Adjust the brightness of 3watt LED

Discussion in 'General Electronics Chat' started by dknaoremcha, Nov 4, 2012.

  1. dknaoremcha

    Thread Starter New Member

    Sep 10, 2012
    1
    0
    Hi, I have an LED driver with MT7201, I configured it for using 2x3watt Philips rebel (3vF/700mA). The brightness is quite good, but in the late night I want the brightness to be decreased at around 10%. As the datasheet mention, to adjust the brightness I need to drive the ADJ pin (free/not use) with PWM signal from open-collector or open-drain transistor. And f<500Hz.
    And it also telling that we drive the ADJ pin with DC voltage 0.25v to 2.5v to adjust output current.

    Please help me making a brightness controller for this driver.
     
  2. bertus

    Administrator

    Apr 5, 2008
    15,645
    2,344
    Hello,

    Reading the datasheet, the output current will follow this curve:

    [​IMG]

    Bertus
     
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