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AS1121

Datasheet - Detailed Descr i pti on

Overtemperature Error/Warning Flags

The AS1121 provides a overtemperature circuit to indicate that the device is in an overtemperature condition. If the device junction temperature

tus can be read out from the AS1121 status register.

To prevent an overtemperature condition the AS1121 offers an temperature warning flag at 125°C typical. This flag can be used to take precau-

tions (e.g. start an external cooling) against a overtemperature condition.

Open LED Detection

The AS1121 integrated open LED detection circuit reports an error if any of the 16 LEDs is open or disconnected from the circuit. The open LED

Note:

The voltage at each OUTn is sampled 1 µs after being switched on. Please refer to Figure 18 on page 11.

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

AS1121 status information data (SID) during a greyscale data input cycle.

Note:

The rising edge of LD latches new data into the internal registers depending on the logic level of the pin MODE. If the pin MODE is tied

Table 6. XERR Truth Table

Error Condition

Error Information

Selected Mode

Status

Temp.

OUTn Voltage

Thermal

Error Flag

Thermal

Warning

Flag

Open LED

Detect

OEN

Mode XERR

O

p

e

n

0

Don't Care

0

0

0

1

normal

0

Don't Care

1

0

0

0

open error

1

Don't Care

0

0

0

0

temp. error

1Don't Care

1

0

0

0

open & temp.

error

T

e

m

p

Don't Care

0

Don't Care

Don't Care

1

0

1

normal

Don't Care

1

Don't Care

Don't Care

1

0

0

temp error

Don't Care

Don't Care

0

Don't Care

1

1

1

normal

Don't Care

Don't Care

1

Don't Care

1

1

0

temp. warn

LD

OEN

GSCLK

SID

LODn

LODn+1

Error

Detection

Start

Error

Detection

End