Abstract:
There is provided a lighting control circuit comprising a duty cycle detection circuit, an averaging circuit, a waveform generator and a comparator circuit. The duty cycle detection circuit generates a first periodic waveform having a duty cycle and frequency corresponding to an input waveform duty cycle and frequency. The averaging circuit generates a first signal having a voltage level corresponding to the duty cycle of the first periodic waveform. The waveform generator outputs a second periodic waveform having a frequency different from the input waveform frequency. The comparator circuit compares the second periodic waveform with the first signal to generate an output waveform having a duty cycle corresponding to the input waveform duty cycle and a frequency corresponding to the frequency of the second periodic waveform. Also, there are provided methods.
Abstract:
There is provided a lighting control circuit comprising a duty cycle detection circuit, an averaging circuit, a waveform generator and a comparator circuit. The duty cycle detection circuit generates a first periodic waveform having a duty cycle and frequency corresponding to an input waveform duty cycle and frequency. The averaging circuit generates a first signal having a voltage level corresponding to the duty cycle of the first periodic waveform. The waveform generator outputs a second periodic waveform having a frequency different from the input waveform frequency. The comparator circuit compares the second periodic waveform with the first signal to generate an output waveform having a duty cycle corresponding to the input waveform duty cycle and a frequency corresponding to the frequency of the second periodic waveform. Also, there are provided methods.
Abstract:
A diode selection circuit for a light emitting apparatus according to some embodiments includes a plurality of light emitting devices coupled in series. The diode selection circuit includes a comparator configured to receive a rectified AC input signal and a reference voltage and to generate a control signal in response to comparison of the rectified AC input signal with the reference voltage, a voltage controlled current source configured to supply a current to the plurality of light emitting diodes that is proportional to the rectified AC input signal, and a switch configured to receive the control signal and to shunt current away from at least one of the plurality of light emitting devices in response to the control signal.
Abstract:
There is provided a lighting control circuit comprising a duty cycle detection circuit, an averaging circuit, a waveform generator and a comparator circuit. The duty cycle detection circuit generates a first periodic waveform having a duty cycle and frequency corresponding to an input waveform duty cycle and frequency. The averaging circuit generates a first signal having a voltage level corresponding to the duty cycle of the first periodic waveform. The waveform generator outputs a second periodic waveform having a frequency different from the input waveform frequency. The comparator circuit compares the second periodic waveform with the first signal to generate an output waveform having a duty cycle corresponding to the input waveform duty cycle and a frequency corresponding to the frequency of the second periodic waveform. Also, there are provided methods.