Low-voltage companding current-mode integrators

Woerd

IEEE Trans. Circuits Syst. I

et al. 1997

Abstract-Log-domain or translinear filters are regarded as being a promising alternative in the area of low-voltage filter design. To date, most publications have reported on synthesis of translinear filters. Although synthesis is more powerful than analysis, it must go together with a generally applicable analysis method in the same domain. In this paper, a general currentmode analysis method is proposed. By using a current-mode approach, we stay close to the existing theory on static translinear circuits, which might be beneficial in developing a general, possibly more powerful synthesis method.

Section: An Analysis Examplementioning

confidence: 99%

Section: An Analysis Examplementioning

confidence: 99%

See 1 more Smart Citation

General current-mode analysis method for translinear filters

Woerd

IEEE Trans. Circuits Syst. I

et al. 1997

“…Although not recognized then, this was actually the first time a first-order linear differential equation was implemented using translinear circuit techniques. In 1990, Seevinck introduced a "companding current-mode integrator" [5], and since then the principle of translinear filtering has been extensively studied by Frey, see, e.g., [6], Punzenberger and Enz [7], Toumazou and Lande [8], Perry and Roberts [9], and Mulder and Serdijn, see, e.g., [10], [11].…”

Section: Introductionmentioning

confidence: 99%

A wide-tunable translinear second-order oscillator

IEEE J. Solid-State Circuits

Woerd

et al. 1998

Abstract-This paper describes the design and measurement of a translinear second-order oscillator. The circuit is a direct implementation of a nonlinear second-order differential equation and follows from a recently developed synthesis method for dynamic translinear circuits. It comprises only two capacitors and a handful of bipolar transistors and can be instantaneously controlled over a very wide frequency range by only one control current, which indicates its suitability for spread-spectrum communications. Its total harmonic distortion can be made small by the design, which enables fully integrated transmitters. A semicustom test chip, fabricated in a standard 2-m, 7-GHz, bipolar IC process, operates from a single supply voltage, which can be as low as 2 V and oscillates over six decades of frequency with 031 dB total harmonic distortion.

“…If also a (frequency) controllable transfer function is required and resistor values become too large for integration, which is the penalty for going to lower and lower currents, the situation becomes even more complicated [2]. It is the quest for a controllable transfer function that produced the idea of "log-domain filtering," first introduced by Adams in 1979 [3] and later thoroughly investigated by Seevinck [4], Frey, see, e.g., [5], Punzenberger and Enz [6], Toumazou and Lande [7], Perry and Roberts [8] and Mulder et al [9], [10].…”

mentioning

confidence: 99%

A low-voltage ultra-low-power translinear integrator for audio filter applications

Broest

IEEE J. Solid-State Circuits

et al. 1997

Abstract-In this paper, the design and measurement of a 1-V translinear integrator and its application in a controllable secondorder lowpass filter for hearing instruments is presented. A semicustom version of the filter has been integrated in a standard 2-m, 7-GHz, bipolar IC process and operates at voltages down to 1 V, consumes only 6 A, and has a dynamic range of 57 dB for a total harmonic distortion below 2%. Its cutoff frequency is linearly adjustable in octaves from 1.6 to 8 kHz.Index Terms-Active filters, bipolar analog integrated circuits, current mode, low power, low voltage.