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Fault condition 2) "open load" or "output short circuit to GND" : the output is switched off and the voltage at the

output drops below the diagnostics threshold, because the load current is lower than the output diagnostic cur-

rent source, the load is interrupted. The diagnostic bit is low.

For outputs 3 to 8 the output status signals, are fed directly to the SPI register.

Table 3. Diagnostic for outputs 1 to 8 in SPI controlled mode.

The fault condition 1) "output short circuit to Vbat" :

For outputs 3 to 6 is the same as of outputs 1 and 2.

For outputs 7 and 8 : the output was switched on and the voltage at the output exceeds the diagnostics thresh-

old. The output operates in current regulation mode or has been switched off due to thermal shutdown. The sta-

tus bit is low.

Fault condition 2) "open load" or "output short circuit to GND" is the same as of outputs 1 and 2.

At the falling edge of NCS the output status data are transferred to the shift register. When NSC is low, data bits

contained in the shift register are transferred to SDO output et every rising CLK edge.

Figure 3. The Pulse Diagram to Read the Outputs Status Register

Figure 4. The Structure of the Outputs Status Register

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)

NCS

CLK

SDI

SDO

MSB

LSB

65

4321

MSB

LSB

654

321

Diag2 Diag4 Diag6 Diag8 Diag1 Diag3 Diag5 Diag7

MSB

LSB

Diagnostic-bit output 7

Diagnostic-bit output 5

Diagnostic-bit output 3

Diagnostic-bit output 1

Diagnostic-bit output 8

Diagnostic-bit output 6

Diagnostic-bit output 4

Diagnostic-bit output 2