JAJSEQ9E November 2013 – December 2017 TPS56520 , TPS56720 , TPS56920 , TPS56C20
PRODUCTION DATA.
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The TPS56x20 works in Auto-Skip Eco-modeTM at light load to boost the efficiency. As the output current decreases from heavy load condition, the inductor current is also reduced and eventually comes to the where its ripple valley touches the zero level, which is the boundary between continuous conduction and discontinuous conduction modes. The rectifying MOSFET is turned off when its zero inductor current is detected. As the load current further decreases the converter run into discontinuous conduction mode. The on-time is kept same as it was in the continuous conduction mode because it takes longer to discharge the output capacitor with smaller load current to the level of the nominal output voltage. The transition point to the light load operation IO(LL) current can be estimated with Equation 2 with 500kHz used as ƒsw.