A mixed-signal control for VRM applications

This paper proposes a mixed-signal control for Voltage Regulated Modules (VRMs), which is based on a digital voltage loop and a peak-modulator digitally controlled by a low-resolution digital-to-analog converter (DAC). Improvement in the dynamic response and elimination of static quantization effects are obtained performing the peak-modulation on a weighted sum of output voltage and inductor current. The control features good dynamic performance, fixed switching frequency, small quantization effects, and low-complexity. Simulation and experimental results on a three-phase interleaved synchronous buck VRM confirm the performance of the proposed solution

[1]  F.C. Lee,et al.  Two-stage voltage regulator for laptop computer CPUs and the corresponding advanced control schemes to improve light-load performance , 2004, Nineteenth Annual IEEE Applied Power Electronics Conference and Exposition, 2004. APEC '04..

[2]  Seth R. Sanders,et al.  Architecture and IC implementation of a digital VRM controller , 2003 .

[3]  D. Maksimovic,et al.  Modeling of Quantization Effects in Digitally Controlled DC–DC Converters , 2004, IEEE Transactions on Power Electronics.

[4]  F.C. Lee,et al.  Adaptive voltage position design for voltage regulators , 2004, Nineteenth Annual IEEE Applied Power Electronics Conference and Exposition, 2004. APEC '04..

[5]  S. Saggini,et al.  An innovative digital control architecture for low-Voltage, high-current DC-DC converters with tight voltage regulation , 2004, IEEE Transactions on Power Electronics.

[6]  Seth R. Sanders,et al.  Architecture and IC implementation of a digital VRM controller , 2001, 2001 IEEE 32nd Annual Power Electronics Specialists Conference (IEEE Cat. No.01CH37230).

[7]  Aleksandar Prodic,et al.  High-frequency digital controller IC for DC/DC converters , 2002, APEC. Seventeenth Annual IEEE Applied Power Electronics Conference and Exposition (Cat. No.02CH37335).

[8]  Fred C. Lee,et al.  Design considerations for VRM transient response based on the output impedance , 2003 .

[9]  George C. Verghese,et al.  Time-varying effects and averaging issues in models for current-mode control , 1997 .

[10]  Seth R. Sanders,et al.  Quantization resolution and limit cycling in digitally controlled PWM converters , 2003 .

[11]  B. H. Cho,et al.  Analysis and interpretation of loop gains of multiloop-controlled switching regulators (power supply circuits) , 1988 .

[12]  Peng Xu,et al.  Design considerations for VRM transient response based on the output impedance , 2002, APEC. Seventeenth Annual IEEE Applied Power Electronics Conference and Exposition (Cat. No.02CH37335).

[13]  F.C. Lee,et al.  Critical bandwidth for the load transient response of voltage regulator modules , 2004, IEEE Transactions on Power Electronics.

[14]  Peng Xu,et al.  Critical inductance in voltage regulator modules , 2002 .

[15]  D. Maksimovic,et al.  Impact of digital control in power electronics , 2004, 2004 Proceedings of the 16th International Symposium on Power Semiconductor Devices and ICs.