This is one of the converter types.
Part Number : KIS-3R33S
Function : 3A, 10 W, DC-DC Step Down Converter
Package : Module type
See the preview image and the PDF file for more information.
This module comes with output voltage preset to 3.3V. However, it is easy to readjust and have output setat any voltage from 1.21 V – 10.43 V, if the circuit is modified then the output voltage can be varied up to 20V. Different LEDs from different manufacturers operateat different maximum continuous voltage, which in
turn determines the maximum current flowing throughthe LED. To protect LED and to provide stable light characteristics it is necessary to limit the voltage output from the KIS-3R33S module according to the specific requirements for each type of power LED, as specified by the manufacturer.