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against recirculation errors, when D3 or D4 is not connected. All these error conditions shut off the power stage

and invert the status output information.

1.6

Error Detection

The status outputs indicate the switching state under normal conditions (status LOW = OFF; status HIGH = ON).

If an error occurs, the logic level of the status output is inverted, as listed in the diagnostic table below. All ex-

ternal errors, for example open load, are filtered internally. The following table shows the detected errors, the

filter times and the detection mode (on/off).

EN&IN=low means that at least one between enable and input is low. For the inputs IN=low means also no input

All protection functions like short circuit of the output, overtemperature, clock failure or power-GND-loss in ON

condition are stored into an internal “fail” register. The output is then shut off. The register must be reset with a

ulated channel, otherwise it is interpreted as a PWM input signal and the register is left in set mode.

Signal-GND-loss and VS-loss are detected in the active on mode, but they do not set the fail register. This type

Open load is detected for all four channels in on- and off-state.

Open load in off condition detects the voltage on the output pin. If this voltage is below 0.33 * VS the error reg-

the output is floating in case of openload and the detection is not assured. In the ON state the load current is

an error occurs. This could happen when no load is connected, the resistivity of the load is too high or the supply

voltage too low.

set on error and all power outputs are shut off. The status signals remain in their state until the clock signal is

outputs of the channel 1 and 2 are low in this case.

ON State

EN &IN = HIGH

OFF State

EN &IN = LOW

Filter time

Reset done by

Short circuit of the load

EN & IN = “LOW”

Open load

(under voltage detection)

Open load

(under current detection)

Overtemperature

EN & IN = “LOW”

Power-GND-loss

XX

in on: EN & IN = “LOW”

Signal-GND-loss

XX

Supply-VS-loss

XX

Clock control

X

X

no

in on: EN & IN = “LOW”

Output voltage clamp active

X

(regulated

channels)

no

in on: EN & IN = “LOW”