The LTC3490 works fine down to 1,4V input voltage. For the test I used a single cell LTO accu with ca.2200mAh capacity and a voltage range from 1.8V to 2.8V.

It is also possible to drive the LTC3490 LED driver board with a single Lithium Ionen or Lithium Polymer accu. The board runs for over 45 mins with this LTO accu.

Detailed measurements shows an power consumption of 4.5W for four LEDs. This shows an efficiency of nearly 90%.

Additionaly the board can be assembled with eight LEDs so the power will increase to 9W and the lumen rises up to 1400lm.

Four groups of the eight LEDs can be indepented enabled/disabled, so a individual dimming can be done with a PWM connected to each of the four channels.

The LTC3490 board can be easly driven by an Arduino or Raspi board due to the 3.3V input compliance, but be attention to the high input current, additionaly the boards can be connection into one chain to increase the lumens.