FIRE LIGHTER CIRCUIT - (ASD)
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Application Specific Discretes
A.S.D.TM
FLC10-200H/B
October 2001 - Ed: 7E
FIRE LIGHTER CIRCUIT
The FLC10 series has been especially developed
for high power capacitance discharge operation.
The main applications are gas lighters or ignitors
such as :
cookers / gas boilers / gas hobs...
Based on ST's ASDTM technology, it provides a
fully integrated function, with high performance
and reliability levels, adapted to severe and hot
temperature environment.
Th: Thyristor for switching operation.
Z: Zener diode to set the threshold voltage.
D: Diode for reverse conduction.
R: 2 k
resistor.
DESCRIPTION
Z
R
D
Th
pin 2 or Tab
pin 1/3 (*)
FUNCTIONAL DIAGRAM
IPAK
FLC10-200H
1
2
3
TAB
s
Dedicated
thyristor
structure
for
capacitance
discharge ignition operation
s
High pulse current capability
240A @ tp= 10
s
s
Fast turn-on operation
s
Designed for high ambient temperature (up to
120C)
FEATURES
s
Space saving thanks to monolithic function
integration
s
High reliability with planar technology
BENEFITS
(*) Pin1 and Pin3 must be shorted together in
the application circuit layout.
1
2
3
TAB
DPAK
FLC10-200B
FLC10-200H/B
2/8
Symbol
Parameter
Value
Unit
Rth(j-a)
IPAK thermal resistance junction to ambient
100
C/W
Rth(j-a)
DPAK thermal resistance junction to ambient S = 0.5cm
2
70
C/W
S = Copper Surface under Tab
THERMAL RESISTANCE
FIRE LIGHTER CIRCUIT
CIRCUIT NUMBER
SCR + Diode + Zener + Resistance
High Power Version
200: V
20V
BO min =
FLC 10 - 200 x
Package:H: IPAK
B: DPAK
ORDERING INFORMATION
Symbol
Parameter
Value
Unit
I
TRM
Repetitive surge peak on state current for thyristor
-30C
T
amb
120
C
tp = 10
s
( note 1)
240
A
I
FRM
Repetitive surge peak on state current for diode
-30C
T
amb
120C
dI/dt
Critical rate of rise time on state current -30C
T
amb
120C
200
A/
s
Tstg
Tj
Storage junction temperature range
Maximum junction temperature
- 40 to + 150
+ 125
C
Toper
Operating temperature range
-30 + 120
C
T
L
Maximum lead temperature for soldering during 10s
260
C
Note 1 : Test current waveform
ABSOLUTE RATINGS (limiting values)
200ms
10s
FLC10-200H/B
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ELECTRICAL CHARACTERISTICS
Symbol
Parameters
V
RM
Stand-off voltage
V
BO
Breakover voltage
V
T
On-state voltage
V
F
Diode forward voltage drop
I
BO
Breakover current
I
RM
Leakage current
T
Temperature coefficient for V
BO
I
I
F
VF
V
T
IRM
I BO
I T
V
RM
V
BO
V
Symbol
Test Conditions
Value
Unit
V
F
I
F
= 2A
tp
500s
Tj = 25C
Max.
1.7
V
DIODE (D) PARAMETER
Symbol
Test conditions
Min
Typ
Max
Unit
I
RM
V
RM
= 200 V
Tj = 25C
10
A
Tj = 125C
100
A
V
BO
at I
BO
Tj = 25C
200
225
250
V
I
BO
at V
BO
Tj = 25C
0.5
mA
V
T
I
T
= 2A
tp
500s
Tj = 25C
1.7
V
T
13
10
-4
/C
THYRISTOR (Th) and ZENER (Z) PARAMETERS
-20
0
20
40
60
80
100
0
0.5
1
1.5
2
2.5
Tj (C)
k = I
(Tj) / I
(25C)
BO
BO
Fig. 1: Relative variation of breakover current
versus junction temperature.
FLC10-200H/B
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Rs
Ds
c
D
Th
Z
R
Ic
AC
MAINS
Ic
t
Fig. 2: BASIC APPLICATION
The applications of the lighter using the capaci-
tance 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
V
V
T
T
k I
AC
BO
amb
BO
max
(
min.
)
[
max .(
.(
))]
.
*
=
-
+
-
2
1
25
* : see fig 1
COMPONENT CHOICE
RS RESISTOR CALCULATION
The Rs resistor allows, in addition with the capacitor C, the spark frequency to be adjusted and the cur-
rent from the mains to be limited. Its value shall allow the thyristor Th to fire even in worst case condi-
tions. In this borderline case, the system must fire with the lowest value of RMS mains voltage while
the breakdown voltage and current of the FLC are at the maximum.
FLC10-200H/B
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Fig. 4: Voltage across the capacitance with Rs = 15k
, C = 1
F and V
BO
= 225V.
4.7
6.8
10
12
15
18
22
27 30
1
2
3
5
10
20
F (Hz)
Rs (k )
Vac=220Vrms, Vbo=225V, Tamb=25C
C=3.3
F
C=2.7
F
C=2.2
F
C=0.47
F
C=0.47
F
C=1
F
C=1
F
C=1.5
F
C=1.5
F
Fig. 3: Spark frequency versus Rs and C
The couple Rs/C can be chosen with the previous
curve. Keep in mind the Rs maximum limit for
which the system would not work when the AC
mains is minimum. The next curve shows the be-
havior with Rs=15k
and C=1
F.
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