V<sup>2</sup> control with capacitor current ramp compensation using lossless capacitor current sensing

Abstract

V <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> control is a popular control architecture in point-of-load Buck converters due to its simplicity and fast transient response. V <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> control with ceramic capacitor has instability issue. This paper reviews the existing solutions and their limitations are studied. A solution using output capacitor current ramp to stabilize the control loop is proposed. The analog capacitor current sensing method based on impedance match is used in the implementation of lossless current sensing. A small signal equivalent circuit is proposed for the analysis of the proposed control method. The proposed solution is superior to existing compensation methods for the excellent transient response for a wide range of duty cycle. The effectiveness of the concept and implementation are verified by experimental results.