Method and apparatus selectively determining universal voltage input for solid state light fixtures

A method for selectively providing universal voltage input to a lighting fixture, including a dimmer, a power converter and a solid state lighting load, the method comprising:

• detecting a phase angle of the dimmer;
• determining whether the detected phase angle is below a determination threshold;
• when the detected phase angle is below the determination threshold, determining a power setting of the power converter based on a previously determined input mains voltage value;
• and
• when the detected phase angle is not below the determination threshold, calculating the input mains voltage value and determining the power setting of the power converter based on the calculated input mains voltage value.

The method of claim 15, wherein performing the peak detection algorithm comprises:

• reading digital values corresponding to a signal waveform of the divided down version of the input rectified voltage;
• comparing the digital values with a previously identified maximum value;
• identifying a current maximum value as a digital value that exceeds the previously identified maximum value;
• identifying a peak value of the signal waveform as the current maximum value;
• and
• calculating a frequency of the signal waveform using the peak value.

The method of claim 16, wherein performing the slope detection algorithm comprises:

• selecting reference criteria based on the calculated frequency of the signal waveform;
• reading sets of digital values corresponding to the signal waveform;
• identifying rising edges of the signal waveform corresponding to the sets of digital values;
• calculating slopes of the identified rising edges;
• and
• calculating the input mains voltage value based on comparing the calculated slopes with the reference criteria.

A method for detecting a dimmer phase angle set by operation of a dimmer for a light-emitting diode (LED), the method comprising:

• receiving a digital input signal corresponding to a dimmed rectified voltage from the dimmer, the dimmed rectified voltage having a signal waveform;
• detecting a rising edge of a pulse of the digital input signal corresponding to a rising edge of the signal waveform;
• sampling the pulse periodically to determine a length of the pulse;
• and
• determining the dimmer phase angle based on the length of the pulse.