Serial lighting interface with embedded feedback

摘要

A system for controlling multiple strings of LEDs includes a group of LED driver ICs, each of which includes a current sense feedback (CSFB) sample latch for storing a digital representation of the forward-voltage drop across a controlled LED string. Each CSFB latch is coupled to a register within a serial lighting interface (SLI) bus that both originates and terminates at an interface IC. As the data on the SLI bus is shifted into the interface IC, the interface IC selects the CSFB word that represents the highest forward-voltage drop of any of the controlled LED strings, which is then used by the interface IC to generate a CSFB signal for setting the appropriate supply voltage for the controlled LED strings.

主权项

1. A method of generating a supply voltage for a first plurality of light-emitting diode (LED) strings comprising:
detecting a highest forward-voltage of the first plurality of LED strings; generating a first digital word representing a value of the highest forward-voltage of the first plurality of LED strings; loading a first address representing a storage location of the first digital word into a first prefix register; copying the first digital word from the storage location to a first data register serially connected to the first prefix register in a serial lighting interface (SLI) bus; and generating the supply voltage for each LED string of the first plurality of LED strings based on the first digital word.