描述

The L9352B is designed to drive inductive loads in low side configurations like hydraulic valves used in ABS/ESC systems. Integrated active Zener diodes clamp (for channel1 and 2) or free wheeling diodes (for channel 3 and 4) allow the recirculation of the inductive loads.
All four channels are monitored with a status output. All wiring to the loads and supply pins of the device are controlled. The device is selfprotected against short circuit at the outputs and overtemperature. For each channel, one independent push-pull status output is used for a parallel diagnostic function.
Channel 3 and 4 work as current controlled channels. The target value of the current is given by the duty cycle (DC) of the 2 kHz PWM input signal.
The output current is controlled through the output PWM of the power stage. The regulator limits of 10% or 90% are detected and monitored with the status signal. The current is measured during the recirculation phase of the load.
Using an external clock frequency of 250 kHz, the PWM output frequancy is 3.9 kHz.
A digital PI (proportional and integrating) regulator is performed in order to internally control the target current basing on the load current measurements.