Resources Contact Us Home
Power source for metal halide lamps and the like

Image Number 4 for United States Patent #5034663.

A power supply for a gas discharge lamp includes a current regulator for regulating the current supplied to a lamp and current steering means for steering current from the current regulator in alternating directions through an isolation transformer primary winding, the secondary winding of the transformer being connected with a lamp through an arc striking circuit. The frequency of alternating the current through the transformer is controlled as a function of the lamp voltage in order to regulate the volt-second product of the transformer through all portions of a lamp operating cycle including arc striking. This reduces saturation of the transformer and allows a much smaller transformer to be used. In a preferred embodiment, the current regulation and steering functions are performed in a bridge circuit having FET switches in each leg and in which the transformer primary spans the sides of the bridge. Pairs of FETs in diametrically opposite legs of the bridge are operated in unison, with one FET of each pair controlling lamp current by pulse-width regulation. The current is steered through the transformer primary by alternatingly operating the FET pairs at a frequency established by a voltage-controlled oscillator responsive to transformer voltage.

  Recently Added Patents
Triple-action pest control formulation and method
System, method and apparatus for pausing multi-channel broadcasts
Per-request control of DNS behavior
Method for improving the performance of browser-based, formula-driven parametric objects
Automated macular pathology diagnosis in three-dimensional (3D) spectral domain optical coherence tomography (SD-OCT) images
Semiconductor device and method of adjusting characteristic thereof
Device and method to automatically configure port forwarding
  Randomly Featured Patents
Bacillus amylollquefaciens strain
Staged rotary mixer
Apparatus for making flexible corrugated rubber tubing
Method of manufacturing implantable tissue stimulating devices
Method for laminating a plastic web onto a plastic substrate
Multi-channel radiation detector array
Image processing device
Composite pigments based on polyalkylenepolyamine-modified nanoparticulate metal oxides and anionic dyes
Cable TV system for guest facilities