Center of gravity compensation of Class-D amplifier
AssigneeDialog Semiconductor GmbH
InventorsJohan Nilsson, Lars Lennartsson, Horst Knoedgen
Life of this patent
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Abstract
In a Class-D Amplifier with PCM (Pulse Code Modulated) input signal, the output pulse width may be adjusted to provide a constant time-voltage-area or the output pulse width may have one of several discrete values to provide a multi-level output system. A fundamental idea of this disclosure is to assure the center of each output pulse is always positioned at the nominal clock or with a fixed delay relative to the nominal clock. Said Class-D Amplifier typically converts the input signal into PDM (Pulse Density Modulated) pulses with a Sigma Delta Modulator and typically drives the output load with an H-Bridge.
Claims45
A circuit to assure the center of each pulse for a Class-D Amplifier is always positioned at its nominal clock position or with a fixed delay relative to said nominal clock position, comprising:
- means to convert the input signal into ideal, yet uncompensated PDM (Pulse Density Modulated) control pulses;
- means to calculate the position of each individual pulse center;
- means to determine the required delay to compensate the deviation of each of said individual pulse centers from their desired nominal pulse position;
- means to generate the corrected power driver control pulses;
- means for a power driver to drive voltage into an output load, controlled by said power driver control pulses;
- and
- means for an output load as the amplifier output's target.
A circuit to compensate the pulse-center-misplacement in a time-voltage-area corrected Class-D Amplifier, comprising:
- means to convert the input signal into ideal, yet uncompensated PDM (Pulse Density Modulated) control pulses;
- means to correct the time-voltage-area, depending on a voltage representing the actual voltage across the output load
- means to define said value, representing the actual voltage across the output load;
- means to define the output pulse area reference;
- means to determine the delay for the power driver control pulses start point;
- means to further generate the corrected power driver control pulses;
- means for a power driver to drive voltage into an output load, controlled by said power driver control pulses;
- and
- means for an output load as the amplifier output's target.
A circuit to assure the pulse-center in a multi-level Class-D Amplifier with various discrete time-voltage-area values is always positioned at the correct nominal clock position or with a fixed delay relative to said nominal clock position, comprising:
- means to convert the input signal into PDM (Pulse Density Modulated) control pulses;
- means to generate pulses with various discrete time-voltage-area values, depending on a pulse length control signal;
- means to define said value, representing the actual voltage across the output load;
- means to define the output pulse area reference;
- means to determine the required delay to compensate the deviation of each of the individual pulse centers from their desired nominal pulse position, thus defining the power driver control pulse's start point;
- means to further generate the corrected power driver control pulses;
- means for a power driver to drive voltage into an output load, controlled by said power driver control pulses;
- and
- means for an output load as the amplifier output's target.
A method to assure the center of each output pulse of said Class-D Amplifier is always positioned at the nominal clock position or with a fixed delay relative to said nominal clock position, comprising:
- providing means to convert said input signal into ideal, yet uncompensated PDM (Pulse Density Modulated) control pulses, means to correct the time-voltage-area, depending on a voltage representing the actual voltage across the output load, means to define said value, representing the actual voltage across the output load, means to determine the delay for the power driver control pulses start point, means to further generate the corrected power driver control pulses, means for a power driver to drive voltage into an output load, controlled by said power driver control pulses and means for an output load as the amplifier output's target;
- converting said input signal into ideal, yet uncompensated PDM control pulses;
- correcting the time-voltage-area, depending on a voltage representing the actual voltage across the output load;
- defining a value representing the actual voltage across the output load
- determining the delay for the power driver control pulses start point;
- further generating said corrected power driver control pulses;
- applying said power driver control pulses to said power driver;
- and
- driving said power driver's output voltage to the output load (typically a loudspeaker).
Dependencies are inferred from the claim text.