AMPLIFIER AND METHOD OF AMPLIFYING A DIFFERENTIAL SIGNAL
First Claim
1. An amplifier, comprising:
- a differential input comprising a positive input and a negative input;
an analog integrator comprising a differential integrator input and a differential integrator output, the analog integrator further comprising an operational amplifier, the operational amplifier comprising a positive operational amplifier input, a negative operational amplifier input, a positive operational amplifier output and a negative operational amplifier output, the differential integrator input being coupled to the differential input;
a ternary pulse width modulator comprising two modulator inputs coupled to the differential integrator output and two modulator outputs;
a first feedback path coupled between a first of the two modulator outputs and the positive operational amplifier input and a second feedback path coupled between a second of the two modulator outputs and the negative operational amplifier input; and
a first divert capacitor coupled between the positive operational amplifier input and a constant voltage reference, and a second divert capacitor coupled between the negative operational amplifier input and the constant voltage reference.
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Accused Products
Abstract
An amplifier includes a differential input with a positive and a negative input and an analog integrator with a differential integrator input and a differential integrator output. The analog integrator further includes an operational amplifier with a positive operational amplifier input, a negative operational amplifier input, a positive operational amplifier output and a negative operational amplifier output. The differential integrator input is coupled to the differential input. A ternary pulse width modulator includes two modulator inputs coupled to the differential integrator output and two modulator outputs. A first feedback path is coupled between a first of the two modulator outputs and the positive operational amplifier input and a second feedback path is coupled between a second of the two modulator outputs and the negative operational amplifier input. A first divert capacitor is coupled between the positive operational amplifier input and a constant voltage reference. A second divert capacitor is coupled between the negative operational amplifier input and the constant voltage reference.
17 Citations
19 Claims
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1. An amplifier, comprising:
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a differential input comprising a positive input and a negative input; an analog integrator comprising a differential integrator input and a differential integrator output, the analog integrator further comprising an operational amplifier, the operational amplifier comprising a positive operational amplifier input, a negative operational amplifier input, a positive operational amplifier output and a negative operational amplifier output, the differential integrator input being coupled to the differential input; a ternary pulse width modulator comprising two modulator inputs coupled to the differential integrator output and two modulator outputs; a first feedback path coupled between a first of the two modulator outputs and the positive operational amplifier input and a second feedback path coupled between a second of the two modulator outputs and the negative operational amplifier input; and a first divert capacitor coupled between the positive operational amplifier input and a constant voltage reference, and a second divert capacitor coupled between the negative operational amplifier input and the constant voltage reference. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A method of amplifying a differential signal, comprising:
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providing a differential input signal to be amplified, the differential input signal comprising two complementary signals; integrating the complementary input signals; modulating the integrated complementary input signals to form a ternary pulse width modulated signal at a differential output; feeding back a signal from a first output of the differential output and feeding back a signal from a second output of the differential output separately; and diverting equal parts of the first feedback signal and the second feedback signal to a constant voltage reference via a first divert capacitor and a second divert capacitor, respectively. - View Dependent Claims (15)
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16. A Class-D amplifier, comprising:
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a loop filter comprising an operational amplifier, the operational amplifier comprising a positive operational amplifier input and a negative operational amplifier input; and a pair of matched divert capacitors coupled between the positive operational amplifier input and the negative operational amplifier input, respectively, and a constant voltage reference, the divert capacitors being configured to protect the operational amplifier from common-mode feedback signals. - View Dependent Claims (17)
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18. A differential amplifier, comprising:
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a first signal input configured to receive an analog input signal; a second signal input configured to receive the inverse analog input signal; an analog integrator coupled to receive the analog input signal and the inverse analog input signal; a first signal output configured to output the analog input signal in a pulse width modulated form; a second signal output configured to output the inverse analog input signal in a pulse width modulated form; a first feedback path coupled to feed the pulse width modulated analog input signal back to the analog integrator as a first feedback signal; a second feedback path coupled to feed the pulse width modulated analog inverse analog input signal back to the analog integrator as a second feedback signal; and a pair of matched divert capacitors, one of the capacitors coupled between the first feedback path and a constant voltage reference to divert part of the first feedback signal, and the other of the capacitors coupled between the second feedback path and the constant voltage reference to divert part of the second feedback signal. - View Dependent Claims (19)
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Specification