概要

The L9349 is a monolithic IC designed to drive inductive loads in low side configurations like hydraulic valves used in ABS systems. Particular care has been taken to protect the device against failures, to avoid electromagnetic interferences and to offer extensive real time diagnostics.
The internal pull down current source at the ENable and INput pins assures, that the device is switched off, in case of open input conditions.
An output voltage slope limitation is implemented to reduce the EMI.
The device is equipped with an integrated Zener diodes clamp for fast inductive load current recirculation. This structure limits the output voltage during the recirculation phase to 50V.
The device is self-protected against short circuit at the outputs and overtemperature.
For the real time error diagnosis, the voltage and the current of the outputs are compared with internally fixed thresholds to recognize open load in OFF and ON conditions.
The output voltages are also compared with each other in OFF condition with a fixed offset, in order to recognize load bypasses.
If the over load current threshold is exceeded, the output current will be limited internally during the diagnostic overload delay switch-off time.
All four channels are monitored with a status output. The diagnostic output level in connection with different enable and input conditions allows it to recognize the different fail states.