This is information on a product in full production.

June 2014

DocID026400 Rev 1

1/21

L9915

C-terminal alternator voltage regulator (CTAVR)

Datasheet

Features

 Fully monolithic design

 High side field driver

 Field short circuit protection

 Regulated voltage driven by ECU (protocol

driven)

 Regulated voltage thermally compensated

(without protocol)

 Lamp driver (wake up and warning detection)

 Self start function

 Load response control (LRC)

 Field monitor (FM) output

 Thermal shutdown

Description

The device is a monolithic alternator voltage

regulator intended for use in automotive

application.

It includes the control section, the field power

stage, fault diagnostic circuit which drives a

warning lamp, and the protection against short

circuits.

This device regulates in close loop the output of

an automotive generator by controlling the field

winding current by means of a pulse-width

modulation (PWM) high side driver at fixed

frequency.

The set-point voltage reference selected by the

Engine Control Unit via C-terminal protocol is

temperature flat. An internal voltage reference

thermally compensated is present in the device

and used when the protocol coming from ECU is

absent or the wire is broken.

A self-bias circuitry is present on L pin in order to

turn-on the warning lamp also when the device is

not supplied (battery connection broken).

Multiwatt8

Table 1. Device summary

Order code

Self start

frequency

threshold

High frequency

threshold to exit

prexcitation option

Freq. threshold to

exit/enter LRC

Temp range,

C

Package Packing

L9915-CB

1. Other values for VBITD, fPHPrex, fMsw and VBisp can be possible. ST reserves the right to decide on a case by case

basis.

fPHPrex,1(1)

fPLRC,1(1)

Tube

www.st.com