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AS1113

Data Sheet - D e t a i l e d D e s c r i p t i o n

8 Detailed Description

The AS1113 is designed to drive up to 16 LEDs through a fast serial interface and 16 constant-current output drivers.

Furthermore, the AS1113 provides diagnostics for detecting open- or shorted-LEDs, as well as over-temperature con-

ditions for LED display systems, especially LED traffic sign applications.

The AS1113 contains an 16-bit shift register and an 16-bit data register, which convert serial input data into parallel out-

put format. At AS1113 output stages, sixteen regulated current sinks are designed to provide uniform and constant cur-

rent 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 50mA using an external resistor for flexibility in controlling the brightness inten-

sity of LEDs. The AS1113 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 AS1113 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 7. Block Diagram

AS1113

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