AS1121-BQFT austriamicrosystems, AS1121-BQFT Datasheet - Page 8

• Manufacturer Part Number: AS1121-BQFT
• Description: IC LED DRIVER 16-CH 30V 32-TQFN
• Manufacturer: austriamicrosystems

Specifications of AS1121-BQFT

• Constant Current: Yes
• Internal Driver: Yes
• Type - Primary: Backlight, General Purpose
• Type - Secondary: Color
• Mounting Type: *
• Topology: PWM
• Number Of Outputs: 16
• Voltage - Supply: 3.1 V ~ 3.6 V
• Voltage - Output: 1.5 V ~ 30 V
• Package / Case: *
• Operating Temperature: -40°C ~ 85°C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Frequency: -
• Other names: AS1121-BQFTTR

AS1121
Datasheet - D e t a i l e d D e s c r i p t i o n
Error Information Output
The open-drain output pin XERR indicates if the device is in error condition (open LED detect or overtemperature). During normal operation, the
internal transistor connected to pin XERR is turned off and the voltage on XERR is pulled up to V
through an external pullup resistor.
CC
If an open LED or an overtemperature condition is detected, the internal transistor is switched on, and XERR is pulled to GND. Because XERR
is an open-drain output, multiple AS1121 devices can be ORed together and pulled up to V
with a single pullup resistor
(see Figure 11 on
CC
page
14). This reduces the number of signals needed to report a system error.
To differentiate the the open LED from the overtemperature condition the status information data (SID) of the AS1121 needs to be read out.
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
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 1 µs after being switched on. Please refer to
Figure 4 on page
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
AS1121 status information data (SID) during a greyscale data input cycle.
Figure 4. Error Detection Timing (GS=FFFF
, DC=3F
)
HEX
HEX
LD
t
ERR
OEN
GSCLK
SID
LODn
LODn+1
Error
Error
Detection
Detection
Start
End
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
GND, the greyscale registers are updated. If the pin MODE is tied to V
, the dot correction registers are updated.
CC
www.austriamicrosystems.com/LED-Driver-ICs
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