flc01-200d STMicroelectronics, flc01-200d Datasheet - Page 4

• Manufacturer Part Number: flc01-200d
• Description: Fire Lighter Circuit
• Manufacturer: STMicroelectronics

FLC01-200D
BASIC APPLICATION
4/7
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 reachesthe 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.
MAINS
AC
Rs
Ds
Rs max
* : see fig 1
Z
R
V
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.
RS RESISTOR CALCULATION
The Rs resistor allows, in addition with the
capacitor C, to adjust the spark frequency and to
limitate the current from the mains. Its value shall
allow the thyristor Th to fire even in the worst case.
In this borderline 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.
The maximum Rs value is equal to :
AC
Th
min. 2
D
[ V
BO
c
k . I
Ic
max . 1
BO
T . T
Ic
amb
25 ]
t