An Optimized Auto-tuning Digital DC--DC Converter Based on Linear-Non-Linear and Predictive PID

Chuang WANG  Zunchao LI  Cheng LUO  Lijuan ZHAO  Yefei ZHANG  Feng LIANG  

IEICE TRANSACTIONS on Electronics   Vol.E97-C   No.8   pp.813-819
Publication Date: 2014/08/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E97.C.813
Type of Manuscript: PAPER
Category: Electronic Circuits
Auto-tuning Control,  Digital DC--DC,  Stability,  Predictive Control,  Power Management,  

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A novel auto-tuning digital DC--DC converter is presented. In order to reduce the recovery time and undershoot, the auto-tuning control combines LnL, conventional PID and a predictive PID with a configurable predictive coefficient. A switch module is used to select an algorithm from the three control algorithms, according to the difference between the error signal and the two initially predefined thresholds. The detection and control logic is designed for both window delay line ADC and Σ Δ DPWM to correct the delay deviation. When the output of the converter exceeds the quantization range, the digital output of ADC is set at 0 or 1, and the delay line stops working to reduce power consumption. Theoretical analysis and simulations in the CSMC CMOS 0.5 μm process are carried out to verify the proposed DC--DC converter. It is found that the converter achieves a power efficiency of more than 90% at heavy load, and reduces the recovery time and undershoot.