Amplifier circuits

Abstract

A composite transistor device is described which comprises a field effect transistor having its transconductance multiplied by the current gain of a current mirror amplifier. The transconductances of such devices can be matched with an accuracy approaching that with which simple field effect transistors can be matched. The higher transconductances of the composite devices make possible a variety of new circuits with distinct performance advantages.

What is claimed is: 
     
       1. A field effect transistor having source and drain electrodes with a channel therebetween, having a gate electrode, and having in combination therewith: means for multiplying the transconductance of said field effect transistor by a constant predictable factor greater than unity, which means comprises:   a current amplifier having an input circuit and an output circuit and exhibiting a current gain G between its input and output circuits determined by the ratio of the transconductances of a pair of its component bipolar transistors;   a series connection of the channel of said field effect transistor and the input circuit of said current amplifier, whereby the channel current of said field effect transistor flows through the input circuit of said current amplifier, and   means connecting said series connection in parallel with the output circuit of said current amplifier, for summing the current flows through them to obtain an output current greater than the channel current flowing through said field effect transistor by a predictable factor equal to (1+G).   
     
     
       2. An amplifier circuit comprising: a current mirror amplifier having an input terminal, an output terminal, a common terminal, first and second bipolar transistors of the same conductivity type, having respective emitter electrodes each connected to said common terminal, having respective collector electrodes respectively connected to said input terminal and to said output terminal, and having respective base electrodes connected to operate at the same potential, and a feedback connection between the collector and base electrodes of said first transistor, said current mirror amplifier exhibiting constant current gains between both its input and output terminals and its input and common terminals;   a field effect transistor having a conduction channel connected between the input and output terminals of said current mirror amplifier and having a gate electrode;   an input circuit for said amplifier circuit comprising the circuit between the gate electrode of said field effect transistor and one of the common and output terminals of said current mirror amplifier; and   an output circuit for said amplifier circuit comprising the circuit between the common and output terminals of said current mirror amplifier.   
     
     
       3. An amplifier circuit as set forth in claim 2 wherein said field effect transistor is of the same conductivity type as said first and second bipolar transistors, said field effect transistor has source and drain electrodes connected respectively to the input terminal and to the output terminal of said current mirror amplifier between which electrodes its conductive channel resides, and the input circuit for said amplifier circuit comprises the circuit between the gate electrode of said field effect transistor and the common terminal of said current mirror amplifier. 
     
     
       4. An amplifier circuit as set forth in claim 2 wherein said field effect transistor is of the opposite conductivity type as first and said second bipolar transistors, said field effect transistor has source and drain electrodes connected respectively to the output terminal and to the input terminal of said current mirror amplifier between which electrodes its conductive channel resides, and the input circuit for said amplifier circuit comprises the circuit between the gate electrode of said field effect transistor and the output terminal of said current mirror amplifier. 
     
     
       5. An amplifier circuit as set forth in claim 2 having in combination therewith: a source of bias current connected between the output and common terminals of said current mirror amplifier; and   a direct-coupled feedback connection between said one of said common and output terminals of said current mirror amplifier and the gate electrode of said field effect transistor, whereby a potential is provided between the output and common terminals of said current mirror amplifier responsive to said bias current.   
     
     
       6. An inverting amplifier comprising: first and second terminals between which an operating potential may be applied;   a third terminal for receiving input signal;   a fourth terminal for delivering output signal;   first and second current mirror amplifiers, each of a type including a respective pair of bipolar mirroring transistors of a first conductivity type and having respective input and common and output terminals, the output terminal of said first current mirror amplifier being connected to said first terminal, the common terminal of said first current mirror amplifier and the output terminal of said second current mirror amplifier being connected to said fourth terminal, and the common terminal of said second current mirror amplifier being connected to said second terminal;   first and second field effect transistors being respectively of said first conductivity type and of a second conductivity type complementary to said first conductivity type, said first and said second field-effect transistors each having a respective gate electrode connected to said third terminal, said first field effect transistor having source and drain electrodes respectively connected to the output terminal and to the input terminal of said first current mirror amplifier, said second field effect transistor having drain and source electrodes connected respectively to the output terminal and to the input terminal of said second current mirror amplifier.   
     
     
       7. An inverting amplifier configuration as set forth in claim 6 additionally comprising: means for supplying first and second current substantially proportionally related to said operating potential;   means for applying said first current to the input terminal of said first current mirror amplifier; and   means for applying said second current to the input terminal of said second current mirror amplifier.   
     
     
       8. A bias potential supply for providing bias potential suitable for biasing a cascode connection of field effect transistors, said supply comprising: first and second terminals;   means for applying a bias current between said first and said second terminals;   first and second field effect transistors each having drain and source electrodes with a channel therebetween and each having a gate electrode;   a current mirror amplifier of a type including a pair of bipolar mirroring transistors of opposite conductivity type to said first field effect transistor, said current mirror amplifier having input and output and common terminal respectively connected to the drain and source and gate electrodes of said first field effect transistor, thereby to form a first two-terminal network with its terminals respectively at the source electrode of said first field effect transistor and at the common terminal of said current mirror amplifier;   a second two-terminal network consisting of said second field effect transistor with gate electrode connected to its drain electrode, the terminals of said second two-terminal network being respectively at the source and at the drain electrodes of said second field effect transistor; and   means serially connecting said first and said second two-terminal networks between said first and said second terminals for conducting said bias current, thereby to develop a bias potential between said first and said second terminals.   
     
     
       9. A bias potential supply as set forth in claim 8 in combination with the following elements to provide an amplifier circuit: third, fourth and fifth terminals for serving respectively as the input, output and common terminals of said amplifier circuit;   third and fourth field effect transistors of the same conductivity type, each having source and drain and gate electrodes, the source and drain electrodes of said third field effect transistor being respectively connected to said fifth terminal and to the source electrode of said fourth field effect transistor, the gate electrode of said third field effect transistor having said third terminal direct coupled thereto, and the drain electrode of said fourth field effect transistor being connected to said fourth terminal;   means for applying the bias potential provided by said bias supply between said fifth terminal and the gate electrode of said fourth field effect transistor in a poling to complete a cascode connection of said third and said fourth field effect transistors.   
     
     
       10. A bias potential supply as set forth in claim 8 in combination with the following elements to provide an amplifier circuit: third, fourth and fifth terminals for serving respectively as the input, output and common terminals of said amplifier circuit;   third, fourth, fifth and sixth field effect transistors of the same conductivity type, each having source and drain and gate electrodes, the source electrodes of said third and said fourth field effect transistors being connected to said fifth terminal, the drain electrodes of said third and said fourth field effect transistors being respectively connected to the source electrode of said fifth field effect transistor and to the source electrode of said sixth field effect transistor, the drain electrodes of said fifth and said sixth field effect transistors respectively connected to said third terminal and to said fourth terminal, the gate electrodes of said third and said fourth field effect transistors having said third terminal direct coupled thereto; and   means for applying the bias potential provided by said bias supply between said fifth terminal and an interconnection between the gate electrodes of said third and said fifth field effect transistors in a poling to implement the cascode operation of said third and said fifth field effect transistors and to implement the cascode operation of said fourth and said sixth field effect transistors.   
     
     
       11. An amplifier circuit comprising: first, second and third terminals for serving respectively as input, output and common terminals of said amplifier circuit;   first, second, third and fourth field effect transistors of a first conductivity type, each of said field effect transistors having source and drain and gate electrodes, said first terminal being connected to the gate electrodes of each of said field effect transistors, the source electrodes of said first and said second field effect transistors being connected to said third terminal, the drain electrodes of said first and said second field effect transistors being respectively connected to the source electrode of said third field effect transistor and to the source electrode of said fourth field effect transistor; and   first and second current mirror amplifiers, each of a type including a respective pair of bipolar mirroring transistors of a second conductivity type complementary to said first conductivity type and having respective input and output and common terminals, the input and output terminals of said first current mirror amplifier being connected to the drain and source electrodes respectively of said third field effect transistor, the input and output terminals of said second current mirror amplifier being connected to the drain and source electrodes respectively of said fourth field effect transistor, and the common terminals of said first and said second current mirror amplifiers being respectively connected to said first terminal and to said second terminal.   
     
     
       12. An amplifier circuit comprising: first, second and third terminals for serving respectively as input, output and common terminals of said amplifier circuit;   first, second, third and fourth field effect transistors of a first conductivity type, each of said field effect transistors having source and drain and gate electrodes, said first terminal being connected to the gate electrodes of said third and said fourth field effect transistors, the source electrodes of said first and said second field effect transistors being connected to said third terminal, the drain electrodes of said first and said second field effect transistors being respectively connected to the source electrode of said third field effect transistor and to the source electrode of said fourth field effect transistor; and   first and second current mirror amplifiers, each of a type including a respective pair of bipolar mirroring transistors of a second conductivity type complementary to said first conductivity type and having respective input and output and common terminals, the input and output terminals of said first current mirror amplifier being connected to the drain and source electrodes respectively of said third field effect transistor, the input and output terminals of said second current mirror amplifier being connected to the drain and source electrodes respectively of said fourth field effect transistor, the common terminals of said first and said second current mirror amplifiers being respectively connected to said first terminal and to said second terminal, and the input terminal of said first current mirror amplifier being direct coupled to an interconnection between the gate electrodes of said first and said second field effect transistors.   
     
     
       13. An amplifier circuit comprising: first, second and third terminals for serving respectively as input, output and common terminals of said amplifier circuit;   first, second, third and fourth field effect transistors of a first conductivity type, each of said field effect transistors having source and drain and gate electrodes, the source electrodes of said first and said second field effect transistors being connected to said third terminal, the drain electrodes of said first and said second field effect transistors being respectively connected to the source electrode of said third field effect transistor and to the source electrode of said fourth field effect transistor; and   first and second current mirror amplifiers, each of a type including a respective pair of bipolar mirroring transistors of a second conductivity type complementary to said first conductivity type and having respective input and output and common terminals, the input and output terminals of said first current mirror amplifier being connected to the drain and source electrodes respectively of said third field effect transistor, the input and output terminals of said second current mirror amplifier being connected to the drain and source electrodes respectively of said fourth field effect transistor, the common terminals of said first and said second current mirror amplifiers being respectively connected to said first terminal and to said second terminal, and the input terminal of said first current mirror amplifier being direct coupled to an interconnection between the gate electrodes of said first and said second field effect transistors and being direct coupled to an interconnection between the gate electrodes of said third and said fourth field effect transistors.   
     
     
       14. An amplifier circuit comprising: first, second and third terminals for serving as the input, output and common terminals respectively of said amplifier circuit,   first and second field effect transistors of a first conductivity type, each having source and drain and gate electrodes, their respective source electrodes being connected to said third terminal;   first and second current mirror amplifiers, each of a type including a respective pair of bipolar mirroring transistors of a second conductivity type complementary to said first conductivity type, said first current mirror amplifier having input and output terminals connected to the drain and source electrodes respectively of said first field effect transistor, said second current mirror amplifier having input and output terminals connected to the drain and source electrodes respectively of said second field effect transistor, said first and said second current mirror amplifiers having respective common terminals respectively connected to said first terminal and to said second terminal; and   means for direct coupling said first terminal to an interconnection between the gate electrodes of said first and second field effect transistors.   
     
     
       15. An amplifier circuit as set forth in claim 14 wherein said means for direct coupling said first terminal to an interconnection consists of a connection between said input terminal and said interconnection. 
     
     
       16. An amplifier as set forth in claim 14 wherein said means for direct coupling said first terminal to an interconnection comprises a connection of the input terminal of said first current mirror amplifier to said interconnection. 
     
     
       17. An amplifier circuit comprising: a current mirror amplifier having input and output and common terminals, said current mirror amplifier having an output circuit between its output and common terminals for connection to subsequent circuitry and exhibiting constant current gains between both its input and output terminals and its input and common terminals, and   a field-effect transistor of similar conductivity type to said current mirror amplifier, having a gate electrode for connection to preceding circuitry and having a channel with source and drain electrodes at opposite ends thereof respectively connected to the input and output terminals of said current mirror amplifier.   
     
     
       18. An amplifier circuit comprising: a current mirror amplifier having input and output and common terminals, said current mirror amplifier having an output circuit between its output and common terminals for connection to subsequent circuitry and exhibiting constant current gains between both its input and output terminals and its input and common terminals, and   a field effect transistor of complementary conductivity type to said current mirror amplifier having a gate electrode for connection to preceding circuitry and having a channel with drain and source electrodes at opposite ends thereof respectively connected to the input and output terminals of said current mirror amplifier. .Iadd. 19. A current amplifier comprising:   input, output, and common terminals;   first and second transistors of a first conductivity type, each having respective output and common electrodes defining the ends of its principal current conduction path and having a respective input electrode, their common electrodes being connected to said common terminal, their input electrodes having an interconnection therebetween, the output electrodes of said first and second transistors connecting respectively to a first circuit node and to a second circuit node, and their conduction characteristics being proportionally related so their output electrodes are conditioned to conduct proportionally related currents owing to the foreclaimed connections of their common and input electrodes applying substantially equal potentials between the common and input electrodes of each of them;   means for applying current received at said input terminal to said first circuit node;   means, connecting to said first circuit node and to said interconnection between the input electrodes of said first and second transistors, for completing a direct-coupled output-electrode to input-electrode feedback connection for said first transistor;   third and fourth transistors of a second conductivity type complementary to said first conductivity type, each having respective output and common electrodes defining the ends of its principal current conduction path and having a respective input electrode, their common electrodes being connected to said output terminal, their input electrodes having an interconnection therebetween, and their conduction characteristics being proportionally related so their output electrodes are conditioned to conduct proportionately related currents owing to the foreclaimed connections of their common and input electrodes applying substantially equal potentials between the common and input electrodes of each of them, the output electrodes of said third and fourth transistors connecting respectively to said second circuit node and to said common terminal; and   means, connecting to said second circuit node and to said interconnection between the input electrodes of said third and fourth transistors, for completing a direct-coupled output-electrode to input-electrode feedback connection for said third transistor, said foreclaimed connections of said first, second, third, and fourth transistors facilitating the current gain of said current amplifier being a predetermined value independent of the variations of the individual conduction characteristics of those transistors. .Iaddend..Iadd. 20. A current amplifier as set forth in claim 19 wherein said means for applying current received at said input terminal to said first circuit node comprises:   fifth and sixth transistors similar to said third and fourth transistors respectively, the common electrodes of said fifth and sixth transistors being connected to said input terminal, their input electrodes having an interconnection therebetween, and their output electrodes connecting respectively to said first circuit node and to said common terminal; and   means, connecting to said first circuit node and to said interconnection between the input electrodes of said fifth and sixth transistors, for completing a direct-coupled output-electrode to input-electrode feedback connection for said fifth transistor. .Iaddend. .Iadd. 21. A current amplifier as set forth in claim 19 wherein said first, second, third, and fourth transistors are disposed on an integrated circuit substrate. .Iaddend..Iadd. 22. A current amplifier as set forth in claim 21 wherein said means for applying current received at said input terminal to said first circuit node comprises:   fifth and sixth transistors similar to said third and fourth transistors respectively, the common electrodes of said fifth and sixth transistors being connected to said input terminal, their input electrodes having an interconnection therebetween, and their output electrodes connecting respectively to said first circuit node and to said common terminal; and   means, connecting to said first circuit node and to said interconnection between the input electrodes of said fifth and sixth transistors, for completing a direct-coupled output-electrode to input-electrode feedback connection for said fifth transistor. .Iaddend..Iadd. 23. A current amplifier as set forth in claim 21 wherein said first and second transistors are field effect transistors; and wherein said third and fourth transistors are bipolar transistors. .Iaddend. .Iadd. 24. A current amplifier as set forth in claim 23 wherein said means for applying current received at said input terminal to said first circuit node comprises:   fifth and sixth transistors similar to said third and fourth transistors respectively, the common electrodes of said fifth and sixth transistors being connected to said input terminal, their input electrodes having an interconnection therebetween, and their output electrodes connecting respectively to said first circuit node and to said common terminal; and   means, connecting to said first circuit node and to said interconnection between the input electrodes of said fifth and sixth transistors, for completing a direct-coupled output-electrode to input-electrode feedback connection for said fifth transistor. .Iaddend. .Iadd. 25. A current mirror amplifier comprising:   input, output, and common terminals;   first and second transistors of a first conductivity type and third and fourth transistors of a second conductivity type complementary to said first conductivity type disposed on an integrated circuit substrate, said first and second transistors having conduction characteristics proportionally related to each other, having respective output electrodes respectively connected to a first circuit node and to a second circuit node, having respective input electrodes with an interconnection therebetween, and having respective common electrodes connected to said common terminal, whereby the common-electrode to input-electrode potentials of said first and second transistors are essentially the same as each other;   said third and fourth transistors having conduction characteristics proportionally related to each other, having at least one output electrode between them each of which output electrodes connects to said common terminal, having respective common electrodes respectively connected to said input terminal and to said output terminal, and having respective input electrodes to which potentials at said first circuit node and at said second circuit node are respectively applied;   means, connected at said first circuit node and at said interconnection between the input electrodes of said first and second transistors, for completing a direct-coupled output-electrode to input-electrode feedback connection of said first transistor; and   first and second conductive means, exhibiting proportionally related conduction characteristics, the first conductive means connected between said first circuit node and said input terminal, and the second conductive means connected between said second circuit node and said output terminal. .Iaddend. .Iadd. 26. A current mirror amplifier as set forth in claim 25, wherein said first and second conductive means comprise fifth and sixth transistors of said second conductivity type also disposed on said integrated circuit substrate, having respective input electrodes to which the potentials at said first and second circuit nodes are respectively applied, having respective output electrodes connected to said first circuit node and to said second circuit node, and having respective common electrodes respectively connected to said input terminal and to said output terminal. .Iaddend. .Iadd. 27. A current mirror amplifier as set forth in claim 26 wherein said first and second transistors are of field-effect transistor type and said third, fourth, fifth and sixth transistors are of bipolar transistor type. .Iaddend. .Iadd. 28. A current mirror amplifier as set forth in claim 25 wherein said first and second transistors are of field-effect transistor type and said third and fourth transistors are of bipolar transistor type. .Iaddend. .Iadd. 29. A composite current mirror amplifier comprising:   input, output, and common terminals; and   first and second component current mirror amplifiers of complementary conductivity types, said first component current mirror amplifier having an input connection to which said input terminal is connected, having a common connection to said common terminal and having an output connection--and said second component current mirror amplifier having an input connection to which the output connection of said first component current mirror amplifier is connected, having an output connection to said common terminal and having a common connection to said output terminal. .Iaddend. .Iadd. 30. A composite current mirror amplifier comprising:   input, output, and common terminals; and   first, second, and third component current mirror amplifiers, the latter two of a conductivity type complementary to that of the first, said first component current mirror amplifier having input and output connections and having a common connection to said common terminal, said second component current mirror amplifier having an input connection to the input connection of said first component current mirror amplifier, having an output connection to said common terminal, and having a common connection to said input terminal, and said third component current mirror amplifier having an input connection to which the output connection of said first component current mirror amplifier is connected, having an output connection to said common terminal, and having a common connection to said output terminal. .Iaddend.