AS1112
Datasheet - Detailed Description
Table 9. XERR Truth Table
Error Condition
Error Information
Selected Mode
Status
Thermal
OpenLED
Warning
Detect
Short
LED
Detect
Thermal
Error Flag
Temp. OUTn Voltage
OEN Mode XERR
Flag
OUTn > VLOD
0
0
1
Don'tCare
Don'tCare
Don'tCare
0
1
0
Don'tCare
Don'tCare
Don'tCare
0
0
0
0
0
0
1
0
0
normal
TJ < TTEF
O
p
OUTn < VLOD
open error
temp. error
OUTn > VLOD
e
n
TJ > TTEF
open &
temp. error
OUTn < VLOD
1
Don'tCare
1
Don'tCare
0
0
0
TJ > TTEF
TJ < TTEF
TJ > TTWF
TJ < TTWF
Don't Care
Don't Care
Don't Care
Don't Care
0
Don'tCare Don'tCare Don'tCare
Don'tCare Don'tCare Don'tCare
1
1
1
1
0
0
1
1
1
0
1
0
normal
temp error
normal
T
e
m
p
1
Don't Care
Don't Care
0
1
Don'tCare Don'tCare
Don'tCare Don'tCare
temp. warn
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 (TJ) 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 (see Table 9) and the voltage at
OUTn is less than VLOD.
Note: The voltage at each OUTn is sampled 1µs after being switched on. Please refer to Figure 8.
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 VLSD.
Note: The voltage at each OUTn is sampled 1µs after being switched on. Please refer to Figure 8.
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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