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DLPA2005: Power Consumption

Go Bravos
Expert 6090 points
Part Number: DLPA2005

Team,

I was looking over the DLPA2005 datasheet and it seems that the input current on VIN should be a typical of 15mA (In active mode with motor excluded). I had a few questions in regard to this…

  1. What is the maximum input current that I can expect at VIN?
  2. Is 15mA the typical current I should be expected to see at each VIN pin (e.g. VINA, VINR, etc.) or in total? It seemed a little low too me, so I just wanted to verify.

Thank you.

  • 0
    TI__Mastermind 28005 points

    Hello,

    This is a good question. Let me inquire with the team and get feedback to you within the next few days.

    Best Regards,

    Philippe Dollo

  • 0 in reply to Philippe Dollo
    TI__Expert 6090 points

    Philippe,

    Please advise ASAP.

    Thanks.

  • 0 in reply to Go Bravos
    TI__Mastermind 28005 points

    Thanks for your patience. I'm still looking into this topic to get a sufficiently detailed answer from our technical experts.

    Will see if I can close out today on this issue.

    Regards,

    Philippe

  • 0 in reply to Philippe Dollo
    TI__Mastermind 28005 points

    The DLPA2005's VIN  current rating (15 mA) is specified here only for the VINA terminal. There are other VINs for the various power regulators which will all be much higher than 15 mA in active mode. This active mode current consumption is specified by the product line which manages the power management ICs (PMICs).

    As a side note, keep in mind that the actual system current consumption will be dominated by the VLED buck-boot (which is driving the LEDs) and may consume up to ~2.4A at output, depending on your particular software configuration.

    I hope this helps. Let me know if you have follow up questions.

    Regards,

    Philippe Dollo

  • 0 in reply to Philippe Dollo
    TI__Expert 6090 points

    Philippe,

    In your reply, it seems that VINA will be ~15mA in active mode. I have a few follow-up questions…

    1. I understand that the LED current can be up to ~2.4A, depending on what your input voltage is. If your LED current is 1A compared to 2.4A, does the VIN power consumption change proportionally?
    2. (Going off of Q1) Are there any power estimates for the other VIN supplies at the different LED current numbers? Would VINA remain the same regardless of LED current drive strength?

    Overall, I am trying to determine what kind of power consumption I should expect at my VIN pins.

    Thank you.

  • 0 in reply to Go Bravos
    TI__Expert 6090 points

    Philippe,

    We haven't heard a response in several days. Please advise.

  • 0 in reply to Go Bravos
    TI__Mastermind 28005 points

    Hello,

    1. There may be some confusion here depending on how I am reading this. You mentioned "LED current can be up to ~2.4A, depending on what your input voltage is". The output LED current (which maximum is 2.4A with this device) is typically controlled via DAC that is trimmed from 0 to 1023 based on SPI commands sent from the DLPC343x. Or are you asking about different system behavior?

    2. VINA is used to drive sensitive reference voltages. The other VIN rails are what will drive the LED current itself.

    If what you ultimately want is power consumption of all VIN pins, you need to look at the system as a whole. The 1.1V rail, for example, drives the controller and DMD, and then there are the DMD bias regulators coming out of the DLPA2005. As such, while the power of the DLPA2005 in particular is dominated by the LED current, the full breakdown of the power consumption will require knowledge of how the other system components are operating too. 

    Let me know if I misunderstood your question.

    Regards,

    Philippe Dollo

  • 0 in reply to Philippe Dollo
    TI__Expert 6090 points

    Team,

    In regards to question 1, I understand the DLPA2005 can drive up to 2.4A, and is controlled via the 10-bit DAC. However, in the datasheet it looks like you need to supply an input of at least 4.5V to get the full spectrum of ILED.

     If I am trying to determine the power consumption of strictly the DLPA2005, what information is needed? Assuming two different scenario’s – 1st each LED is driven at 350mA and 2nd, each LED is driven at 700mA.

  • 0 in reply to Go Bravos
    TI__Intellectual 830 points

    The DLPA2005 has four power domains:

    1. VINA as mentioned before drive internal references, etc. It does not vary based on consumption of any other domains.

    2. VINC in the input for the 1.1V regulator which had a 600mA max output and a switch current limit of 1A. This is the core voltage of the DLPC343x. The DLPC current draw varies but is usually in the 100mA range. If the recommended passives are used this regulator should be 85%-90% efficient. Input current varies with the voltage of VINC. The power in will be in the range of 122mW {(100mA * 1.1V) / .9}. You can determine the average current in by dividing 0.122W by the voltage in. A 5V Vin would have an average current of about 25mA.

    3. VINR is the input for a regulator that supplies VOFS, VBIAS and VRST to the DMD. Current out varies depending on the DMD used and other system variables. From the data sheet the max power is

    VOFS -> 10V * 3mA = 30mW

    VBIAS -> 18V * 4mA = 72mW

    VRST -> 14V * 4mA = 56mW

    Total is 158mW, efficiency should be about 70% so max average current in at 5V vin is about 45mA  {(0.158/5V)/.7} 

    4. VINL is the input for the LED regulator. It should be 80% to 90% efficient. Current in depends on the LED current and the forward voltage of the LEDs. If all the LEDs have a Vf of 3V and you are driving 1A then the average current into VINL is about 670mA  {((3V*1A)/.9)/5}. Max AC current is the switch current limit of 4A.

  • 0 in reply to Kevin Lowderman
    TI__Expert 6090 points

    Kevin,

    Thank you. Did you intend to attach images? It looks like they did not make it through.

  • 0 in reply to Go Bravos
    TI__Intellectual 830 points

    I just cut and pasted some sections from the Electrical Characteristics table in the DLPA2005 datasheet. Not sure why they didn't take. This table starts on page 6.

    -Kevin