SP6683 Datasheet, PDF (5/10 Pages) Sipex Corporation – High Power LED Driver for Parallel Configuration

in this way.
Anode
FB
3-wire W-LED module
GND
Fig 10. 3-wire white LED module
In figure 11, SP6683 was used to drive a 2-wire
white LED module without internal series resis-
tors as a current source. The bias resistor R_B is
selected to regulate the total current of the white
LED module instead of the current of single
LED as in figure 9.
V_{OUT 1}
Anode
SP6683
5
V_FB
GND
8
2-wire W-LED module
Cathode
Rb
Figure 11. Driving 2-wire white LED module as current
source
OPERATION: Continued
In this application, the bias resistor can be se-
lected by:
R_B = ^VFB
I_{LED (TOTAL)}
where I_LED(TOTAL) is the total operating current
of all the white LEDs.
To use SP6683 as a voltage source for fixed
voltage applications, a voltage divider is need to
program the ouput voltage, as shown in figure 12.
The output voltage is set by the ratio of the two
resistors and the feedback control voltage as
shown by:
V_OUT
=
(
1
+
R₅
R₆
)
•
V_FB
V_{OUT 1}
Anode
R5
SP6683
1uF
V_FB
5
R6
GND
8
2-wire W-LED
module
Cathode
Figure 12. Driving 2-wire white LED module as
voltage source
Date: 07/07/04
SP6683 White LEDs Driver for Parallel Configuration
5
© Copyright 2004 Sipex Corporation