L9959 Datasheet, PDF (27/49 Pages) STMicroelectronics – Single and dual PMOS high-side H-bridge

L9959
4.2.2
4.2.3
Application information
Current limitation
The H-Bridge output current can be limited to three different values (see Table 15: Current
limiting). If the current reaches the current limiting threshold ICL, the output driver is
switched off after the blanking time t_b, and switched on again after the current dropped
below the lower current limit hysteresis threshold (I_CL – I_HYS). The current limiting
thresholds can be adjusted using the resistor at pin CF. The values in Table 15 refer to a
5.1k Ohm external resistor. The current limiting threshold can be calculated by (4.5V/R_CF -
I_OFFSET) * (I_CLx*5.1k/4.45V) from Table 15 and I_OFFSET =10μA (typical). R_CF is the resistor
used at pin CF.
The overcurrent threshold is not changed by RCF (see Table 16). The current limitation is
active as long as the output driver is switched on. The information that the device is in
current limitation is stored in the diagnosis register 2 (DIA_REG2).
Figure 16. Current limitation
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Temperature dependent current reduction
If the device reaches the temperature TILR, the current will be reduced (see Figure 17:
Temperature dependent current reduction). If the temperature reaches the temperature
shutdown threshold TSD, the outputs are switched off. The current limitation information is
written into the diagnosis register 2 (DIA_REG2).
Figure 17. Temperature dependent current reduction
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