l9733 STMicroelectronics, l9733 Datasheet - Page 25

• Manufacturer Part Number: l9733
• Description: Octal Self Configuring Low/high Side Driver
• Manufacturer: STMicroelectronics

L9733
7.1.2
2.
3.
The use of the IN6-8 pins for PWM control on the outputs 6-8 could generates bad
diagnostic behavior when the falling edge of CS happens a short time after the falling edge
of IN6-8 during the power MOS transient. Software filtering may be needed to ignore fault
signals during Drn6-8 transient after falling edge of IN6-8.
Latch mode
This diagnostic operating mode latches all faults when they happen.
1.
2.
3.
Vth_GND. An internal current limited voltage regulator fixes the drain voltage inside the
described range when no load is connected.
Short circuit to GND
The diagnostic of short circuit to GND is detected only in OFF condition sensing the
Drn1-8 output voltage. This fault is detected on the falling edge of the CS input if the
power drain voltage is lower than the Vth_GND threshold.
Overcurrent
The diagnostic of overcurrent is detected only in ON condition, if the switching OFF
protection of the channel is enabled (default), sensing the current level of the output
power transistor. If the output current has been above the short threshold Iovc for the
filtering time Tdel the output power is switched off and at the same time an overcurrent
fault is written in the fault register.
There are three possibilities to restart one output after the fault has occurred:
–
–
–
–
Open load
The diagnostic of open load is detected only in OFF condition sensing the Drn1-8
output voltage. This fault is detected if the power drain voltage is inside the voltage
range limited by the two thresholds Vth_Vbat and Vth_GND for the filtering time Tfilt.
An internal current limited voltage regulator fixes the drain voltage inside the described
range when no load is connected.
Short circuit to GND
The diagnostic of short circuit to GND is detected only in OFF condition sensing the
Drn1-8 output voltage. This fault is detected if the power drain voltage is lower than the
Vth_GND threshold for the filtering time Tfilt.
Overcurrent
The diagnostic of overcurrent is detected only in ON condition, if the switching OFF
protection of the channel is enabled (default), sensing the current level of the output
power transistor. If the output current has been above the short threshold Iovc for the
filtering time Tdel the output power is switched off and at the same time an overcurrent
fault is written in the fault register. If the switching OFF protection is not active the On
Automatically after a time Tres
On the rising edge of CS if two valid DI byte has been received and first the Output
Status in the command register is written with logic '0' and then with a logic “1” in
the following SPI cycle
On the rising edge (low to high transition) at the corresponding parallel input pin
(only for Outputs 6-8).
If the switching OFF protection is not active the On phase overcurrent protection is
a linear current limitation and no diagnosis is available.
Fault operation
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