L6567 STMicroelectronics, L6567 Datasheet - Page 5

• Manufacturer Part Number: L6567
• Description: HIGH VOLTAGE DRIVER FOR CFL
• Manufacturer: STMicroelectronics

ELECTRICAL CHARACTERISTCS (Continued)
(*) Before starting the first commutation; when switching 6V is guaranteed.
General operation
The L6567 uses a small amount of current from a supply resistor(s) to start the operation of the IC. Once start
up condition is achieved, the IC turns on the lower MOS transistor of the half bridge which allows the bootstrap
capacitor to charge. Once this is achieved, the oscillator begins to turn on the upper and lower MOS transistors
at high frequency, and immediately ramps down to a preheat frequency. During this stage, the IC preheats the
lamp and after a predetermined time ramps down again until it reaches the final operating frequency. The IC
monitors the current to determine if the circuit is operating in capacitive mode. If capacitive switching is detected,
the IC increases the output frequency until zero-voltage switching is resumed.
Startup and supply in normal operation
At start up the L6567 is powered via a resistor connected to the R
current charges the C
V
assures that the bootstrap capacitor is charged. When V
the R
LOW SIDE DRIVER SECTION
HIGH SIDE DRIVER SECTION
BOOTSTRAP SECTION
AVERAGE RESISTOR
G1
------------------------------------------ -
G2
S LOW1
Ron G2 so
Ron G1 so
R
Ron G2 si
Ron G1 si
Symbol
DON
DON
Boot Th
G2
AVERAGE
I
I
S1 LK
HV
FSLK
DON
+
+
pin does not provide anymore the supply current for the IC (see fig.1).
G1
G2
(max 6V), the low side MOS transistor is turned on while the high side one is kept off. This condition
ON
ON
On Delay of G2 Output
Ratio between Delay Time +
Conduction Time of G1 and G2
G2 Source Output Resistance
G2 Sink Output Resistance
G1 Source Output Resistance
G1 Sink Output Resistance
Leakage Current of FS PIN to
GND
Leakage Current of S1 PIN to
GND
BOOTSTRAP Threshold
Average Resistor
S
capacitor connected to the V
Parameter
I
V
V
V
V
V
V
V
V
V
RHV
S
S
S
S
FS
FS
S1
S1
S
= 12V, V = 3V
= 12V, V = 3V
= 10V, V = 3V
= 10V, V = 3V
= 10.6V before turn on
= 568V; G1 = L
= 568V; G1 = H
= 568V; G1 = L
= 568V; G1 = H
= 1mA; Cl = 5V
S
Test Conditio n
pin (pin 5). When the V
S HIGH1
Cl = 0V
threshold is reached the oscillator starts, and
HV
pin (pin 13) from the rectified mains. The
S
Min.
1.05
0.87
0.77
5 (*)
80
65
80
65
27
voltage reaches the threshold
Typ.
38.5
1.4
Max.
1.75
1.15
1.30
190
125
190
125
50
5
5
5
5
L6567
Unit
k
V
A
A
A
A
s
5/15