LMZ22008

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SNVS712H – FEBRUARY 2010 – REVISED AUGUST 2015

7.4 Device Functional Modes

7.4.1 Discontinuous Conduction and Continuous Conduction Modes

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

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.

Following is a comparison pair of waveforms showing both the CCM (upper) and DCM operating modes.

Figure 49. CCM and DCM Operating Modes

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