A CMOS current-mode S-shape correction circuit with shape-adjustable control is proposed for suiting different LCD panel's characteristics from different manufactures. The correction shape is divided into three segments for easy curve-fitting using three lower order polynomials. Each segment could be realized by a corresponding current-mode circuit. The proposed circuit consists of several control points which are designed for tuning the correction shape. The S-shape correction circuit was fabricated using the 0.35 µm TSMC CMOS technology. The measured input dynamic range of the circuit is from 0 µA to 220 µA. The -3 dB bandwidth of the circuit is up to 262 MHz in a high input current region.

A CMOS current-mode companding divider is presented. Currents of both dividend and divisor are compressed into log-domain. Then the logarithm current of divisor is subtracted from the logarithm current of dividend. After expanding the subtraction result, the division function could be achieved. The simulation results indicate that the proposed divider has with good performance at only 1.8 V supply voltage.

A CMOS current-mode nth-switchable-root circuit composed of a compact logarithm circuit, a divide-by-n circuit, and a compact exponential circuit is proposed. The n can be selected from 5 values by three switches. Simulation results indicate that the compact nth-switchable-root circuit has a wide input-current range for relative errors less than 3%, low power dissipations below 630 µW, and high bandwidth over 330 MHz.

A two-quadrant CMOS current divider using a two-variable second-order Taylor series approximation is proposed. The approximation divider is realized with a compact circuit. The simulation results indicate that the compact divider has with sufficient accuracy, small distortion, and high bandwidth for only 1.8 V supply voltage.

A two-quadrant CMOS current-mode plug-in divider using a compact 1/x device is presented. The mismatch errors of 1/x device cancel part of mismatch errors of the proposed divider. The simulation results indicate that the plug-in divider is feasible by the proposed approximation method. The adjustable 1/x device could be applied in difference ranges.