System and method for improved amplitude shift keying (ASK) communication in wireless power transfer applications

A method, comprising:

• a) in response to a finish of a modulated signal frame, resetting a hysteresis of an adjustable hysteresis comparator;
• b) digital to analog converting a pulsed signal output from the adjustable hysteresis comparator to an analog signal;
• c) analog to digital converting the analog signal to a digital signal value;
• d) comparing the digital signal value to a threshold value;
• e1) where the digital signal value is less than the threshold value, incrementing a hysteresis value of the adjustable hysteresis comparator and return to step b);
• and
• e2) where the digital signal value is not less than the threshold value, utilizing the hysteresis value of the adjustable hysteresis comparator until finish of a following modulated signal frame.

A wireless power transfer system, comprising:

• a wireless power transmitter;
• a wireless power receiver;
• wherein said wireless power transmitter and wireless power receiver are coupled for power transfer from the wireless power transmitter to the wireless power receiver and coupled for information transmission from the wireless power receiver to the wireless power transmitter;
• wherein the wireless power transmitter comprises:
• circuitry configured to receive a modulated information transmission signal from the wireless power receiver and generate a modulated signal contaminated by in-band noise;
• a comparator having a hysteresis value which is adjustable in response to a hysteresis setting control signal;
• wherein an input of the comparator is configured to receive the modulated signal contaminated by in-band noise;
• a digital to analog converter circuit configured to convert a pulsed signal output from the comparator to an analog signal;
• an analog to digital converter configured to convert the analog signal to a digital signal value;
• and
• a comparison circuit configured to compare the digital signal value to a threshold value and generate the hysteresis setting control signal to adjust the hysteresis value of the comparator in response to a result of the comparison in order to suppress the in-band noise from the output of the pulsed signal output from the comparator.