www.ams.com/LED-Driver-ICs/AS1110 Revision 1.6 8 - 24
AS1110
Datasheet - Detailed Description
8 Detailed Description
The AS1110 is designed to drive up to 16 LEDs through a fast serial interface and 16 constant-current output drivers. Furthermore, the AS1110
provides diagnostics for detecting open- or shorted-LEDs, as well as over-temperature conditions for LED display systems, especially LED traffic
sign applications.
The AS1110 contains an 16-bit shift register and an 16-bit data register, which convert serial input data into parallel output format. At AS1110
output stages, sixteen regulated current sinks are designed to provide uniform and constant current with excellent matching between ports for
driving LEDs within a wide range of forward voltage variations. External output current is adjustable from 0.5 to 100mA using an external resistor
for flexibility in controlling the brightness intensity of LEDs. The AS1110 guarantees to endure 15V maximum at the outputs.
The serial interface is capable of operating at a minimum of 30 MHz, satisfying the requirements of high-volume data transmission.
Using a multiplexed input/output technique, the AS1110 adds additional functionality to pins SDO, LD and OEN. These pins provide highly useful
functions (open- and shorted-LED detection, over-temperature detection), thus reducing pin count. Over-temperature detection will work on-the-
run, whereas the open- and shorted-LED detection can be used on-the-run or in low-current diagnostic mode (see page 15).
Figure 8. AS1110 - Block Diagram
8.1 Serial Interface
Data accesses are made serially via pins SDI and SDO. At each CLK rising edge, the signal present at pin SDI is shifted into the first bit of the
internal shift register and the other bits are shifted ahead of the first bit. The MSB is the first bit to be clocked in. In error-detection mode the shift
register will latch-in the corresponding error data of temperature-, open-, and short-error register with each falling edge of LD.
AS1110
REXT
OEN
CLK
SDI
LD
Current
Generators
Detailed
Error
Detection
16-Bit Data
Register
16-Bit Shift
Register
Temperature
Detection
16-Bit Open
Detection & Error
Register
16-Bit Short
Detection & Error
Register
Global Error
Detection
SDO
Indicates 16 Bit Path
Control Logic
+VLED
OUTN0
OUTN1
OUTN2
OUTN3
OUTN4
OUTN5
OUTN6
OUTN7
OUTN8
OUTN9
OUTN10
OUTN11
OUTN12
OUTN13
OUTN14
OUTN15
