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1 Introduction
User's Guide
SLVU187A – September 2006 – Revised June 2007
TLC5924EVM
This user’s guide describes the characteristics, operation, and use of the TLC5924EVM-186 evaluation
module (EVM). This EVM is designed to help the user evaluate and test the various operating modes of
the TLC5923 and TLC5924 LED drivers. This user’s guide includes setup instructions for the hardware
and software, a schematic diagram, a bill of materials (BOM), and PCB layout drawings for the evaluation
module.
Contents
1 Introduction ................................................................................................................... 1
2 Board Layout ................................................................................................................. 6
3 Schematic and Bill of Materials ............................................................................................ 9
List of Figures
1 Hardware Setup .............................................................................................................. 3
2 Assembly Layer .............................................................................................................. 6
3 Top Layer Routing ........................................................................................................... 7
4 Layer 2 Routing .............................................................................................................. 7
5 Layer 3 Routing .............................................................................................................. 8
6 Bottom Layer Routing ....................................................................................................... 8
7 TLC5924EVM-186 Schematic (a) ......................................................................................... 9
8 TLC5924EVM-186 Schematic (b) ........................................................................................ 10
List of Tables
1 J1 – Interface Connector .................................................................................................... 4
2 J2, J3, J4, J5 – Power Connectors ........................................................................................ 4
3 EVM Power Requirements ................................................................................................. 4
4 TLC5924EVM-186 Bill of Materials ...................................................................................... 11
The Texas Instruments TLC5923 is a 16-channel, constant-current LED driver that is capable of driving up
to 80 mA per channel. The integrated circuit (IC) contains integrated DOT correction circuitry that adjusts
the DC current for each output channel to compensate for brightness difference among LEDs. DOT
correction information can be written into internal registers. The TLC5924 is a device nearly identical to
the TLC5923, with the exception of an added precharge FET. The precharge FET eliminates the ghosting,
or spike current effect, that is associated with driving time-multiplexed strings of LEDs from a single IC.
This EVM contains a TLC5923 IC connected in parallel with a TLC5924 IC. The two ICs drive 16 red and
16 green light-emitting diodes (LED). The LEDs are separated into two banks, so that all red LEDs reside
on bank A, while all green LEDs reside on bank B. Both the TLC5923 and TLC5924 contain 16 outputs
each and every output is connected to a different pair of red and green LEDs. A switch on the EVM (S1)
selects which IC to activate, so that only one IC is on during normal operation. Using the supplied
software, the user individually controls the DOT correction and on/off values for each LED. Two modes of
operation are present in the software: Single-Bank Mode and Multiplex Mode. In Single-Bank Mode, the
user selects which bank of LEDs to activate, so that only the red or green LEDs are programmable. In
Multiplex Mode, both rows of LEDs are programmed sequentially at a high rate, giving the appearance
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SLVU187A – September 2006 – Revised June 2007 TLC5924EVM 1
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