JAJSTV6 May 2024 TPSM86637 , TPSM86638
PRODUCTION DATA
TPSM86637 operates in Eco-mode, which maintains high efficiency at light loading. As the output current decreases from heavy load conditions, the inductor current is also reduced and eventually comes to a point where the rippled valley touches zero level, which is the boundary between continuous conduction and discontinuous conduction modes. The rectifying MOSFET is turned off when the zero inductor current is detected. As the load current further decreases, the converter runs into discontinuous conduction mode. The on-time is kept almost the same as the on-time was in continuous conduction mode so that discharging the output capacitor with smaller load current to the level of the reference voltage takes longer. This fact makes the switching frequency lower, proportional to the load current, and keeps the light load efficiency high.
TPSM86638 operates in forced CCM (FCCM) mode. The switching frequency is maintained at an almost constant level over the entire load range which is designed for applications requiring tight control of the switching frequency and output voltage ripple at the cost of lower efficiency under light load.