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Power LED Driver

santhosh raju
Intellectual 305 points
Other Parts Discussed in Thread: TPS61500

Hello,

The application that is intended to be developed makes use of 20 high power infra-red LEDs. The forward voltage of each LED is 2.9V to 3.4V max, driven at a current of 1A. Now, when two sets of 10 such series LEDs are connected in parallel, the voltage that is consumed totally is 34V(max) at 2A. 

Is there any LED driver that implements a Boost regulator, which can accept an input voltage of 12V, there by providing an output voltage of 34V or high with a constant current of 2A, with PWM dimming included in it?

Thanks

  • 0
    Intellectual 310 points

    I think TPS61500 is solve your problems. Output range is up to 38 V. Please check it.

  • 0 in reply to Ilkay
    Intellectual 305 points
    I went through the data sheet of the suggested product. It can supply sufficient voltage to drive the LEDs. But the thing is, I should be able to vary the supply voltage to the LED rail by adjusting the resistor value that is connected with the LED rail, there by varying the intensity of the LEDs.

    For example, I should be able to increase or decrease the voltage levels by varying the resistance connected with the LEDs, using a Potentiometer kind of thing. But here, I will not be able to do such adjustments. At a moment, I will be able to drive the LEDs with only one voltage level.

    Is there any other driver, which have an option for varying the voltage levels by changing the "Feed Back" level?

    Thanks for the suggestion :-)
  • 0 in reply to santhosh raju
    Intellectual 310 points
    I don't understand why do you want to change LED's voltage. If you mention about dimming, the part is capable with dimming function.
  • 0 in reply to Ilkay
    Intellectual 305 points
    The dimming process is done here only using the variation in PWM. Apart from that, the application requires dimming by directly sensing the output voltage through the Feed back and control it.
  • 0 in reply to santhosh raju
    Intellectual 310 points
    Could you give some information about your application ? Why do you need to sense output voltage ?

    If I understand your application, I think I may give right informations.
  • 0 in reply to Ilkay
    Intellectual 305 points
    The application is quite simple. Its just a series LED rail, with above mentioned specs. But the special case is that, LEDs are Infra-Red. The output of the driver should be connected to the LED rail and to a digital Potentiometer as well so that when the pot is adjusted, the signal is sent to the feedback, thereby adjusting the output of the LED.
    Here PWM dimming is also employed. Still for the purpose of accuracy and to know the exact range and distance up to which the IR beam can be projected, a digital pot is used.