DRIVER CIRCUIT FOR POWERING DC LAMP IN NON-DC LAMP FITTING

摘要

A driver circuit for adapting an LED (Light Emitting Diode) lamp or an LED lamp array to be used in a lamp fitting for a non-LED type lamp without modification of the lamp fitting is disclosed. The driver circuit is such that the LED lamp or the LED lamp array can be inserted into the lamp fitting as a replacement for a non-LED lamp such that the combined unit of the LED lamp and the driver circuit are retained in the lamp fitting and make electrical connections with the lamp fitting's electrical contacts for powering the inserted lamp. The driver circuit enables the LED lamp of the lamp array to operate with any of an AC (Alternating Current) power supply, an electromagnetic ballast or an electronic ballast. The driver circuit comprises a first stage comprising a filter circuit and having an input connectable to any of the AC power supply, the electromagnetic ballast or the electronic ballast of the lamp fitting, a second stage comprising a high frequency switched network and having an input connected to an output of the first stage, and a third stage comprising an AC/DC (Direct Current) converter and having an input connected to an output of the second stage and an output connectable to the LED lamp. The third stage is configured to deliver DC power to the connected LED lamp. The second stage is configured to operate in a low frequency mode when the driver circuit is connected to the AC power supply or the electromagnetic ballast of the lamp fitting and configured to operate in a high frequency mode when the driver circuit is connected to the electronic ballast of the lamp fitting.