Electrical specifications

L9823

12/19

DocID7791 Rev 7

2.4

Power outputs characteristics for flyback current, outputs

short circuit protection and diagnostics

For output currents flowing into the circuit the output voltages are limited. The typical value

of this voltage is 50V. This function allows that the flyback current of a inductive load

recirculates into the circuit; the flyback energy is absorbed in the chip.

Output short circuit protection SFPD = Low (dedicated for loads without inrush current):

when the output current exceeds the short circuit threshold, the corresponding output

is started after each rise of CSB and valid datas are transferred to the output control

register. If the short takes place after the delay time has elapsed the shutdown is immediate

(within 15 µs).

Output short circuit protection SFPD = High (dedicated for loads with inrush current, as

lamps): when the load current would exceed the short circuit limit value, the corresponding

output goes in a current regulation mode. The output current is determined by the output

characteristics and the output voltage depends on the load resistance. In this mode high

power is dissipated in the output transistor and its temperature increases rapidly. When the

power transistor temperature exceeds the thermal shutdown threshold, the overload latch is

set and the corresponding output switched off.

For the load diagnostic in output off condition each output features a diagnostic current sink,

of typ 60 µA.