AS1109 Datasheet, PDF (17/25 Pages) ams AG – Constant-Current, 8-Bit LED Driver with Diagnostics

AS1109
Datasheet - Application Information
9 Application Information
9.1 Error Detection
The AS1109 features two types of error detection. The error detection can be used on-the-fly, for active LEDs, without any delay, or by entering
into low-current diagnosis mode.
9.1.1 Error Detection On-The-Fly
Error detection on-the-fly will output the status of active LEDs during operation. Without choosing an error mode this will output the temperature
flag at every input/output cycle. Triggering one clock pulse for open or two clock pulses for short detection during error detection mode outputs
the detailed open- or short-error report with the next input/output cycle (see Figure 20). LEDs that are turned off cannot be tested and their digits
at the error output must be ignored.
Figure 20. Normal Operation with Error Detection During Operation – 128 Cascaded AS1109s
Display
SDI
SDO
CLK
OEN
LD
Current
Data1
Data2
Data3
Data2
Data3
Data4
T/O or S Error Code Data0
Data0
1024x
GEF
Clock for Error
Mode 0x/1x/2x
Rising Edge of OEN
Acquisition of Error Status
T/O or S Error Code
Data1
1024x
GEF
Clock for Error
Mode 0x/1x/2x
Rising Edge of OEN
Acquisition of Error Status
T/O or S Error Code
Data2
1024x
Falling Edge of LD; Error Register is copied
into Shift Register
Falling Edge of LD; Error Register is copied
into Shift Register
≤ 100mA
GEF = Global Error Flag
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