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

Revision 1.21

11 - 24

AS1109

Datasheet - Detailed Descr i p ti on

8.5 Error Detection Functions

8.5.1 Open-LED Detection

OEN and stored internally. While detecting open-LEDs the output port must be turned on. Open LED detection can be started with 1 clock pulse

during error detection mode while the output port is turned on.

Note:

LEDs which are turned off at test time cannot be tested.

8.5.2 Shorted-LED

edge of OEN and stored internally. While detecting shorted-LEDs the output port must be turned on. Shorted-LED detection can be started with

2 clock pulses during error detection mode while the output port is turned on.

Note:

LEDs which are turned off at test time cannot be tested.

8.5.3 Overtemperature

Thermal protection for the AS1109 is provided by continuously monitoring the device’s core temperature. The overtemperature status is aquired

at the rising edge of OEN and stored internally.

Table 6. Open LED Detection Modes

Output Port State

Effective Output

Point Conditions

Detected Open-LED

Error Status Code

Meaning

On

0

Open Circuit

On

1

Normal

Table 7. Shorted LED Detection Modes

Output Port State

Effective Output

Point Conditions

Detected Shorted-LED

Error Status Code

Meaning

On

0

Short Circuit

On

1

Normal

Table 8. Overtemperature Modes

Output Port State

Effective Output

Point Conditions

Detected Overtemperature

Status Code

Meaning

Don’t Care

0

Overtemperature Condition

Don’t Care

1Normal