Electricity: power supply or regulation systems – Self-regulating – Using a three or more terminal semiconductive device as the...
Patent
1997-12-16
1999-05-04
Berhane, Adolf Deneke
Electricity: power supply or regulation systems
Self-regulating
Using a three or more terminal semiconductive device as the...
323315, G05F 326
Patent
active
059007257
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
The invention relates to a circuit arrangement for current transformation with four current branches, containing a first, a second, a third and a fourth transistor, coupled in pairs.
Circuit arrangements for current transformation are known for example from the publication U. Tietze, Ch. Schenk: Halbleiter-Schaltungstechnik, Springer-Verlag, 7.sup.th ed., 1985, pp. 364ff. A current mirror thereby functions as the simplest transformation circuit. It is often necessary to produce a current with particular characteristics that cannot be realized with the known circuit arrangements. Other circuit arrangements can be integrated only poorly, e.g. because they require resistances with particular characteristics, e.g. temperature-constant resistances.
In particular, circuit arrangements that produce an output current by means of multiplication or division of currents, or that are suited for temperature compensation or, for producing a predetermined temperature coefficient, can be integrated only with great expense and are little known.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a circuit arrangement for current transformation that can be integrated and that is suited, in particular, for the production of a current with a predetermined temperature coefficient.
The invention solves object with the features of patent
According to the present invention, a circuit arrangement is provided for current transformation having four current branches containing a respective first, second, third and fourth transistor. The transistors are coupled in pairs such that terminals of charge carrying sources of the first and fourth transistors are connected with the first node point, and terminals of charge carrying sources of the second and third transistors are connected with the second node point. A control terminal and a terminal of the charge carrying drain of the second and of the third transistors are connected with one another. The control terminals of the first and the second transistors are connected with one another and control terminals of the third and fourth transistors are connected with one another.
The invention has the advantage that it is suited both for the production of a current by means of multiplication or division of single currents and also as a circuit for temperature compensation or for the production of a predetermined temperature coefficient. For example, the circuit arrangement is suited for the production of a current that is proportional to the absolute temperature, without requiring a temperature constant resistance. In the same way, an output current with a linear temperature coefficient can be produced from a given parent current.
The invention is explained in more detail on the basis of two exemplary embodiments shown in the figures in the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a first exemplary embodiment of a circuit arrangement for current transformation, and
FIG. 2 shows a second exemplary embodiment of a current transformation circuit with two output currents.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
According to FIG. 1, the circuit arrangement for current transformation contains four current branches with transistors T1 to T4, which are connected with one another in pairs at the emitter side. The control terminals of the transistors are connected in pairs in cross-coupled fashion. Of the transistors having a common control terminal, one is respectively connected as a diode. According to FIG. 1, the circuit arrangement thus has four current branches with a first transistor T1, a second transistor T2, a third transistor T3 and a fourth transistor T4. The transistors T1 and T4 are connected with one another at the emitter side, and the transistors T2 and T3 are connected with one another at the emitter side. The transistors T1 and T2 are connected with one another at the base side, and the transistors T3 and T4 are connected with one another at the base side. Each of the transistors T2 and T3 is connected as a diode
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U. Tietze Ch. Schenk--Halbleiter-Schaltungstechnik 1985 3 pages.
Berhane Adolf Deneke
Siemens Aktiengesellschaft
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