l9733 STMicroelectronics, l9733 Datasheet - Page 24

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

Fault operation
7
Table 11.
7.1
7.1.1
24/33
MSB
b15
D1
OUT 8
b14
D0
Fault operation
The fault diagnostic capability consists of one internal 16 bits shift register and 2 bits are
used for each output. The diagnostic information are: no fault present, overcurrent, open
load and short circuit.
All of the faults will be cleared on the rising edge of Chip Select if a valid DI byte was
received
Fault register definition
Table 12.
If all the bits b0-b15 of the fault register have value '1' it means that a thermal fault, at least
on one of the eight independent Outputs, occurred.
Low side configured output fault operation
The diagnostic circuitry verifies for the low side configured output the following condition:
Normal operation, open load, short circuit to GND and overcurrent (only if the switching OFF
protection, selectable for each channel via SPI bus, is active).
The diagnostic circuitry operates in two different modes, selected for each channel by SPI:
no latch mode and latch mode. The fault priority is overcurrent and then open load or short
circuit to GND, this means that if an overcurrent occurs the fault register is always
overwritten and following open load or short to GND faults that happen before that the
register is cleared will be ignored.
No latch mode
This diagnostic operating mode doesn't latch open load and short to GND faults.
1.
b13
D1
Open load
The diagnostic of open load 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 inside the voltage range limited by the two thresholds Vth_Vbat and
OUT 7
D1
0
0
1
1
b12
D0
Fault logic definition
b11
D1
OUT6
D0
0
1
0
1
b10
D0
No fault is present
Open load
Short circuit to GND (low side) or Short circuit to Vbat (high side)
Overcurrent
D1
b9
OUT5
D0
b8
D1
b7
OUT4
D0
b6
Fault status
D1
b5
OUT3
D0
b4
D1
b3
OUT2
D0
b2
D1
b1
OUT1
L9733
LSB
D0
b0