STEVAL-ILB008V1 STMicroelectronics, STEVAL-ILB008V1 Datasheet - Page 22

• Manufacturer Part Number: STEVAL-ILB008V1
• Description: BOARD EVAL BALLAST FOR L6585DE
• Manufacturer: STMicroelectronics
• Type: Power Factor Correctionr

Specifications of STEVAL-ILB008V1

• Main Purpose: Lighting, Ballast Control
• Embedded: No
• Utilized Ic / Part: L6585DE
• Primary Attributes: 4 x 18w, T8 Lamps
• Secondary Attributes: Preheating Ignition
• Input Voltage: 90 V to 265 V
• Product: Power Management Modules
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: L6585DE
• Other names: 497-10544

Ballast section
6.4
6.5
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Old lamp management during run mode
During run mode, an old lamp can exhibit three different abnormal behaviors:
●
●
●
Rectifying effect
The rectifying effect is related to a differential increase of the ohmic resistance of the two
cathodes. The lamp equivalent resistance is therefore higher when the lamp current flows in
one direction than in the other. The current waveform is distorted and the mean value of the
lamp current is no longer zero. The EOL pin is the input of an internal window comparator
that can be triggered by a voltage variation due to rectifying effect.
The reference of this comparator and the amplitude of the window can be set by connecting
a suitable resistor to EOLP pin as indicated in following table:
Table 5.
The reference of this comparator can be set at a fixed voltage or at the same voltage as the
CTR pin.
The fixed reference configuration (see
to ground, and requires two Zener diodes in order to shift the mean value of the lamp
voltage to 2.5 V. The values of the two Zeners affect the symmetry of the intervention of the
protection: the best symmetry is obtained choosing two values whose difference is equal to
twice the reference voltage:
●
●
●
●
Where V
The tracking configuration (see
choke and blocking capacitor in the block capacitor-to-ground configuration. In this
configuration the voltage across the blocking capacitor is affected by the voltage ripple
superimposed on the PFC output. Using a reference affected by the same ripple helps to
reject it and avoid premature triggering of the comparator.
As soon as the comparator is triggered, a Tch cycle starts in order to improve the noise
immunity.
Rectifying effect
Over-current
Hard switching event
V
V
V
2 V
UP
DOWN
UP
REF
EOLP resistor range
UP
= V
= - V
and V
220 k ÷ 270 k
= V
= V
EOL window comparator configuration table
REF
22 k ÷ 27 k
75 k ÷ 91 k
DOWN
> 680 k
Z1
REF
+ V
DOWN
− V
Z2
– (V
Z2
+ V
are the maximum allowed values of V
Z1
F1
+ V
+ W/2
Figure 13
F2
) – W/2
Figure 12
) is useful when the lamp is connected between
Reference
2.5 V
2.5 V
V
V
CTR
CTR
) can be used when the lamp is connected
K
Window amplitude (Wv)
+ 250 mV / -240 mV
+160 mV / -150 mV
240 mV
720 mV
L6585DE