FLC21-65A STMICROELECTRONICS [STMicroelectronics], FLC21-65A Datasheet - Page 4

• Manufacturer Part Number: FLC21-65A
• Description: LOW POWER FIRE LIGHTER CIRCUIT
• Manufacturer: STMICROELECTRONICS [STMicroelectronics]

FLC21 FAMILY
Fig. 3: BASIC DC APPLICATION
1/ IGNITION MODE
PHASE 1
The AC voltage is rectified by the diode Ds.
The ignition energy is supplied by the mains
and stored into the capacitor C.
4/6
Fig. 2: BASIC AC MAINS APPLICATION
MAINS
AC
S
1
S
1
Oscillator
DC/AC
Rs
Ds
Ds
Rs
Z
R
Z
R
PHASE 2
At the end of the phase 1, the voltage across the
capacitor C reaches the avalanche threshold of
the Zener diode Z. Then, a current flows through
this Zener diode into the gate of the thyristor Th
which is triggered.
The thyristor turn on generates an alternating
current through the capacitor C. Its positive parts
flow through the capacitor C, the primary of the HV
transformer and the thyristor Th. Its negative parts
of the current flow through C, D and the primary of
the H.V transformer.
Th
D
Th
D
c
Ic
c
Ic
Ic
Ic
t
t