AS1122
Datasheet ꢀ Detailed Description
For n devices in a chain only one identifier needs to be send to set all n devices to the same register setting.
Figure 30. Command Data for n-devices
Setting Dot Correction
The AS1122 can perform independent fineꢀadjustments to the output current of each channel. Dot correction is used to adjust brightness deviaꢀ
tions of LEDs connected to the output channels (OUT0:OUT11).
The device powers up with the following default settings: DC = 0 and GS = 0.
The 12 channels can be individually programmed with a 6ꢀbit word for Dot Correction. The channel output can be adjusted in 64 steps from 0 to
100% of the maximum output current (IMAX). The output current for each OUTn channel can be calculated as:
DCn
IOUTn = IMAX x
(EQ 1)
63
Where:
IMAX is the maximum programmable output current for each output;
DCn is the programmed dot correction value for output (DCn = 0 to 63);
n = 0 to 11
Dot correction data are simultaneously entered for all channels. The complete dot correction data format consists of 12 x 6ꢀbit words, which
forms a 72ꢀbit serial data packet (see Figure 31) and 8ꢀbit for the identifier. Channel data is put on one by one, and the data is clocked in with the
MSB first.
Figure 31. Dot Correction Data Packet Format
The Dot Correction data is only valid if the exact identifier byte was send. Otherwise the data will be ignored.
Setting Greyscale Brightness (PWM)
The brightness of each channel output can be adjusted using a 12 bitsꢀperꢀchannel PWM control scheme which results in 4096 brightness steps,
from 0% to 100% brightness. The brightness level for each output is calculated as:
GSn
%Brightness =
x 100
(EQ 2)
4095
Where:
GSn is the programmed greyscale value for OUTn (GSn = 0 to 4095);
n = 0 to 11 greyscale data for all outputs.
The device powers up with the following default settings: GS = 0 and DC = 0.
www.austriamicrosystems.com/LEDꢀDriverꢀICs
Revision 1.00
13 ꢀ 22
AMSCO [ AMS(艾迈斯) ]
