Sigma-delta DPWM controllers for 12MHz DC-DC switch-mode power supplies.

摘要

The aim of this work is to develop a power efficient digital controller for DC-DC Switch-Mode Power Supplies (SMPS) operating at switching frequencies up to 12MHz. The controller should be able to achieve both fast transient response and low power consumption.; The proposed controller utilizes a new power-efficient DPWM architecture based on multi-bit Sigma-Delta modulation. The DPWM has a low-power low-resolution DPWM. The DPWM resolution is improved using a 2nd order sigma-delta modulator. In addition, the conventional PID compensator is replaced by a dual-mode PID compensator. The compensator is able to "recognize" the mode of operation and adjust its parameters automatically. Finally, the new nonlinear ADC architecture for SMPS applications reduces the influence of noise, temperature and process variations on operation of SMPS. The controller is implemented on a mixed-signal IC in 0.18mum CMOS technology and it consumes 672 muA of current at a switching frequency of 12MHz.