Consideration of operating frequency variation in a constant-on-time synchronous Buck converter

A constant on-time PWM control with input feed-forward results in ultra-fast transient response while maintaining relatively constant switching frequency over the entire input voltage range. However, in practical design case, the operating frequency is changed by various load conditions. In this paper, variation of the switching frequency in a constant on-time Buck converter was analyzed in details. Experimental results were proposed to verify the characteristics.