DC-DC step-up and step-down LED driving PT4115

The PT4115E is a continuous conduction mode  inductive step-down converter, designed for driving  single or multiple series connected LED efficiently  from a voltage source higher than the total LED chain  voltage. The device operates from an input supply  between 6V and 50V and provides an externally  adjustable output current of up to 1.5A.  The PT4115E includes the power switch and a  high-side output current sensing circuit, which uses an  external resistor to set the nominal average output  current, and a dedicated DIM input accepts either a DC  voltage or a wide range of pulsed dimming. Applying a  voltage of 0.3V or lower to the DIM pin turns the  output off and switches the device into a low current  standby state.  The PT4115E is available in SOT89-5 package.