AS1109_1 AMSCO [austriamicrosystems AG], AS1109_1 Datasheet - Page 17

• Manufacturer Part Number: AS1109_1
• Description: Constant-Current, 8-Bit LED Driver with Diagnostics
• Manufacturer: AMSCO [austriamicrosystems AG]

AS1109
Data Sheet - A p p l i c a t i o n I n f o r m a t i o n
9 Application Information
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.
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
Figure 20. Normal Operation with Error Detection During Operation – 128 Cascaded AS1109s
Error Detection with Low-Current Diagnosis Mode
This unique feature of the AS1109 uses an internal all 1s test pattern for a flicker free diagnosis of all LEDs. This error
detection mode can be started anytime, and does not require any SDI input
Figure 21. Low-Current Diagnosis Mode with Internal All 1s Test Pattern – 128 Cascaded AS1109s
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Current
Display
Current
Display
SDO
OEN
CLK
SDO
OEN
CLK
SDI
(see Figure
SDI
LD
LD
Load Internal All 1s Test Pattern
T/O or S Error Code
20). LEDs that are turned off cannot be tested and their digits at the error output must be ignored.
Acquisition of Error Status
Data0
Data2
1024x
Data1
Data0
≤ 100mA
Rising Edge of OEN
3x Clocks Low-
Current Mode
Clock for Error
Mode 0x/1x/2x
GEF
≤ 0.8mA
Clock for Error
Mode 1x/2x
Falling Edge of LD; Error Register is
copied into Shift Register
Rising Edge of OEN
Acquisition of Error Status
GEF
2µs Low-Current Diagnosis Mode
Revision 1.18
T/O or S Error Code
Falling Edge of LD; Error Register
is copied into Shift Register
Acquisition of Error Status
Data1
≤ 100mA
1024x
O or S Error Code of
Data2
Data3
Rising Edge of OEN
All 1s Test Patern
Data1
1024x
Mode 0x/1x/2x
Clock for Error
(see Figure
≤ 100mA
GEF
GEF
GEF = Global Error Flag
Falling Edge of LD; Error Register is
copied into Shift Register
GEF = Global Error Flag
21).
Temperature Error Code
T/O or S Error Code
Data2
Data3
Data1
1024x
1024x
Data4
Data2
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