Device description

L6984

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DocID025378 Rev 3

3.3

Soft-start

The soft-start feature minimizes the inrush current and decreases the stress of the power

components during the power-up phase. The L6984 implements the soft-start clamping the

device current limitation in four different steps.

During normal operation a new soft-start cycle takes place in case of:



Thermal shutdown event



UVLO event



EN pin rising

Figure 7 shows the soft-start feature. The green trace represents the inductor current which

shows different current protection thresholds.

Figure 7. Soft-start feature

3.4

Light load operation

The LNM pinstrapping during the power-up phase determines the light load operation.

3.4.1

Low noise mode (LNM)

Low noise mode implements a forced PWM operation over the different loading conditions.

The LNM features a constant switching frequency to minimize the noise in the final

condition never skips pulses and it operates in continuous conduction mode (CCM) over the

different loading conditions.