EVAL6569 STMicroelectronics, EVAL6569 Datasheet - Page 9

• Manufacturer Part Number: EVAL6569
• Description: BOARD EVAL LIGHTING L6569
• Manufacturer: STMicroelectronics
• Type: Charge Pumpsr

Specifications of EVAL6569

• Mfg Application Notes: L6569, AN880 App Note
• Main Purpose: Lighting, Ballast Control
• Embedded: No
• Utilized Ic / Part: L6569
• Primary Attributes: 18 W, Optimized for a CF18DT/E/830, 120 or 230 VAC
• Secondary Attributes: Preheating Done with a PTC
• Input Voltage: 230 V
• Product: Power Management Modules
• Supply Current: 0.17 A
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: L6569
• Other names: 497-4738

line voltage V
starts. The ballast has to start directly with its
nominal conditions to remove any transient oscil-
lation. Hence the operation runs in ZVS mode
with no spurious lamp ignition. This situation does
not occur with the saturable transformer drive, be-
cause the saturation limits naturally the current by
increasing the frequency.
In the example the resonant capacitors are pre-
set to be compatible with the choke current rise
(see figure 19). The blocking capacitor is pre-
charged to approximately half V
resistors, and the lower Mosfet also discharges
the resonant capacitor to ground (see figure 20).
Therefore the blocking capacitor never goes
above 2/3 of the line voltage V
the operation is safe in ZVS mode. The L6569 is
here preferred to the L6569A, because the lower
Figure 19: Waveforms of the choke current and
Mosfet is on at power-up.
Figure 20: Configuration of the resonant network during the initialization of the driver.
5 s/dv ; 50 V/dv ; 0.5 A/dv
the capacitor voltages in steady state
preheat.
V
BI
VS<UVLO
DC
IDEAL INITIAL TIME
L6569
is applied when the oscillator
I
I
DC
DC
V
(250V rating),
B
by 2 biasing
ON
2.4 mH
2 x 180 k
GND
GND
V
B
The lamp removal protection
Used in TL ballast, the lamp removal protection is
frequently also requested in the "plug-in" CFL bal-
last . Depending of the topology and the preheat
mode, the lamp removal behaves as:
When the circuit is open, the choke is not sup-
plied. The MOSFETs turn off slowly generating
bridge cross conduction, and undesirable dissipa-
tion losses (see figure 21). The detection stops
the switching to eliminate the cross conduction.
Figure 21: Drain current and voltage STP8NA50
V
V
I
- a noload resonant mode when the choke and
- an open circuit mode when the lamp filaments
D
D
GS
the capacitor are still connected to the in-
verter ; a required overcurrent protection in-
creases the frequency to reduce the current;
are inserted in the resonant circuit.
I
MOSFET operating with noload.
100 ns/dv ; 50 V/dv ; 5V/dv ; 1 A/dv
I
AN880 APPLICATION NOTE
100 nF
I
D
= 2 A peak
V
BI
4nF
GND
GND
GND
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