5/15

L6567

(*) 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

On Delay of G2 Output

1.05

1.4

1.75

µs

Ratio between Delay Time +

Conduction Time of G1 and G2

Cl = 0V

0.87

0.77

1.15

1.30

LOW SIDE DRIVER SECTION

Ron G2 so

G2 Source Output Resistance

80

190

Ω

Ron G2 si

G2 Sink Output Resistance

65

125

Ω

Ron G1 so

G1 Source Output Resistance

80

190

Ω

Ron G1 si

G1 Sink Output Resistance

65

125

Ω

HIGH SIDE DRIVER SECTION

Leakage Current of FS PIN to

GND

5

5

µA

µA

Leakage Current of S1 PIN to

GND

5

5

µA

µA

BOOTSTRAP SECTION

Boot Th

BOOTSTRAP Threshold

5 (*)

V

AVERAGE RESISTOR

Average Resistor

27

38.5

50

k

Ω

Symbol

Parameter

Test Conditio n

Min.

Typ.

Max.

Unit

G1

DON

G1

ON

+

G2

DON

G2

ON

+

-------------------------------------------

ELECTRICAL CHARACTERISTCS (Continued)