AS1112
Datasheet - D e t a i l e d D e s c r i p t i o n
Table 9. XERR Truth Table
Error Condition
Temp.
T
J
< T
TEF
Thermal
OUTn Voltage Error Flag
OUTn > V
LOD
OUTn < V
LOD
OUTn > V
LOD
T
J
> T
TEF
T
J
> T
TEF
T
J
< T
TEF
T
J
> T
TWF
T
J
< T
TWF
OUTn < V
LOD
Don't Care
Don't Care
Don't Care
Don't Care
0
0
1
1
0
1
Don't Care
Don't Care
Error Information
Thermal
Warning Open LED
Detect
Flag
Don't Care
Don't Care
Don't Care
Don't Care
0
1
0
1
Selected Mode
Short
LED
Detect
Don't Care
Don't Care
Don't Care
Don't Care
OEN Mode XERR
0
0
0
0
1
1
1
1
0
0
0
0
0
0
1
1
1
0
0
0
1
0
1
0
normal
open error
temp. error
open &
temp. error
normal
temp error
normal
temp. warn
Status
O
p
e
n
T
e
m
p
Don't Care Don't Care Don't Care
Don't Care Don't Care Don't Care
0
1
Don't Care Don't Care
Don't Care Don't Care
Overtemperature Error/Warning Flags
The AS1112 provides a overtemperature circuit to indicate that the device is in an overtemperature condition. If the
device junction temperature (T
J
) exceeds the threshold temperature (150°C typ), the overtemperature circuit trips and
pulls XERR to ground. The overtemperature flag status can be read out from the AS1112 status register.
To prevent an overtemperature condition the AS1112 offers an temperature warning flag at 125°C typical. This flag can
be used to take precautions (e.g. start an external cooling) against a overtemperature condition.
Open LED Detection
The AS1112 integrated open LED detection circuit reports an error if any of the 16 LEDs is open or disconnected from
the circuit. The open LED detection circuit trips when the error detection is activated
and the voltage at
OUTn is less than V
LOD
.
Note:
The voltage at each OUTn is sampled 1µs after being switched on. Please refer to
The open LED detection circuit also pulls XERR to GND when tripped. The open LED status of each channel can also
be read out from the AS1112 status information data (SID) during a greyscale data input cycle.
Shorted LED Detection
The AS1112 integrated shorted LED detection circuit detects if any of the 16 LEDs is short-circuited. The shorted LED
detection circuit trips when the error detection is activated and the voltage at OUTn is higher than V
LSD
.
Note:
The voltage at each OUTn is sampled 1µs after being switched on. Please refer to
The shorted LED status of each channel can only be read out from the AS1112 status information data (SID) during a
greyscale data input cycle.
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