Circuit and method for providing an output current with a prescribed temperature coefficient
First Claim
1. A current supply circuit for producing an output current having a selected output temperature coefficient defining a variation of said output current dependent on temperature, said circuit comprising:
- a first current sink or source having a first current terminal that produces a first internal current having a first temperature coefficient;
a second current sink or source having a second current terminal that produces a second internal current having a second temperature coefficient; and
a current coupling element that has a first input connected to said first current terminal of said first current sink or source, a second input connected to said second current terminal of said second current sink or source, and an output connected to a circuit output of said circuit;
wherein said current coupling element couples and combines said first internal current and said second internal current to produce said output current at said circuit output.
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Abstract
A circuit includes two internal current sources or sinks coupled together by a coupling element, which may be a direct junction as a summing element or a current mirror as a subtracting element. In an associated method, the currents of the two internal current sinks or sources are summed or subtracted by the coupling element to form an output current. The magnitudes and/or temperature coefficients of the two internal currents differ from one another. The temperature coefficient of the output current is determined by the addition or subtraction of the internal currents, and can be selected as desired, simply and economically, by appropriately selecting the temperature coefficients of the internal currents and the adding or subtracting carried out by the coupling element. The output current can even have a negative temperature coefficient, based on economical internal components having only positive temperature coefficients.
16 Citations
24 Claims
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1. A current supply circuit for producing an output current having a selected output temperature coefficient defining a variation of said output current dependent on temperature, said circuit comprising:
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a first current sink or source having a first current terminal that produces a first internal current having a first temperature coefficient;
a second current sink or source having a second current terminal that produces a second internal current having a second temperature coefficient; and
a current coupling element that has a first input connected to said first current terminal of said first current sink or source, a second input connected to said second current terminal of said second current sink or source, and an output connected to a circuit output of said circuit;
wherein said current coupling element couples and combines said first internal current and said second internal current to produce said output current at said circuit output. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method of producing an output current having a selected output temperature coefficient defining a variation of said output current dependent on temperature, comprising the steps:
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a) producing a first internal current having a first temperature coefficient by a first current sink or source;
b) producing a second internal current having a second temperature coefficient by a second current sink or source, wherein said second temperature coefficient is different from said first temperature coefficient and/or a first magnitude of said first internal current is different from a second magnitude of said second internal current; and
c) adding or subtracting one of said internal currents relative to another of said internal currents, to produce said output current. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24)
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Specification