Integrated Voltage Regulator for Low-Power Mobile Applications

摘要

Battery powered mobile devices demand very efficient power management integrated circuits to extend battery life along with a small form-factor. Integrated voltage regulators has inductors and capacitors on-chip to reduce its foot-print. However, these on-chip passives occupy major amount of the silicon real-estate. Improvement in the capacitance/inductance densities will result in smaller form-factor. Also, coupled inductor can reduce the foot-print to nearly half compared to uncoupled inductor. Coupled inductor can also enhance the performance of the voltage regulators where it is used as power transfer element and as filter element. Hence, in this paper, a comparative study of different inductor configurations is undertaken to find the optimum case that can result in best converter performance with respect to efficiency and form-factor. Buck converter regulating 1.8 V to 1.0 V with anti-coupled inductor configuration using out-of-phase input signals produced the best-in-class results. An output voltage ripple of only 18 mVpk-pk, resulting in a peak efficiency of 86.2% for a load current of 300 mA is achieved.