Figure 1 : Application Circuit.

PROTECTION

SHORT CIRCUIT PROTECTION

The integrated darlington is protected against short

circuits of the lamp. The short circuit current is lim-

ited at 600 mA and if this condition persistes thermal

protection will intervene.

DUMP PROTECTION

The whole IC is protected against load dump tran-

sients (100 V, 300 ms with a rise time greater than

5 ms) in the typical application circuit. The only com-

ponent to which this transient is directly applied (no

series resistances) is the lamp driver darlington.

During transients the darlington is kept off and can

withstand peak voltages of 100 V. Additionally, the

IC can withstand low energy spikes up to 300 V.

These spikes are clamped by an internal 100 V

zener on the collector of the lamp driver darlington.

THERMAL PROTECTION

When the IC temperature reaches 170

°C the lamp

driver darlington is kept off.

The device is able to withstand all the voltage tran-

sients mentioned in ISO DP7637/1. If voltage tran-

sients more severe than the above ISO standard

have to be withstood, an external protection device

(transil) must be connected between pin 15 and

µs,

Ω, the transil P6KE100P is recom-

mended.

L585

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