EVAL6569 Datasheet, PDF (6/14 Pages) Panasonic Semiconductor – THE L6569 A NEW HIGH VOLTAGE IC DRIVER FOR ELECTRONIC LAMP BALLAST

AN880 APPLICATION NOTE
charged and the circuit can restart immediately.
This method is suitable when the inverter uses
only one DC blocking capacitor connected to the
power ground, as used on figure 11 for Compact
Fluorescent Lamp. Pulling the VS voltage below
the UVLO turns off the oscillator and gives the
same bridge configuration.
For the L6569A, discharging the VS supply below
the UVLO turns off both MOSFETs. An SCR like
the X0202MA may be used for the reset function.
If the current flowing through the supply resistor is
higher than the SCR holding current (see figure
12), the SCR will remain on and the two MOS-
FETs off. Removing power or commutating the
SCR allows a new start up [4].
Otherwise a disable circuitry that turns off the two
MOSFETs (see figure13), can achieve the shut-
down function. Compared to the SCR solution,
the shutdown is immediate and the inverter can
restart on the disable order.
Figure 11: L6569 shutdown through the CF oscillator pin.
L 6569
R_L
R_F
C_F
ON
Figure 12: Shutdown with a thyristor & a serial resistor to slow down the supply voltage decay.
L 6569A
Rs
R
C
OFF
R
shutdown
OFF
Figure 13: L6569 disable circuitry with both MOSFETs off.
V IN
DISABLE
Vs
5.6k
HCF4011
VS BOOT
RF HVG
CF OUT
GND LVG
L6569
4.7 k W
100nF
H.V.
200
200
22
BC327
6/14