MAX16807_09 Datasheet, PDF (16/19 Pages) Maxim Integrated Products – Integrated 8-Channel LED Driver with Switch-Mode Boost and SEPIC Controller

Integrated 8-Channel LED Driver with
Switch-Mode Boost and SEPIC Controller
LE
CLK
DIN
DOUT
t_CL
t_CH
t_DH
t_DS
D7
t_LW
t_LS
t_CP
D0
t_DO
D7
OE
OUT_
Figure 3. 4-Wire Serial-Interface Timing Diagram
t_OEW
t_OEF
t_f
t_OER
80%
20%
t_r
LE
t_LRF
OUT_
LE
OUT_
CLK
OUT_
CLK
OUT_
t_LRR
t_CRF
t_CRR
Figure 4. LE and CLK to OUT_ Timing
Stand-Alone Operation
In stand-alone operation, the MAX16807 does not use
the 4-wire interface (see the Typical Operating
Circuits). Connecting DIN and LE to V+ provides at
least 8 external clock pulses to CLK to enable 8 out-
puts. This startup pulse sequence can be provided
either using an external clock or the PWM signal. The
external clock can also be generated using the signal
at RTCT and an external comparator.
LED Dimming
PWM Dimming
All the output channels can be dimmed simultaneously
by applying a PWM signal (50Hz to 30kHz) to OE. This
allows for a wide range of dimming up to a 5000:1 ratio.
Each channel can be independently turned on and off
using a 4-wire serial interface. The dimming is propor-
tional to the PWM duty cycle.
LED Current Amplitude Adjustment
Using an analog or digital potentiometer as R_SET allows
for LED current amplitude adjustment and linear dimming.
16 ______________________________________________________________________________________