Design of a Programmable Gain, Temperature Compensated Current-Input Current-Output CMOS Logarithmic Amplifier.

Area of Science:

• * Electrical Engineering
• * Biomedical Engineering
• * Integrated Circuit Design

Background:

• * Conventional logarithmic amplifiers often use transimpedance techniques, producing voltage outputs.
• * Programmable gain and temperature compensation are crucial for precision in signal processing.
• * Existing designs may lack flexibility or efficiency for specific biomedical applications.

Purpose of the Study:

• * To design a programmable gain, temperature-compensated, current-mode CMOS logarithmic amplifier.
• * To achieve a direct current output logarithmic function of the input current.
• * To enable gain programmability and robust temperature compensation for biomedical signal processing.

Main Methods:

• * Employed Hart's extended translinear principle for circuit synthesis.
• * Integrated floating-gate trimming circuits for programmable gain.
• * Utilized a translinear-based resistive cancellation technique for temperature compensation.

Main Results:

• * Fabricated prototypes in a 0.5 μm CMOS process.
• * Achieved a wide input dynamic range of 120 dB.
• * Demonstrated low temperature sensitivity of 230 ppm/°C (27 °C-57 °C) and power consumption under 100 nW.

Conclusions:

• * The proposed current-mode logarithmic amplifier offers a flexible and efficient solution for biomedical signal processing.
• * Direct current output and programmable gain enhance its applicability.
• * Low power consumption and good temperature stability make it suitable for sensitive biomedical instrumentation.