DS4742 Rev 7

9/13

L9914

Electrical specifications

12

2.5.2

Regulation feature

Table 9. Regulation feature characteristics

Symbol

Parameter

Test conditions

Min.

Typ.

Max.

Unit

0.65

0.9

1.15

V

0.3

-

1.5

mA

Initiation of regulation detection

-

0.4

-

V

Fault detection phase voltage

-

789

V

Sinking current @ P terminal

0.5

1

1.8

mA

Initiation of field regulation

frequency

for L9914A

61

72

83

Hz

FSDF

Field strobe duty factor

for L9914A

-

13.5

-

%

LRC

for L9914A

2.125

4.25

2.5

5.0

2.875

5.75

s

LRC transition frequency

LRC disabled above this value

for L9914A

263

310

357

Hz

Δgnd

Difference between ECM &

alternator ground

-

-0.2

-

0.2

V

Overvoltage

-

16.5

-

22

V

L saturation voltage

-

-

1.55

V

Fault indication delay time

-

0.935

1.1

1.265

s

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

3. 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.

4. This is the time duration the L9914 takes to ramp up from 0% to 100% duty cycle in response to an increased load on the

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