50%

50%

td

td

t

90%

90%

10%

10%

tf

tr

t

Vin

Vout

D94IN127A

50%

50%

Figure 3: Switching Waveforms

DIAGNOSTIC TRUTH TABLE

Diagnostic Conditions

Input

Output

Diag1

Diag2

Normal Operation

L

H

L

H

H

H

H

H

H

L

H

H

L

H

H

L

H

H

H

L

L

H

H

(pin ON-DELAY grounded)

H

H (*)

L

H

H

H

H

Output DMOS Open

L

H

L

L

H

L

H

H

Overtemperature

L

H

L

L

H

H

L

L

H

L

L

L

L

L

L

(*) According to the intervention of the current limiting block.

(**) A cold lamp filament, or a capacitive load may activate the current limiting circuit of the I PS, when the IPS is initially turned on.

Vs

D95IN212

Voth2

Vshys

Voth1

Figure 2: Undervoltage Comparator Hysteresis

L6370

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