Lighting devices

A lighting device, comprising:

• a non-regulated isolation DC to DC converter, generating an output voltage in a predetermined voltage range according to the corrected DC voltage from a power factor correction circuit, wherein the non-regulated isolation DC to DC converter is an open-loop controlled buck DC to DC converter and comprises a first transformer electrically isolating the corrected DC voltage and the output voltage;
• a plurality of light emitting diode modules;
• and
• a plurality of regulated non-isolation DC to DC converters, generating a fixed current or a fixed voltage according to the output voltage output from the non-regulated isolation DC to DC converter, thereby driving the light emitting diode module.

A lighting device, comprising:

• a light emitting diode module, each comprising a plurality of light emitting diodes;
• a power factor correction circuit, performing a power factor correction on an AC power source and outputting a corrected DC voltage;
• a non-regulated isolation DC to DC converter, generating an output voltage in a predetermined voltage range according to the corrected DC voltage, wherein the non-regulated isolation DC to DC converter is controlled with an open-loop such that the output voltage is not maintained in a fixed voltage;
• and
• a regulated non-isolation DC to DC converter, generating a fixed current or a fixed voltage according to the output voltage output from the non-regulated isolation DC to DC converter, thereby driving the light emitting diode module, wherein the non-regulated isolation DC to DC converter comprises a first transformer to electrically isolate the corrected DC voltage and the output voltage, and does not comprises transformer.