US Patent No. 9,992,833

MULTI-STAGE LED DRIVER WITH CURRENT PROPORTIONAL TO RECTIFIED INPUT VOLTAGE AND LOW DISTORTION


Patent No. 9,992,833
Issue Date June 05, 2018
Title Multi-stage Led Driver With Current Proportional To Rectified Input Voltage And Low Distortion
Inventorship Bret Ross Howe, Irvine, CA (US)
Narasimham Patibandla, Lake Forest, CA (US)
Assignee IXYS, LLC, Milpitas, CA (US)

Claim of US Patent No. 9,992,833

1. A method comprising:receiving a rectified AC input signal at an input node of an LED string formed by a plurality of LED groups having interconnecting nodes and a last node that are connected to a plurality of current cells;
enabling a selected current cell based on the input signal, wherein the selected current cell regulates current flowing from a selected node to an output resistor;
generating feedback voltages based on an output voltage generated by the output resistor; and
disabling current cells that are upstream from the selected current cell.