Fully-integrated digital average current-mode control 12V-to-1.xV voltage regulator module IC

This paper introduces a fully-integrated 12-to-1.xV voltage regulator module IC. A fully synthesizable digital two-loop controller has been realized through HDL tools. Several new IP blocks have been developed: a window delay-line based ADC, two independent PI compensators with shared hardware for calculations, high-resolution digital PWM (HR-DPWM), and a programmable dead-time module. The mixed-signal IC has been fabricated on a 0.18μm 5V CMOS process. It incorporates the digital core and a synchronous rectifier power-stage, including a drive circuitry operating at 1.25MHz with the ability to deliver up to 10W from 12V input. The digital core has been realized by an automated synthesis process and place-and route tools, resulting in effective silicon area of 0.16mm2. Post-layout and experimental results of the fabricated IC operating in closed-loop are provided, demonstrating the performance and benefits of the new controller for meeting the requirements of tight output voltage regulation.