Replica transistor voltage regulator
First Claim
1. A voltage regulator comprising:
- an operational amplifier (OPAMP) having a non-inverting input coupled to a reference voltage (Vref);
an output source follower coupled to and controlled by an output of the OPAMP, the output source follower including a drain coupled to a voltage source and a source coupled to an output-node of the voltage regulator;
a replica source follower coupled to and controlled by the output of the OPAMP in parallel with the output source follower, the replica source follower including a drain coupled to the voltage source and a source coupled to a circuit ground through a resistor network; and
a feedback circuit extending from the output-node through a feedback resistor to the source of the replica source follower and through at least a first resistor of the resistor network to an inverting input of the OPAMP to couple a feedback voltage (Vfbk) thereto to regulate a voltage (Vout) at the output-node in response to a comparison between Vfbk and Vref.
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Accused Products
Abstract
A voltage regulator is provided having high accuracy, low PSRR, and no headroom limitation. Generally, the regulator includes: an operational amplifier (OPAMP) having a non-inverting input coupled to a reference voltage; an output source follower coupled to and controlled by an output of the OPAMP, the output source follower including a drain coupled to a voltage source and a source coupled to an output-node of the regulator; a replica source follower coupled to and controlled by the OPAMP, the replica source follower including a drain coupled to the voltage source and a source coupled to circuit ground through a resistor network; and a feedback circuit extending from the output-node through a feedback resistor to the source of the replica source follower and through at least a first resistor of the resistor network to an inverting input of the OPAMP to couple a feedback voltage thereto. Other embodiments are also provided.
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Citations
19 Claims
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1. A voltage regulator comprising:
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an operational amplifier (OPAMP) having a non-inverting input coupled to a reference voltage (Vref); an output source follower coupled to and controlled by an output of the OPAMP, the output source follower including a drain coupled to a voltage source and a source coupled to an output-node of the voltage regulator; a replica source follower coupled to and controlled by the output of the OPAMP in parallel with the output source follower, the replica source follower including a drain coupled to the voltage source and a source coupled to a circuit ground through a resistor network; and a feedback circuit extending from the output-node through a feedback resistor to the source of the replica source follower and through at least a first resistor of the resistor network to an inverting input of the OPAMP to couple a feedback voltage (Vfbk) thereto to regulate a voltage (Vout) at the output-node in response to a comparison between Vfbk and Vref. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A voltage regulator comprising:
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an operational amplifier (OPAMP) having a non-inverting input coupled to a predetermined reference voltage (Vref); an output source follower coupled to and controlled by an output of the OPAMP, the output source follower including a drain coupled to a voltage source and a source coupled to an output-node of the voltage regulator; a replica source follower coupled to and controlled by the output of the OPAMP in parallel with the output source follower, the replica source follower including a drain coupled to the voltage source and a source coupled to a circuit ground through a resistor network; and a feedback circuit extending from the output-node through a feedback transistor to the source of the replica source follower and through at least a first resistor of the resistor network to an inverting input of the OPAMP to couple a feedback voltage (Vfbk) thereto to regulate a voltage (Vout) at the output-node in response to a comparison between Vfbk and Vref. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17)
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18. A method for operating a voltage regulator comprising:
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coupling a reference voltage (Vref) to a non-inverting input of an operational amplifier (OPAMP); controlling with a voltage (Vgate) from an output of the OPAMP an output source follower coupled thereto, the output source follower including a drain coupled to a voltage source and a source coupled to an output-node of the voltage regulator; controlling with Vgate a replica source follower coupled to the output of the OPAMP in parallel with the output source follower, the replica source follower including a drain coupled to the voltage source and a source coupled to a circuit ground through a resistor network; and coupling a feedback voltage (Vfbk) from the output-node to an inverting input of the OPAMP through a feedback circuit extending through at least a first resistor of the resistor network to regulate a voltage (Vout) at the output-node in response to a comparison between Vfbk and Vref, wherein the feedback circuit comprises a feedback resistor coupled between the output-node and the source of the replica source follower.
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19. A method for operating a voltage regulator comprising:
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coupling a reference voltage (Vref) to a non-inverting input of an operational amplifier (OPAMP); controlling with a voltage (Vgate) from an output of the OPAMP an output source follower coupled thereto, the output source follower including a drain coupled to a voltage source and a source coupled to an output-node of the voltage regulator; controlling with Vgate a replica source follower coupled to the output of the OPAMP in parallel with the output source follower, the replica source follower including a drain coupled to the voltage source and a source coupled to a circuit ground through a resistor network; and coupling a feedback voltage (Vfbk) from the output-node to an inverting input of the OPAMP through a feedback circuit extending through at least a first resistor of the resistor network to regulate a voltage (Vout) at the output-node in response to a comparison between Vfbk and Vref, wherein the feedback circuit comprises a feedback transistor coupled between the output-node and the source of the replica source follower and controlled by a biasing voltage that can be varied to adjust a magnitude of Vfbk.
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Specification