TI Designs: TIDA Mono Color LED Matrix With Fast Refresh Rates and Ghosting Reduction Reference Design

Size: px

Start display at page:

Download "TI Designs: TIDA Mono Color LED Matrix With Fast Refresh Rates and Ghosting Reduction Reference Design"

Kathleen Stephens
5 years ago
Views:

TI Designs: TIDA-01617 16 16 Mono Color LED Matrix With Fast Refresh Rates and Ghosting Description This reference design showcases a solution using the TLC59283 16-channel LED driver to drive a 16

1 TI Designs: TIDA Mono Color LED Matrix With Fast Refresh Rates and Ghosting Description This reference design showcases a solution using the TLC channel LED driver to drive a mono-color LED matrix with 1/16 multiplexing ratio. The design allows designers to drive 256 LEDs with only one TLC59283 and 8 Dual P-MOSFETs, which can be used for LED video walls, elevator calling button operating panels, smart speakers, home appliances, and other LED message board or LED indicator applications. Each constant-current output channel has a pre-charge field-effect transistor (FET) that can reduce ghosting on the multiplexing (dynamic) drive LED display, leading to better contrast and picture in the display. Resources TIDA TLC59283 SimpleLink MSP432P401R LaunchPad Development Kit Design Folder Product Folder Tool Folder Features Pre-Charge FET for Ghosting Reduction High Data Transfer Rate Supports Multi-Channel for Fast Refresh Rates Precise Current-Matching Between LED Strings for Uniform Brightness Minimum Device PCS in the LED Matrix System Multiple Modules Cascading Support Applications LED Video Wall Calling Buttons Operating Panel E-Bikes Smart Speakers Elevator Calling Boards Air Conditioner Indoor Unit Cooking Solutions Refrigerators ASK Our E2E Experts 1

2 System Description An IMPORTANT NOTICE at the end of this TI reference design addresses authorized use, intellectual property matters and other important disclaimers and information. 1 System Description This reference design uses the 16-channel LED driver TLC59283 to drive a mono-color LED matrix with 1/16 multiplexing ratio, which can drive 256 LEDs, combined with 8 dual P-MOSFETs. The MSP432P401R LaunchPad sends the control signals to switch the P-MOSFETs and the TLC59283 output channels. 1.1 Key System Specifications Table 1 details the key system specifications. Input voltage range PARAMETER Table 1. Key System Specifications 3.0 V 5.5 V SPECIFICATIONS Output channel current 35 ma (VCC 3.6 V), 45 ma (VCC > 3.6 V) Current sinks accuracy Date transfer rate LED numbers 256 ±1.4% (typical) Channel-to-channel and ±2% (typical) device-to-device Up to 33 MHz Operating temperature 40 C 85 C 2

3 2 System Overview System Overview 2.1 Block Diagram Figure 1 shows the TIDA block diagram. Figure 1. TIDA Block Diagram 2.2 Highlighted Products The following highlighted products are used in this reference design. The key features for selecting the devices for this reference design are outlined in the following subsections. For the complete details of the highlighted devices, refer to their respective product data sheets TLC Channel, Constant-Current LED Driver With Pre-Charge FET The TLC59283 is a 16-channel, constant-current sink, light-emitting diode (LED) driver. Each channel can be individually controlled with a simple serial communications protocol that is compatible with 3.3- or 5-V CMOS logic levels, depending on the operating VCC. When the serial data buffer is loaded, a LAT rising edge transfers the data to the OUTn outputs. The BLANK pin can be used to turn off all OUTn outputs during power-on and output data latching to prevent unwanted image displays during these times. The constant-current value of all 16 channels is set by a single external resistor. Each constant-current output has a pre-charge field-effect transistor (FET) that can reduce ghosting on the multiplexing (dynamic) drive LED display. Multiple TLC59283s can be cascaded together to control additional LEDs from the same processor. 3

4 System Overview SimpleLink MSP432P401R LaunchPad Development Kit The SimpleLink MSP432P401R LaunchPad Development Kit is an easy-to-use evaluation module for the SimpleLink MSP432P401R microcontroller. It contains everything needed to start developing on the SimpleLink MSP432 low-power + performance ARM 32-bit Cortex -M4F microcontroller (MCU), including onboard debug probe for programming, debugging, and energy measurements. The MSP432P401R device supports low-power applications requiring increased CPU speed, memory, analog, and 32-bit performance. At the same time, the MSP432P401R features up to a 48-MHz system clock, and up to eight serial communication channels (I2C, SPI, UART, and IrDA) 2.3 System Design Theory This reference design uses multiplexing topology to drive 16 lines and 16 columns LEDs. The 16-CH TLC59283 controls the 16 columns while 8 dual P-MOSFETs control the 16 lines by 1/16 multiplexing ratio. Taking full advantage of the TLC59283 device features, this reference design provides the following benefits Ghost Removal For multiplexed LED modules, ghost is a common phenomenon. A detailed description is found in Build a High-Density, High-Refresh Rate, Multiplexing Panel With the TLC5957. One cause of the ghost is the charging current for parasitic capacitance of the OUTXn through the LED when the supply voltage switches from one common line to the next common line. To prevent this unwanted charging current, the TLC59283 uses an internal FET to pull OUTXn up to VCC-1.4 V during the common line switching period. Thus, no charging current flows through the LED and the ghosting is eliminated. Another cause of the ghost is the line voltage is not discharged quickly due to parasitic capacitance of the line. Thus, a Zener diode is added to discharge each line when the line MOSFET is off. Combining the two previous methods, the ghost phenomenon is removed in this reference design Fast Refresh Rates The TLC59283 high-data transfer rate supports multiple-channels for fast refresh rates, which are important for dynamic displays that are far beyond the ability of human eyes to distinguish. The TLC59283 device features up to a 35-MHz data transfer rate, which is higher than the MSP432P401R device which has up to a 16-MHz IO clock frequency. Based on the data write and output on or off timing diagram for the TLC59283 device, one frame needs 16 IO clocks, 1 system clock setup time, and 1 system clock hold time, which is approximately 1 µs. When switching the P-MOSFETs one by one for 16 lines, the LED matrix would be refreshed at the speed up to 62.5 khz. 2.4 System Schematic The system schematic is shown in Figure 2 4

5 System Overview Figure 2. TIDA System Schematic 5

6 Hardware, Software, Testing Requirements, and Test Results 3 Hardware, Software, Testing Requirements, and Test Results Required Hardware and Software Hardware To get started with this reference design, connect the MSP EXP432P401R LaunchPad and the LED panel through the BoosterPack plug-in module.. Then plug in the USB wire for the MSP EXP432P401R LaunchPad and the patterns will run automatically. Afterwards, connect the J8(TSW G-S) pin 1(VCC) to a 3.3-Vto 5-V power source to supply the TLC59283 and pin 2 (VLED) to 5 V (higher than VCC) power source to supply for 8 dual MOSFETs Software The firmware for designed patterns are downloaded to the MSP432P401R LaunchPad. The source code is compiled in Code Composer Studio (CCS). To edit the code or design new patterns, it is necessary to install the CCS Integrated Development Environment (IDE) in the PC first. 6

7 Hardware, Software, Testing Requirements, and Test Results Testing and Results Test Setup Connect the MSP EXP432P401R LaunchPad and the LED panel through the BoosterPack plug-in module. Then plug in the USB wires for the LED panel and the MSP EXP432P401R LaunchPad, in that order. The patterns will run automatically Test Results Figure 3 shows the "OK" characters through dynamic refresh. Figure 4 shows the Up signature for an elevator application. Observing the display results, there is no ghost issue when applying a stripe, and the LED panel works normally. Figure 3. "OK" Characters TIDUE48 May

8 Hardware, Software, Testing Requirements, and Test Results Figure 4. Elevator Up Signature 8 TIDUE48 May 2018

9 4 Design Files Design Files 4.1 Schematics To download the schematics, see the design files at TIDA Bill of Materials To download the bill of materials (BOM), see the design files at TIDA PCB Layout Recommendations Layout Prints To download the layer plots, see the design files at TIDA Altium Project To download the Altium Designer project files, see the design files at TIDA Gerber Files To download the Gerber files, see the design files at TIDA Assembly Drawings To download the assembly drawings, see the design files at TIDA Software Files To download the software files, see the design files at TIDA Related Documentation 1. Texas Instruments,16 Channel Constant Current LED Driver with Pre-Charge FET Data Sheet 2. Texas Instruments,Build a High-Density, High-Refresh Rate, Multiplexing Panel With the TLC5957 User's Guide 3. Texas Instruments,MSP432P401R SimpleLink Microcontroller LaunchPad Development Kit (MSP EXP432P401R) User's Guide 6.1 Trademarks E2E, LaunchPad, SimpleLink, BoosterPack are trademarks of Texas Instruments. ARM, Cortex are registered trademarks of ARM Limited. Altium Designer is a registered trademark of Altium LLC or its affiliated companies. All other trademarks are the property of their respective owners. 7 About the Author (Optional) SHAWN DING is an application engineer at Texas Instruments, where he is responsible for developing reference designs in the LED drivers application area. Shawn earned his bachelor of science in electrical engineering (BSEE) degree from Hefei University of technology, Hefei, Anhui, China and a master of science in instrument and meter engineering (MSIME) degree from Zhejiang University at Hangzhou, Zhejiang, China. 9

10 IMPORTANT NOTICE FOR TI DESIGN INFORMATION AND RESOURCES Texas Instruments Incorporated ( TI ) technical, application or other design advice, services or information, including, but not limited to, reference designs and materials relating to evaluation modules, (collectively, TI Resources ) are intended to assist designers who are developing applications that incorporate TI products; by downloading, accessing or using any particular TI Resource in any way, you (individually or, if you are acting on behalf of a company, your company) agree to use it solely for this purpose and subject to the terms of this Notice. TI s provision of TI Resources does not expand or otherwise alter TI s applicable published warranties or warranty disclaimers for TI products, and no additional obligations or liabilities arise from TI providing such TI Resources. TI reserves the right to make corrections, enhancements, improvements and other changes to its TI Resources. You understand and agree that you remain responsible for using your independent analysis, evaluation and judgment in designing your applications and that you have full and exclusive responsibility to assure the safety of your applications and compliance of your applications (and of all TI products used in or for your applications) with all applicable regulations, laws and other applicable requirements. You represent that, with respect to your applications, you have all the necessary expertise to create and implement safeguards that (1) anticipate dangerous consequences of failures, (2) monitor failures and their consequences, and (3) lessen the likelihood of failures that might cause harm and take appropriate actions. You agree that prior to using or distributing any applications that include TI products, you will thoroughly test such applications and the functionality of such TI products as used in such applications. TI has not conducted any testing other than that specifically described in the published documentation for a particular TI Resource. You are authorized to use, copy and modify any individual TI Resource only in connection with the development of applications that include the TI product(s) identified in such TI Resource. NO OTHER LICENSE, EXPRESS OR IMPLIED, BY ESTOPPEL OR OTHERWISE TO ANY OTHER TI INTELLECTUAL PROPERTY RIGHT, AND NO LICENSE TO ANY TECHNOLOGY OR INTELLECTUAL PROPERTY RIGHT OF TI OR ANY THIRD PARTY IS GRANTED HEREIN, including but not limited to any patent right, copyright, mask work right, or other intellectual property right relating to any combination, machine, or process in which TI products or services are used. Information regarding or referencing third-party products or services does not constitute a license to use such products or services, or a warranty or endorsement thereof. Use of TI Resources may require a license from a third party under the patents or other intellectual property of the third party, or a license from TI under the patents or other intellectual property of TI. TI RESOURCES ARE PROVIDED AS IS AND WITH ALL FAULTS. TI DISCLAIMS ALL OTHER WARRANTIES OR REPRESENTATIONS, EXPRESS OR IMPLIED, REGARDING TI RESOURCES OR USE THEREOF, INCLUDING BUT NOT LIMITED TO ACCURACY OR COMPLETENESS, TITLE, ANY EPIDEMIC FAILURE WARRANTY AND ANY IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND NON-INFRINGEMENT OF ANY THIRD PARTY INTELLECTUAL PROPERTY RIGHTS. TI SHALL NOT BE LIABLE FOR AND SHALL NOT DEFEND OR INDEMNIFY YOU AGAINST ANY CLAIM, INCLUDING BUT NOT LIMITED TO ANY INFRINGEMENT CLAIM THAT RELATES TO OR IS BASED ON ANY COMBINATION OF PRODUCTS EVEN IF DESCRIBED IN TI RESOURCES OR OTHERWISE. IN NO EVENT SHALL TI BE LIABLE FOR ANY ACTUAL, DIRECT, SPECIAL, COLLATERAL, INDIRECT, PUNITIVE, INCIDENTAL, CONSEQUENTIAL OR EXEMPLARY DAMAGES IN CONNECTION WITH OR ARISING OUT OF TI RESOURCES OR USE THEREOF, AND REGARDLESS OF WHETHER TI HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. You agree to fully indemnify TI and its representatives against any damages, costs, losses, and/or liabilities arising out of your noncompliance with the terms and provisions of this Notice. This Notice applies to TI Resources. Additional terms apply to the use and purchase of certain types of materials, TI products and services. These include; without limitation, TI s standard terms for semiconductor products evaluation modules, and samples ( Mailing Address: Texas Instruments, Post Office Box , Dallas, Texas 75265

TI Designs: TIDA Power Supply Reference Design for Automotive Microcontroller in Gateway and Body Control Module

TI Designs: TIDA Power Supply Reference Design for Automotive Microcontroller in Gateway and Body Control Module TI Designs: TIDA-1412 Power Supply Reference Design for Automotive Microcontroller in Gateway Description This discrete power supply reference design demonstrates a complete power solution for the Freescale