US 11,906,993 B2
Nonlinear feedforward correction in a multilevel output system
John L. Melanson, Austin, TX (US); and Thomas H. Hoff, Austin, TX (US)
Assigned to Cirrus Logic Inc., Austin, TX (US)
Filed by Cirrus Logic International Semiconductor Ltd., Edinburgh (GB)
Filed on Oct. 5, 2022, as Appl. No. 17/960,335.
Claims priority of provisional application 63/275,142, filed on Nov. 3, 2021.
Prior Publication US 2023/0139467 A1, May 4, 2023
Int. Cl. G05F 1/46 (2006.01)
CPC G05F 1/46 (2013.01) 9 Claims
OG exemplary drawing
 
1. 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.