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Author Topic: i want to dim my led's  (Read 2180 times)

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dazzer_up_north

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i want to dim my led's
« on: September 23, 2010, 20:34:55 PM »
Hello all.

My plan. is to use a GHL profilux aquatic computer to adjust the brightness of a large led array.

simples?

the GHL can adjust a 0v-10v line output according to time and a determinable output.
i.e. at 7 am put 1v on line 1, at 8am make it 2v etc etc.

i can buy PWM dimmable drivers easily. (based on the MBI6651) and nice and cheap from the bay.

i'd like a circuit that outputs a PWM signal that the duty cycle is adjusted by the 0-10v...

the PWM needs to be 5v and 1khz.(max)

i hope someone can help. i have trawled and trawled the web, i can find loads of ccts that will allow dimming via a pot. but i want the 0-10v to do it..

thanks in advance.

daz


kam

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Re: i want to dim my led's
« Reply #1 on: September 23, 2010, 22:04:36 PM »
A friend of mine wanted to have something very similar. So i designed this:
Voltage Controlled PWM Generator

I think this is exactly what you are looking for.  Only that it works with 5 volts, and thus the voltage input is 0 to 5 volts. You can change of course the supply to 10 or 12 volts, but you may need to re-calculate the 3 resistors around the transistor. You need to test it. Make it on a breadboard

If you can use only the scale from 0 to 5 volts as input, then there will be no problem. Connect your analog output to the pin "DC voltage level input" and remove completely the 5K potentiometer and the 1.5K resistor before this pin...

kam

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Re: i want to dim my led's
« Reply #2 on: September 23, 2010, 22:06:19 PM »
... and let me not forget... the triangle wave oscillator needed for the circuit to operate, can be found here: Triangle wave oscillator