A Fully-Differential Delay-Line Based Control for Resonant Switched-Capacitor Converter

Abstract

This paper presents a new control method to regulate the output current of a resonant switched-capacitor converter (ReSCC). Starting from a fixed switching frequency operation, the phase-shift required to regulate the average output current is modulated through a fully-differential control scheme composed by a fully-differential OTA, a differential compensation network and two identical voltage-controlled delay lines. The proposed method eliminates any restriction on the minimum achievable phase-shift, is suitable for integration in a scaled technology and for high-frequency operation. Moreover, it allows a seamless control between output current sourcing and sinking capabilities, extending the load current range, and improving the response to load transients. A circuit design has been performed on a 110-nm BCD technology, with 3.7 V to 1.8 V voltage conversion, 60 mA of output current and 10 MHz operation. Simulations demonstrate the effectiveness of the proposed method.