Adaptive zero-current switching control scheme for diode emulation operation

A voltage regulator typically can achieve higher efficiency at very light load by operating in diode emulation mode rather than in continuous conduction mode. A very common approach to detect zero current crossing is to compare the phase-node voltage with zero volts or a few millivolts (mV) reference voltage. However the parasitic inductance may introduce some extra offset, resulting in early turn-off of the LGATE and extra power losses. The impact of power-train parasitics and operating conditions in diode emulation operation are studied in detail in this paper. A novel technique to compensate these variables and achieve zero-current switching (ZCS) diode emulation operation is presented. Experimental results are provided to verify the concept.