LED Drivers/LCD Bias

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TLC5947
Related Posts

  • Forum Post: interfacing the TLC5947

    Rene Wassenburg
    Hi there, I'm new on this forum, so i hope i posted this topic in the right forum section. I'm using a TLC5947, and i want to drive 1W LEDs. For this is I want to use a buck converter from Zetex; the ZXLD1350. http://www.diodes.com/zetex/_pdfs/3.0/pdf/ZXLD1350.pdf The outputs of...
    on Nov 6, 2009

  • Forum Post: Re: TLC5947 Interfacing with a FPGA

    Michael Day
    There are no special requirements for a buffer if one is used between the FPGA and the TLC5947 LED driver. You can buy a standard buffer or you can make your own from an opamp. The required bulk capacitance is a function of how much voltage ripple you can allow in your system. If you assume that the...
    on Mar 24, 2010

  • Forum Post: TLC5947 - Higher output current

    Hecklebone
    Hello all, I am a neophyte to this, so please be kind to the noob. I am interfacing with a series of 6 TLC5947s. I'm using a PIC to send the 288 bits for 24 outputs over SPI for each 5947. I have chosen the 5947 because it is a simple matter to connect them with SPI and the density of 24 outputs...
    on Apr 26, 2010

  • Forum Post: Re: TLC5947

    Michael Day
    Be aware that the TLC5947 is not designed to be fully SPI compliant. The TLC5947 datasheet describes the timing requirements in detail, so please review these. You can use the any of the methods you describe above. If you use npn or n-ch devices, your LEDs will turn off when the TLC5947 LED driver turns...
    on Apr 26, 2010

  • Forum Post: TLC5947 not working

    Jair Ramos
    Hello, I'm using the driver to control only one LED in each output. The voltage applied to the driver and LEDs is 5V, the chip package is HTSSOP and the resistor Riref is 2.2k Since I'm working with a prototype, I soldered the device with a regular solder iron and used silicone grease...
    on Aug 20, 2010

  • Wiki Page: TLC5947; Riref; output current setting

    Michael Day
    Q: TLC5947; Riref; output current setting by 1004451 I have a question about part TLC5947. I’m wondering about the functionality of the current setting resistor on the device. Does it set the total current through all channels or through any one channel. A: Re: FW: Customer...
    on Aug 30, 2010

  • Forum Post: Re: Looking for some advice for 8x8 RGB Led matrix driver

    Brigitte
    Hello Eduardo, The decision which part fits your requirements best is dependent on the requirements you have in your system. For example is your controller fast enough to drive all 24 channels in series. If the controller is not fast enough to drive the 24 channels in series then you should have a...
    on Sep 9, 2010

  • Forum Post: Re: TLC5947 not working

    Brigitte
    Hello Jair, For the TLC5947, the power pad should be connected to ground. It can be left floating, but this probably isn't the best option thermally. Even if you connect the power pad to ground, please be aware that the IC ground pin should be used for all ground connections and return paths....
    on Sep 9, 2010

  • Forum Post: Re: Looking for some advice for 8x8 RGB Led matrix driver

    Brigitte
    Hello Eduardo, It is right, you need 3 serial ports for TLC5951 and if you just want to use one, then this one is not the right part for you. TLC5947 has a grayscale register per channel and TLC5951 has a brightness control register per color group. So if you want to display animations or text...
    on Sep 10, 2010

  • Forum Post: Re: TLC5947 Single Shot

    Brigitte
    Hello Martin, Sorry, but I do not understand what you mean with single shot mode. Could you please explain in a little more detail what you want to achieve? TLC5947 just turns on the outputs based on the data in the GS latch. So after BLANK goes low at the fifth internal oscillator rising edge...
    on Sep 22, 2010

  • Forum Post: Re: TLC5947 Single Shot

    Brigitte
    Hello Martin, Sorry, but with TLC5947 you do not have the possibility to know when the signal is shown once without observing the outputs. The internal oscillator is not given and has some variation. You might have a look on TLC5951 which gives you full control over the GS clock. Best regards,...
    on Sep 23, 2010

  • Forum Post: Re: TLC5947 Single Shot

    Brigitte
    Hello Martin, Let me try to understand your problem to find a suitable solution: You have 192 LEDs you want to either turn on or off in a refresh rate of 60Hz. These 192 LEDs (or channels with more than one LED) are grouped in 24 LEDs (or channels) in 8 rows. Is this right? Now you want to control...
    on Sep 27, 2010

  • Wiki Page: TLC59xx for low current LCD drive

    Michael Day
    Q: TLC59xx for low current LCD drive by 8947 I want to use the TLC59xx family for driving LCD panels or LCD 7 segment displays. These use much lower current than LED displays. So the question that arises is this: Which of these TLC59xx parts can have accurate current control at currents...
    on Oct 21, 2010

  • Forum Post: TLC5947 - minimum current

    Eric Jonardi
    When driving all LEDs at either a 99.6% duty cylce (all grayscale registers = 4080/4096) or a 0% duty cycle (all grayscale registers = 0/4096) the device behaves as expected, driving the LEDs at full power or fully off (respectively). However, when the grayscale register is set to alternating values...
    on Nov 18, 2010

  • Forum Post: Re: TLC5947 - minimum current

    Michael Day
    If the TLC5947 grayscale value is set to 0, the LEDs should not sink any current. The tolerance you refer to on page 4 are only valid when the TLC5947 is sinking current. Can you provide pictures of the LED current in this "on/off' condition. A clip on current probe probably doesn't have...
    on Nov 18, 2010

  • 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: 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: Need land pattern for HTSSOP 32 for TLC5947DAP

    Brigitte
    Hello Rick, In general if you are searching for CAD data, you can find HTSSOP package CAD data in the TLC5924 folder which uses the same package. Here attached you can find the package drawing: (Please visit the site to view this file) and the PowerPad dimensions: (Please visit the site...
    on Apr 15, 2011

  • Forum Post: Re: Using TLC5947 (or other LED driver) with incandescent bulbs

    Brigitte
    Hello Mr. Johnson, To be honest, I do not expect that anyone within Texas Insturments tested if the TLC5947 can work with incandescent bulbs. TLC5947 has regulated current sinks therefore the current will stay constant as long as the IC is able to reduce the resistance of OUTx enough to keep the...
    on Apr 15, 2011

  • Forum Post: Re: Using TLC5947 (or other LED driver) with incandescent bulbs

    Brigitte
    Hello Iko, You are right, all outputs can be on at the same time. I expect your question is about power dissipation inside the IC, right? If this is the case, if all outputs are on with 28V on each output, the IC will not be able to stand this power. The most power dissipation is not inside...
    on Apr 18, 2011

  • Forum Post: TLC5947 high current leakage

    Allan Wang
    I have a board with TLC5947's where some of the pins have high current leakage, causing LED's to dimly glow when they should be completely off. In around 5% of the outputs, I get around 1uA of leakage current. Some pins even have 5uA+ which is very visible. The current rapidly decays when sinked...
    on Apr 19, 2011

  • Forum Post: Re: TLC5947 high current leakage

    Brigitte
    Hallo Allan, The leakage current in the datasheet is specified with 0.1uA maximum. Therefore as long as the IC is not damaged, the leakage through the OUTx pin to GND is not bigger than this. As long as you follow the soldering recommendations, these parameter should not change. What we sometimes...
    on Apr 19, 2011

  • Forum Post: Re: TLC5947 high current leakage

    Brigitte
    Hello Allan, Please check if 100kOhm from VLED to OUTx helps. The resistor shall not be in series with the LED, but parallel to the LED. Best regards, Brigitte
    on Apr 20, 2011

  • Forum Post: Re: TLC5947 high current leakage

    Brigitte
    Hello Iko, I expect that there is some type of leakage path in the board which is going through the LED. Now if you place a resistor from the high voltage to the OUTx pin, this resistor is used to charge the leakage path and not the diode. This should overcome the leakage issue. If the resistor...
    on Apr 21, 2011

  • Forum Post: TLC5947

    AMID ALE
    I have a question about TLC5947. try to understand how this device is connected in cascade mode to driving individual RGB LEDs but do not understand the information on the datasheet
    on May 26, 2011
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