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EP0383397A2 Expired / Lapsed EP ⏱️ 0.0 years remaining

Current conveyor circuit

Assignee: Philips Electronics UK Ltd
•
Filing: 1990-02-13
•
Granted: —
•
Expires: 2010-02-13
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Abstract

Abstract A second generation current conveyor circuit for accepting a current at an input (100) at low impedance and providing an output current of the same or a related value at an output (101) at high impedance comprises a first transistor (T101) whose main current conducting path is connected between the input and a second diode connected transistor (T102) whose other end is connected to a voltage supply, a third transistor (T103) whose main current carrying path is connected between the voltage supply and a fourth diode connected transistor (T104) whose other end is connected to an input terminal (102) for the application of a reference potential, and a fifth transistor (T105) whose control electrode is connected to the control electrodes of the second and third transistors (T1-2 and T103) and whose main current conducting path is connected between the supply voltage and the output (101). The control electrodes of the first T101) and fourth (T104) transistors being commoned. Means are provided for internally generating a cancelling current for cancelling the current through the fourth transistor (T104) so that no current is drawn through the input terminal (T102). The means for internally generating the cancelling current comprises a sixth transistor (T106) whose control electrode is connected to the control electrode of the second transistor (T102) and which is connected to produce the cancelling current and means comprising a current mirror circuit (T107, T108) for feeding the cancelling current to the fourth transistor (T104).

Inventors

  • 👤 John Barry Hughes

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-10-31 21:05
CPC Classifications
G; G05; G05F; G05F3/00; G05F3/02; G05F3/08; G05F3/10; G05F3/16; G05F3/20; G05F3/26; G05F3/262; G05F3/24; H; H03; H03F; H03F1/00; H03F1/56; H03F3/00; H03F3/34; H03F3/343; H03F3/345

Claims Analysis

Total Claims: 8
Claim 1
Independent Claim 174 words
A current conveyor circuit for accepting a current at an input at low impedance and providing an output current of the same or a related value at an output at high impedance comprising a first transistor whose main current conducting path is connected between the input and a second diode connected transistor whose other end is connected to a voltage supply, a third transistor whose main current carrying path is connected between the voltage supply and a fourth diode connected transistor whose other end is connected to an input terminal for the application of a reference potential, and a fifth transistor whose control electrode is connected to the control electrodes of the second and third transistors and whose main current conducting path is connected between the supply voltage and the output, wherein the control electrodes of the first and fourth transistors are commoned characterised in that means are provided for internally generating a cancelling current for cancelling the current through the fourth transistor so that substantially no current is drawn through the input terminal.
Claim 2
Dependent Claim 174 words
A current conveyor circuit for accepting a current at an input at low impedance and providing an output current of the same or a related value at an output at high impedance comprising a first transistor whose main current conducting path is connected between the input and a second diode connected transistor whose other end is connected to a voltage supply, a third transistor whose main current carrying path is connected between the voltage supply and a fourth diode connected transistor whose other end is connected to an input terminal for the application of a reference potential, and a fifth transistor whose control electrode is connected to the control electrodes of the second and third transistors and whose main current conducting path is connected between the supply voltage and the output, wherein the control electrodes of the first and fourth transistors are commoned characterised in that means are provided for internally generating a cancelling current for cancelling the current through the fourth transistor so that substantially no current is drawn through the input terminal.
Claim 3
Dependent Claim 56 words
A current conveyor circuit as claimed in Claim 1 in which the means for internally generating the cancelling current comprises a sixth transistor whose control electrode is connected to the control electrode of the second transistor and which is connected to produce the cancelling current and means for feeding the cancelling current to the fourth transistor.
Claim 4
Dependent Claim 23 words
A current conveyor circuit as claimed in Claim 2 in which the means for feeding the cancelling current comprises a current mirror circuit.
Claim 5
Dependent Claim 18 words
A current conveyor circuit as claimed in any preceding claim in which the transistors are field effect tranistors.
Claim 6
Dependent Claim 17 words
A current conveyor circuit substantially as described herein with reference to Figure 2 of the accompanying drawings.
Claim 7
Dependent Claim 17 words
A current conveyor circuit substantially as described herein with reference to Figure 2 of the accompanying drawings.
Claim 8
Dependent Claim 26 words
Any novel integer or novel combination of integers either implicitly or explicitly disclosed herein whether or not it falls within the scope of any preceding claim.

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