Audio amplifiers
First Claim
1. An amplifier comprising:
- an integrator comprising at least three integrator stages coupled in series; and
control circuitry coupled to the integrator and configured to maintain a mode of a first or a last integrator stage of the at least three integrator stages and to modify a mode of at least one intermediate integrator stage of the at least three integrator stages while maintaining the mode of the first or the last integrator stage, wherein the control circuitry is configured to modify the mode of the at least one intermediate integrator stage by discharging a capacitive element in a feedback network of the at least one intermediate integrator stage.
1 Assignment
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Accused Products
Abstract
Certain aspects of the present disclosure provide amplifiers. Certain aspects of the present disclosure provide methods and apparatus for protecting an such amplifiers, for example an audio amplifier, or a delta-sigma modulator from saturation. One example amplifier generally includes an output stage comprising a plurality of transistors; and a feedback network having an input coupled to an output of the output stage and comprising a plurality of integrators connected in series. At least one of the plurality of integrators generally includes an operational amplifier having an input and an output, a first resistive element coupled to the input of the operational amplifier, a capacitive element coupled between the input and the output of the operational amplifier; and a first switch coupled between the input and the output of the operational amplifier. For certain aspects, the amplifier may be a class-D amplifier or a direct digital feedback amplifier (DDFA).
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Citations
27 Claims
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1. An amplifier comprising:
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an integrator comprising at least three integrator stages coupled in series; and control circuitry coupled to the integrator and configured to maintain a mode of a first or a last integrator stage of the at least three integrator stages and to modify a mode of at least one intermediate integrator stage of the at least three integrator stages while maintaining the mode of the first or the last integrator stage, wherein the control circuitry is configured to modify the mode of the at least one intermediate integrator stage by discharging a capacitive element in a feedback network of the at least one intermediate integrator stage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A method of operating an amplifier comprising a plurality of integrators and an analog-to-digital converter (ADC), comprising:
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generating an amplified signal in the amplifier based on an input signal; and resetting at least one of the integrators based on a variation in at least one of the input signal, an output of the ADC, or one or more outputs of the integrators, wherein the resetting comprises closing a switch connected in parallel with a capacitive element of the at least one of the integrators to discharge the capacitive element. - View Dependent Claims (10, 11, 12, 13, 14, 15)
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16. An amplifier comprising:
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an output stage comprising a plurality of transistors; and a feedback network having an input coupled to an output of the output stage and comprising a plurality of integrators connected in series, wherein at least one of the plurality of integrators comprises; an operational amplifier having an input and an output; a first resistive element coupled to the input of the operational amplifier; a first capacitive element coupled between the input and the output of the operational amplifier; and a first switch coupled between the input and the output of the operational amplifier, wherein a first terminal of the first switch is coupled to the input of the operational amplifier, and a second terminal of the first switch is coupled to the output of the operational amplifier. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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Specification