Linear Current Mirror Research Articles

Tunable linear CMOS current mirror

Based on triode MOSFETs as tunable devices, a tunable linear current mirror is proposed, whose current gain is tunable over a wide range. Simulations show that, total harmonic distortion on the output current is within 2% for a tuning range of almost five octaves. Although the structure is in the form of an active-input current mirror, keeping the tuned MOSFETs in triode region significantly relaxes the stability problems of an active-input current mirror. This issue is revealed by theoretical analyses and further simulations are included for demonstration. An application example is also supplied.

A low-Voltage 10-bit CMOS DAC in 0.01-mm/sup 2/ die area

A low-voltage 10-bit digital-to-analog converter (DAC) for static/dc operation is fabricated in a standard 0.18-/spl mu/m CMOS process. The DAC is optimized for large integrated circuit systems where possibly dozens of such DAC would be employed for the purpose of digitally controlled analog circuit calibration. The DAC occupies 110 /spl mu/m/spl times/94 /spl mu/m die area. A segmented R-2R architecture is used for the DAC core in order to maximize matching accuracy for a minimal use of die area. A pseudocommon centroid layout is introduced to overcome the layout restrictions of conventional common centroid techniques. A linear current mirror is proposed in order to achieve linear output current with reduced voltage headroom. The measured differential nonlinearity by integral nonlinearity (DNL/INL) is better than 0.7/0.75 LSB and 0.8/2 LSB for 1.8-V and 1.4-V power supplies, respectively. The DAC remains monotonic (|DNL|<1 LSB) as INL reaches 4 LSB down to 1.3-V operation. The DAC consumes 2.2 mA of current at all supply voltage settings.

BiCMOS adjustable linear current mirror

Two novel BiCMOS adjustable gain linear current mirrors are presented. Variable gain is achieved by introducing a DC voltage into the control loop. Simulation and experimental results indicate that the gain is linear over several decades of signal current. The circuits are designed for maximum voltage swing with cascoded output to provide high output resistance.

A CMOS rectifier-integrator for amplitude detection in hard disk servo loops

In this paper a CMOS alternative amplitude detection system is presented. It is designed as an alternative for the, bipolar, amplitude detection in hard disk servo systems. The amplitude is detected by converting the input voltage to a current, rectifying the current, and integrating it on a capacitor. For this a new OTA topology and a rectifier cell are designed. This circuitry is expanded with a very linear current mirror and an automatic offset compensation system to cope with technology spread. The measured accuracy of the amplitude detector is 0.2% (9 b). This makes the circuit suitable for implementation in state-of-the art hard disk systems with very high track densities and very short access times. Because the circuit is realized in standard CMOS it is a further step toward CMOS only hard disk electronics. Because the circuit operates from a single 3 V power supply and has limited power consumption it can be used in battery powered systems.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Wide range gain programmable class AB linear current mirrors for low supply operation

Class AB wide range programmable linear current mirrors in bipolar and CMOS technology are presented. Bipolar mirrors can operate with /spl plusmn/0.75 V supplies, CMOS mirrors with /spl plusmn/1.5 V supplies. They are characterized by having an approximately constant bandwidth that is independent of the gain adjustment. Experimental and simulation results are shown that verify the proposed structures.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>