Integrated circuit current regulator with differential amplifier control

Claim 2

A current regulator circuit for maintaining constant output current from a power supply to an output terminal, including in combination, impedance means and a current control device connected in series between the power supply and the output terminal, said current control device including a pair of transistors connected in a Darlington circuit with a control Terminal connected to the base electrode of one of the transistors; first and second transistors of the same conductivity type forming a differential amplifier, each transistor having control, common and output electrode means; first current source means coupling said common electrode means of each of said first and second transistors to the power supply; reference means coupled to said control electrode means of said first transistor to provide a substantially fixed bias therefor; means coupling said control electrode means of said second transistor to the junction between said impedance means and said control device; means coupling said output electrode means of said second transistor to ground potential; second current source means connected between said output electrode means of said first transistor and ground potential, said second current source means constructed to conduct current of a value one-half that of the current provided by said first current source means; means coupling said output electrode means of said first transistor to said control terminal to thereby control the current supplied by said current control device to the output terminal; and a frequency compensation capacitor coupled between said control electrode means of said second transistor and said output electrode means of said first transistor to maintain frequency stability.

Claim 3

A current regulator circuit provided on an integrated circuit chip for maintaining constant output current over a wide range of temperatures and currents, and which has a control terminal adapted to be connected to impedance means connected to a direct current power supply for supplying current therefrom, such regulator circuit including in combination: first and second power supply terminals for connection to the direct current power supply; a differential amplifier having first and second transistors of the PNP type, each of said transistors having control, common and output electrode means; means including first current source means coupling said common electrode means of said first and second transistors to said first power supply terminal; reference means coupled to said control electrode means of said first transistor for providing a reference potential thereto; means coupling said control electrode means of said second transistor to the control terminal; current control means coupling an output terminal means to the control terminal; means including second current source means coupling said output electrode means of said first transistor to said second power supply terminal, said second current source means constructed to conduct current of a value one-half that of the current provided by said first current source means; and means coupling said output electrode means of said first transistor to said current control means, said current control means controlling the current supplied to said output terminal means in accordance with the current supplied thereto from said first transistor.

Claim 4

A current regulator circuit provided on an integrated circuit chip for maintaining constant output current over a wide range of temperatures and currents, and which has a control terminal adapted to be connected to impedance means connected to a direct current power supply for supplying current therefrom, such regulator circuit including in combination: first and second power supply terminals for connection to the direct current power supply; a differential amplifier having first and second transistors of the PNP type, each of said transistors having control, common and output electrode means; means including first current source means coupling said common electrode means of said first and second transistors to said first power supply terminal; reference means coupled to said control electrode means of said first transistor for providing a reference potential thereto; means coupling said control electrode means of said second transistor to the control terminal; current control means coupling an output terminal means to the control terminal; means including second current source means coupling said output electrode means of said first transistor to said second power supply terminal, said second current source means constructed to conduct current of a value one-half that of the current provided by said first current source means; and means coupling said output electrode means of said first transistor to said current control means, said current control means controlling the current supplied to said output terminal means in accordance with the current supplied thereto from said first transistor.

Claim 5

A current regulator circuit in accordance with claim 2 including capacitor means external to the integrated circuit chip coupled between the control terminal and said output electrode means of said first transistor to maintain frequency stability.

Claim 6

A current regulator circuit according to claim 2 wherein said current control means includes a pair of transistors connected as a Darlington pair.

Claim 7

A current regulator circuit according to claim 2 wherein said differential amplifier includes a third transistor coupling said reference means to said control electrode means of said first transistor, and a fourth transistor coupling the control terminal to said control electrode means of said second transistor.

Claim 8

A current regulator circuit for maintaining constant output current from a power supply to first and second output terminals, including in combination, impedance means connected to the power supply; first and second current control devices connected respectively between said impedance means and said first and second output terminals; first and second transistors of the same conductivity type forming a differential amplifier, each transistor having control, common and output electrode means, said output electrode means of said first transistor including first and second output electrodes; means coupling said common electrode means of each of said first and second transistors to the power supply; reference means coupled to said control electrode means of said first transistor to provide a substantially fixed bias therefor; means coupling said control electrode means of said second transistor to the junction between said impedance means and said control devices; means coupling said output electrode means of said second transistor to ground potential; and means coupling said first and second output electrodes of said first transistor to said first and second current control devices, respectively, to thereby control the current supplied to the first and second output terminals.

Claim 9

A current regulator circuit for maintaining constant output current from a power supply to first and second output terminals, including in combination, impedance means connected to the power supply; first and second current control devices connected respectively between said impedance means and said first and second output terminals; first and second transistors of the same conductivity type forming a differential amplifier, each transistor having control, common and output electrode means, said output electrode means of said first transistor including first and second output electrodes; means coupling said common electrode means of each of said first and second transistors to the power supply; reference means coupled to said control electrode means of said first transistor to provide a substantially fixed bias therefor; means coupling said control electrode means of said second transistor to the junction between said impedance means and said control devices; means coupling said output electrode means of said second transistor to ground potential; and means coupling said first and second output electrodes of said first transistor to said first and second current control devices, respectively, to thereby control the current supplied to the first and second output terminals.

Claim 10

A current regulator circuit in accordance with claim 6 further including first and second switch means, said first switch means being coupled between first output electrode and ground potential, and said second switch means being coupled between said second output electrode and ground potential.

Claim 11

A current regulator circuit provided on an integrated circuit chip for maintaining constant output current over a wide range of temperatures and currents, and which has a control terminal adapted to be connected to impedance means connected to a direct current power supply for supplying current therefrom, such regulator circuit including in combination: first and second power supply terminals for connection to the direct current power supply; a differential amplifier having first and second transistors of the PNP type, each of said transistors having control, common and first and second output electrodes; means including first current source means coupling said common electrode means of said first and second transistors to said first power supply terminal; reference means coupled to said control electrode means of said first transistor for providing a reference potential thereto; means coupling said control electrode means of said second transistor to the control terminal; first and second control circuits coupled between said first and second output electrodes and first and second output terminals, respectively, said control circuits coupling said first and second output terminals with the control terminal; means including second and third current source means coupling said first and second output electrodes, respectively, of said first transistor to said second power supply terminal; first and second switch means coupled between said respective first and second output electrodes of said first transistor and said second power supply terminal; and means coupling said first and second output electrodes of said first transistor to said first and second current control means, respectively, said first and second current control means controlling the current supplied to said output terminals in accordance with the current supplied thereto from said first transistor.

Claim 12

A current regulator circuit provided on an integrated circuit chip for maintaining constant output current over a wide range of temperatures and currents, and which has a control terminal adapted to be connected to impedance means connected to a direct current power supply for supplying current therefrom, such regulator circuit including in combination: first and second power supply terminals for connection to the direct current power supply; a differential amplifier having first and second transistors of the PNP type, each of said transistors having control, common and first and second output electrodes; means including first current source means coupling said common electrode means of said first and second transistors to said first power supply terminal; reference means coupled to said control electrode means of said first transistor for providing a reference potential thereto; means coupling said control electrode means of said second transistor to the control terminal; first and second control circuits coupled between said first and second output electrodes and first and second output terminals, respectively, said control circuits coupling said first and second output terminals with the control terminal; means including second and third current source means coupling said first and second output electrodes, respectively, of said first transistor to said second power supply terminal; first and second switch means coupled between said respective first and second output electrodes of said first transistor and said second power supply terminal; and means coupling said first and second output electrodes of said first transistor to said first and second current control means, respectively, said first and second current control means controlling the current supplied to said output terminals in accordance with the current supplied thereto from said first transistor.

Claim 13

A current regulator circuit according to claim 8 wherein each of said control circuits includes a pair of transistors connected as a Darlington pair.

Claim 14

A current regulator circuit according to claim 8 wherein each of said switch means includes a transistor connected to shunt the current from one of said output electrodes of said first transistor to said second power supply terminal.