ZHCSF95C December 2015 – February 2018 LMR23610
PRODUCTION DATA.
When the load current is lower than half of the peak-to-peak inductor current in CCM, the LMR23610 operates in discontinuous conduction mode (DCM), also known as diode emulation mode (DEM). In DCM, the LS switch is turned off when the inductor current drops to IL_ZC (–40 mA typical). Both switching losses and conduction losses are reduced in DCM, compared to forced-PWM operation at light load.
At even lighter current loads, PFM is activated to maintain high efficiency operation. When either the minimum HS switch ON time (tON_MIN ) or the minimum peak inductor current IPEAK_MIN (300 mA typ) is reached, the switching frequency decreases to maintain regulation. In PFM, switching frequency is decreased by the control loop when load current reduces to maintain output voltage regulation. Switching loss is further reduced in PFM operation due to less frequent switching actions. The external clock synchronizing will not be valid when LMR23610 enters into PFM mode.