Avoiding common-mode feedback in continuous-time g/sub m/-C filters by use of lossy integrators

Wyszynski, A.; Schaumann, R.

doi:10.1109/iscas.1994.409360

Cited by 19 publications

(5 citation statements)

References 9 publications

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“…With the inclusion of the inverting amplifiers, this SCC structure might look similar to the biquadratic-based Gm-C filter in [38]. However in this case, there is no requirement to load the output of each transconductor with a small adjustable…”

Section: A Basic Scc Structure With DC Stabilizationmentioning

confidence: 99%

Low-Power, Low-Voltage Complex Gm-C Filter Structure With Self-Common-Mode Control

Khumsat¹

2020

Preprint

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<div>This work develops a low-power and low-voltage differential Gm-C filter structure that effectively achieves selfcommon-mode control (SCC), including DC stabilization and common-mode (CM) rejection, without employing extra control circuitry. The structure relies upon an incorporation of voltageinverting amplifiers to make it inherently contain no CM positive feedback loops for DC stabilization, and to enable splitting of the core transconductors into pairs for CM signal rejection. A DC CM stability analysis reveals that stabilization of the SCC structure can be reached without any dedicated CM control circuitry. An analytical comparison on power consumption of a high-order lowpass Gm-C filter implemented using an inverter-based</div><div>transconductor for the SCC structure and the same transconductor with a CM control network (the Nauta’s technique) for the conventional structure indicates theoretical</div><div>overhead power saving by over 50%. Furthermore, an even</div><div>higher overhead power saving at over 70Ên be achieved in the complex SCC Gm-C filter because no additional inverting</div><div>amplifiers are required to eliminate CM positive feedback loops in the crossing transconductors for complexification. The impact of the inverting amplifiers on the noise and frequency characteristics as well as the compensation technique are outlined to enable design optimization. The SCC filter was verified via extensive simulations of a 5th-order 1.1-MHz elliptic complex filter in a 0.18-m CMOS process. As compared to the conventional filter counterpart with similar SNR (~63dB) and inband/out-of-band SFDRs (~52dB/56dB), the proposed structure yields an overhead power saving by 70% with an improved figure-of-merit over 40% under a 1-V supply.</div>

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Section: A Basic Scc Structure With DC Stabilizationmentioning

confidence: 99%

Low-Power, Low-Voltage Complex Gm-C Filter Structure With Self-Common-Mode Control

Khumsat¹

2020

Preprint

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“…Also, some studies have been done in order to avoid requiring a CMFB circuit in fully di®erential circuits. 4,10,11 In this paper, to achieve higher speed and accuracy, some modi¯cations have been applied on the DDA CMFB circuit.…”

Section: Introductionmentioning

confidence: 99%

A Fast and Low Settling Error Continuous-Time Common-Mode Feedback Circuit Based on Differential Difference Amplifier

Khaneshan

Naghavi

Nematzade

et al. 2014

J CIRCUIT SYST COMP

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A high-speed and high-accuracy continuous-time common-mode feedback block (CMFB) is presented. To satisfy speed and accuracy requirements, some modi¯cations have been applied on di®erential di®erence ampli¯er (DDA) CMFB circuit. The proposed method is applied to a folded cascode op-amp with power supply of 3.3 V. In order to verify the proposed circuit, simulations are done in 0.35 m standard CMOS technology. In the worst condition when the output common-mode (CM) voltage is initialized to VCC or GND, only 1.1 ns is required to set the output CM voltage on the desired level. Also in a wide range of input CM voltage variations, the deviation of the output CM voltage from reference voltage is less than 6 mV, so simulation results con¯rm the expected accuracy and speed while simultaneously the proposed CMFB circuit preserves other characteristics of DDA CMFB circuit such as unity gain frequency, 3-dB bandwidth, phase margin and linearity. 1450065-3 J CIRCUIT SYST COMP 2014.23. Downloaded from www.worldscientific.com by FLINDERS UNIVERSITY LIBRARY on 02/03/15. For personal use only. A Fast and Low Settling Error Continuous-Time CM Feedback Circuit 1450065-13 J CIRCUIT SYST COMP 2014.23. Downloaded from www.worldscientific.com by FLINDERS UNIVERSITY LIBRARY on 02/03/15. For personal use only. A Fast and Low Settling Error Continuous-Time CM Feedback Circuit 1450065-15 J CIRCUIT SYST COMP 2014.23. Downloaded from www.worldscientific.com by FLINDERS UNIVERSITY LIBRARY on 02/03/15. For personal use only.

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“…In pseudo-differential circuits the control of the CM output voltage can be easily done by using the lossytransconductors which are generally present in a filter structure to introduce dumping [ 4 ] . In fact, these transconductors, if the common-mode signal is not cancelled out, create a negative feedback for either the differential or the CM signals.…”

Section: Cancellation Of CM Input Signalsmentioning

confidence: 99%

A 3 V pseudo-differential transconductor with intrinsic rejection of the common-mode input signal

Rezzi

Baschirotto

Castello

Proceedings of 1994 37th Midwest Symposium on Circuits and Systems

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Transconductance differential amplifiers directly r e f e r r e d t o g r o u n d (we will call them "pseudo-differential" structures to distinguish from the fully-differential ones) a r e not intrinsically capable of rejecting the common-mode (CM) input signal. This paper deals with the problems related to the propagation of t h e CM signal in differential circuits. A new pseudo-differential transconductor architecture with a high Common-Mode Rejection Ratio (CMRR) is proposed. The novel structure is based on a transconductor sensible only to CM signals which is added in parallel to the original one, in order to implement a feed-forward cancellation of the CM output signal current. An efficient circuital implementation of this struct u r e is presented. Comparative simulations demons t r a t e t h a t the proposed technique is competitive with the classical fully-differential one particularly a t high frequency when the CMRR rapidly degrades.

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Avoiding common-mode feedback in continuous-time g/sub m/-C filters by use of lossy integrators

Cited by 19 publications

References 9 publications

Low-Power, Low-Voltage Complex Gm-C Filter Structure With Self-Common-Mode Control

Low-Power, Low-Voltage Complex Gm-C Filter Structure With Self-Common-Mode Control

A Fast and Low Settling Error Continuous-Time Common-Mode Feedback Circuit Based on Differential Difference Amplifier

A 3 V pseudo-differential transconductor with intrinsic rejection of the common-mode input signal

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