Half- or quarter-cycle current regulator for non-isolated, line voltage L.E.D. ballast circuits

摘要

A current regulator for non-isolated, line voltage LED Driver circuits solves the problem of LED flicker caused by line noise in the visible frequency range. In one aspect of the invention, LED flicker frequency may be increased beyond the line frequency. In another aspect, line voltages in excess of LED voltage ratings may be tolerated. The driver may be implemented using discrete circuit elements or in software and utilizes separate current regulation for different segments of an AC line voltage cycle.

主权项

1. A circuit for use with an alternating current voltage source and one or more light-emitting diodes, comprising:
a rectifier; a sensor; an electrically variable resistor; and a regulator capable of applying a voltage, comprising:
at least two integrators;a timer; andat least one switch; wherein:
said rectifier rectifies said alternating current voltage source to produce a rectified voltage source and provides the rectified voltage source to said one or more light-emitting diodes;said sensor detects a circuit condition and provides a sensor output related to said alternating current voltage source;at least one of said integrators provides an integration output based at least on said sensor output;each said integrator only provides an integration output based on said sensor output while said integrator is selected by said switch;said at least one switch selects said integration output based on a timing signal from said timer;said regulator applies a voltage corresponding to said selected integration output to said electrically variable resistor; andsaid electrically variable resistor reacts to said applied voltage in order to limit the influence of undesirable variations in said rectified voltage source on said one or more light-emitting diodes.