Using MOS current dividers for linearization of programmable gain amplifiers

Sanz, M.T.; Celma, S.; Calvo, B.

doi:10.1002/cta.450

Cited by 17 publications

(12 citation statements)

References 15 publications

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“…There has been extensive research in improving OTAs in this respect [21][22][23][24][25][26] but as of this time there are no highly linear commercially available OTAs. In addition, more robust programmable gain amplifiers could be utilized instead, which exhibit high linearity [27]. The linearizing diodes of the LM13700 could be utilized to yield a more linear I-V characteristic.…”

Section: Circuit Realization Of Line Modelsmentioning

confidence: 99%

OTA‐based transmission line model with variable parameters for analog power flow computation

Leger

Nwankpa

2008

Circuit Theory & Apps

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Analog computation has some inherent benefits over traditional digital computation methods and fosters a continued interest in research, specifically in power systems, due to its associated strengths. Among these advantages are physically realizable solutions, much faster computation times and more accurate models. To realize an analog computation environment for power system analysis analog models and their circuit realizations are required. This paper focuses on the design, simulation and hardware verification of transmission line models with variable parameters for the purpose of analog power flow computation. Specifically, pi equivalent lumped parameter and distributed parameter transmission line models with parametric variation based on temperature and frequency are presented. Operational transconductance amplifiers (OTAs) are the primary circuit elements in the hardware designs and allow remote reconfigurability and variation of transmission line parameters via transconductance gain. Test results are presented from a hardware prototype, which was developed and tested based on the proposed analog line models.

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Section: Circuit Realization Of Line Modelsmentioning

confidence: 99%

OTA‐based transmission line model with variable parameters for analog power flow computation

Leger

Nwankpa

2008

Circuit Theory & Apps

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“…Therefore, the dynamic range and the efficiency of the differential pair using MOS transistors are limited [5,[19][20][21]. A number of techniques for improving the linear properties of CMOS transconductance elements based on the source-coupled differential pairs have been proposed [22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38]. These techniques employ MOS transistors operating both in saturation in triode regions.…”

Section: Introductionmentioning

confidence: 99%

Programmable feedforward linearized CMOS OTA for fully differential continuous‐time filter design

Szczepański

Pankiewicz

Koziel

2009

Circuit Theory & Apps

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SUMMARYIn this paper, a feedforward linearization method for programmable CMOS operational transconductance amplifier (OTA) is described. The proposed circuit technique is developed using simple source-coupled differential pair transconductors, a feedback-loop amplifier for self-adjusting transcoductance (g m ) and a linear reference resistor (R). As a result, an efficient linearization of a transfer characteristic of the OTA is obtained. SPICE simulations show that for 0.35 m AMS CMOS process with a single +3 V power supply, total harmonic distortion at 1 V pp and temperature range from −30 to +90 • C is less than −49.3 dB in comparison with −35.8 dB without linearization. Moreover, the input voltage range of linear operation is increased. Power consumption of the linearized OTA circuit is 0.86 mW. Finally, the OTA is used to design a third-order elliptic low-pass filter in high-frequency range. The cut-off frequency of the operational transconductance amplifier-capacitor (OTA-C) filter is tunable in the range of 322.6 kHz-10 MHz using the feedforward linearized OTAs with the digitally programmable current mirrors.

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“…However, the resistive feedback amplifiers usually provide high linearity but not suitable for high frequency applications. Due to the large current required of high frequency operational amplifier, the area consumption is increased [10]. For high frequency applications, open-loop amplifiers using variable transconductance (g m ) or variable output loads (R L ) [2,3] techniques are provided.…”

Section: Introductionmentioning

confidence: 99%

Two digitally programmable gain amplifiers based on current conveyors

Angkeaw

Prommee

2010

Analog Integr Circ Sig Process

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Two digitally programmable gain amplifiers based on current conveyors (CCIIs) are presented. The first digitally programmable gain amplifier consists of a CCII, an operational transconductance amplifier (OTA), and current mirrors. The second one is composed of current conveyor analogue switches (CCASs). Both proposed digitally programmable gain amplifiers do not need switches but they maintain the linear gain at any digital signal levels similar to the digitally programmable gain amplifier using switches; hence the proposed amplifiers are easier to realize, use narrower chip area, and consume lower power. The first proposed amplifier is verified by constructing the circuit using the CCII in an AD844 IC, the OTA in a CA3080 IC, and some bipolar current mirrors. The second proposed amplifier is verified by simulating the circuit using the parameters extracted from the layout (including parasitic capacitance) in the 0.25 lm MOS technology, the level 49 MOS model obtained through MOSIS is used. The results show that the operations of two proposed amplifiers are in accordance with the theories.

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Using MOS current dividers for linearization of programmable gain amplifiers

Cited by 17 publications

References 15 publications

OTA‐based transmission line model with variable parameters for analog power flow computation

OTA‐based transmission line model with variable parameters for analog power flow computation

Programmable feedforward linearized CMOS OTA for fully differential continuous‐time filter design

Two digitally programmable gain amplifiers based on current conveyors

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