Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

SMD LED Constant Current Driver Project.

Status
Not open for further replies.

Hammer

New Member
Hi All,

My first post here. :D

I'm trying to build a 20mAh-30mAh constant current driver for SMD LED's for my Micro RC Helicopters. I found these SMD 10mA chips from Infineon...the info says they're easily used in parallel to increase current. I tried stacking them and the current didn't increase.

**broken link removed**

**broken link removed**

What am I missing?

Here's a little video of the little scale RC Helicopter projects I'm working on.

YouTube - CB100 MD500E CHP Build Log Stage 11: Flying the Finished Project

Any help would be greatly appreciated. :)

Regards,
John
 

Attachments

  • leddriver3.jpg
    leddriver3.jpg
    332.6 KB · Views: 280
What's wrong with just using a resistor?.

But if you want to use the chip, just add an external resistor to set the current, as shown in the page you posted.
 
You don't "stack" them to increase the current, you put the outputs in parallel.

But just use an external resistor (Rext) to increase the current as Nigel suggested.
 
Hi guys,
I'm an architect and building contractor by trade, I'm pretty ignorant regarding electronic schematics. Thanks for your help.

What's wrong with just using a resistor?.
Nigel,
These little helicopters are very weight sensitive. My gaol is to build a complete 8 LED light set weighing 2 grams or less, a resistor for each LED would just weigh too much.

You don't "stack" them to increase the current, you put the outputs in parallel.

But just use an external resistor (Rext) to increase the current as Nigel suggested.
Carl,
I think I'm getting a better understanding of how these chips work.

Thanks again to you both for your help, it is greatly appreciated. :)

I hope to have time tomorrow to experiment based on my newly gained knowledge, I'll post my results. ;)

Regards,
John
 
Last edited:
My gaol is to build a complete 8 LED light set weighing 2 grams or less, a resistor for each LED would just weigh too much.
You can buy small surface mount resistors that weigh virtually nothing, much less than the weight of the LEDs or the IC.
 
Just use a surface-mount components to make this circuit. Connect the 4k7 to positive rail for continual output:
**broken link removed**
 
Last edited:
I have SMD resistors I can barely see! My 0402 resistors weighs only 0.0010 grams - surely this isn't too heavy?

Even a big 1206 thick film SMD resistor is only 0.016 grams!
 
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top