MAX16809 Datasheet, PDF (17/23 Pages) Maxim Integrated Products – Integrated 16-Channel LED Drivers with Switch-Mode Boost and SEPIC Controller

Integrated 16-Channel LED Drivers with
Switch-Mode Boost and SEPIC Controller
LE
CLK
DIN
DOUT
t_CL
t_CH
t_DH
t_DS
D15
D14
t_LW
t_LS
t_CP
D1
t_DO
D0
D15
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
t_LRR
OUT_ _
CLK
t_CRF
OUT_ _
CLK
t_CRR
OUT_ _
Figure 4. LE and CLK to OUT_ _ Timing
Watchdog (MAX16810)
The MAX16810 includes a watchdog circuit that moni-
tors the CLK, DIN, and LE inputs. If there is no transi-
tion on any one of these inputs for nominally 1s, the
output latches are cleared and outputs OUT0–OUT15
go high impedance like the initial power-up condition.
This turns off all LEDs connected to the outputs. The
shift-register data does not change, just the output-
latch data. When the watchdog triggers, the outputs
remain off until the driver output latches are updated
with data turning them on. Recovery is therefore auto-
matic if the transmission failure is temporary because
the MAX16810 does not lock up in the watchdog timeout
state. The MAX16810 operates correctly when the serial
interface is next activated, and the watchdog circuit is
reset and starts monitoring the serial interface again. The
watchdog function requires no software change to the
application driving the MAX16810. The rise time for CLK,
DIN, and LE should be less than 10µs.
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