SPSB081 datasheet(38/135 Pages) STMICROELECTRONICS

38 / 135 page

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If OUTx_CCM_EN = 1, after driver has been started in ON, PWM, timer modes then CCM bit is ignored;

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If OUTx_CCM_EN bit is cleared by the microcontroller before timeout, then the driver is switched to ON

mode;

The short-circuit and overcurrent detection are enabled in ON, PWM, timer and DIR modes, but not in constant

current mode. The default value for the OUTx_CCM_EN bit is 0, that is, the CCM is disabled by default.

Figure 24. Constant current mode

3.20

Temperature warning and shutdown

If any of the cluster junction temperatures rises above the temperature warning threshold (TW ON), a temperature

warning flag is set after the temperature warning filter time (tfTjTW) and can be read via SPI. If the junction

temperature increases above the temperature shutdown threshold (TSD1 OFF), the thermal shutdown bit is set

and the power transistors of all output stages are switched off to protect the device after the thermal shutdown

filter time. The temperature warning and thermal shutdown flags are latched and must be cleared by the

microcontroller. This is done by a read and clear command on the relevant status register (TSD1 is bit 4 in

status register 1 while TW is bit 8 in status register 2).

After these bits have been cleared, the output stages are reactivated. If the temperature is still above the thermal

warning threshold, the thermal warning bit is set after tfTjTW. Once this bit is set and the temperature is above the

temperature shutdown threshold, temperature shutdown is detected after tfTjTW and the outputs are switched off.

Therefore, the minimum time after which the outputs are switched off after the bits have been cleared in case the

temperature is still above the thermo shutdown threshold is twice the thermo warning/shutdown filter time tfTjTW.

SPSB081

Temperature warning and shutdown

DS14048 - Rev 1

page 38/135

SPSB081 Datasheet(PDF) 38 Page - STMicroelectronics