Current regulator and method
First Claim
1. A current regulator, comprising:
- a voltage source for providing a reference voltage;
an output stage for providing an output current;
circuit means for providing bias drive to said output stage to control the magnitude of said output current, said circuit means having a first input coupled to said voltage source and a second input at which is produced a voltage that is directly proportional to said reference voltage;
a current source for supplying a reference current to said second input of said circuit means the magnitude of which is a function of said voltage appearing at said second input of said circuit means; and
feedback circuit means responsive to said output stage for providing a feedback signal to said second input of said circuit means that is a function of said magnitude of said output current such that the bias drive to said output stage is varied to regulate said output current to a value that is proportional to said reference current, said feedback circuit means including a current mirror.
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Accused Products
Abstract
An integrated circuit for providing a regulated output current comprises an output transistor for producing the output current, a feedback circuit including a current mirror for sensing the magnitude of the output current and providing a feedback current proportional thereto and a driver circuit for comparing the feedback current to an externally generated current and biasing the output transistor accordingly to regulate the magnitude of the output current to a predetermined value. Preferably, the external current is generated through an external resistor coupled to an input of the driver curcuit and the current mirror wherein the magnitude of the external current is directly proportional to a reference voltage provided on chip and applied to an additional input of the driver circuit the latter of which functions as an operational amplifier.
53 Citations
11 Claims
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1. A current regulator, comprising:
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a voltage source for providing a reference voltage; an output stage for providing an output current; circuit means for providing bias drive to said output stage to control the magnitude of said output current, said circuit means having a first input coupled to said voltage source and a second input at which is produced a voltage that is directly proportional to said reference voltage; a current source for supplying a reference current to said second input of said circuit means the magnitude of which is a function of said voltage appearing at said second input of said circuit means; and feedback circuit means responsive to said output stage for providing a feedback signal to said second input of said circuit means that is a function of said magnitude of said output current such that the bias drive to said output stage is varied to regulate said output current to a value that is proportional to said reference current, said feedback circuit means including a current mirror. - View Dependent Claims (2, 3, 4, 5)
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6. An integrated circuit for providing a regulated output current, comprising:
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an output stage for providing at least a first output current at an output of the circuit; a driver circuit for providing a bias drive signal to said output stage, said driver circuit having first and second inputs and an output, said output being coupled to an input of said output stage; a voltage source coupled to said first input of said driver circuit for providing a reference voltage; and a feedback circuit for sensing the magnitude of said output current and providing a feedback signal at said second input of said driver circuit means. - View Dependent Claims (7, 8, 9, 10)
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11. A method for producing a regulated current comprising the steps of:
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generating a first current; generating a second current the magnitude of which is directly proportional to a reference voltage; sensing the magnitude of said first current and providing a feedback current that is proportional to said magnitude of said first current; and comparing said feedback current to said second current; and varying the magnitude of said first current accordingly until said feedback current equals said second current.
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Specification