MAX16823_15 Datasheet, PDF (8/12 Pages) Maxim Integrated Products – High-Voltage, 3-Channel Linear High-Brightness LED Driver with Open LED Detection

MAX16823
High-Voltage, 3-Channel Linear High-Brightness
LED Driver with Open LED Detection
PWM dimming operation is disabled and the LEDs light
up to full brightness. See the ICM7555 data sheet for
formulas to calculate the dimming frequency and the duty
cycle.
Outputs Latch-Off
Figure 3 shows a circuit with DIM1, DIM2, DIM3, and
LEDGOOD connected through a resistor to V_REG. This
circuit is useful for applications that require all outputs to
latch off when one of the LEDs opens. The MAX16823
resumes current regulation again through power cycling,
once the fault condition is removed.
t_ON
Other Applications
The application circuit in Figure 4 implements a two-level
brightness current for TAIL/STOP lights. In TAIL opera-
tion, Q1 is off and R_CS1 sets the output current. In STOP
operation, Q1 turns on and the output current is set by a
parallel combination of R_CS1 and R2.
Figure 5 shows an application circuit with the MAX16823
using a single BJT to provide high output current. For
proper operation:
V_IN(MIN) > V_BE(MAX) + V_FT(MAX) + V_{CS_} + V_DO(MAX)
For minimized dropout, the LEDs can be placed in the
collector.
DIM
LEDGOOD
t_OFF
LEDGOOD GOES
LOW WHEN t_OFF > t_DELAY
Figure 1. LEDGOOD Timing Delay
STOP
D1
TAIL
D4
R1
C1
R2
D2
DIS
IN
OUT
R3
D3
TH
GND
100kΩ
TRG
C2
ICM7555
IN
OUT3
OUT2
OUT1
REG
0.1µF
MAX16823
LEDs
DIM1
CS1
DIM2
R_CS1
CS2
DIM3
R_CS2
CS3
GND
R_CS3
Figure 2. PWM Dimming Operation with ICM7555
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