Constant Current LED driver dimming help?

Other Hardware LEDs and Multiplexing
1

Hi all.
If i wanted to dim a lets say 10w led 10-12v forward voltage and 1a.
If i where to use a basic/cheap constant current like

http://www.ebay.co.uk/itm/1pc-DC-DC-LM2596-Step-down-Adjustable-Power-Supply-Module-CC-CV-LED-Driver-AR-/400739932544?pt=UK_BOI_Electrical_Components_Supplies_ET&hash=item5d4df61980

or
http://www.ebay.com/itm/1pcs-Power-Driver-for-1x10w-LED-Light-Lamp-950mA-12V-MR16-/121080902070?roken=cUgayN&soutkn=TotL42

Could i use a TIP120/TIP122 to dim with an arduino ?

Any help tips advise would be great?

2

No.

The driver uses feedback to keep the current constant. If you mess with the signal then the driver gets confused.

You need a controller with a PWM input.

eg. led driver 10w pwm for sale | eBay

3

There is also this unit, which is quite good.

http://www.ebay.com/itm/370632520478?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Take note of bullet spec #8 - DO NOT CONNECT V+ TO ARDUINO, only GND + PWM Pins to Arduino. I learnt the hard way before he put that on the listing.

Chris

4

The driver that looks like a base from an MR16 bulb can be modified to dim. It uses the same PT4115 chip as the module iisfaq posted. Beware though that PT4115 chips don't dim well on the low end; they tend to get to about 20% then just turn off completely.
See DX New Forum – Discuss Cheap Electronics and Find Smart Tech Here