This application note describes the use of the L5970D/L5973D high intensity LED driver. The driver can operate over a wide range of input voltages to drive a series of LEDs, providing efficient energy source.
The document details an evaluation board design that uses the L5973D monolithic step-down converter configured as a constant current driver. It is designed to operate with series strings of one to several LEDs, supporting both low voltage AC sources (like landscape lighting) and low voltage DC sources (such as automotive applications). The circuit allows for easy configuration of different output currents without changing components.
The L5973D is able to deliver 2A at output voltages from 1.25V to 35V.
An internal oscillator fixes the switching frequency at 250kHz.
The minimum operating voltage specification for the L5973D is 4.4V.