Functional description

L9380

10/18

In application which don’t use the overload protection or if one channel is not used, the

Timer pin of this channel must be connected to ground and the drain pin with a resistor to

than the source pin (see Figure 4). In the switching point the comparator input source pin

equal external resistors (RD = RS) at drain and source pin are imperative. The drain sense

comparator, which detects the overload, has a symmetrical hysteresis of 20 mV (see

Figure 5).

Exceeding the source pin voltage by 10 mV with respect to the drain voltage forces the timer

capacitor to discharge. Decreasing the source pin voltage 10 mV lower than the drain pin

voltage an overload of the external MOS is detected and the timer capacitor will be loaded.

channel is switched off. In this case the overload is stored in the timer capacitor.

The timer capacitor will be discharged with a ’High’ signal at the input (see Figure 3). After

able to switch on again.

Figure 3.

Timing characteristic

Figure 4.

Drain, source input current.

4.4V

0.4V

D98AT392

=

V

D

0

D98AT393