Miscellaneous active electrical nonlinear devices – circuits – and – Signal converting – shaping – or generating – Converting input voltage to output current or vice versa
Reexamination Certificate
2000-10-23
2002-01-08
Cunningham, Terry D. (Department: 2816)
Miscellaneous active electrical nonlinear devices, circuits, and
Signal converting, shaping, or generating
Converting input voltage to output current or vice versa
C327S102000, C327S563000
Reexamination Certificate
active
06337585
ABSTRACT:
TECHNICAL FIELD
The invention relates to a transconductor.
BACKGROUND OF THE INVENTION
FIG. 1
illustrates a known transconductor comprising a voltage input terminal Vin1, a current output terminal Iout1, a supply voltage terminal Vcc1, and two control voltage terminals Vreg1+ and Vreg1−. A control voltage is to be applied between the control voltage terminals Vreg1= and Vreg1− to control the transconductance of the transconductor.
The voltage input terminal Vin1 is connected to the base of a transistor Q
11
, whose emitter is connected to a ground terminal via a resistor R
11
and whose collector is connected to an interconnection point between emitters of two transistors Q
12
and Q
13
. The base of the transistor Q
12
is connected to the control voltage terminal Vreg1+, while the base of the transistor Q
13
is connected to the control voltage terminal Vreg1−. The collector of the transistor Q
12
is connected to the current output terminal Iout1, while the collector of the transistor Q
13
is connected to the supply voltage terminal Vcc1.
By varying the voltage between the control voltage terminals Vreg1+ and Vreg1−, the output current on the current output terminal Iout1 will vary correspondingly.
The known transconductor shown in
FIG. 1
cannot be used at low supply voltages applied between the supply voltage terminal Vcc1 and ground since it requires quite a large voltage range due to the fact that the transistors Q
11
, Q
12
and Q
13
are stacked on each other.
SUMMARY OF THE INVENTION
The object of the invention is to bring about a transconductor that enables power control also at low supply voltages.
This is attained in the transconductor according to the invention in that it comprises only two transistors without stacking.
Hereby, operation at a lower supply voltage is enabled.
REFERENCES:
patent: 4461042 (1984-07-01), Tanabe et al.
patent: 4934770 (1990-06-01), Anderson et al.
patent: 5079454 (1992-01-01), Benton et al.
patent: 5166645 (1992-11-01), Watts
patent: 5233311 (1993-08-01), Chevallier
patent: 5434544 (1995-07-01), Van Veenendaal
patent: 5596299 (1997-01-01), Persico et al.
patent: 5652543 (1997-07-01), Fenk et al.
patent: 5859558 (1999-01-01), Chen et al.
patent: 6188282 (2001-02-01), Montalvo
patent: 0915561 (1999-05-01), None
patent: 10-126300 (1998-05-01), None
Cunningham Terry D.
Nguyen Long
Telefonaktiebolaget LM Ericsson (publ)
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