Estimation of Non-Idealities in Sigma-Delta Modulators for Test and Correction Using Unscented Kalman Filters

Abstract

In this paper, an enhanced unscented Kalman filter is used for the estimation of non-idealities in sigma-delta modulators. As sigma-delta modulator based analog-to-digital converters are known to be prone to performance degradation from many circuit non-idealities, testing and selection of the manufactured chips as well as post-correction procedures are required to ensure a reliable performance. In contrast to most state-of-the art techniques, the proposed estimator is capable of simultaneously tracking a large set of non-ideal parameters with high accuracy and in a very short offline time within the range of microseconds. Three possible implementations are proposed and it is shown how the technique is used to perform an in situ non-ideality estimation and subsequent calibration of a manufactured chip, bringing the modulator back into its designed performance range. It is further demonstrated that the estimator can reliably detect the non-idealities over a wide range when intentionally degrading the performance of the chip by manually sweeping its trimming parameters. The presented hardware measurement results prove that the proposed technique is practically applicable to the test and/or calibration of sigma-delta data converters.

Low-Pass Filtering SC-DAC for Reduced Jitter and Slewing Requirements on CTSDMs

“…(15) shows that the proposed compensation technique consists of matching an RC time constant with a time constant implemented with both a switched capacitor and an ordinary resistor. Since PVT-variations [12], [23], [24] have a different impact on the switched capacitor than on the resistors, they will result in mismatch between these time constants. PVTvariations will also cause a mismatch between the equivalent resistance of the two input branches of the first integrator.…”

Unscented kalman filtering on euclidean and riemannian manifolds

“…A filtragem de Desde o seu trabalho precursor [2], os Filtros de Kalman Unscented (FKUs) vêm sendo usado em diversas aplicações. Por exemplo, podemos encontrá-los sendo utilizados para estimar variáveis relativas a baterias [3][4][5][6][7], geradores eólicos [8], controle de frequência de sistemas de potências [9], circuitos integrados [10], moduladores sigmadelta [11], sistemas de navegação inerciais [12], satélites [13], imagens médicas [14], cirurgias assistidas por computador [15], insulinas plasmáticas [16], cápsulas endoscópicas [17], microfones [18], tomografias acústicas da atmosfera [19], robôs móveis [20][21][22], entre outros.…”

“…Since the seminal work [2], Unscented Kalman Filters (UKF's) have been used in numerous applications. For instance, we can find them being used to estimate variables related to batteries [3][4][5][6][7], wind generators [8], frequency control of power systems [9], integrated circuits [10], sigma-delta modulators [11], inertial navigation systems [12], satellites [13], medical imagings [14], computer-assisted surgeries [15], plasma insulins [16], endoscopy capsules [17], microphones [18], acoustic tomographies of the atmosphere [19], mobile robots [20][21][22], among others. Some UKF's properties can be well understood when these filters are put in relation with the widely known Extended Kalman Filter (EKF).…”