SNVS690I January 2011 – August 2021 LMZ14201H
At light-load, the regulator will operate in discontinuous conduction mode (DCM). With load currents above the critical conduction point, it will operate in continuous conduction mode (CCM). When operating in DCM the switching cycle begins at zero amps inductor current; increases up to a peak value, and then recedes back to zero before the end of the OFF-time. During the period of time that inductor current is zero, all load current is supplied by the output capacitor. The next ON-time period starts when the voltage on the FB pin falls below the internal reference. The switching frequency is lower in DCM and varies more with load current as compared to CCM. Conversion efficiency in DCM is maintained because conduction and switching losses are reduced with the smaller load and lower switching frequency.