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TLC5940
Related Posts

  • Forum Post: Re: Propery Color Mixing with TLC

    Michael Day
    Properly reproducing a color is actually a fairly complicated process. Generating a pure red color that is perceived by the human eye to be a pure red color requires driving all three LED colors. A pure red pixel will be generated with the red LED almost fully on with the green and blue LED at very low...
    on Mar 5, 2010

  • Forum Post: TLC59401 drive circuit through 50ft cable

    Saied ZARGAR
    Customer is using TLC59401 and wants to know if it can be used to drive circuit through 50ft of cable to a board. Any forseable problems with this? If not, what design considerations muist customer take into account? Voltage drop across cable?
    on Mar 26, 2010

  • Wiki Page: TLC5940 - How do you manage dot correction when paralleling outputs?

    Michael Day
    Q: TLC5940 - How do you manage dot correction when paralleling outputs? by 1166427 Question/Problem: How do you manage dot correction when paralleling outputs? Answer: First, I do not recommend this because the currents will not be matched due to differing drops in the diode. Dot correction...
    on Mar 30, 2010

  • Forum Post: Re: tlc5940 with higher current LEDs

    Chris Glaser
    This app note is applicable to the TLC5940 also: http://focus.ti.com/lit/an/slva253/slva253.pdf We also have high current LED drivers in a boost topology, such as the TPS61500.
    on Mar 30, 2010

  • Forum Post: Re: Dot correction on the TLC5940

    Michael Day
    You should be able to see the difference between dot correction and grayscale by looking at the diode voltage and current on an oscilloscope. Grayscale dimming turns the LED on for some percentage of the display frame. Example, if you program the grayscale register with 2048, the LED will be on for 2048...
    on May 10, 2010

  • Forum Post: Re: TLC5941-Q1 Pin Connections

    Michael Day
    Unused TLC5941 outputs can be left open. They do not need to be connected. The unused outputs should be programmed to be off to minimize the quiescent current to the IC. Having an unused output disconnected but programmed to sink current increases the quiescsent current to the IC because the internal...
    on May 25, 2010

  • Forum Post: Re: Problem using TLC5940EVM

    Brigitte
    Hello Aparna, The interface board is relatively slow compared to the data speed, therefore the delay between the loops could be caused by this low communication speed. Could you send me the frames that you used and also the setting of the software that I can recheck it on another EVM? I never heard...
    on Aug 10, 2010

  • Forum Post: Re: Configuring TLC59401 using FPGA

    Brigitte
    Hello Praveen, What do you mean with architecture? For a lot more technical information then in the TLC59401 product folder, please review the EVM document and the application notes you can find in the TLC5940 product folder. Maybe this helps to solve your issues. TLC5940 and TLC59401 are almost identical...
    on Aug 18, 2010

  • Forum Post: Re: Problem using TLC5940EVM

    Brigitte
    Hello Aparna, During my evaluation in the lab I could reproduce the issue. The problem is that the driver board and the LED board have different power supplies and different grounds. When I am installing resistor R18 and connecting the grounds of the 2 boards together, the flashing of the green and...
    on Sep 10, 2010

  • Wiki Page: TLC5940 - Current Limitation

    Michael Day
    Q: TLC5940 - Current Limitation by 1140759 We inherited a design from another company which uses the TLC5940 to drive a set of infrared LEDs at high-current. The VCC they are applying to the LEDs and the 5940 chip is 3.6V. We are setting the current using a 332 ohm resistor on pin 27 (IREF)...
    on Sep 29, 2010

  • Forum Post: Re: TLC5941 to MPU timing madness

    Brigitte
    Hello Chuck, Let me try to answer your questions: 1. Calculation is almost correct, just some time for XLAT and BLANK has to be there, which increases the data transfer speed. 2. The e xtra clock is just needed once after all bits are clocked through the 4 series parts. So for clocking in the...
    on Oct 19, 2010

  • Forum Post: Re: TLC5940 with only 3 micro pins?

    Brigitte
    Hello Logan, To be honest, I never tested it, but I do not think so. You need SIN and SCLK for data to be clocked into the IC. You need GSCLK to turn on and off the outputs and you need XLAT to latch the new data into the GS registers. In addition, I do not think that this will work without having...
    on Dec 14, 2010

  • Forum Post: Re: TLC5940 with only 3 micro pins?

    Brigitte
    Hello Logan, In the datasheet on page 19 you can find a description of the grayscale PWM operation. The following sentence is the first one: " The grayscale PWM cycle starts with the falling edge of BLANK." A falling edge on BLANK starts the GS cycle, therefore you should not pull BLANK...
    on Dec 15, 2010

  • Forum Post: Re: TLC5940 with only 3 micro pins?

    Michael Day
    Yes, you can connect VPRG and BLANK together. Please note that you can not shift in any grayscale data into the IC when VPRG and BLANK are pulled high because the TLC5940 will put the data into the Dot Correction Register. Also note that you must program the dot correction register after power up and...
    on Dec 17, 2010

  • Forum Post: Re: TLC5940 with no load

    Michael Day
    The TLC5940 is operating properly. If you have the output programmed to sink current, but the output is open, the IC trys harder and harder to turn on the internal FETs which results in higher input current to the IC. This will not damage the IC. If you want to reduce power consumption, program unused...
    on Dec 28, 2010

  • Forum Post: Updating TLC5940 Dot Correction

    Samuel Loho
    Hi, I am working on a project involving TLC5940 chip and i have a question regarding the dot correction mode on the chip. I am aware that the dot correction register must be set at the power up if I were to use the dot correction value stored on the register. Is it possible to update the register...
    on Jan 6, 2011

  • Forum Post: Re: Updating TLC5940 Dot Correction

    Michael Day
    You can change the TLC5940 (and all other TLC59xx products with dot correction build to date) at any time. The conditions for changing dot correction at power up are the same as changing dot correction at any other time. Figure 15 shows the correct sequence. You should look in detail at the timing of...
    on Jan 6, 2011

  • Forum Post: Re: TLC59401/TLC5941 use without GSCLK

    Brigitte
    Hello Matthieu, Sorry, but the GSCLK is absolutely needed for this part. The part just turns on the outputs, if a GSCLK is connected. In addition, there are no default values for the gray scale register, therefore your connection will not work. Please have a look at TLC5947 which has 24 channels...
    on Feb 21, 2011

  • Forum Post: Re: TLC59401/TLC5941 use without GSCLK

    Brigitte
    Hello Iko, What do you mean with "if the generation of GSCLK is stopped"? Do you mean you stop for a while to keep the outputs on for longer than in general? How long is this while? What do you want to achieve with stopping the GSCLK? Why not just making the GSCLK slower? Best regards...
    on Feb 23, 2011

  • Forum Post: Re: TLC59401/TLC5941 use without GSCLK

    Michael Day
    You are correct that if you stop applying a clock signal to the tLC5941 (TLC5940) GSCLK pin, the internal counter does not count and the outputs remain fixed and do not change. Note that if you pull BLANK high, the outputs turn off and the internal counter is reset. You can not turn the outputs on again...
    on Feb 23, 2011

  • Forum Post: Re: TLC59401/TLC5941 use without GSCLK

    Brigitte
    Hello Iko, 1) Initialisation of the device: - G.S. witht random value (10 for exemple) - Dot with zero value Must input both value(GS/DC) for turned on.and these are selected by MODE pin. MODE=H ; DC Data MODE=L ; GS Data But customer’s condition is below. - MODE : routed on Vcc...
    on Mar 15, 2011

  • Forum Post: Application for dimming white LEDs on multiple channels

    Todd Larson
    I have an application for dimming white LEDs on multiple channels. I have tried using the TLC5940 with 16 channels with dot correction and grayscale PWM with some success. Generating the GS clock is messy at best. If a 25MHz internal oscillator was provided for the GS clock, this would be a nearly perfect...
    on Apr 12, 2011

  • Forum Post: Re: TLC5940

    Brigitte
    Hello Paul, All outputs are current sinks which can be paralleled. The application note http://www.ti.com/litv/pdf/slva253 is also valid for TPS5940. Best regards, Brigitte
    on Apr 15, 2011

  • Forum Post: Re: TLC5940 - thermal pad electrical connection

    Brigitte
    Hello Andrew, You are right, the thermal pad should be connected to GND if possible. In the datasheet you can find some typical characteristics for ICs where the pad is not soldered. Best regards, Brigitte
    on Jul 4, 2011

  • Forum Post: Re: TLC5940 - thermal pad electrical connection

    Brigitte
    Hello Andrew, No, it is not indicated in the datasheet. It is indicated in the EVM user's guide in the product folder. Best regards, Brigitte
    on Jul 5, 2011
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