L9788 datasheet(62/264 Pages) STMICROELECTRONICS

Part #	L9788

Description	Multifunction IC for automotive engine management system

PDF	264 Pages

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Manufacturer	STMICROELECTRONICS [STMicroelectronics]

Direct Link	http://www.st.com

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Multi-voltage regulator supplies

L9788

62/264

DS12308 Rev 4

Multi-voltage regulator supplies

The chip has one pre-boost regulator and one pre-buck regulator, which will supply a 5 V

regulator with external MOS. Three 5 V tracking regulators are included. One charge pump

is used for HS channel and by the 5 V linear regulator to drive the external MOS. See the

diagram in Figure 21. The chip becomes to be supplied and the regulators are enabled in

the sequence: VB_in grows till is higher than VB_IN_uv threshold, then internal 3V3 supply,

charge pump and buck, pre-boost regulator, 5 V linear regulator, 5 V tracking regulator 1, 2

and 3 are switched on. Then the power on reset is released and the chip is working.

Figure 21. Power supply block diagram with pre-boost regulator and MRD

GADG2911161223PS

MRD

VBAT

VB_IN

Rg_pd

VB_STBY

Boost_G

WK_IN

KEY

VBsense

Boost

Supply

Internal

U-chip power structure

VB_IN_SW

C_BST

BUCK_C_BST

VPRE

BUCK_SW

Vtrack 1/2/3

Track Regulator

Buck

Linear

5V Regulator

L9788 Datasheet(PDF) 62 Page - STMicroelectronics