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Three step color temperature adjustable solution

Jonas
Intellectual 540 points
Other Parts Discussed in Thread: TPS92075

Hi

My customer have a new project need the solution request: 3 step tunable CCT driver solution. other parameter request as below. 

1. input voltage: AC120V

2. freqency:47~63Hz

3. output current: 330mA or 200mA

4. output voltage: 36V or 60V

5. output power: 12W

6. current accuracy: 5%

7. efficiecny: >85%

 
Does we have suitable solution can suggest ? thanks 

Jonas zhang

  • 0
    TI__Mastermind 28655 points

    Hello Jonas,

    Is this two different designs (36V, 330 mA or 60V, 200mA)?  If this is one design are there two outputs?

    What is controlling the 3 step tunable?

    Are there controls to switch the LED load and if so are they referenced to the secondary (if this needs to be isolated)?

    Does this need to be isolated?

    We have parts that can do this but getting more information can narrow it down to better choices.

    Does this have to dim?  If so what type of dimming?

    Regards,

  • 0 in reply to Irwin Nederbragt
    Intellectual 540 points
    Dear Irwin:

    1. There are two design. 1st: 36V330mA output, 2nd: 60V 200mA output.
    2. customer will use hard switch to control the 3 steptunable. 1st push switch, will be 3000k, 2nd push switch, will be 4000k, and 3rd push switch, will be 5000k.
    3. isolate solution or non-isolate solution both can be accept
    4. not need diming, customer use two white LED(color temperature:3000K,5000k) . one condition is the LED of 5000K color temperature lighted on, 2nd condition is only the LED of 3000K color temperature is lighted on. and the 3rd condition is two LED are lighted at the same time, but not the same driver current.

    Jonas zhang
  • 0 in reply to Jonas
    TI__Mastermind 28655 points

    Hello Jonas,

    3)  What power factor and THD does this require?  The TPS92075 is an off-line buck converter which is a fairly simple topology but when the LED stack voltage gets higher THD will get higher and power factor lower.  Isolated will be larger, and possibly more expensive.  A non-isolated flyback would provide good PFC and THD but requires a custom magnetic.

    4)  How will they control current to two LED strings?  For 3000K it will just be one string, one current source, same for 5000K.  4000K will require two current sources since they cannot be paralleled and share current.

    Regards,

  • 0 in reply to Irwin Nederbragt
    Intellectual 540 points
    Hi Irwin:

    Thanks for your reply
    3) Customer not require PFC and THD value. I will reply after checked with customer
    4) The best solution is that one driver IC can driver two channel independently, and can control current separetly. If no this, customer should be use two driver IC to achieve。

    Jonas zhang
  • 0 in reply to Jonas
    TI__Mastermind 28655 points

    Hello Jonas,

    There really isn't any two channel current regulator that runs from rectified AC.  Of the two strings, 3000K and 5000K what are the LED stack voltages?  Are they almost the same?  There are a few methods this can be done but maintaining 85% efficiency eliminates or reduces the possibility of a few choices.  A 60 volt output also limits the use of some of the DC/DC parts.  Perhaps two TPS92075s or other simple LED drive is the best choice knowing 4000K will be a little less efficient since two converters are running at about half power.

    Regards,