L7983 datasheet(20/43 Pages) STMICROELECTRONICS

Part #	L7983

Description	60 V, 300 mA synchronous step-down switching regulator with 10 μA quiescent current

PDF	43 Pages

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Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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5.6.1

Overcurrent protection (OCP)

In normal operation the HS MOS is turned off when the sensed current is equal to programmed current (refer to

Figure 2). The maximum available current is limited by the internal OCP (overcurrent protection) comparator,

cycle by cycle. The IPK threshold is gradually reduced during the switching period by slope contribution, as shown

in Figure 18.

Figure 18. Peak current limit

IPK

ILX

TON_min

The inductor current is also monitored during LS MOS on-time. This feature, also known as “valley current

limitation”, is effective in case of current runaway due to HS MOS minimum on-time limitation and very low

VOUT / VIN ratio. This protection can avoid the HS MOS turn-on if the inductor current, sensed during LS MOS

on-time, is higher than the IVY threshold (Figure 19).

Figure 19. Valley current limit

IPK

IVY

TON_min

ILX

L7983

Fault management

DS13354 - Rev 1

page 20/43

L7983 Datasheet(PDF) 20 Page - STMicroelectronics