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Fully differential (F-D) analogue circuits are usually designed focusing only on their differential-mode (DM) behaviour, without considering common-mode (CM) responses. A technique is presented for the design of both DM and CM circuit responses, using fully balanced operational amplifiers (FBOAs) as analogue building blocks. FBOAs work with CM and DM voltages as a whole, having an ideally infinite gain for both modes. This allows independent design of CM and DM dynamics. Inverting and non-inverting F-D topologies can be implemented in a simple way, similar to the implementation of their single-ended counterparts. Some typical application circuits are analysed and discussed and, as a design example, a ‘double-mode oscillator’ (a circuit that has independent CM and DM oscillations) was built and experimentally evaluated.
References
-
-
1)
-
J. Karki
.
(2003)
Fully differential amplifiers.
-
2)
-
Horrocks, D.H.: `Fully balanced second order active filter circuits having few op-amps', Proc. IEEE ISCAS' 94, 1994, 3, p. 759–762.
-
3)
-
O. Casas ,
R. Pallas-Areny
.
Basis of analog differential filters.
IEEE Trans. Instrum. Meas.
,
1 ,
275 -
279
-
4)
-
H. Alzaher ,
M. Ismail
.
A CMOS fully balanced differential difference amplifier and its applications.
IEEE Trans. Circuit Syst. II
,
6 ,
614 -
620
-
5)
-
Z. Czarnul ,
T. Itakura ,
N. Dobashi
.
Design of fully balanced analog systems based on ordinary and/or modified single-ended opamps.
Analog Integr. Circuit Signal Process.
,
189 -
207
-
6)
-
R. Pallas Areny ,
J. Webster
.
(1999)
Analog signal processing.
-
7)
-
E. Spinelli ,
N. Martinez ,
M. Mayosky
.
A novel fully-differential biopotential amplifier with DC suppression.
IEEE Trans. Biomed. Eng.
,
8 ,
1444 -
1448
-
8)
-
E. Spinelli ,
M. Mayosky ,
R. Pallas-Areny
.
AC-coupled front-end for biopotential measurements.
IEEE Trans. Biomed. Eng.
,
3 ,
391 -
395
-
9)
-
R. White
.
Phase compensation of the three op amp instrumentation amplifier.
IEEE Trans. Instrum. Meas.
,
3 ,
842 -
844
-
10)
-
E. Spinelli ,
M. Mayosky
.
Independent common mode and differential mode design of fully-differential analog circuits.
IEEE Trans. Circuits Syst. II
,
7 ,
572 -
576
-
11)
-
Van Peteghem, P.M., Duque-Carrillo, J.F.: `A general description of common-mode feedback in fully-differential amplifiers', Proc. IEEE Int. Symp. Circuits and Systems 1990, 1990, 4, p. 3209–3212.
-
12)
-
S. Seshu ,
N. Balabanian
.
(1959)
Linear network analysis.
-
13)
-
E. Spinelli ,
M. Mayosky
.
A fully-balanced operational amplifier.
IEEE Latin Am. Trans.
-
14)
-
E. Sackinger ,
W. Guggenbuhl
.
A versatile building block: the CMOS differential difference amplifier.
IEEE J. Solid-State Circuits
,
2 ,
287 -
294
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