L9826

Functional description

Doc ID 7214 Rev 10

15/19

5.3.1

Diagnostic on Outputs 1 and 2 controlled via NON1/NON2

Fault condition (1) "output shorted to Vbat"

The output has been previously switched-on and its voltage exceeds the diagnostics

threshold. It operates in current regulation mode or it is switched-off if thermal shutdown

threshold (TJSC) is reached. The status bit is low.

Fault condition (2) "open load" or "output shorted to GND"

The output is switched-off and its voltage drops below the diagnostics threshold because

the load current is lower than the output diagnostic current source. The diagnostic bit is low.

5.3.2

Diagnostic on Outputs 1 to 8 controlled via SPI

Fault condition (1) "output shorted to Vbat"

The output was previously switched-on, its voltage exceeds the diagnostic threshold and the

result is that the output is switched-off. The diagnostic bit is high.

Fault condition (2) "open load" or "output shorted to GND"

It is the same behavior explained for the outputs 1 and 2 (see paragraph 5.3.1), at NCS

falling edge the output status data are transferred to the shift register.

Load diagnostic: when the output is in OFF condition a typical diagnostic current of 60 µA is

sinked.

Table 8.

Diagnostic table for outputs 1 and 2 in parallel controlled mode

Output 1, 2

Output-voltage

Status-bit

Output-mode

off

> DG-threshold

high

correct operation

off

< DG-threshold

low

fault condition 2)

on

< DG-threshold

high

correct operation

on

> DG-threshold

low

fault condition 1)

Table 9.

Diagnostic table for outputs 1 to 8 in SPI controlled mode

Output 1 ... 8

Output-voltage

Status-bit

Output-mode

off

> DG-threshold

high

correct operation

off

< DG-threshold

low

fault condition 2)

on

< DG-threshold

low

correct operation

on

> DG-threshold

high

fault condition 1)