Low-voltage improved accuracy Gaussian function generator with fourth-order approximation

An original realization of a CMOS Gaussian function generator is presented. The proposed method is based on a new approximation function that is able to fourth-order match the Gaussian function. The current-mode operation of the circuit strongly reduces the technological-caused errors and the errors introduced by temperature variations, with the result of an important increasing of the accuracy for the squaring circuit that represents the functional core of the Gaussian generator (0.1%). Additionally, the bandwidth of the generator is increased as a result of its current-mode operation. Because of the utilization of the new fourth-order approximation function, the deviation from the ideal Gaussian function is smaller than 1 dB for an extended range of the input variable. The circuit is designed for implementing in 0.18 μm CMOS technology, its proposed architecture being compatible with a low-voltage operation (VDD=1 V). The proposed Gaussian function generator based on the new approximation function allows to extend its capability of generating any continuous mathematical functions, this feature being obtained by changing the approximation function coefficients.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► We proposed an improved accuracy Gaussian function generator. ► In order to obtain the Gaussian function, a new fourth-order approximation function has been used. ► The current-mode operation strongly increases the overall circuit accuracy. ► The proposed circuit is designed for a low-voltage operation. ► The developed method can be generalized for implementing any continuous mathematical function.