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US 9,401,679 B1Granted
Apparatus and method for improving power supply rejection ratio
AssigneeAnalog Devices Global
InventorSharad Vijaykumar
Life of this patent
Estimating the term…
Abstract
A compensation capacitor can be added to an amplifier for stability. Disclosed are systems and methods for improving the power supply rejection ratio (PSRR) performance of an amplifier in the presence of one or more compensation capacitors.
Claims20
An apparatus comprising:
- a first output transistor of an amplifier, wherein the first output transistor is electrically coupled to an output node;
- an amplifier compensation circuit comprising a compensation capacitor and an isolating transistor, wherein:
- the compensation capacitor has a first end and a second end, wherein the first end is electrically coupled to the output node, wherein the second end is electrically coupled to a first node;
- a source and a drain of the isolating transistor are in a conductive path between the first node and a gate of the first output transistor;
- and
- a biasing transistor in series with the isolating transistor, wherein the biasing transistor is configured to bias the isolating transistor, wherein the biasing transistor is part of a current mirror load of a first stage of the amplifier;
- wherein the isolating transistor is biased by diverting a first current from the first stage of the amplifier and returning the first current to the first stage of the amplifier.
4 more elements
An electrically implemented method of amplifier compensation, the method comprising:
- electrically coupling a first output transistor of an amplifier, to an output node;
- electrically coupling a first end of a compensation capacitor to the output node, and electrically coupling a second end of the compensation capacitor to a first node;
- electrically coupling a source and a drain of an isolating transistor in a conductive path between the first node and a gate of the first output transistor;
- biasing the isolating transistor with a biasing transistor in series with the isolating transistor;
- mirroring a current from a current mirror load of a first stage of the amplifier to the biasing transistor;
- and
- diverting a first current from the first stage of the amplifier and returning the first current to the first stage of the amplifier.
4 more elements
An apparatus comprising:
- means for outputting an output of an amplifier to an output node;
- means for compensation, wherein a first end of the compensation means is configured to be electrically coupled to the output node, and a second end of the compensation means is configured to be electrically coupled to a first node;
- means for isolating the output node, wherein the isolating means is in a conductive path between the first node and a gate terminal of the outputting means;
- means for biasing the isolating means, wherein the biasing means is in series with the isolating means;
- means for mirroring a first current to the biasing means;
- and
- means for diverting the first current from a first stage of the amplifier and returning the first current to the first stage of the amplifier.
4 more elements
Dependencies are inferred from the claim text.