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Serial Interface Data Transfer Rate

TLC5923

SIN

SOUT

OUT0

OUT15

SCLK

MODE

XLAT

BLANK

IREF

XERR

TLC5923

SIN

SOUT

OUT0

OUT15

SCLK

MODE

XLAT

BLANK

IREF

XERR

IC 0

IC n

5

SIN

SCLK

MODE

XLAT

BLANK

XERR

Controller

SOUT

100 k

100 nF

V(LED)

V(LED)

V(LED)

V(LED)

VCC

100 nF

VCC

VCC

f_(SCLK) + 112

f_(update)

n

(3)

Operating Modes

TLC5923

SLVS550 – DECEMBER 2004

The TLC5923 includes a flexible serial interface, which can be connected to microcontroller or digital signal

processor. Only 3 pins are in required to input data into the device. The rising edge of SCLK signal shifts the

data from SIN pin to internal shift register. After all data is clocked in, a rising edge of XLAT latches the serial

data to the internal registers. All data is clocked in with MSB first. Multiple TLC5923 devices can be cascaded by

connecting SOUT pin of one device with SIN pin of following device. The SOUT pin can also be connected to

controller to receive LOD information from TLC5923.

Figure 11. Cascading Devices

Figure 11 shows a example application with n cascaded TLC5923 devices connected to a controller. The

maximum number of cascaded TLC5923 devices depends on application system and data transfer rate.

Equation 3 calculates the minimum data input frequency needed.

where:

f_(SCLK): The minimum data input frequency for SCLK and SIN.

f_(update): The update rate of the whole cascaded system.

n: The number of cascaded TLC5923 devices.

The TLC5923 has different operating modes depending on MODE signal. Table 2 shows the available operating

modes.

Table 2. TLC5923 Operating Modes Truth Table

MODE SIGNAL

INPUT SHIFT REGISTER

MODE

LOW

16 bit

On/Off Mode

HIGH

112 bit

Dot Correction Data Input Mode

9