Audio frequency power amplifiers with actively damped filter

Claim 2

An amplifier system for generating an output signal that tracks an audio input signal comprising: linear amplification means for amplifying an input signal to obtain an amplified output signal, the linear amplification means having at least one supply terminal; first amplification means for generating a first supply signal and applying the first supply signal to the at least one supply terminal of the linear amplification means, where the first amplification means comprises first control means for generating a first control signal based on the input signal, first switch means for generating a first pulsed power signal based on the first control signal, and first filter means for filtering the first pulsed power signal to obtain the first supply signal, the first filter means comprising a first filter inductor and a first filter capacitor; and first active damping means for damping perturbations in the first filter means, the first active damping means comprising current measuring means for generating a second control signal based on a current through the output capacitor, and means for altering the first control signal based on the second control signal.

Claim 3

The amplifier system as recited in claim 1, further comprising first compensation means for compensating at least in part for the frequency response of the damped first filter means.

Claim 4

The amplifier system as recited in claim 1, in which the linear amplification means comprises first and second supply terminals and the first supply signal is applied to the first supply terminal, the amplifier system further comprising second amplification means for generating a second supply signal and applying the second supply signal to the second supply terminal of the linear amplification means, where the second amplification means comprises second control means for generating a second control signal based on the input signal, second switch means for generating a second pulsed power signal based on the second control signal, and second filter means for filtering the second pulsed power signal to obtain the second supply signal, the second filter means comprising a second filter inductor and a second filter capacitor; and second active damping means for damping perturbations in the second filter means.

Claim 5

The amplifier system as recited in claim 3, further comprising: first compensation means for compensating at least in part for the frequency response of the damped first filter means; and second compensation means for compensating at least in part for the frequency response of the damped second filter means.

Claim 6

The amplifier system as recited in claim 4, further comprising discharge means for discharging the first and second filter capacitors to prevent floating of the first and second supply voltages.

Claim 7

The amplifier system as recited in claim 3, in which the first active damping means damps perturbations in the first filter means based on a current through the first filter capacitor and the second active damping means damps perturbations in the second filter means based on a current through the second filter capacitor.

Claim 8

The amplifier system as recited in claim 1, in which the first active damping means damps perturbations in the first filter means by altering the first control signal.

Claim 9

The amplifier as recited in claim 3, in which the first active damping means damps perturbations in the first filter means by altering the first control signal and the second active damping means damps perturbations in the second filter means by altering the second control signal.

Claim 10

The amplifier system as recited in claim 2 in which the first compensation means compensates for the damped first filter means by altering the first control signal.

Claim 11

The amplifier as recited in claim 4, in which the first compensation means compensates for the damped first filter means by altering the first control signal and the second compensation means compensates for the damped second filter means by altering the second control signal.

Claim 12

The amplifier as recited in claim 1, further comprising a sense resistor arranged in series with the output capacitor, in which the first active damping means damps perturbations based on a voltage across the sense resistor.

Claim 13

The amplifier as recited in claim 1, further comprising a current sense circuit comprising a sampling capacitor and a sense resistor arranged in series with the sampling capacitor, where the sense circuit is arranged in parallel with the output capacitor and the first active damping means damps perturbations based on a voltage across the sense resistor.

Claim 14

The amplifier as recited in claim 12, in which a value of the sampling capacitor is at least three times the value of the output capacitor.

Claim 15

The amplifier as recited in claim 1, further comprising a sense circuit comprising: a sampling capacitor having first and second terminals; an operational amplifier having first and second input terminals and an output terminal, where the second input terminal is connected to the second terminal of the sampling capacitor; and a resistor connected between the second input terminal and the output terminal of the operational amplifier; wherein the sense circuit is connected in parallel across the output capacitor; and the first active damping means damps perturbations based on a voltage across the output terminal and the first input terminal of the operational amplifier.

Claim 16

The amplifier as recited in claim 1, further comprising a sense circuit comprising: a current transformer having input and output windings, in which the input windings are connected in series with the output capacitor; and a sense resistor connected across the output terminals of the current transformer; wherein the first active damping means damps perturbations based on a voltage across the sense resistor.

Claim 17

The amplifier as recited in claim 1, further comprising a hall effect device arranged in series with the output capacitor, in which the first active damping means damps perturbations based on a voltage generated by the hall effect device.

Claim 18

An amplification method comprising the steps of: generating a first control signal based on an input signal the amplitude of which varies over time; operating a switch based on the first control signal to obtain a pulsed power signal; filtering the pulsed power signal with an output filter to obtain an output signal that tracks the input signal; generating a second control signal based on a current through an output capacitor in the output filter; and altering the first control signal based on the second control signal to damp perturbations in the output filter.

Claim 19

An amplification method comprising the steps of: generating a first control signal based on an input signal the amplitude of which varies over time; operating a switch based on the first control signal to obtain a pulsed power signal; filtering the pulsed power signal with an output filter to obtain an output signal that tracks the input signal; generating a second control signal based on a current through an output capacitor in the output filter; and altering the first control signal based on the second control signal to damp perturbations in the output filter.

Claim 20

A method as recited in claim 17, further comprising the step of generating a second control signal based on a current through an output capacitor in the output filter, in which the step of altering the first control signal comprises the step Of altering the first control signal based on the second control signal.

Claim 21

A method as recited in claim 17, further comprising the step of altering the first control signal to compensate at least in part for the frequency response of the damped output filter.

Claim 22

A method as recited in claim 17, in which the step of generating the first control signal comprises the step of summing the input signal with a feedback signal derived from the output signal to obtain a voltage loop error signal, the first control signal being generated based on the voltage loop error signal.

Claim 23

A method as recited in claim 20, in which the step of altering the first control signal based on the second control signal comprises the step of adding the voltage loop error signal to the second control signal to obtain a current damping loop error signal, the first control signal being generated based on the current damping loop error signal.

Claim 24

A method as recited in claim 21, further comprising the step of modulating the current damping loop error signal based on a periodic signal to obtain the first control signal.

Claim 25

A method as recited in claim 22, further comprising the step of altering the voltage loop error signal to compensate at least in part for the frequency response of the damped output filter.

Claim 26

A method as recited in claim 17, further comprising the steps of arranging a sense resistor arranged in series with the output capacitor, in which the first active damping means damps perturbations based on a voltage across the sense resistor.

Claim 27

A method as recited in claim 17, further comprising the steps of: providing a current sense circuit comprising a sampling capacitor and a sense resistor series with the sampling capacitor; arranging the current sense circuit in parallel with the output capacitor; and damping perturbations in the first active damping means based on a voltage across the sense resistor.

Claim 28

A method as recited in claim 25, in which a value of the sampling capacitor is at least three times the value of the output capacitor.

Claim 29

A method as recited in claim 17, further comprising the steps of: providing a sense circuit comprising (a) a sampling capacitor having first and second terminals and (b) an operational amplifier having first and second input terminals and an output terminal; and connecting the second input terminal to the second terminal of the sampling capacitor; connecting a resistor between the second input terminal and the output terminal of the operational amplifier; connecting the sense circuit, in parallel across the output capacitor; and damping perturbations based on a voltage across the output terminal and the first input terminal of the operational amplifier.

Claim 30

A method as recited in claim 17, further comprising the steps of: providing a current transformer having input and output windings; connecting the input windings of the current transformer in series with the output capacitor; connecting a sense resistor across the output terminals of the current transformer; and damping perturbations based on a voltage across the sense resistor.

Claim 31

A method as recited in claim 17, further comprising the steps of: arranging a hall effect device series with the output capacitor; and damping perturbations based on a voltage generated by the hall effect device.

Claim 32

An amplifier comprising: control means for generating a first control signal based on an input signal the amplitude of which varies over time and a voltage loop feedback signal derived from an output signal; switch means for generating a pulsed power signal based on the control signal; output filter means for filtering the pulsed power signal to obtain the output signal such that the output signal tracks the input signal, where the output filter means comprises a filter inductor and a filter capacitor; and active damping means for damping perturbations in the output filter means, the active damping means comprising current measuring means for generating a second control signal based on a current through the output capacitor and means for altering the first control signal based on the second control signal.

Claim 33

An amplifier comprising: control means for generating a first control signal based on an input signal the amplitude of which varies over time and a voltage loop feedback signal derived from an output signal; switch means for generating a pulsed power signal based on the control signal; output filter means for filtering the pulsed power signal to obtain the output signal such that the output signal tracks the input signal, where the output filter means comprises a filter inductor and a filter capacitor; and active damping means for damping perturbations in the output filter means, the active damping means comprising current measuring means for generating a second control signal based on a current through the output capacitor and means for altering the first control signal based on the second control signal.

Claim 34

An amplifier as recited in claim 30, in which the active damping means damps perturbations based on a current in the filter capacitor.

Claim 35

An amplifier as recited in claim 30, further comprising compensation means for compensating at least in part for the damped filter means.

Claim 36

An amplifier as recited in claim 30, in which the control means comprises means for summing the voltage loop feedback signal with the input signal to obtain a voltage loop error signal.

Claim 37

An amplifier as recited in claim 33, in which the active damping means comprises: means for generating a current damping loop feedback signal corresponding to the current within the filter capacitor; and means for altering the control signal by summing the voltage loop error signal with the current damping loop feedback signal to obtain a current damping loop error signal.

Claim 38

An amplifier as recited in claim 34, further comprising modulator means for modulating the current damping loop error signal based on a periodic signal to obtain the control signal.

Claim 39

An amplifier that generates an output signal based on an input signal, comprising: control means for generating a control signal based on an input signal the amplitude of which varies over time and a feedback signal derived from an output signal; switch means for generating a pulsed power signal based on the control signal; output filter means comprising an output inductor and an output capacitor for filtering the pulsed power signal to obtain the output signal, where the output signal varies with time; active damping means for damping perturbations in the output filter means; and compensation means for compensating at least in part for a frequency response of the damped output filter means.

Claim 40

An amplifier that generates an output signal based on an input signal, comprising: control means for generating a control signal based on an input signal the amplitude of which varies over time and a feedback signal derived from an output signal; switch means for generating a pulsed power signal based on the control signal; output filter means comprising an output inductor and an output capacitor for filtering the pulsed power signal to obtain the output signal, where the output signal varies with time; active damping means for damping perturbations in the output filter means; and compensation means for compensating at least in part for a frequency response of the damped output filter means.

Claim 41

An amplifier as recited in claim 36, in which the control means comprises means for summing the voltage loop feedback signal with the input signal to obtain a voltage loop error signal.

Claim 42

An amplifier as recited in claim 37, in which the active damping means comprises: means for generating a current damping loop feedback voltage corresponding to the current within the filter capacitor; and means for altering the control signal by summing the voltage loop error signal with the current damping loop feedback signal to obtain a current damping loop error signal.

Claim 43

An amplifier as recited in claim 38, further comprising modulator means for modulating the current damping loop signal based on a periodic signal to obtain the control signal.

Claim 44

An amplifier as recited in claim 39, in which the compensating means comprises means for altering the voltage loop error signal to compensate for the frequency response of the damped filter.

Claim 45

In a switch mode amplifier system having a first feedback loop for generating a control signal based on an input signal and a voltage loop feedback signal derived from an output signal of the amplifier; switching means for generating a pulsed power signal based on the control signal; and an output filter having an inductor and a capacitor, where the output filter contributes first and second poles to the amplifier system that lie in the left half of the s-plane adjacent to the imaginary axis, where the first pole is spaced above real axis and the second pole is spaced below the real axis; a method of stabilizing the amplifier system comprising the step of actively damping the output filter by altering the control signal based on a current through the capacitor of the output filter such that the first and second poles are moved away from the right half of the s-plane and substantially onto the real axis.

Claim 46

In a switch mode amplifier system having a first feedback loop for generating a control signal based on an input signal and a voltage loop feedback signal derived from an output signal of the amplifier; switching means for generating a pulsed power signal based on the control signal; and an output filter having an inductor and a capacitor, where the output filter contributes first and second poles to the amplifier system that lie in the left half of the s-plane adjacent to the imaginary axis, where the first pole is spaced above real axis and the second pole is spaced below the real axis; a method of stabilizing the amplifier system comprising the step of actively damping the output filter by altering the control signal based on a current through the capacitor of the output filter such that the first and second poles are moved away from the right half of the s-plane and substantially onto the real axis.

Claim 47

A method as recited in claim 41, further comprising the step of forward compensating at least in part for the frequency response of the actively damped output filter by providing circuitry that contributes first and second zeros to the amplifier system, where the first zero substantially cancels the first pole and the second zero substantially cancels the second pole.

Claim 48

An amplifier system for generating an output signal that tracks an audio input signal comprising: linear amplification means for amplifying an input signal to obtain an amplified output signal, the linear amplification means having at least one supply terminal; first amplification means for generating a first supply signal and applying the first supply signal to the at least one supply terminal of the linear amplification means, where the first amplification means comprises first control means for generating a first control signal based on the input signal, first switch means for generating a first pulsed power signal based on the first control signals and first filter means for filtering the first pulsed power signal to obtain the first supply signal, the first filter means comprising a first filter inductor and a first filter capacitor; first active damping means for damping perturbations in the first filter means; and first compensation means for compensating at least in part for the frequency response of the damped first filter means.

Claim 49

An amplifier system for generating an output signal that tracks an audio input signal comprising: linear amplification means for amplifying an input signal to obtain an amplified output signal, the linear amplification means having at least one supply terminal; first amplification means for generating a first supply signal and applying the first supply signal to the at least one supply terminal of the linear amplification means, where the first amplification means comprises first control means for generating a first control signal based on the input signal, first switch means for generating a first pulsed power signal based on the first control signals and first filter means for filtering the first pulsed power signal to obtain the first supply signal, the first filter means comprising a first filter inductor and a first filter capacitor; first active damping means for damping perturbations in the first filter means; and first compensation means for compensating at least in part for the frequency response of the damped first filter means.

Claim 50

The amplifier system as recited in claim 43, in which the first compensation means compensates for the damped first filter means by altering the first control signal.

Claim 51

An amplifier system for generating an output signal that tracks an audio input signal comprising: linear amplification means for amplifying an input signal to obtain an amplified output signal, the linear amplification means having first and second supply terminals and the first supply signal is applied to the first supply terminal; first amplification means for generating a first supply signal and applying the first supply signal to the first supply terminal of the linear amplification means, where the first amplification means comprises first control means for generating a first control signal based on the input signal, first switch means for generating a first pulsed power signal based on the first control signal, and first filter means for filtering the first pulsed power signal to obtain the first supply signal, the first filter means comprising a first filter inductor and a first filter capacitor; second amplification means for generating a second supply signal and applying the second supply signal to the second supply terminal of the linear amplification means, where the second amplification means comprises second control means for generating a second control signal based on the input signal, second switch means for generating a second pulsed power signal based on the second control signals and second filter means for filtering the second pulsed power signal to obtain the second supply signals the second filter means comprising a second filter inductor and a second filter capacitor; first active damping means for damping perturbations in the first filter means; second active damping means for damping perturbations in the second filter means; first compensation means for compensating at least in part for the frequency response of the damped first filter means; and second compensation means for compensating at least in part for the frequency response of the damped second filter means.

Claim 52

An amplifier system for generating an output signal that tracks an audio input signal comprising: linear amplification means for amplifying an input signal to obtain an amplified output signal, the linear amplification means having first and second supply terminals and the first supply signal is applied to the first supply terminal; first amplification means for generating a first supply signal and applying the first supply signal to the first supply terminal of the linear amplification means, where the first amplification means comprises first control means for generating a first control signal based on the input signal, first switch means for generating a first pulsed power signal based on the first control signal, and first filter means for filtering the first pulsed power signal to obtain the first supply signal, the first filter means comprising a first filter inductor and a first filter capacitor; second amplification means for generating a second supply signal and applying the second supply signal to the second supply terminal of the linear amplification means, where the second amplification means comprises second control means for generating a second control signal based on the input signal, second switch means for generating a second pulsed power signal based on the second control signals and second filter means for filtering the second pulsed power signal to obtain the second supply signals the second filter means comprising a second filter inductor and a second filter capacitor; first active damping means for damping perturbations in the first filter means; second active damping means for damping perturbations in the second filter means; first compensation means for compensating at least in part for the frequency response of the damped first filter means; and second compensation means for compensating at least in part for the frequency response of the damped second filter means.

Claim 53

The amplifier system as recited in claim 45, further comprising discharge means for discharging the first and second filter capacitors to prevent floating of the first and second supply voltages.

Claim 54

The amplifier as recited in claim 45, in which the first compensation means compensates for the damped first filter means by altering the first control signal and the second compensation means compensates for the damped second filter means by altering the second control signal.

Claim 55

An amplifier system for generating an output signal that tracks an audio input signal comprising: linear amplification means for amplifying an input signal to obtain an amplified output signal, the linear amplification means having first and second supply terminals and the first supply signal is applied to the first supply terminal; first amplification means for generating a first supply signal and applying the first supply signal to the first supply terminal of the linear amplification means, where the first amplification means comprises first control means for generating a first control signal based on the input signal, first switch means for generating a first pulsed power signal based on the first control signal, and first filter means for filtering the first pulsed power signal to obtain the first supply signal, the first filter means comprising a first filter inductor and a first filter capacitor; second amplification means for generating a second supply signal and applying the second supply signal to the second supply terminal of the linear amplification means, where the second amplification means comprises second control means for generating a second control signal based on the input signal, second switch means for generating a second pulsed power signal based on the second control signals and second filter means for filtering the second pulsed power signal to obtain the second supply signal, the second filter means comprising a second filter inductor and a second filter capacitor; first active damping means for damping perturbations in the first filter means; second active damping means for damping perturbations in the second filter means; wherein the first active damping means damps perturbations in the first filter means based on a current through the first filter capacitor and the second active damping means damps perturbations in the second filter means based on a current through the second filter capacitor.

Claim 56

An amplifier system for generating an output signal that tracks an audio input signal comprising: linear amplification means for amplifying an input signal to obtain an amplified output signal, the linear amplification means having first and second supply terminals and the first supply signal is applied to the first supply terminal; first amplification means for generating a first supply signal and applying the first supply signal to the first supply terminal of the linear amplification means, where the first amplification means comprises first control means for generating a first control signal based on the input signal, first switch means for generating a first pulsed power signal based on the first control signal, and first filter means for filtering the first pulsed power signal to obtain the first supply signal, the first filter means comprising a first filter inductor and a first filter capacitor; second amplification means for generating a second supply signal and applying the second supply signal to the second supply terminal of the linear amplification means, where the second amplification means comprises second control means for generating a second control signal based on the input signal, second switch means for generating a second pulsed power signal based on the second control signals and second filter means for filtering the second pulsed power signal to obtain the second supply signal, the second filter means comprising a second filter inductor and a second filter capacitor; first active damping means for damping perturbations in the first filter means; second active damping means for damping perturbations in the second filter means; wherein the first active damping means damps perturbations in the first filter means based on a current through the first filter capacitor and the second active damping means damps perturbations in the second filter means based on a current through the second filter capacitor.

Claim 57

An amplifier system for generating an output signal that tracks an audio input signal, comprising: linear amplification means for amplifying an input signal to obtain an amplified output signal, the linear amplification means having first and second supply terminals and the first supply signal is applied to the first supply terminal; first amplification means for generating a first supply signal and applying the first supply signal to the first supply terminal of the linear amplification means, where the first amplification means comprises first control means for generating a first control signal based on the input signal, first switch means for generating a first pulsed power signal based on the first control signal, and first filter means for filtering the first pulsed power signal to obtain the first supply signal, the first filter means comprising a first filter inductor and a first filter capacitor; second amplification means for generating a second supply signal and applying the second supply signal to the second supply terminal of the linear amplification means, where the second amplification means comprises second control means for generating a second control signal based on the input signal, second switch means for generating a second pulsed power signal based on the second control signal, and second filter means for filtering the second pulsed power signal to obtain the second supply signal, the second filter means comprising a second filter inductor and a second filter capacitor; first active damping means for damping perturbations in the first filter means; second active damping means for damping perturbations in the second filter means; wherein the first active damping means damps perturbations in the first filter means by altering the first control signal and the second active damping means damps perturbations in the second filter means by altering the second control signal.

Claim 58

An amplifier system for generating an output signal that tracks an audio input signal, comprising: linear amplification means for amplifying an input signal to obtain an amplified output signal, the linear amplification means having first and second supply terminals and the first supply signal is applied to the first supply terminal; first amplification means for generating a first supply signal and applying the first supply signal to the first supply terminal of the linear amplification means, where the first amplification means comprises first control means for generating a first control signal based on the input signal, first switch means for generating a first pulsed power signal based on the first control signal, and first filter means for filtering the first pulsed power signal to obtain the first supply signal, the first filter means comprising a first filter inductor and a first filter capacitor; second amplification means for generating a second supply signal and applying the second supply signal to the second supply terminal of the linear amplification means, where the second amplification means comprises second control means for generating a second control signal based on the input signal, second switch means for generating a second pulsed power signal based on the second control signal, and second filter means for filtering the second pulsed power signal to obtain the second supply signal, the second filter means comprising a second filter inductor and a second filter capacitor; first active damping means for damping perturbations in the first filter means; second active damping means for damping perturbations in the second filter means; wherein the first active damping means damps perturbations in the first filter means by altering the first control signal and the second active damping means damps perturbations in the second filter means by altering the second control signal.

Claim 59

An amplifier system for generating an output signal that tracks an audio input signal comprising: linear amplification means for amplifying an input signal to obtain an amplified output signal, the linear amplification means having at least one supply terminal; first amplification means for generating a first supply signal and applying the first supply signal to the at least one supply terminal of the linear amplification means, where the first amplification means comprises first control means for generating a first control signal based on the input signal, first switch means for generating a first pulsed power signal based on the first control signal, and first filter means for filtering the first pulsed power signal to obtain the first supply signal, the first filter means comprising a first filter inductor and a first filter capacitor; first active damping means for damping perturbations in the first filter means based on a current through the first filter capacitor; first compensation means for compensating at least in part for the frequency response of the damped first filter means; and a current sense circuit comprising a sampling capacitor and a sense resistor arranged in series with the sampling capacitor, where the sense circuit is arranged in parallel with the output capacitor and the first active damping means damps perturbations based on a voltage across the sense resistor.

Claim 60

An amplifier system for generating an output signal that tracks an audio input signal comprising: linear amplification means for amplifying an input signal to obtain an amplified output signal, the linear amplification means having at least one supply terminal; first amplification means for generating a first supply signal and applying the first supply signal to the at least one supply terminal of the linear amplification means, where the first amplification means comprises first control means for generating a first control signal based on the input signal, first switch means for generating a first pulsed power signal based on the first control signal, and first filter means for filtering the first pulsed power signal to obtain the first supply signal, the first filter means comprising a first filter inductor and a first filter capacitor; first active damping means for damping perturbations in the first filter means based on a current through the first filter capacitor; first compensation means for compensating at least in part for the frequency response of the damped first filter means; and a current sense circuit comprising a sampling capacitor and a sense resistor arranged in series with the sampling capacitor, where the sense circuit is arranged in parallel with the output capacitor and the first active damping means damps perturbations based on a voltage across the sense resistor.

Claim 61

The amplifier as recited in claim 50, in which a value of the sampling capacitor is at least three times the value of the output capacitor.

Claim 62

An amplifier system for generating an output signal that tracks an audio input signal comprising: linear amplification means for amplifying an input signal to obtain an amplified output signal, the linear amplification means having at least one supply terminal; first amplifications means for generating a first supply signal and applying the first supply signal to the at least one supply terminal of the linear amplification means, where the first amplification means comprises first control means for generating a first control signal based on the input signal, first switch means for generating a first pulsed power signal based on the first control signal, and first filter means for filtering the first pulsed power signal to obtain the first supply signal, the first filter means comprising a first filter inductor and a first filter capacitor; first active damping means for damping perturbations in the first filter means based on a current through the first filter capacitor; first compensation means for compensating at least in part for the frequency response of the damped first filter means; and a sense circuit comprising a sampling capacitor having first and second terminals; an operational amplifier having first and second input terminals and an output terminal, where the second input terminal is connected to the second terminal of the sampling capacitor; and a resistor connected between the second input terminal and the output terminal of the operational amplifier; wherein the sense circuit is connected in parallel across the output capacitor; and the first active damping means damps perturbations based on a voltage across the output terminal and the first input terminal of the operational amplifier.

Claim 63

An amplifier system for generating an output signal that tracks an audio input signal comprising: linear amplification means for amplifying an input signal to obtain an amplified output signal, the linear amplification means having at least one supply terminal; first amplifications means for generating a first supply signal and applying the first supply signal to the at least one supply terminal of the linear amplification means, where the first amplification means comprises first control means for generating a first control signal based on the input signal, first switch means for generating a first pulsed power signal based on the first control signal, and first filter means for filtering the first pulsed power signal to obtain the first supply signal, the first filter means comprising a first filter inductor and a first filter capacitor; first active damping means for damping perturbations in the first filter means based on a current through the first filter capacitor; first compensation means for compensating at least in part for the frequency response of the damped first filter means; and a sense circuit comprising a sampling capacitor having first and second terminals; an operational amplifier having first and second input terminals and an output terminal, where the second input terminal is connected to the second terminal of the sampling capacitor; and a resistor connected between the second input terminal and the output terminal of the operational amplifier; wherein the sense circuit is connected in parallel across the output capacitor; and the first active damping means damps perturbations based on a voltage across the output terminal and the first input terminal of the operational amplifier.

Claim 64

An amplifier system for generating an output signal that tracks an audio input signal comprising: linear amplification means for amplifying an input signal to obtain an amplified output signal, the linear amplification means having at least one supply terminal; first amplification means for generating a first supply signal and applying the first supply signal to the at least one supply terminal of the linear amplification means, where the first amplification means comprises first control means for generating a first control signal based on the input signal, first switch means for generating a first pulsed power signal based on the first control signal, and first filter means for filtering the first pulsed power signal to obtain the first supply signal, the first filter means comprising a first filter inductor and a first filter capacitor; first active damping means for damping perturbations in the first filter means based on a current through the first filter capacitor; first compensation means for compensating at least in part for the frequency response of the damped first filter means; and a sense circuit comprising a current transformer having input and output windings, in which the input windings are connected in series with the output capacitor; and a sense resistor connected across the output terminals of the current transformer; wherein the first active damping means damps perturbations based on a voltage across the sense resistor.

Claim 65

An amplifier system for generating an output signal that tracks an audio input signal comprising: linear amplification means for amplifying an input signal to obtain an amplified output signal, the linear amplification means having at least one supply terminal; first amplification means for generating a first supply signal and applying the first supply signal to the at least one supply terminal of the linear amplification means, where the first amplification means comprises first control means for generating a first control signal based on the input signal, first switch means for generating a first pulsed power signal based on the first control signal, and first filter means for filtering the first pulsed power signal to obtain the first supply signal, the first filter means comprising a first filter inductor and a first filter capacitor; first active damping means for damping perturbations in the first filter means based on a current through the first filter capacitor; first compensation means for compensating at least in part for the frequency response of the damped first filter means; and a sense circuit comprising a current transformer having input and output windings, in which the input windings are connected in series with the output capacitor; and a sense resistor connected across the output terminals of the current transformer; wherein the first active damping means damps perturbations based on a voltage across the sense resistor.

Claim 66

An amplifier system for generating an output signal that tracks an audio input signal comprising: linear amplification means for amplifying an input signal to obtain an amplified output signal, the linear amplification means having at least one supply terminal; first amplification means for generating a first supply signal and applying the first supply signal to the at least one supply terminal of the linear amplification means, where the first amplification means comprises first control means for generating a first control signal based on the input signal, first switch means for generating a first pulsed power signal based on the first control signal, and first filter means for filtering the first pulsed power signal to obtain the first supply signal, the first filter means comprising a first filter inductor and a first filter capacitor; first active damping means for damping perturbations in the first filter means based on a current through the first filter capacitor; first compensation means for compensating at least in part for the frequency response of the damped first filter means; and a hall effect device arranged in series with the output capacitor, in which the first active damping means damps perturbations based on a voltage generated by the hall effect device.

Claim 67

An amplifier system for generating an output signal that tracks an audio input signal comprising: linear amplification means for amplifying an input signal to obtain an amplified output signal, the linear amplification means having at least one supply terminal; first amplification means for generating a first supply signal and applying the first supply signal to the at least one supply terminal of the linear amplification means, where the first amplification means comprises first control means for generating a first control signal based on the input signal, first switch means for generating a first pulsed power signal based on the first control signal, and first filter means for filtering the first pulsed power signal to obtain the first supply signal, the first filter means comprising a first filter inductor and a first filter capacitor; first active damping means for damping perturbations in the first filter means based on a current through the first filter capacitor; first compensation means for compensating at least in part for the frequency response of the damped first filter means; and a hall effect device arranged in series with the output capacitor, in which the first active damping means damps perturbations based on a voltage generated by the hall effect device.

Claim 68

An amplification method comprising the steps of: generating a first control signal based on an input signal the amplitude of which varies over time; operating a switch based on the first control signal to obtain a pulsed power signal; filtering the pulsed power signal with an output filter to obtain an output signal that tracks the input signal; generating a second control signal based on a current through an output capacitor in the output filter; and altering the first control signal based on the second control signal to damp perturbations in the output filter.

Claim 69

An amplification method comprising the steps of: generating a first control signal based on an input signal the amplitude of which varies over time; operating a switch based on the first control signal to obtain a pulsed power signal; filtering the pulsed power signal with an output filter to obtain an output signal that tracks the input signal; generating a second control signal based on a current through an output capacitor in the output filter; and altering the first control signal based on the second control signal to damp perturbations in the output filter.

Claim 70

An amplification method comprising the steps of: generating a first control signal based on an input signal the amplitude of which varies over time; operating a switch based on the first control signal to obtain a pulsed power signal; filtering the pulsed power signal with an output filter to obtain an output signal that tracks the input signal; altering the first control signal to damp perturbations in the output filter; and altering the first control signal to compensate at least in part for the frequency response of the damped output filter.

Claim 71

An amplification method comprising the steps of: generating a first control signal based on an input signal the amplitude of which varies over time; operating a switch based on the first control signal to obtain a pulsed power signal; filtering the pulsed power signal with an output filter to obtain an output signal that tracks the input signal; altering the first control signal to damp perturbations in the output filter; and altering the first control signal to compensate at least in part for the frequency response of the damped output filter.

Claim 72

An amplification method comprising the steps of: generating a first control signal based on an input signal the amplitude of which varies over time by summing the input signal with a feedback signal derived from the output signal to obtain a voltage loop error signal, where the first control signal is generated based on the voltage loop error signal; operating a switch based on the first control signal to obtain a pulsed power signal; filtering the pulsed power signal with an output filter to obtain an output signal that tracks the input signal; and altering the first control signal to damp perturbations in the output filter.

Claim 73

An amplification method comprising the steps of: generating a first control signal based on an input signal the amplitude of which varies over time by summing the input signal with a feedback signal derived from the output signal to obtain a voltage loop error signal, where the first control signal is generated based on the voltage loop error signal; operating a switch based on the first control signal to obtain a pulsed power signal; filtering the pulsed power signal with an output filter to obtain an output signal that tracks the input signal; and altering the first control signal to damp perturbations in the output filter.

Claim 74

A method as recited in claim 57, in which the step of altering the first control signal based on the second control signal comprises the step of adding the voltage loop error signal to the second control signal to obtain a current damping loop error signal, the first control signal being generated based on the current damping loop error signal.

Claim 75

A method as recited in claim 58, further comprising the step of modulating the current damping loop error signal based on a periodic signal to obtain the first control signal.

Claim 76

A method as recited in claim 59, further comprising the step of altering the voltage loop error signal to compensate at least in part for the frequency response of the damped output filter.

Claim 77

An amplification method comprising the steps of: generating a first control signal based on an input signal the amplitude of which varies over time; operating a switch based on the first control signal to obtain a pulsed power signal; filtering the pulsed power signal with an output filter to obtain an output signal that tracks the input signal; providing a current sense circuit comprising a sampling capacitor and a sense resistor series with the sampling capacitor, arranging the current sense circuit in parallel with the output capacitor, and damping perturbations in the first active damping means based on a voltage across the sense resistor.

Claim 78

An amplification method comprising the steps of: generating a first control signal based on an input signal the amplitude of which varies over time; operating a switch based on the first control signal to obtain a pulsed power signal; filtering the pulsed power signal with an output filter to obtain an output signal that tracks the input signal; providing a current sense circuit comprising a sampling capacitor and a sense resistor series with the sampling capacitor, arranging the current sense circuit in parallel with the output capacitor, and damping perturbations in the first active damping means based on a voltage across the sense resistor.

Claim 79

A method as recited in claim 61, in which a value of the sampling capacitor is at least three times the value of the output capacitor.

Claim 80

An amplification method comprising the steps of: generating a first control signal based on an input signal the amplitude of which varies over time; operating a switch based on the first control signal to obtain a pulsed power signal; filtering the pulsed power signal with an output filter to obtain an output signal that tracks the input signal; providing a sense circuit comprising (a) a sampling capacitor having first and second terminals and (b) an operational amplifier having first and second input terminals and an output terminal; connecting the second input terminal to the second terminal of the sampling capacitor; connecting a resistor between the second input terminal and the output terminal of the operational amplifier; connecting the sense circuit in parallel across the output capacitor; and altering the first control signal based on a voltage across the output terminal and the first input terminal of the operational amplifier to damp perturbations in the output filter.

Claim 81

An amplification method comprising the steps of: generating a first control signal based on an input signal the amplitude of which varies over time; operating a switch based on the first control signal to obtain a pulsed power signal; filtering the pulsed power signal with an output filter to obtain an output signal that tracks the input signal; providing a sense circuit comprising (a) a sampling capacitor having first and second terminals and (b) an operational amplifier having first and second input terminals and an output terminal; connecting the second input terminal to the second terminal of the sampling capacitor; connecting a resistor between the second input terminal and the output terminal of the operational amplifier; connecting the sense circuit in parallel across the output capacitor; and altering the first control signal based on a voltage across the output terminal and the first input terminal of the operational amplifier to damp perturbations in the output filter.

Claim 82

An amplification method comprising the steps of: generating a first control signal based on an input signal the amplitude of which varies over time; operating a switch based on the first control signal to obtain a pulsed power signal; filtering the pulsed power signal with an output filter to obtain an output signal that tracks the input signal; providing a current transformer having input and output windings; connecting the input windings of the current transformer in series with the output capacitor; connecting a sense resistor across the output terminals of the current transformer; and altering the first control signal based on a voltage across the sense resistor to damp perturbations in the output filter.

Claim 83

An amplification method comprising the steps of: generating a first control signal based on an input signal the amplitude of which varies over time; operating a switch based on the first control signal to obtain a pulsed power signal; filtering the pulsed power signal with an output filter to obtain an output signal that tracks the input signal; providing a current transformer having input and output windings; connecting the input windings of the current transformer in series with the output capacitor; connecting a sense resistor across the output terminals of the current transformer; and altering the first control signal based on a voltage across the sense resistor to damp perturbations in the output filter.

Claim 84

An amplification method comprising the steps of: generating a first control signal based on an input signal the amplitude of which varies over time; operating a switch based on the first control signal to obtain a pulsed power signal; filtering the pulsed power signal with an output filter to obtain an output signal that tracks the input signal; arranging a hall effect device in series with the output capacitor; and altering the first control signal based on a voltage generated by the hall effect device to damp perturbations in the output filter.

Claim 85

An amplification method comprising the steps of: generating a first control signal based on an input signal the amplitude of which varies over time; operating a switch based on the first control signal to obtain a pulsed power signal; filtering the pulsed power signal with an output filter to obtain an output signal that tracks the input signal; arranging a hall effect device in series with the output capacitor; and altering the first control signal based on a voltage generated by the hall effect device to damp perturbations in the output filter.

Claim 86

An amplifier comprising: control means for generating a control signal based on an input signal the amplitude of which varies over time and a voltage loop feedback signal derived from an output signal; switch means for generating a pulsed power signal based on the control signal; output filter means for filtering the pulsed power signal to obtain the output signal such that the output signal tracks the input signal, where the output filter means comprises a filter inductor and a filter capacitor; active damping means for damping perturbations in the output filter means based on a current in the filter capacitor; and compensation means for compensating at least in part for the damped filter means.

Claim 87

An amplifier comprising: control means for generating a control signal based on an input signal the amplitude of which varies over time and a voltage loop feedback signal derived from an output signal; switch means for generating a pulsed power signal based on the control signal; output filter means for filtering the pulsed power signal to obtain the output signal such that the output signal tracks the input signal, where the output filter means comprises a filter inductor and a filter capacitor; active damping means for damping perturbations in the output filter means based on a current in the filter capacitor; and compensation means for compensating at least in part for the damped filter means.

Claim 88

An amplifier comprising: control means for generating a control signal based on an input signal the amplitude of which varies over time and a voltage loop feedback signal derived from an output signal, the control means comprising means for summing the voltage loop feedback signal with the input signal to obtain a voltage loop error signal; switch means for generating a pulsed power signal based on the control signal; output filter means for filtering the pulsed power signal to obtain the output signal such that the output signal tracks the input signal, where the output filter means comprises a filter inductor and a filter capacitor; active damping means for damping perturbations in the output filter means, the actives damping means comprising means for generating a current damping loop feedback signal corresponding to the current within the filter capacitor; and means for altering the control signal by summing the voltage loop error signal with the current damping loop feedback signal to obtain a current damping loop error signal.

Claim 89

An amplifier comprising: control means for generating a control signal based on an input signal the amplitude of which varies over time and a voltage loop feedback signal derived from an output signal, the control means comprising means for summing the voltage loop feedback signal with the input signal to obtain a voltage loop error signal; switch means for generating a pulsed power signal based on the control signal; output filter means for filtering the pulsed power signal to obtain the output signal such that the output signal tracks the input signal, where the output filter means comprises a filter inductor and a filter capacitor; active damping means for damping perturbations in the output filter means, the actives damping means comprising means for generating a current damping loop feedback signal corresponding to the current within the filter capacitor; and means for altering the control signal by summing the voltage loop error signal with the current damping loop feedback signal to obtain a current damping loop error signal.

Claim 90

An amplifier as recited in claim 67, further comprising modulator means for modulating the current damping loop error signal based on a periodic signal to obtain the control signal.

Claim 91

In a switch mode amplifier system having a first feedback loop for generating a control signal based on an input signal and a voltage loop feedback signal derived from an output signal of the amplifier; switching means for generating a pulsed power signal based on the control signal; and an output filter having an inductor and a capacitor, where the output filter contributes first and second poles to the amplifier system that lie in the left half of the s-plane adjacent to the imaginary axis, where the first pole is spaced above real axis and the second pole is spaced below the real axis; a method of stabilizing the amplifier system comprising the steps of: actively damping the output filter such that the first and second poles are moved away from the right half of the s-plane and substantially onto the real axis; and forward compensating at least in part for the frequency response of the actively damped output filter by providing circuitry that contributes first and second zeros to the amplifier system, where the first zero substantially cancels the first pole and the second zero substantially cancels the second pole.

Claim 92

In a switch mode amplifier system having a first feedback loop for generating a control signal based on an input signal and a voltage loop feedback signal derived from an output signal of the amplifier; switching means for generating a pulsed power signal based on the control signal; and an output filter having an inductor and a capacitor, where the output filter contributes first and second poles to the amplifier system that lie in the left half of the s-plane adjacent to the imaginary axis, where the first pole is spaced above real axis and the second pole is spaced below the real axis; a method of stabilizing the amplifier system comprising the steps of: actively damping the output filter such that the first and second poles are moved away from the right half of the s-plane and substantially onto the real axis; and forward compensating at least in part for the frequency response of the actively damped output filter by providing circuitry that contributes first and second zeros to the amplifier system, where the first zero substantially cancels the first pole and the second zero substantially cancels the second pole.