L6984 datasheet(20/34 Pages) STMICROELECTRONICS

Part #	L6984

Description	36 V 400 mA synchronous step-down switching regulator

PDF	34 Pages

Scroll/Zoom	100%

Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

Logo

20 / 34 page

Device description

L6984

20/34

DocID025378 Rev 3

3.5.2

LNM

Equation 11 is also valid when the device works in LNM and it can boost the efficiency at the

medium load since the regulator always operates in continuous conduction mode.

3.6

Overcurrent protection

The current protection circuitry features a constant current protection, so the device limits

the maximum current (see Table 5: Electrical characteristics on page 7) in overcurrent

condition.

The low-side switch pulse-by-pulse current sensing, called “valley”, implements the constant

current protection. In overcurrent condition the internal logic keeps the low-side switch

conducting as long as the switch current is higher than the valley current threshold.

As a consequence the maximum DC output current is:

Equation 12

Figure 13. Constant current operation in dynamic short-circuit

IMAX

IVALLEY_TH

IRIPPLE

--------------------

IVALLEY_TH

VIN VOUT

–

------------------------------ TON



L6984 Datasheet(PDF) 20 Page - STMicroelectronics