TMR/GMR amplifier with input current compensation
First Claim
1. An amplifier system with feedback current cancellation, comprising:
- an amplifier that includes an input, an output, and at least one stage;
a feedback network that includes a first resistance having a first end that communicates with the input of the amplifier and an opposite end that communicates with the output of the amplifier;
first and second replica circuits that approximately replicate DC characteristics of the output and the input of the amplifier, respectively;
a buffer that includes an input that communicates with the first replica circuit and an output;
a second resistance that includes a first end that communicates with the output of the buffer and an opposite end;
a third resistance that includes a first end that communicates with the opposite end of the second resistance and an opposite end that communicates with the second replica circuit;
an operational amplifier (op-amp) that includes a first input that communicates with the first end of the third resistance, a second input that communicates with the opposite end of the third resistance, and an output;
a transistor that includes a control terminal that communicates with the output of the op-amp and a first terminal that communicates with the opposite end of the second resistance; and
a first current mirror that provides a first current at the input of the amplifier that is proportional to a second current flowing through the transistor.
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Accused Products
Abstract
An amplifier system with feedback current cancellation comprises an amplifier with at least one stage, a feedback network, first and second replica circuits, a buffer, second and third resistances, an operational amplifier (op-amp), a transistor, and a current mirror. The feedback network includes a first resistance that communicates with an input and an output of the amplifier. The first and second replica circuits approximately replicate DC characteristics of the output and the input of the amplifier, respectively. An output of the op-amp communicates with a control terminal of the transistor. The current mirror provides a current at the input of the amplifier that is proportional to a second current flowing through the transistor. The buffer communicates with the first replica circuit. The second resistance communicates with an output of the buffer. The third resistance communicates with the second resistance and with the second replica circuit.
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Citations
12 Claims
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1. An amplifier system with feedback current cancellation, comprising:
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an amplifier that includes an input, an output, and at least one stage; a feedback network that includes a first resistance having a first end that communicates with the input of the amplifier and an opposite end that communicates with the output of the amplifier; first and second replica circuits that approximately replicate DC characteristics of the output and the input of the amplifier, respectively; a buffer that includes an input that communicates with the first replica circuit and an output; a second resistance that includes a first end that communicates with the output of the buffer and an opposite end; a third resistance that includes a first end that communicates with the opposite end of the second resistance and an opposite end that communicates with the second replica circuit; an operational amplifier (op-amp) that includes a first input that communicates with the first end of the third resistance, a second input that communicates with the opposite end of the third resistance, and an output; a transistor that includes a control terminal that communicates with the output of the op-amp and a first terminal that communicates with the opposite end of the second resistance; and a first current mirror that provides a first current at the input of the amplifier that is proportional to a second current flowing through the transistor. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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Specification