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| TLC59401 Datasheet, PDF (22/29 Pages) Texas Instruments – 16-CHANNEL LED DRIVER WITH DOT CORRECTION AND GRAYSCALE PWM CONTROL | |||
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TLC59401
SBVS137 â DECEMBER 2009
www.ti.com
When using Equation 10 with very high GSCLK frequencies and very low grayscale PWM values, the resulting
T_on-time may be negative. If T_on is negative, the output does not turn on. For example, using f(GSCLK) = 30
MHz, GSn = 1, and the typical ton_err = 50 ns, Equation 10 calculates that OUTn turns on for â16.6 ns. This
output may not turn on under these conditions. Increasing the PWM value or reducing the GSCLK clock
frequency ensures turn-on.
SERIAL DATA TRANSFER RATE
Figure 22 shows a cascading connection of n TLC59401 devices connected to a controller, building a basic
module of an LED display system. There is no TLC59401 limitation to the maximum number of ICs that can be
cascaded. The maximum number of cascading TLC59401 devices depends on the application system.
Equation 11 calculates the minimum frequency needed:
f(GSCLK) + 4096 f(update)
f(SCLK) + 193 f(update) n
(11)
where:
f(GSCLK): minimum frequency needed for GSCLK
f(SCLK): minimum frequency needed for SCLK and SIN
f(update): update rate of whole cascading system
n: number cascaded of TLC59401 device
APPLICATION EXAMPLE
VCC
V(LED)
V(LED)
V(LED)
V(LED)
Controller
SIN
XERR
SCLK
XLAT
GSCLK
MODE
BLANK
SOUT
100 k
VCC
SIN
XERR
SCLK
XLAT
GSCLK
MODE
BLANK
TEST
OUT0
TLC59401
IC 0
6
OUT15
SOUT
VCC
100 nF
IREF
VCC
SIN
XERR
SCLK
XLAT
GSCLK
MODE
BLANK
TEST
OUT0
TLC59401
IC n
OUT15
SOUT
VCC
100 nF
IREF
Figure 22. Cascading Devices
22
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Product Folder Link(s): TLC59401
Copyright © 2009, Texas Instruments Incorporated
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