FLC01-200x

4/8

Rs

Ds

c

D

Th

Z

R

Ic

AC

MAINS

Ic

t

FLC01-200x

Fig. 2: BASIC APPLICATION

The

applications

of

the

lighter

using

the

capacitance discharge topology operate in 2

phases :

PHASE 1

The energy coming from the mains is stored into

the capacitor C. For that, the AC voltage is rectified

by the diode Ds.

PHASE 2

At the end of the phase 1, the voltage across the

capacitor C reaches the avalanche threshold of

the zener. Then a current flows through the gate of

the thyristor Th which fires.

The firing of the thyristor causes an alternating

current to flow through the capacitor C.

The positive parts of this current flow through C,

Th and the primary of the HV transformer.

The negative parts of the current flow through C, D

and the primaty of the HV transformer.

The maximum Rs value is equal to :

Rs

VV

T

T

kI

AC

BO

amb

BO

max

(

min.

)

[

max .(

.(

))]

.*

=

−+

−

21

25

α

* : see fig 1

RS RESISTOR CALCULATION

The Rs resistor allows, in addition with the capacitor C, the spark frequency to be adjusted and the current

from the mains to be limited. Its value shall allow the thyristor Th to fire even in the worst case. In this case

the system must fire with the lower RMS mains voltage value while the breakdown voltage and current of

the FLC are at the maximum.