High power LED drive through microcontroller

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chanchal.chauhan

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Dear ALL,

How to drive High power LED through microcontroller?

Here as of my knowledge we have to use PWM pulses to drive the LED through MOSFET.

What frequency & Duty cycle i have to use?

Please share ur ideas.

Thanks in Advance
Chanchal Chauhan
 

Its fairly simply dear friend.

Use a 10K resistor and connect +ve of Led to VDD thr resistor and -ve of Led to MCU.

U can use a simple counter or if using PWM, 50 duty cycle shuld be OK.Pefect Square wave shuld come.


Port A = 0X00h;
Delay(50ms); // write a delay function using for loop or using inbuilt counter/timers.
Port A = 0xFFh;
Delay(50ms);
 
Hi,
You can use 50% or any duty cycle. The lower the duty cycle, the dimmer the light. You can use 1kHz frequency. You just need to make sure the voltage limit of the LED isn't crossed, as some power LEDs have a stated maximum supply voltage, which are not very high.

Hope this helps.
Tahmid.
 
I have one more query

What is the difference between to drive LED with PWM Pulse with microcontroller and current limiting resistor using hardware to drive led?

Regards
Chanchal
 

Hi,
I didn't get your question clearly, but you have to understand that even in PWM, you have to use current limiting resistor. One advantage to PWM is you can efficiently dim the LED brightness, rather than tediously calculating and experimenting what resistor value you have to use for required brightness level.

Hope this helps.
Tahmid.
 
HI

Whatever scheme you use, limiting resistor is a must for a LED to ensure in the worst case (including transients) the current flowing through LED is going to be limited.

Cheers
 

RGB LED PWM Driver for High Power 350mA LEDs :

http://picprojects.org.uk/projects/hbld/V3/hbldv3.htm
 
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