Method and system for compensating for variations in supply voltage applied to pulse width modulation conversion circuits

A method of producing a PWM signal, comprising:

• powering a digital comparator with a supply voltage;
• converting the supply voltage from an analog value to a digital value;
• creating a digital carrier signal having a maximum count value equal to the digital value of the supply voltage;
• and
• using the digital comparator to compare the digital carrier signal with a digital modulating signal to create the PWM signal.

A pulse width modulation conversion system, comprising:

• an input modulating signal;
• an analog-to-digital conversion stage that converts an analog voltage reference to a digital voltage reference;
• a digital counter having a maximum value input coupled to the analog-to-digital conversion stage to receive the digital voltage reference, the digital counter being structured to produce a digital carrier signal having a maximum value equal to the digital voltage reference received at the maximum value input;
• and
• a digital comparator coupled to the digital counter and analog-to-digital converter and having a power input that receives the voltage reference, a first signal input that receives the input modulating signal, a second signal input that receives the carrier signal from the digital counter, and an output, the comparator being structured to produce at the output a PWM signal based on a comparison of the carrier signal with the modulating signal.