MAX16808 Maxim Integrated Products, MAX16808 Datasheet - Page 17

• Manufacturer Part Number: MAX16808
• Description: (MAX16807 / MAX16808) Integrated 8-Channel LED Drivers
• Manufacturer: Maxim Integrated Products

Figure 3. 4-Wire Serial-Interface Timing Diagram
Figure 4. LE and CLK to OUT_ Timing
OUT_
LE
OUT_
LE
CLK
OUT_
CLK
OUT_
DOUT
OUT_
CLK
DIN
Switch-Mode Boost and SEPIC Controller
OE
LE
______________________________________________________________________________________
t
t
LRF
t
Integrated 8-Channel LED Drivers with
LRR
CRF
t
CRR
t
DS
D7
t
DH
t
CL
t
OEF
t
f
t
t
CH
OEW
80%
20%
The MAX16808 includes circuitry that detects open-cir-
cuit LEDs automatically. An open-circuit fault occurs
when an output is sinking current less than approxi-
mately 50% of the programmed current flows. Open cir-
cuits are checked just after the falling edge of OE. The
fault data is latched on the rising edge of LE and is
shifted out when new LED data is loaded into the out-
put latches from the shift register. If one or more output
ports are detected with an open-circuit fault, the D6
and D5 bits of DOUT go high. If no open-circuit faults
are detected, D6 and D5 are set to low. The data in the
other 6 bit positions in DOUT are not altered. Fault sta-
tus is shifted out on DOUT for the first two rising edges
of the clock after the falling edge of LE (see Figure 5).
LE is normally taken high after all 8 bits of new LED
Figure 5. Fault Timing
t
OER
DOUT
CLK
OE
t
LE
r
t
DO
t
CP
LED Fault Detection (MAX16808)
D0
t
LS
D7
t
LW
D7
FAULT STATUS BITS
D6
D5
D4
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