EFS

10/14

The driver determines the preheat duration by counting mains cycles. This numeric solution brings

naturally a good precision depending only on the mains frequency tolerance.

With the 2 driver versions, the EFS startlight-kit provides a choice of 4 preheat duration’s. The following

table gives the preheat duration before the first ignition attempt. The seven next preheat duration’s, in case

of unsuccessful ignition attempt, last the half of the first one

6/ PREHEAT PHASE DURATION 50-60Hz:

PREHEAT DURATION

MAINS FREQUENCY

50Hz

60Hz

DRIVER VERSION

EFS2A

EFS2B

EFS2B

Pin 2 connection

GND

VCC

GND

VCC

GND

VCC

1.5s

2.56s

0.74s

1.24s

0.62s

1.03s

During the ignition sequence or once the lamp is lit, the starter checks the state of the lamp (lit or off).

To determine this state, the driver reads the lamp voltage through the resistor bridge (R1+R2+R3, R4).

- If the lamp is off, its voltage equal the mains voltage.

- If the lamp is lit, its voltage is only 80 V (for a 58W lamp).

Thus the lamp state is determined by comparison of the lamp voltage with a programmed detection level.

7/ TUBE STATE DETECTION:

DL

DL

TC

min

min

MAX

LIT Lamp

Voltage

OFF Lamp

Voltage

CORRECT SETTING = NO WAVEFORM

ACROSS THE GREY AREA

Tolerance effects:

Tolerances on resistors (R1, R2, R3 and R4) as

well as on the integrated comparator bring a

tolerance on the set detection level. Thus the

detection level is included in a range delimited by

the maximum and the minimum detection levels

The driver checks the state of the lamp when

mains voltage is maximum, that is to say 5 ms after

the zero crossing mains voltage (50Hz). Here

again internal tolerances bring a tolerance on the

How to set the detection level?

Only the R4 resistor value can be set to adjust the detection level. Values of resitors R1 to R3 must match

values of the table RECOMMENDED COMPONENTS ACCORDING TO APPLICATION CONDITIONS of

the page 5. Practically the R4 resistor value has to be set so that neither the OFF lamp voltage nor the LIT

lamp voltage cross the grey area.

DL

xR

R

R

R

R

DL

MAX

MAX

MAX

MAX

=

++

+

1265

4

1

2

3

4

.(

)

and

min

min

++

+

1122

4

1

2

3

4

.(

)

min

min

min

xR

R

R

R

R

MAX

MAX