L9915-CB C-terminal alternator voltage regulator (CTAVR)

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).