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L9474

Table 8. Regulation Features

Notes:

5. A 128Hz PWM signal applied to L input, higher than this threshold, will turn on the device.

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

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

the loss of phase signal, a 31.25% duty cycle is applied to field output when phase drops below Vp2 and Vgo is above setpoint.

8. This is the time duration the L9474 takes to rump up from 0 % to 100% duty cycle in response to an increased load on the gen-

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

Symbol

Parameter

Test Condition

Min.

Typ.

Max.

Unit

fL = 128Hz +/-5%

0.65

0.9

1.15

V

VL = 0.65V

0.3

1.5

mA

Initiation of regulation detection

0.35

V

Fault detection phase voltage

7

89V

Sinking current @ P terminal

0.5

1

1.8

mA

Initiation of field regulation

frequency

72

Hz

FSDF

Field Strobe Duty Factor

12.5

%

LRC

2.125

2.5

2.875

s

LRC transition frequency

LRC disabled above this value

263

310

357

Hz

∆gnd

Difference between ECM &

Alternator ground

-0.2

0.2

V