Rainbow Electronics MAX16823 - Manual (Page 10)

MAX16823
High-Voltage, 3-Channel Linear High-Brightness
LED Driver with Open LED Detection
10 ______________________________________________________________________________________
Preload Current
Figure 6 shows the MAX16823 with a preload circuit. In
the circuit, the BJT, R
PRELOAD , and REG generate a
preset load current. The preset load current I
PRESET
is
determined with the following formula:
This circuit is used with older body controllers that
monitor minimum RCL current to detect failures.
I
V V
R
PRESET
REG
PRELOAD
=
− 0 7 .
IN
DIM_
GND
R CS_
LEDs
Q1
C IN
V IN
OUT_
CS_
MAX16823
REG
C2
PWM DIMMING
Figure 5. Increased LED Current (Amper Range) with a Single
BJT
R CS1 R CS2 R CS3
OUT3
CS1
CS2
CS3
GND
DIM2
DIM1
STOP
TAIL IN
IN
IN
C IN
R PRELOAD
C LGC C REG
LGC
DIM3
REG
OUT2
OUT1
MAX16823
TAIL
TAIL
STOP
100kΩ
100kΩ
Figure 6. Preload Current Setting