STEVAL-ILL013V1 Datasheet, PDF (34/43 Pages) STMicroelectronics – 80 W offline LED driver with PFC

UM0670
Design features
voltage on the emitter of Q102 is below the limit established by voltage divider R125
and R128 (upper limit set to 16.6 V) the transistor is opened and charges C110 and C107.
Therefore, it is possible to change the brightness between 0% and 100% on the STEVAL-
ILL013V1. The real measurement is shown in Figure 43, and it is evident that the supply
voltage on capacitor C110 is not below 12.5 V during no brightness.
Figure 42. Design improvement allowing zero dimming
Vc = 16 V
Supplying PWM generator with ST7LITEU05
Supplying L6562A in modified BUCK converter
D104
ZCD COMP INV
VCC _{L6562A GD}
MULT
GND
CS
C110
C107
R125
R126
Q102
R128
VOUT = 400 V
Allowing
0% dimming
AM00401
Doc ID 15327 Rev 2
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