Notch filter for control signals in PWM controlled systems

A method comprising:

• calculating a first difference between a control signal a pulse width modulation (PWM) system and a feedback value;
• calculating a second difference between the first difference and a delayed second difference;
• generating the delayed second difference by introducing a one period delay to the second difference, wherein the period is based on a Nyquist frequency of the control signal;
• generates the feedback value by applying a gain to the delayed second difference;
• and
• generating a filtered control signal by calculating a difference between the signal and the feedback value, wherein the filtered control signal controls an operating parameter of the PWM system.

A system for a switched-mode power supply, the system comprising:

• a first difference module that calculates a first difference between a control signal of the switched-mode power supply and a feedback value;
• a second difference module that calculates a second difference between the first difference and a delayed second difference;
• a delay module that generates the delayed second difference by introducing a one period delay to the second difference, wherein the period is based on a Nyquist frequency of the switched-mode power supply;
• and
• a gain module that generates the feedback value by applying a gain to the delayed second difference.

A method for a switched-mode power supply, the method comprising:

• calculating a first difference between a control signal of the switched-mode power supply and a feedback value;
• calculating a second difference between the first difference and a delayed second difference;
• generating the delayed second difference by introducing a one period delay to the second difference, wherein the period is based on a Nyquist frequency of the switched-mode power supply;
• and
• generating the feedback value by applying a gain to the delayed second difference.