to derive the gain and offset errors separately to form the generalized architecture. The objective is performed with the adjustment of the rational coefficient for each error. Simplicity and low hardware consumption will constitute the notable advantages of the proposed algorithm. Mathematical expressions have been provided to explain the principles.A special case in which all triple errors could exist together has also been analyzed. Then, the proposed architecture was implemented at the system level. Finally, the behavioral simulation results for a 12-bit four-channel TI-ADC have been demonstrated to confirm the accuracy of the proposed algorithm. The simulation environment has consisted of the sampling frequency of 8 GHz for TI-ADC and 1 GHz single-tone input frequency for each channel (associated with the Gaussian noise). Based on the results, the maximum value of 77.21 dB for SFDR has been achieved after the calibration process when the average error of 9% for timing skew and 6% tolerance for gain were considered for the channels of TI-ADC.

An 18‐bit 1‐GS/s time interleaved analog‐to‐digital converter with timing skew calibration based on an adaptive genetic algorithm

“…If P m is large, it will make the GA into a purely random search method, but a small P m may make the GA converge prematurely. In this paper, the above problem is solved by the method of adaptive mutation, whose formula is shown in Equation (15). The adaptive mutation is similar to the adaptive crossover, the mutation probability is adjusted adaptively according to the fitness of the chromosome.…”

“…Since this method is a background calibration method, it has a slow convergence rate compared to foreground calibration methods. In Yuan et al, 11 Hyun-Wook et al, 12 Xiao et al, 13 and Sarkis et al, 14,15 a reference channel is introduced to detect and calibrate timing skews in the TIADC system. However, this introduced reference channel will add additional power consumption and area, and affect the input impedance of the TIADC system.…”

A new background continuous‐time offset cancelation and gain calibration strategy for open‐loop residue amplifiers in high‐speed and high‐resolution ADC's

“…In the foreground method, 5,9,11,13 amplification is interrupted during the correction time, and specific pattern input is applied to the residue amplifier during the calibration phase. One of the main difficulties in this method is the discontinuity of ADC data.…”