In case the current diverges because of the high-side masking time, the low-side power element is turned on until

the switch current level drops below the valley current sense threshold. The low-side operation is able to prevent

the high-side turn-on, so the device can skip pulses decreasing the switching frequency.

In a worst case scenario, reported in Figure 20 of the overcurrent protection, the switch current is limited to:

IMAX=IVY+VIN−VOUT

L ∙TMASKHS

(4)

Where IVY is the current threshold of the valley sensing circuitry (please refer to Electrical characteristics table)

In most of the overcurrent conditions, the conduction time of the high-side switch is higher than the masking time

and so the peak current protection limits the switch current.

IMAX=IPEAKTH

(5)

The DC current flowing in the load in overcurrent condition is:

IDCOUT=IMAX−IRIPPLEVOUT

2 =IMAX− VIN− VOUT

2∙L ∙TON

(6)

L6982

Over current protection

DS13683 - Rev 1

page 19/48