AS1112_1 Datasheet, PDF (1/18 Pages) ams AG – 16-Channel LED Driver with Dot Correction and Greyscale PWM

AS1112
16-Channel LED Driver with Dot Correction and
Greyscale PWM
Datasheet
1 General Description
2 Key Features
The AS1112 is a 16-channel, constant current-sink LED
driver. Each of the 16 channels can be individually
adjusted by 4096-step greyscale PWM brightness con-
trol and 64-step constant-current sink (dot correction).
The dot correction circuitry adjusts the brightness varia-
tions between the AS1112 channels and other LED driv-
ers. Greyscale control and dot correction circuitry are
accessible via the SPI-compatible serial interface. A sin-
gle external resistor sets the maximum current value of
all 16 channels.
The open & short LED detection function indicates a
broken, shorted or disconnected LED at one or more of
the outputs. The overtemperature flag indicates that the
device is in an overtemperature condition.
Table 1. Standard Products
Model
Power-Down
TEST pin
AS1112
Yes
Connect to GND
AS1112B
No
Connect to VCC
An additional power-down pin puts the AS1112 into a
40nA standby-mode.
The AS1112 is available in a 32-pin TQFN 5x5 mm
package.
Figure 1. Block Diagram
1 CLK 2 SDI
32 LD
! 16 Channels
! Greyscale PWM Control: 12-Bit (4096 Steps)
! Dot Correction: 6-Bit (64 Steps)
! Drive Capability (Constant-Current Sink): 0 to 80mA
! LED Power Supply Voltage: Up to 15V
! Supply Voltage Range: 3.0 to 5.5 V
! SPI-Compatible Serial Interface
! Controlled In-Rush Current
! Data Transfer & PWM Clock Rate: up to 30 MHz
! CMOS Level I/O
! Diagnostic Features
- LED Open/Short Detection
- Overtemperature Flag
! 32-pin TQFN 5x5 mm Package
3 Applications
The device is ideal for mono-, multi-, and full-color LED
displays, LED signboards, and display backlights.
29 PD
26
IREF
24
GSCLK
31
OEN
3
MODE
27
VCC
Max OUTn VREF =
Current 1.24V
Greyscale
Counter
Control
Status
Open LED Detect,
Overtemperature
Flag, Dot
Correction Data
Thermal
Flag
Open
LED
Detect
22
XERR
30
GND
AS1112
Input
Shift
Register
Input
Shift
Register
Control
Greyscale
0 Register 11
12-Bit Greyscale
PWM Control
Dot Correction
0 Register 5
6-Bit Dot
Correction
Open&Short LED Detection
Control
Greyscale
12 Register 23
12-Bit Greyscale
PWM Control
Dot Correction
6-Bit Dot
6 Register 11
Correction
. _{Open&Short LED Detection}
.
.
Control
Greyscale
180 Register191
12-Bit Greyscale
PWM Control
Dot Correction
90 Register 95
6-Bit Dot
Correction
Open&Short LED Detection
Constant Current
Driver
Delay
x0
Constant Current
Driver
Delay
x1
Constant Current
Driver
Delay
x15
4
OUT0
5
OUT1
.
.
.
21
OUT15
23
SDO
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Revision 1.06
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