Accelerated Low Gate Count Parameter Identification for Integrated Switched-Mode Power Supplies with Digital Control

Abstract

Parameter identification in digital switched-mode power supplies (SMPS) enables new features in terms of design, diagnostics, and autotuning. It is beneficial for plug and play solutions, which allow to choose practically any inductor or capacitor for the SMPS meeting the application, cost and quality requirements. Parameter identification enables indication of component failure cases and adaption to unwanted parameter variations due to production tolerances, aging, and temperature changes. This paper proposes an identification concept for inductance and capacitance, the most influential parameters in SMPS. It allows for autotuning during startup and operation. The SMPS parameters are identified with very short identification time (85 µs during startup / 2 µs during operation), low gate count (8778 gates), small output voltage perturbations (0.4 % of the nominal output voltage), and high identification accuracy (max. 5 % deviation for inductance / max. 13 % deviation for capacitance). Experimental results are shown for a variable input voltage (3-6 V), 6.3 V output voltage, 1 A digitally controlled boost converter with 500 kHz switching frequency.