Constant Current LED driver dimming help?

Projects General Guidance
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

Can you use PWM to control a power (logic level) MOSFET

3

For the LM2596-based driver, I don't know if a transistor would work with that to make a dimmable driver.

For the MR16-shaped driver, that is based on the PT4115 chip and is dimmable if you just tap into the right pin on the driver. See DX New Forum – Discuss Cheap Electronics and Find Smart Tech Here. Note that his experience with being unable to dim it below ~20% is normal for the PT4115.