Apparatus and method for removing offset in a gain circuit
First Claim
1. An offset-removing gain circuit comprising:
- a first circuit having a first transfer function to provide a gain of the circuit; and
a second circuit having a second transfer function, coupled to the first circuit, to provide an integrator output to be fed back to the first circuit;
the first and second circuits being arranged and configured to be capable of producing a plurality of different gains while allowing a frequency response of the circuit to remain unaffected.
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Accused Products
Abstract
An offset-removing gain circuit where the detected offset is independent of the gain of the circuit. The gain circuit includes a differential amplifier transfer circuit with an input and a output, an integrator connected to the output of the differential amplifier transfer circuit through a first impedance, and a second impedance connecting an output of the integrator to the input of the differential amplifier. The impedances may include resistors, capacitors or combinations thereof. The circuit may further include a switched capacitor circuit, where a plurality of capacitors are connected between input and output terminals using switches, whereby the capacitance of the switched capacitor circuit is altered by the switches to remove offset at the integrator output without changing the frequency response thereof.
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Citations
19 Claims
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1. An offset-removing gain circuit comprising:
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a first circuit having a first transfer function to provide a gain of the circuit; and a second circuit having a second transfer function, coupled to the first circuit, to provide an integrator output to be fed back to the first circuit; the first and second circuits being arranged and configured to be capable of producing a plurality of different gains while allowing a frequency response of the circuit to remain unaffected. - View Dependent Claims (2, 3, 4, 5, 6, 7, 17)
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8. A CMOS transceiver on a single device, including:
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conditioning circuitry conditioning a received signal; an offset-removing gain circuit comprising; a first circuit having a first transfer function to provide a gain of the circuit; a second circuit having a second transfer function, coupled to the first circuit, to provide an integrator output to be fed back to the first circuit; the first and second circuits being arranged and configured to be capable of producing a plurality of different gains while allowing a frequency response of the circuit to remain unaffected; and processing circuitry processing an output signal from the offset-removing gain circuit for receipt outside the device. - View Dependent Claims (9, 10, 11, 12, 18, 19)
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13. A method of removing offset from a signal while amplifying, the method comprising:
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feeding an input signal into a differential amplifier via a first impedance device having a first impedance; feeding an output of the differential amplifier through a feedback path including a second impedance device having a second impedance; feeding the output signal from the differential amplifier though a third impedance device having a third impedance into an integrator; feeding an inverted integrated signal from the integrator through a fourth impedance device having a fourth impedance into the differential amplifier; and changing the first impedance of the first impedance device to change a gain of the differential amplifier while selecting the third and fourth impedances of the third and fourth impedance devices to remove an offset at the integrator output and allow the frequency response of the circuit to remain unaffected. - View Dependent Claims (14, 15, 16)
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Specification