Clean and energy efficient LED dimming

After thinking i cant open the LED without breaking it i have it open now.
The 3 LEDs are series-connected.
The electronic was sealed in some silicon.
Looks close to this ones: http://detail.china.alibaba.com/pic/914205741.html

Its a MT7201 1A LED driver: http://www.maxictech.com/en/UploadFiles/MT7201_rev1.1_EN.pdf
And the circuit is close to this one: getaktete LED-Treiber
But there are some diodes in front of it as rectifier.

Looks like you can PWM control this driver.
I will try to reverse engineer the circuit/PCB to find out what the LEDs need.

If i build my own driver, is it better to

  1. put the MOSFET and driver near the LED
  2. put the MOSFET near the Arduino and the driver near the LED
  3. put the MOSFET and the driver near to the Arduino

And sure there are dimable LEDs out there, but they are not cheap and this have a really
good Colour Rendering Index and Color temperature.