The L9409 is a monolithic multifunction alternator voltage regulator intended for use in automotive applications. The device regulates the output of an automotive generator by controlling the field winding current by means of either an analog fixed frequency PWM signal or digital fixed frequency PWM signal (LRC). The Load Response Control function is activated in order to eliminate IC engine speed fluctuation and vibrations caused by the insertion of sudden electrical loads during alternator low speed operations (f < 310 Hz). Both the analog and digital duty cycle are applied to a high side driver. The device is able to regulate the voltage either using a feedback signal from B pin or from S pin depending on the application needs. S pin is intended to have a clear direct connection with the positive terminal of the car battery. If this connection gets lost, the device will enter a failsafe mode and provide protection to the power system.
The L9409 is a monolithic multifunction alternator voltage regulator intended for use in automotive applications. It regulates the output of an automotive generator by controlling the field winding current using either an analog or digital fixed frequency PWM signal. The device includes a Load Response Control (LRC) function to eliminate engine speed fluctuations caused by sudden electrical loads.
| Thermal shutdown temperature | 175 °C |
|---|---|
| Regulation set-point voltage @ 25 °C | 14.5 V |
The Load Response Control function activates after an initial time delay to eliminate IC engine speed fluctuation and vibrations caused by the insertion of sudden electrical loads.
The device uses double sensing of battery voltage via the VB and VS pins; if the S pin connection is lost, it regulates voltage using the B pin for fail-safe functionality.