Constant on time (COT) buck converter has been widely used because of its advantage of fast transient response. Traditional ripple compensation method uses passive components and high gain-bandwidth amplifiers to enhance loop stability and improve output voltage accuracy, which leads to increased power consumption and decreased compactness. This paper proposes a novel Internal ripple compensation (IRC) technology with DC offset cancellation. To enhance loop stability, IRC circuit emulates virtual ripple by using RC filter. To improve output voltage accuracy, DC offset calibration module eliminates DC offset of virtual ripple by using full-wave rectification and high-precision current operational techniques. The effectiveness of this method has been verified through cadence platform. Experimental results demonstrate that when the converter load current is 1A and the output voltage is 5V, the output voltage DC offset is reduced from 0.56%(28mV) to 0.12%(6mV) and the output voltage ripple is 4mV.

Constant on time (COT),Internal ripple compensation (IRC),Buck converter,Output voltage DC offset