AUTO-TUNING METHOD FOR TIME CONSTANT MATCHING IN VRMMULTIPHASE DC/DC CONVERTER

摘要

Recently, there has been a growing interest in inductor current sense in current programmedcontroller for big power delivery system. This technique requires an external series-connected resistorcapacitorpair shunted across the inductor. The time constant of the resistor-capacitor is chosen to match thatof the inductor. If the time constants match, the voltage across the capacitor will be identical to the voltageacross the inductor's parasitic resistance. This method is well recognized for high efficiency and easyimplementation, but a time constant mismatching decreases the controller transient performance. In fact theaccuracy of this measurement depends on the tolerance of the components used across a range of operatingconditions. The proposed paper presents a novel digital auto-tuning system for time constant matchingdeveloped for VRM current programmed controllers. This system allow to meet the load-line requirementsusing conventional and low cost components, solving problems such as aging effect, temperature and lotvariation. There isn't an actual state of the art and the implementation of this solution is extremely simple andrequires small silicon area.