Power supply for class g amplifier

Abstract

A Class G amplifier system including a processing unit configured to receive an input signal and output a delayed processed input signal, a class G amplifier configured to receive the delayed processed input signal, and a power supply. The power supply includes a regulator configured to operate in a plurality of configurations, each configuration outputs a different supply voltage to the class G amplifier and a control circuit configured to receive the input signal and determine the supply voltage required from the regulator when the delayed processed input signal is received at the class G amplifier, and output a signal to the regulator to indicate the required configuration for the required supply voltage.

1 . A power supply to provide power to an electrical device, comprising:
 an amplifier having multiple power rails and configured to provide different power supply voltages at the multiple power rails;   an interpolator configured to receive a first audio input signal;   an active noise cancellation circuit configured to receive a second audio input signal and an output signal from the interpolator;   a control circuit configured to receive the first audio input signal and an output signal from the active noise cancellation circuit and determine the power supply voltages to be provided by the amplifier at the multiple power rails based on the first audio input signal and the output signal from the active noise cancellation circuit; and   a voltage regulator configured to receive an output signal from the control circuit and produce the power supply voltages for the amplifier based on the received output signal.   
     
     
         2 . The power supply of  claim 1  further comprising a summer configured to mix the output signal from the interpolator with the output signal from the active noise cancellation circuit. 
     
     
         3 . The power supply of  claim 1  further comprising a digital-to-analog converter configured to receive an output from the voltage regulator and provide the determined power supply voltages to the amplifier based on the received output. 
     
     
         4 . The power supply of  claim 1  wherein the control circuit is configured to determine the power supply voltages based on an amplitude of the second audio input signal. 
     
     
         5 . The power supply of  claim 1  wherein the voltage regulator includes a multi-mode buck charge pump. 
     
     
         6 . The power supply of  claim 5  wherein the voltage regulator further includes an inverting charge pump. 
     
     
         7 . The power supply of  claim 6  in which the control circuit is further configured to determine whether a soft start up is enabled. 
     
     
         8 . The power supply of  claim 7  in which the control circuit is further configured to modify a switching resistance of switches in the buck charge pump based on a determination that the soft start up is enabled. 
     
     
         9 . The power supply of  claim 1  in which the voltage regulator is a digital regulator. 
     
     
         10 . The power supply of  claim 1  in which the voltage regulator is a configurable discrete regulator. 
     
     
         11 . The power supply of  claim 1  in which the amplifier is a class G amplifier. 
     
     
         12 . A circuit to determine voltages to be provided to an amplifier having multiple power rails, the circuit comprising:
 an interpolator configured to receive a first audio input signal;   an active noise cancellation circuit configured to receive a second audio input signal and an output signal from the interpolator;   a control circuit configured to receive the first audio input signal and an output signal from the active noise cancellation circuit and determine the power supply voltages to be provided by the amplifier at the multiple power rails based on the first audio input signal and the output signal from the active noise cancellation circuit; and   a regulator device configured to receive an output signal from the control circuit and produce the power supply voltages for the amplifier based on the output signal from the control circuit.   
     
     
         13 . The circuit of  claim 12  further comprising a digital-to-analog converter configured to receive an output from the regulator device and provide the determined power supply voltages to the amplifier based on the received output. 
     
     
         14 . A method for providing voltages to an amplifier, comprising:
 receiving a first audio input signal by an interpolator and a control circuit;   receiving a second audio input signal by the active noise cancellation circuit;   determining by a control circuit a selectable pair of power supply voltages for multiple power rails of the amplifier based on the first audio input signal and an output signal from the active noise cancellation circuit;   receiving an output signal from the control circuit by a regulator device; and   producing the selectable pair of power supply voltages by the regulator device based on the received output signal.   
     
     
         15 . The method of  claim 14  further comprising generating a delayed audio input signal by the interpolator and passing it to the active noise cancellation circuit. 
     
     
         16 . The method of  claim 15  in which the determining by the control circuit is further based on the delayed audio input signal. 
     
     
         17 . The method of  claim 14  wherein determining the selectable pair of power supply voltages is based on an amplitude of the second audio input signal. 
     
     
         18 . The method of  claim 14  further comprising determining whether a soft start up is enabled by the control circuit. 
     
     
         19 . The method of  claim 18  further comprising modifying a switching resistance of switches in a buck charge pump of the regulator device based on a determination that the soft start up is enabled. 
     
     
         20 . The method of  claim 18  further comprising switching between the power supply voltages based on a configuration of the amplifier.