Circuit with adjustable gain current mirror amplifier

Claim 2

A composite current mirror amplifier having a current gain which can be trimmed, responding to an input current to supply an output current, and comprising: a fixed gain current mirror amplifier having an input circuit and an output circuit; an adjustable gain direct-coupled current amplifier having an input circuit and an output circuit; means connecting the input circuits of said fixed gain current mirror amplifier and of said adjustable gain current amplifier in parallel for splitting said input current between said input circuits; and means connecting the output circuits of said fixed gain current mirror amplifier and of said adjustable gain current amplifier in parallel for supplying said output current.

Claim 3

The composite current mirror amplifier set forth in claim 1 wherein: said fixed-gain current mirror amplifier comprises a first transistor, said first transistor having a base and an emitter electrodes with a base-emitter junction therebetween and having a collector electrode, connected in common-emitter amplifier configuration with a first diode connected transistor connected in parallel with its base-emitter junction, and said adjustable-gain current amplifier comprises a second transistor, said second transistor having a base and an emitter electrodes with a base emitter junction therebetween and having a collector electrode, connected in common-emitter amplifier configuration with a first adjustable resiStive element connected in a first series combination with the base-emitter junction of said second transistor to provide emitter degeneration resistance thereto.

Claim 4

The composite current mirror amplifier set forth in claim 2 wherein said first and said second transistors are of the same conductivity type.

Claim 5

The composite current mirror amplifier set forth in claim 2 wherein said adjustable-gain current amplifier further includes: a second diode and a second adjustable resistive element connected in a second series combination parallelly connected with said first series combination.

Claim 6

The composite current mirror amplifier set forth in claim 4 wherein: said first and second adustable resistive elements are arranged to be mutually adjustable such that the resistance of one is increased while the other is decreased and vice versa.

Claim 7

The composite current mirror amplifier set forth in claim 5 wherein: said first and second resistive elements are provided by a resistive potentiometer, said first resistive element being between a first end terminal of said potentiometer and its slider or tap terminal and said second resistive element being between a second end terminal of said potentiometer and its slider or tap terminal.

Claim 8

The composite current mirror amplifier set forth in claim 4 wherein at least one of said first and said second diodes each comprises an auxiliary transistor having an emitter and a collector electrodes and having a base electrode connected to its collector electrode.

Claim 9

The composite current mirror amplifier set forth in claim 2 wherein said first adjustable resistive element is connected between the emitter electrodes of said first and said second transistors.

Claim 10

The composite current mirror amplifier set forth in claim 8 wherein: a second diode and a second adjustable resistive element are connected in a second series combination which second series combination is connected in parallel with said first series combination.

Claim 11

The composite current mirror amplifier set forth in claim 9 wherein said first and said second resistive elements are provided by a resistive potentiometer, said first resistive element being between a first end terminal of said potentiometer and its slider or tap terminal and said second resistive element being between a second end terminal of said potentiometer and its slider or tap terminal, said slider or tap terminal being connected to said first transistor emitter electrode.

Claim 12

The composite current mirror amplifier set forth in claim 4 having in combination therewith: a third and a fourth transistors of complementary conductivity type to said first transistor, each having a base and an emitter and a collector or equivalent electrodes, and means for applying direct bias between the base and emitter electrodes of said third transistor; means for applying direct bias between the base and emitter electrodes of said fourth transistor; means for applying signal between the base electrodes of said third and said fourth transistors and direct current conductive connections of said third and fourth transistor collector electrodes respectively to separate ones of said first transistor base and collector electrodes.

Claim 13

The combinations set forth in claim 11 having in combination therewith: a fifth transistor of the same conductivity type as said first transistor, said fifth transistor having a base and an emitter electrodes respectively connected to said first transistor collector and emitter electrodes and having a collector electrode, and further means connecting said fifth transistor in common-emitter amplifier configuration.

Claim 14

In combination: a first and a second terminals for application of a first and a second input currents, respectively; a third terminal for connection to a reference potential; a fourth and a fifth terminals; a first and a second and a third and a fourth transistors of the same conductivity type, each having a principal conductive path between a first and a second electrodes and having a control electrode, the conductivity of the principal conductive path of each said transistor being determined in accordance with potential applied between its control and first electrodes; the second electrodes of said first and said third transistors being coupled to said first terminal, the second electrodes of said second and said fourth transistors being coupled to said second terminal; the first electrodes of said first and said second transistors being connected to separate ones of said fourth and said fifth terminals, the first electrodes of said third and said fourth transistors being directly connected to said third terminal; degenerative feedback means connecting said first terminal to each of the control electrodes of said first, said second, said third and said fourth transistors; and an adjustable potentiometer having ends connected to said fourth and said fifth terminals and a tap connected to said third terminal.

Claim 15

In combination: a first and a second terminals for application of a first and a second input currents, respectively; a third terminal for connection to a reference potential; a fourth and a fifth terminals; a first and a second and a third and a fourth transistors of the same conductivity type, each having a principal conductive path between a first and a second electrodes and having a control electrode, the conductivity of the principal conductive path of each said transistor being determined in accordance with potential applied between its control and first electrodes; the second electrodes of said first and said third transistors being coupled to said first terminal, the second electrodes of said second and said fourth transistors being coupled to said second terminal; the first electrodes of said first and said second transistors being connected to separate ones of said fourth and said fifth terminals, the first electrodes of said third and said fourth transistors being directly connected to said third terminal; degenerative feedback means connecting said first terminal to each of the control electrodes of said first, said second, said third and said fourth transistors; and an adjustable potentiometer having ends connected to said fourth and said fifth terminals and a tap connected to said third terminal.

Claim 16

The combination set forth in claim 13 having in combination therewith: a fifth and a sixth transistors of complementary conductivity type to that of said first transistor, each having a principal conductive path between a first and a second electrodes and having a control electrode, the conductivity of the principal conductive path of each being determined in accordance with the potential applied between its control and first electrodes; means for applying direct bias between the control and first electrodes of said fifth transistor; means for applying direct bias between the control and first electrodes of said sixth transistor; means for applying signal between the control electrodes of said fifth and said sixth transistors; and means for direct current conductively coupling the second electrodes of said fifth and said sixth transistors to separate ones of the second electrodes of said first and said second transistors, respectively.

Claim 17

The combination set forth in claim 13 wherein said first and said third transistors are comprised within a first dual-emitter transistor structure, and said second and said fourth transistors are comprised within a second dual-emitter transistor structure.

Claim 18

A current mirror amplifier comprising: an input terminal for receiving an input current; an output terminal for supplying an output current, which is in substantially constant proportion to said input current; a common terminal for return of said input current and said output current; a transistor having a base electrode connected to said input terminal, a collector electrode connected to said output terminal, an emitter electrode connected to said common terminal, and a base-emitter junction between its said base and emitter electrodes; a first diode, having a first end and a second end respectively connected to said input terminal and to said common terminal for parallel forward conduction with said base-emitter junction for all values of said input current of a polarity to forward-bias said base-emitter junction; a first adjustable-resistance element; a second diode serially connected with said adjustable-resistance element between the first and second ends of said first diode for parallel forward conduction with said base-emitter junction and said first diode, for all values of said input current of said polarity to forward bias said base-emitter junction, the adjustment of said adjustable-resistance element being over a range of resistance values to affect the flow of current through itself and said second diode to alter said substantially constant proportion.

Claim 19

A current mirror amplifier comprising: an input terminal for receiving an input current; an output terminal for supplying an output current, which is in substantially constant proportion to said input current; a common terminal for return of said input current and said output current; a transistor having a base electrode connected to said input terminal, a collector electrode connected to said output terminal, an emitter electrode connected to said common terminal, and a base-emitter junction between its said base and emitter electrodes; a first diode, having a first end and a second end respectively connected to said input terminal and to said common terminal for parallel forward conduction with said base-emitter junction for all values of said input current of a polarity to forward-bias said base-emitter junction; a first adjustable-resistance element; a second diode serially connected with said adjustable-resistance element between the first and second ends of said first diode for parallel forward conduction with said base-emitter junction and said first diode, for all values of said input current of said polarity to forward bias said base-emitter junction, the adjustment of said adjustable-resistance element being over a range of resistance values to affect the flow of current through itself and said second diode to alter said substantially constant proportion.

Claim 20

A composite current mirror amplifier with current gain which can be trimmed, comprising in combination: an input terminal for said composite current mirror amplifier; an output terminal for said composite current mirror amplifier; a common terminal for said composite current mirror amplifier; a fixed gain current mirror amplifier having an input terminal connected to said input terminal for said composite current mirror amplifier, a common terminal connected to said common terminal for said composite current mirror amplifier, and an output terminal connected to said output terminal for said composite current mirror amplifier; and an adjustable gain current amplifier having an input terminal connected to said input terminal for said composite current mirror amplifier, a common terminal connected to said common terminal for said composite current mirror amplifier, and an output terminal connected to said output terminal for said composite current mirror amplifier.

Claim 21

A composite current mirror amplifier with current gain which can be trimmed, comprising in combination: an input terminal for said composite current mirror amplifier; an output terminal for said composite current mirror amplifier; a common terminal for said composite current mirror amplifier; a fixed gain current mirror amplifier having an input terminal connected to said input terminal for said composite current mirror amplifier, a common terminal connected to said common terminal for said composite current mirror amplifier, and an output terminal connected to said output terminal for said composite current mirror amplifier; and an adjustable gain current amplifier having an input terminal connected to said input terminal for said composite current mirror amplifier, a common terminal connected to said common terminal for said composite current mirror amplifier, and an output terminal connected to said output terminal for said composite current mirror amplifier.