SNVS710I March 2011 – December 2015 LMZ13608
PRODUCTION DATA.
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, inductor current is maintained to an average value equaling IOUT . In DCM the low-side switch will turn off when the inductor current falls to zero, this causes the inductor current to resonate. Although it is in DCM, the current is allowed to go slightly negative to charge the bootstrap capacitor.
In CCM, current flows through the inductor through the entire switching cycle and never falls to zero during the OFF-time.
Figure 46 is a comparison pair of waveforms showing both the CCM (upper) and DCM operating modes.