Nonlinear feedforward correction in a multilevel output system
AssigneeCirrus Logic, Inc.
InventorsJohn L. Melanson, Thomas H. Hoff
Life of this patent
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Abstract
A feedforward correction block for use in a multi-level output system may include circuitry configured to determine an occurrence of a mode transition between operating modes of the multi-level output system, capture a loop filter output of a signal path of the multi-level output system occurring before and after the occurrence of the mode transition, and based on the transition and a change in the loop filter output responsive to the transition, determine a transition-specific compensation function to apply to a feedforward input signal of the signal path that is combined with the loop filter output.
Claims9
A feedforward correction block for use in a multi-level output system having an output driver subsystem for outputting an output driving signal response to an input signal, comprising:
- circuitry configured to:
- determine an occurrence of a mode transition between operating modes of the multi-level output system;
- capture a loop filter output of a signal path of the multi-level output system occurring before and after the occurrence of the mode transition;
- and
- based on the transition and a change in the loop filter output responsive to the transition, determine a transition-specific compensation function to apply to a feedforward input signal of the signal path that is combined with the loop filter output;
- wherein:
- the multi-level output system is configured to operate in a selected operating mode selected from a plurality of operating modes based on the input signal;
- and
- a supply voltage for the output driver subsystem is selected based on the selected operating mode.
A method for feedforward correction in a multi-level output system having an output driver subsystem for outputting an output driving signal response to an input signal, comprising:
- determining an occurrence of a mode transition between operating modes of the multi-level output system;
- capturing a loop filter output of a signal path of the multi-level output system occurring before and after the occurrence of the mode transition;
- and
- based on the transition and a change in the loop filter output responsive to the transition, determining a transition-specific compensation function to apply to a feedforward input signal of the signal path that is combined with the loop filter output;
- wherein:
- the multi-level output system is configured to operate in a selected operating mode selected from a plurality of operating modes based on the input signal;
- and
- a supply voltage for the output driver subsystem is selected based on the selected operating mode.
A multi-level output system, comprising:
- an output driver subsystem for outputting an output driving signal response to an input signal, wherein:
- the multi-level output system is configured to operate in a selected operating mode selected from a plurality of operating modes based on the input signal;
- and
- a supply voltage for the output driver subsystem is selected based on the selected operating mode;
- and
- a feedforward correction block comprising circuitry configured to:
- determine an occurrence of a mode transition between operating modes of the multi-level output system;
- capture a loop filter output of a signal path of the multi-level output system occurring before and after the occurrence of the mode transition;
- and
- based on the transition and a change in the loop filter output responsive to the transition, determine a transition-specific compensation function to apply to a feedforward input signal of the signal path that is combined with the loop filter output.
Dependencies are inferred from the claim text.