Claims
- 1. A current source having a high output impedance at an output terminal, comprising:a current-determining transistor determining an output current, said current-determining transistor having a source terminal, a drain terminal, a gate terminal, and a source-drain voltage; a source-follower circuit providing an output signal; a control circuit having: an output terminal; and an input connected to said source-follower circuit and receiving said output signal of said source-follower circuit; a control transistor connected in series with said current-determining transistor, said control transistor having a source terminal, a drain terminal, and a gate terminal; one of said source terminal and said drain terminal of said current-determining transistor being connected with one of said source terminal and said drain terminal of said control transistor and another one of said source terminal and said drain terminal of said current-determining transistor being connected with a pole of a voltage supply; an input voltage supplied to said gate terminal of said current-determining transistor for determining a current output by the current source; one of said source terminal and said drain terminal of said control transistor being connected with one of said source terminal and said drain terminal of said current-determining transistor and another one of said source terminal and said drain terminal of said control transistor being the output terminal of the current source from which output current is generated by the current source; a node between said current-determining transistor and said control transistor defining a potential; said gate terminal of said control transistor being connected with said output terminal of said control circuit; said control circuit ensuring that said source-drain voltage of said current-determining transistor has and maintains a required value by applying a suitable drive to said control transistor; and said source-follower circuit having an input receiving said potential between said current-defining transistor and said control transistor.
- 2. The current source according to claim 1, wherein said source-follower circuit includes at least one transistor.
- 3. The current source according to claim 1, wherein said source-follower circuit includes a plurality of transistors.
- 4. The current source according to claim 3, wherein at least one of said plurality of said transistors is embodied as a current source.
- 5. The current source according to claim 1, wherein said control circuit includes an amplifier circuit having at least one transistor.
- 6. The current source according to claim 1, wherein said control circuit includes at least one control transistor.
- 7. The current source according to claim 1, including a correcting element operatively connected with one of said source terminal and said drain terminal of said current-determining transistor.
- 8. The current source according to claim 7, wherein said correcting element includes at least one transistor.
- 9. The current source according to claim 7, wherein said correcting element includes two transistors.
- 10. The current source according to claim 1, wherein said input voltage is supplied only to said gate terminal of said current-determining transistor.
Priority Claims (1)
Number |
Date |
Country |
Kind |
199 40 382 |
Aug 1999 |
DE |
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CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation of copending International Application No. PCT/DE00/02937, filed Aug. 24, 2000, which designated the United States.
US Referenced Citations (12)
Foreign Referenced Citations (1)
Number |
Date |
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43 15 299 |
Jun 1994 |
DE |
Continuations (1)
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Number |
Date |
Country |
Parent |
PCT/DE00/02937 |
Aug 2000 |
US |
Child |
10/082337 |
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US |