Intersil – Flower Power reference design demonstrates efficiency of switching regulator in low-current application


Intersil has developed a ‘Flower Power’ reference design which demonstrates the capabilities of its ISL85005 high-efficiency synchronous buck regulator, as well as other Intersil analogue and sensing products.

The reference design board is intended to be a fun office adornment. A press of the button on the back powers up the board: the flower will then play one of five classic ‘Summer of Love’ songs and create an eye-catching pattern by driving the colour LEDs mounted on the petals of the flower-shaped board. The board comes with a suction-cup hanger which can be used to hang the board on a window or any smooth surface.

At the heart of the Flower Power reference design is Intersil’s 5A ISL85005, a switching regulator with an input-voltage range of 4.5V to 18V: this is ideal for use with the board’s two CR2032 batteries which, in series, produce a nominal output voltage of 6V.

While the ISL85005 is capable of delivering up to 5A of output current, this design draws less than 50mA when playing a song. This low-current application shows off the Diode Emulation Mode (DEM) feature of the ISL85005, which greatly improves efficiency at light loads. The board is able to play more than 1,000 song-play cycles before the batteries are fully discharged.

The device converts the 6V battery input to a 3.3V output, providing a power rail for the rest of the active components on the board. The PCB is shaped like a five-petal flower and comes in two colours, purple and yellow.

It has five RGB LEDs on the front and an Intersil ambient light sensor to control the LED brightness.


  • ISL29102 low-power ambient light-to-voltage non-linear converter
  • ISL21080 300nA NanoPower voltage reference
  • ISL28915 NanoPower push/pull output comparator
  • Microchip ATmega328P-AU 8-bit AVR® RISC microcontroller
  • Abracon ASPI-0630LR power inductor, offering low DC resistance and high saturation current
  • Murata PKLCS1212E4001-R1 surface-mount piezoelectric sounder

Orderable Part Number: ISLAT-FLOWER1Z