L9823(2003) データシートの表示（PDF） - STMicroelectronics

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L9823
(Rev.:2003)

Octal low-side driver for bulb, resistive and inductive loads with serial input control, output protection and diagnostic

STMicroelectronics 

L9823

Output Stages Control

Each output is controlled with its latch and with a common Reset line, which enables all outputs.

The control data are transmitted via the SI input, the timing of the serial interface is shown in Fig. 1.

The device is selected with low CSB signal and the input data are transferred into the 8 bit shift register at every

falling SCLK edge. The rising edge of the CSB latches the new data from the shift register to the drivers.

Figure 1. Timing of the Serial Interface

CSB

tsclch thclcl

tclh

tcll

SCLK

tcsdv

tpcld

SO

not defined

D7

tscld

thcld

SI

D7

D6

tsclcl

thclch

tpchdz

D0

D0

The SPI register data are transferred to the output latch at rising CSB edge. The digital filter between CSB and

the output latch ensures that the data are transferred only after 8 SCLK cycles or multiple of 8 SCLK cycles

since the last CSB falling edge. The CSB changes only at low SCLK.

Diagnostics

The output voltage at all outputs is compared with the diagnostic threshold, typ 0,55 • VDD = VDG.

Diagnostic Table for outputs:

Output

off

off

on

on

Output-voltage

> DG-threshold

< DG-threshold

< DG-threshold

> DG-threshold

Status-bit

high

low

low

high

Output-mode

correct operation

fault condition 2)

correct operation

fault condition 1)

Fault condition 1) "output short circuit to Vbat" : For SFPD = Low the output was switched on and the voltage at

the output exceeded the diagnostics threshold due to overcurrent, the output overload latch was set and the

output has been switched off. The diagnostic bit is high.

: For SFPD = High the output was switched on and the voltage at the output exceeds the diagnostics threshold.

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

bit is high.

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.

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

contained in the shift register are transferred to SO output at every rising SCLK edge.

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