DocID026400 Rev 1

15/21

L9915

Electrical specification

20

3.3.5

Pin "PH"

To convert phase frequency (Hz) to rotation speed (rpm) according to alternator poles pair

number (N), use the following equation: rotation speed (rpm) = phase frequency (Hz) * 60 / N.

Principle of phase regulation

When VB is above the set-point voltage, the field driver is controlled to keep phase peak

voltage from falling below VPprTh. If phase peak voltage drops below VPLTh, phase

regulation does not work.

Figure 11. Principle of phase regulation

Table 10. Electrical characteristics - Pin "PH"

Symbol

Parameter

Test condition

Min

Typ

Max

Unit

High voltage threshold of hysteresis

input buffer

-

300

375

450

mV

Low voltage threshold of hysteresis

input buffer

-

225

275

325

mV

Pull-down resistor

-

7

15

22

kΩ

Spike rejection time

-

50

115

180

μs

-

1.5

2

3.5

mA

High frequency threshold to exit pre-

excitation option1

-

102

120

138

Hz

Frequency hysteresis

-

10

20

30

Hz

Low frequency threshold to enter pre-

excitation

Hz

Self start frequency threshold

-

255

300

345

Hz

Frequency threshold to exit/enter in

LRC option1

272

320

368

Hz

Phase regulation voltage threshold

-

6.7

7.7

8.7

V