L9301 datasheet(22/51 Pages) STMICROELECTRONICS

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Configurable high/low side driver

L9301

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DocID028688 Rev 6

8.2

Driver diagnostic

8.2.1

Thermal protection

Each solenoid channel has a dedicated temperature sensor that continuously monitors the

temperature of the PowerMOS.

In case the shutdown temperature Tsd is reached the related channel is turned off and the

dedicated diagnostic bits are set. t_sdl_x is the bit that latches the thermal shut down and it

is cleared after sending dedicated SPI to clear the bit, t_sd_x is the other thermal shut down

bit and once it is set by thermal shut down condition it is cleared only when the Tj decreases

below the thermal shut down threshold (hysteresis). If the microcontroller, when the device

is still in temperature shut down condition (t_sd_x = 1), clears the t_sdl_x and tries to turn on

the output, the actuation is not performed and the t_sdl_x will be set again. To avoid these

multiple interrupts the microcontroller can poll the t_sd_x bit and enable the next actuation

only when the bit is zero.

To re-switch on the channel after thermal shut down, the SPI needed to switch off the

channel is required.

8.2.2

Overcurrent protection

An overcurrent protection is present for each driver DRN/SRC1...4. The overcurrent

threshold is selectable through oc_thres_x (where x indicates the channel). In case of

overcurrent the output driver is turned off, the related SPI command bit is set to 0 and a

dedicated diagnostic bit is set oc_x where x indicates the channel where the fault occurred.

If bit oc_restart = 0, to restart the channel the microcontroller has to clear the fault bit

(reading the fault register), and to write to 1 the SPI command bit or to provide a rising edge

on the parallel input command.

If bit oc_restart = 1, the restart function is activated. The slew rate of the channel in fault

condition is automatically set to the higher value to limit dissipation issue then to restart the

channel the microcontroller has to write to 1 the SPI command bit or to provide a rising edge

on the parallel input command. The diagnostic bit oc_x can be cleared only by writing it to 0

in the corresponding driver status register by SPI however the channel can be restarted as

described above.

8.2.3

Output status

During the ON phase, the output voltage is compared with the VTopen threshold voltage in

order to verify if the output status is aligned with the ON command:



in case of low side usage if the DRNx voltage is above the VTopen threshold a

dedicated bit is set to indicate the anomaly



in case of high side usage if the SRCx voltage is below the VTopen threshold a

dedicated bit is set to indicate the anomaly

8.2.4

Charge Pump (CP)

The charge pump is enabled when the selected configuration includes high side drivers (like

configuration 2, 3, 4). In configuration 1 the charge pump is internally shorted to VB.

On the CP pin it's required to connect a 100 nF capacitor toward the VB line.

The charge pump is ON if VB > UV threshold & VDD > UV threshold

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