AN2809

Configuration

11/22

Otherwise, when SW2 is set to the lower position, the MODE pin is connected to AVCC and

the corresponding fault management is summarized in the second column of

Table 4.

Figure 6.

SW2 (MODE) setting

7.3

SW3 enable function

The terminals of the switch SW3 are connected on one side to the EN pin and on the other

side to ground. Therefore, when the switch is not pressed, the EN pin is floating, which

implies that the device is working. When the SW3 pin is pressed, the EN pin is connected to

ground. When the SW3 is released, the device re-starts (the soft-start is performed). The

SW3 switch can be activated whenever a new start-up is required or to escape a latched

condition.

Table 4.

Fault management summary

Fault

MODE to GND

MODE to VCC

Internal MOSFET over

current

Fault pin HIGH

Power MOSFET turned OFF

Output overvoltage

FAULT pin LOW

Device turned OFF, latched condition

Thermal shutdown

FAULT pin LOW. Device turned OFF.

Automatic restart after 30°C temperature drop.

LED short circuit

Fault pin LOW

Device turned OFF at first

occurrence, latched condition

Fault pin LOW

Faulty row(s) disconnected. Device

keeps on working with the remaining

Open row(s)

Fault pin LOW

Device turned OFF at first

occurrence, latched condition

FAULT pin HIGH

Faulty row(s) disconnected. Device

keeps on working with the remaining

row(s)