The development of bipolar log domain filters in a standard CMOS process

A novel CMOS exponential transconductor which employs only three NMOS transistors operating in weak inversion, is presented. The main advantage of the proposed circuit is its wide range of exponential behaviour, which reaches up to five decades of current range, and above 10 mA to an input voltage range of 800 mV. The physical realisation is achieved in two forms: in the first one, the circuit is implemented with discrete MOS transistor arrays by CD4007 series; in the second one, the circuit is fully integrated in a 0.5 mm CMOS standard process. Simulated and experimental results of the proposed exponential transconductor are also presented.

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“…(Sheingold 1976;Serdijn, van der Woerd, Davidse, and van Roermund 1994;Duerden, Roberts, and Deen 2001;Yamaji, Kanou, and Ikatura 2002).…”

Section: Introductionunclassified

A novel CMOS exponential transconductor operating in weak inversion

Jesus-Peregrina

Díaz-Sánchez

Tlelo‐Cuautle

et al. 2008

International Journal of Electronics

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“…The notion of log-domain filtering was first introduced in 1979 [1], and recently the approach has seen an increase in interest, with parallel development of circuits and applications [2][3][4][5][6][7][8][9] and general design methodologies [10][11][12]. Log-domain filters are current-mode circuits that are linear in their inputs and outputs, but in which temporal processing takes place on logarithmically compressed internal voltage variables.…”

Section: Introductionmentioning

confidence: 99%

A Methodology for Long Time Constant Log-Domain Filters in CMOS

Shoemaker

2005

Analog Integr Circ Sig Process

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A simple methodology for implementation of low-order, current-mode, log-domain filters in CMOS technology is presented. The key transistors in the circuit are operated in weak inversion and in contrast with previous approaches may pass into the triode regime. The concept is particularly suited to implementation in silicon-on-insulator technology, because dielectric isolation of the transistors eliminates leakage currents, and because influence of the body effect on circuit function is limited. Very long time constants, on the order of 1 s or more, are obtainable. A simple elaboration of the basic unit circuit allows the time constant to be controlled by a bias current.

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“…More importantly, TL circuits realized with CMOS transistors operating in weak inversion regime have demonstrated significant potential in terms of power efficiency, which is, as mentioned previously, a very important task for this design. Furthermore, the drawback of limited maximum bandwidth of CMOS realizations of TL circuits, with respect to bipolar realization [20], [21], is not a concern at all in this case, due to the characteristic frequencies of cardiac signals.…”

Section: Introductionmentioning

confidence: 99%

A Fully Integrated Dual-Channel Log-Domain Programmable Preamplifier and Filter for an Implantable Cardiac Pacemaker

Gerosa

Maniero

Neviani

2004

IEEE Trans. Circuits Syst. I

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A programmable-gain preamplifier and filter for detection of spontaneous heart activity in an implantable cardiac pacemaker is presented. The system is fully integrated in a standard 0.35-m CMOS technology, including all auxiliary circuits. Two channels are available in order to process both atrial and ventricular signals. CMOS translinear circuits, with particular emphasis on log-domain techniques, have been exploited in order to contain current consumption and to allow correct operation with a reduced supply voltage, due to battery discharging. Indeed, the realized system can operate down to 1.8 V of supply voltage and dissipates at most 1.8 A, granting at least 47 dB of dynamic range (DR) for the atrial chain, which is compatible with advanced digital sensing. Current consumption can be further reduced at the expense of DR if a simpler sensing like peak detection is adopted. All system performance have been verified by measurements results and are compatible with the requirements of cardiac pacemakers. This work, therefore, demonstrates how a proper design approach, exploiting low-power and low-voltage techniques, allows one to optimize performance for the cardiac pacemaker.

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The development of bipolar log domain filters in a standard CMOS process

Cited by 12 publications

References 29 publications

A novel CMOS exponential transconductor operating in weak inversion

A novel CMOS exponential transconductor operating in weak inversion

A Methodology for Long Time Constant Log-Domain Filters in CMOS

A Fully Integrated Dual-Channel Log-Domain Programmable Preamplifier and Filter for an Implantable Cardiac Pacemaker

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