L7292 datasheet(43/60 Pages) STMICROELECTRONICS

Part #	L7292

Description	Five buck regulators power management unit

PDF	60 Pages

Scroll/Zoom	100%

Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

Logo

43 / 60 page

DocID028601 Rev 1

43/60

L7292

Buck regulator description

Figure 15. Operating mode

11.4

Soft-start

To limit the inrush current in each buck regulator a soft-start circuit is embedded inside. This

feature is performed using a sequence of 96 pulses of three current levels to increase the

output voltage in a controlled manner.

The complete the sequence is:



96 current pulses at PFM current peak / 2



96 current pulses at current limit / 4



96 current pulses at current limit / 2

According to the load current during the soft-start one or all of the three current levels could

be used.

For example, in light-load condition only the “PFM current peak” step could be enough to

reach the target Vout in short time. If the load current is higher, the “current limit / 4" step is

enabled (Figure 16); if again this isn't enough, the “current limit / 2" is applied.

L7292 Datasheet(PDF) 43 Page - STMicroelectronics