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EP0131340A1 Expired / Lapsed EP ⏱️ 0.0 years remaining

Current stabilising circuit

Assignee: Koninklijke Philips NV
•
Filing: 1984-07-10
•
Granted: —
•
Expires: 2004-07-10
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Abstract

Abstract Arranged between a first and a second common terminal (5 and 6), the circuit comprises a first circuit formed by the series arrangement of a first PNP-transistor (T,) and a second NPN-transistor (T<sub>2</sub>), and a second circuit formed by the series arrangement of a third PNP-transistor (T<sub>3</sub>), a fourth NPN-transistor (T.) and a first resistor (R,). The commonned bases of the second and fourth transistors (T<sub>2</sub> and T.) are driven by a first differential amplifier (3), whose non-inverting input is coupled to the collector of the second transistor (T<sub>2</sub>) and whose inverting input is coupled to a tap (7) of a voltage divider (R<sub>2</sub>, R<sub>3</sub>) formed by a second and a third resistor. The commonned bases of the first and third transistors (T, and T<sub>3</sub>) are driven by a second differential amplifier (4), whose non-inverting input is coupled to the collector of the third transistor (T<sub>3</sub>) and inverting input to the tap (7) of the voltage divider (R<sub>2</sub>, R<sub>3</sub>). Because of the drive by means of the first and second amplifiers (3 and 4). the collector-base voltages of the first and third transistors (T<sub>2</sub> and T<sub>3</sub>) and of the second and fourth transistors (T<sub>2</sub> and T.) vary to an equal extent in the event of supply voltage variations, as a consequence of which the symmetry of the circuit is preserved

Inventors

  • 👤 Johannes Otto Voorman

Bibliographic Details

Application Number —
Jurisdiction EP
Data Source google_patents
Last Synchronized 2026-11-02 16:23
CPC Classifications
G; G05; G05F; G05F3/00; G05F3/02; G05F3/08; G05F3/10; G05F3/16; G05F3/20; G05F3/30

Claims Analysis

Total Claims: 4
Claim 1
Independent Claim 220 words
A current stabilising circuit comprising first and second circuits arranged in parallel between first and second common terminals, the first circuit being formed by the series arrangement of the collector-emitter path of a first transistor of a first conductivity type and the collector-emitter path of a second transistor of a second conductivity type, the second circuit being formed by the series arrangement of the collector-emitter path of a third transistor of the first conductivity type, the collector-emitter path of a fourth transistor of the second conductivity type and a resistor, the first and third transistors having commonned control electrodes and the second and fourth transistors having commonned control electrodes which are driven by an output of a differential amplifier having a first and a second input, the first input being coupled to the first circuit between the first and second transistors, characterized in that the commonned control electrodes of the first and third transistors are driven by an output of a second differential amplifier having a first and a second input, the first input being coupled to the second circuit between the third and fourth transistors, that a voltage divider is included between the first and second common terminals and that the second inputs of the first and second differential amplifiers are coupled to a tap of the voltage divider.
Claim 2
Dependent Claim 220 words
A current stabilising circuit comprising first and second circuits arranged in parallel between first and second common terminals, the first circuit being formed by the series arrangement of the collector-emitter path of a first transistor of a first conductivity type and the collector-emitter path of a second transistor of a second conductivity type, the second circuit being formed by the series arrangement of the collector-emitter path of a third transistor of the first conductivity type, the collector-emitter path of a fourth transistor of the second conductivity type and a resistor, the first and third transistors having commonned control electrodes and the second and fourth transistors having commonned control electrodes which are driven by an output of a differential amplifier having a first and a second input, the first input being coupled to the first circuit between the first and second transistors, characterized in that the commonned control electrodes of the first and third transistors are driven by an output of a second differential amplifier having a first and a second input, the first input being coupled to the second circuit between the third and fourth transistors, that a voltage divider is included between the first and second common terminals and that the second inputs of the first and second differential amplifiers are coupled to a tap of the voltage divider.
Claim 3
Dependent Claim 49 words
A current stabilising circuit as claimed in Claim 1, characterized in that in at least the first and second circuits between the collector-emitter paths of respectively the first and second transistor and the third and fourth transistors is included a semiconductor junction which is connected in the forward direction.
Claim 4
Dependent Claim 51 words
A current stabilising circuit as claimed in Claim 2, the voltage divider being formed by the series arrangement of a second and a third impedance, characterized in that the voltage divider also comprises at least one semiconductor junction connected in the forward direction and arranged between the second and third impedances.

References Cited (Backward Citations)

US3914683A Cited
DE2647640A1 Cited
FR2357875A1 Cited
WO1982001105A1 Cited

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