AS1121-BQFT austriamicrosystems, AS1121-BQFT Datasheet - Page 11

• 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
Setting Greyscale Brightness
The brightness of each channel output can be adjusted using a 12 bits-per-channel PWM control scheme which results in 4096 brightness steps,
from 0% to 100% brightness. The brightness level for each output is calculated as:
Where:
GSn is the programmed greyscale value for OUTn (GSn = 0 to 4095);
n = 0 to 15 greyscale data for all outputs.
The device powers up with the following default seetings: GS = 4095 and DC = 63.
The input shift register shifts greyscale data into the greyscale register for all channels simultaneously. The complete greyscale data format con-
sists of 16 x 12 bit words, which forms a 192-bit wide data packet
Note: The data packet must be clocked in with the MSB first.
Figure 7. Greyscale Data Packet Format
When pin MODE is tied to GND, the AS1121 enters greyscale data input mode. The device switches the input shift register to 192-bit width. After
all data is clocked in, the rising edge of the LD signal latches the data into the greyscale register
All greyscale data in the input shift register is replaced with status information data (SID) after latching into the greyscale register.
Figure 8. Greyscale Data Input Timing Diagram
MODE
www.austriamicrosystems.com/LED-Driver-ICs
SDO
CLK
SDI
LD
GS15.11
Dot Correction Mode
MSB
191
Data Input Cycle
MSB-1
DCn-1
GS OUT15
96
...
DCn-1
LSB
t
H2
DCn-1
MSB
t
H3
GS15.0
180
t
SU2
x
MSB
GS14.11
GSn
Data Input Cycle After Dot Correction Input
179
t
1
H0
x
t
SU3
1st Greyscale Mode
x
%Brightness =
t
SU1
192
t
H3
GS OUT14:GS OUT1
(see Figure
Revision 1.00
GSn
LSB
...
4095
GSn
SIDn
7).
MSB
x 100
1
GSn+1
MSB
Following Greyscale Mode
MSB-1
SIDn
(see Figure
t
PD0
Data Input Cycle
GS1.0
12
MSB-2
SIDn
192
8).
GS0.11
GSn+1
11
LSB
GS OUT0
SIDn
LSB
...
GS0.0
SIDn
MSB
LSB
0
(EQ 4)
11 - 18