SERIAL INTERFACE MODE

SCLK AND GSCLK FREQUENCY

f

=4096

f

´

GSCLK

UPDATE

(4)

f

=192

f

´

SCLK

UPDATE

n

´

(5)

¼

SIN

XERR

SCLK

XLAT

MODE

GSCLK

SOUT

VCC

GND

TLC59461

IC1

OUT0

OUT15

XHALF

¼

¼

V

LED

¼

SIN

SCLK

XLAT

BLANK

R

IREF

IREF

SOUT

TLC59461

ICn

OUT0

OUT15

OUT

XERR

SCLK

XLAT

MODE

BLANK

GSCLK

IN

¼

R

IREF

IREF

Controller

6

BLANK

GSCLK

MODE

XERR

VCC

GND

XHALF

V

CC

V

LED

V

LED

V

LED

V

CC

V

CC

TLC59461

www.ti.com............................................................................................................................................... SLVS896A – NOVEMBER 2008 – REVISED MARCH 2009

The serial interface has two input modes defined by the MODE pin, as Table 3 shows. XLAT must be low when

the MODE pin goes high-to-low or low-to-high to change back and forth between GS mode and DC mode.

Table 3. Serial Interface Input Mode

MODE

INPUT MODE

INPUT SHIFT REGISTER

GND

Grayscale PWM data

192 bits

VCC

Dot correction data

96 bits

Figure 31 shows a cascading connection of n TLC59461 devices connected to a single controller, building a

basic module of an LED display system. There is no limitation to the maximum number of ICs that can be

cascaded. However, the maximum number of cascading TLC59461 devices depends on the application system

and is in the range of 40 devices. Equation 4 and Equation 5 show the minimum frequencies for GSCLK and

SCLK.

where:

• f

GSCLK = minimum frequency of GSCLK

• f

SCLK = minimum frequency of SCLK

• f

UPDATE = update rate of entire cascading system

• n = number of cascaded TLC59461 devices

Figure 31. Cascading Device Connections

Copyright © 2008–2009, Texas Instruments Incorporated

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