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L9468

3FAULT

The following table lists the conditions that cause the fault lamp driver to function. To prevent lamp flicker, spe-

cific faults are required to be present for TDELAY seconds before the lamp driver is activated. This delay is

indicated in the table.

Table 7.

Table 8. Regulation Features

Notes:

6.

Lamp and Ignition are cooperative. Either can turn on the device when the other is left open or held low. When both go below

their minimum thresholds the L9468 goes into "L" Terminal Control (LTC). The L9468 will remain in LTC until the phase (P) voltage

drops below VP2 and the frequency drops below fIRF at the VP1 threshold then the L9468 is disabled.

7.

This threshold on the phase signal is used to detect the phase frequency, fIFR, for the Initiation of field regulation.

8.

This threshold on the phase signal is used to sense the presence of the phase for fault detection purposes.

9.

This is the time duration the L9468 takes to rump up from 0 % to 100% duty cycle in response to an increased load on the enerator.

The LRC ratio is set 1:4 and the Vreg comparator status is latched at foundamental frequency rate.

10. Cut-back occurs when both the "L" and "I" terminals are LOW . If the "I" terminal is disconnected it will assume a logic LOW

allowing the "L" terminal to perform the function alone. In cut-back, to prevent the loss of phase signal, a 31.25% duty cycle is

applied to field output when phase drops below Vp2

Conditions

Delay

1. Key-on (wiring check), lamp stays on for 1 ± 0.15 sec regardless

other conditions

No

Yes

Yes

4. Phase Voltage < VP2 AND VGO / S < setpoint

Yes

Yes

6. No connection between Battery and VGO

No

7. FAILSAFE

Yes

Symbol

Parameter

Test Condition

Min.

Typ.

Max.

Unit

0.8

1

1.15

V

Lamp term current sensitivity

0.09

0.78

mA

Initiation of regulation detection

2.5

3

3.5

V

Fault detection phase voltage

7

89V

Sinking current @ P terminal

0.5

1

1.8

mA

Initiation of field regulation

frequency

53.04

61

70.15

Hz

FSDF

Field Strobe Duty Factor

31.25

%

LRC

2.125

2.5

2.875

s

LRC transition frequency

LRC is enabled below this value

263.5

310

356.5

Hz

"L" term. Cut-Back Setpoint

20%

25%

V