STMicroelectronics EVALHVLED815W10 and EVALHVLED815W15 Evaluation Board for the Offline LED Driver with Primary-Sensing and High Power Fact EVALHVLED815W10 Hoja De Datos
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EVALHVLED815W10
DocID023409 Rev 5
27/34
HVLED815PF
Device description
34
Figure 22. High power factor implementation connection - single range input
The components selection flow starts from the R
DMG
resistor: this resistor has to be
selected in order to minimize the internal feedforward effect.
The maximum selectable value is limited by the minimum internal current circuitry I
DMG
needed to guarantee the correct functionality of the internal circuitry:
Equation 16
where N
AUX
and N
PRIM
are the auxiliary and primary turn's number respectively and V
IN_MIN
is the minimum rms input voltage of the application (i.e. 88 V for 110 Vac or 175 V for 230
Vac range).
Vac range).
The R
FB
resistor defines the V
OUT
output voltage value in the open circuit condition (no-load
condition, i.e. no LED on the output of LED driver) and it can be selected using the following
relationship:
relationship:
Equation 17
where N
AUX
and N
SEC
are the auxiliary and secondary turn's number respectively and V
REF
is the internal reference voltage (V
REF
= 2.51 V typ - see
The R
1
resistor is typically selected in the range of 500
- 1.5 k in order to minimize the
internal feedforward effect and to minimize the power dissipation on the R
A
/R
B
resistor
offset circuitry.
AM13572v1
COS
.
DRAIN
SOURCE
IFF
Feedf orward
Logic1
Logic1
+
-
CC
Rf f
Rsense
PWM
LOGIC2
DMG
CC
Block1
ROS
R1
RPF
RB
RA
VIN (after bridge diode)
CS
Aux
Rf b
Rdmg