www.ams.com/LED-Driver-ICs/AS1109

Revision 1.21

16 - 24

AS1109

Datasheet - Application In form atio n

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

T/O or S Error Code

Data1

T/O or S Error Code Data0

Data0

T/O or S Error Code

Data2

1024x

1024x

1024x

Clock for Error

Mode 0x/1x/2x

Rising Edge of OEN

Acquisition of Error Status

Falling Edge of LD; Error Register is copied

into Shift Register

≤ 100mA

GEF

GEF

GEF = Global Error Flag

Falling Edge of LD; Error Register is copied

into Shift Register

Clock for Error

Mode 0x/1x/2x

Rising Edge of OEN

Acquisition of Error Status

Data2

Data3

Data4