Low-voltage CMOS current-mode exponential circuit with 70 dB output dynamic range

Wide Range High Precision CMOS Exponential Circuit Based on Linear Least Squares Approach

“…The most important aspects of EXPFG circuits include output dynamic range, linearity of the output in dB, accuracy, power consumption, and area efficiency. In the following, the literature review verified that most of the above mentioned parameters have a trade off with each other, and then different design techniques have been presented [10][11][12][13][14][15][16][17][18][19][20][21] to satisfy the compromise between the characteristics.…”

“…The third group deals with presenting new approximations of function in a limited range [14], [15], [20], [21] in which each term of the approximated series is realized using a voltage-mode [14], [15] or current-mode [20] circuits. The method presented in [14], [15] use pseudo-exponential functions which result in simple realization of the circuits and relatively low power consumption, however the precision and dynamic range have been sacrificed.…”

“…The method presented in [14], [15] use pseudo-exponential functions which result in simple realization of the circuits and relatively low power consumption, however the precision and dynamic range have been sacrificed. Higher-order terms proposed in [20] benefit from higher dynamic range in comparison with above mentioned methods, at the cost of complex implemented circuits and lack of area efficiency which leads to increasing in power dissipation. Beside these classifications, designing the circuit with single power supply is preferred to those in dual mode; while the circuits reported in [7], [10], [13][14][15], [18], [19] require dual supply voltages.…”

High-Precision CMOS Analog Computational Circuits Based on a New Linearly Tunable OTA

“…The second group emphasizes on the use of piecewise linear approximation method [18][19][20], expansion of the functions using Taylor series [21], [22] and presenting a new approximation [23], [24] in which each term of the approximated series is realized using a current-mode [18][19][20][21], [23], [24] or voltage-mode [22] basic building block. In order to make the realization of the functions simple, some of these approximations have used only second-order [21], [22] or third-order [18], [24] terms which leads to low-precise implementation of computational circuits.…”

“…In order to make the realization of the functions simple, some of these approximations have used only second-order [21], [22] or third-order [18], [24] terms which leads to low-precise implementation of computational circuits. Following this, the higher order approximations [20], [23] have been proposed to achieve higher accuracy at the expense of complex structure and consequently higher consumption of power. The complex structures reported in [25], [26], but not based on the piecewise linear approximation method or expansion of Taylor series or not CMOS-based circuits can be located in this group, owing to the fact that they also consume more power.…”