Abstract: A lighting apparatus includes a string of serially-connected light emitting devices and a bypass circuit coupled to first and second nodes of the string and configured to variably conduct a bypass current around at least one of the light-emitting devices responsive to a temperature and/or a total current in the string. In some embodiments, the bypass circuit includes a variable resistance circuit coupled to the first and second nodes of the string and configured to variably conduct the bypass current around the at least one of the light-emitting devices responsive to a control voltage applied to a control node and a compensation circuit coupled to the control node and configured to vary the control voltage responsive to a temperature and/or total string current.

Abstract: A lighting apparatus includes a string with a plurality of serially-connected light emitting device sets, each set comprising at least one light emitting device. The apparatus further includes at least one controllable bypass circuit configured to variably bypass current around at least one light emitting device of a set of the plurality of light emitting device sets responsive to a control input. The control input may include, for example, a temperature input, a string current sense input and/or an adjustment input. The control input may be varied, for example, to adjust a color point of the string.

Abstract: A lighting apparatus includes a first substrate including a switching circuit, the switching circuit including a first port, a second port and a current control circuit configured to generate a current at the second port of the current control circuit responsive to a varying voltage at the first port. The apparatus further includes a second substrate mounted on the first substrate and including at least two LEDs electrically coupled to the second port of the current control circuit of the first substrate.

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: A lighting apparatus includes a first substrate including a switching circuit, the switching circuit including a first port, a second port and a current control circuit configured to generate a current at the second port of the current control circuit responsive to a varying voltage at the first port. The apparatus further includes a second substrate mounted on the first substrate and including at least two LEDs electrically coupled to the second port of the current control circuit of the first substrate.

Abstract: A lighting apparatus includes a first substrate including a switching circuit, the switching circuit including a first port, a second port and a current control circuit configured to generate a current at the second port of the current control circuit responsive to a varying voltage at the first port. The apparatus further includes a second substrate mounted on the first substrate and including at least two LEDs electrically coupled to the second port of the current control circuit of the first substrate.

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: 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.

Abstract: A lighting apparatus includes a first substrate including a switching circuit, the switching circuit including a first port, a second port and a current control circuit configured to generate a current at the second port of the current control circuit responsive to a varying voltage at the first port. The apparatus further includes a second substrate mounted on the first substrate and including at least two LEDs electrically coupled to the second port of the current control circuit of the first substrate.

Abstract: A lighting control circuit comprises a dimming level detection circuit, a waveform generator and a comparator circuit. The dimming level detection circuit is configurable to generate a first voltage level signal corresponding to a selected one of at least two different types of dimming signals selected from among an AC phase cut dimming signal, a DC voltage level dimming signal or a PWM dimming signal. The waveform generator is configured to output a periodic waveform. The comparator circuit is configured to compare the periodic waveform with the first voltage level signal to generate an output waveform having a duty cycle corresponding to a dimming level of the one of the at least two different input dimming signals and a frequency corresponding to the frequency of the periodic waveform. Also, methods of controlling lighting.

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.

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 lighting apparatus includes a string of serially-connected light emitting devices and a bypass circuit coupled to first and second nodes of the string and configured to variably conduct a bypass current around at least one of the light-emitting devices responsive to a temperature and/or a total current in the string. In some embodiments, the bypass circuit includes a variable resistance circuit coupled to the first and second nodes of the string and configured to variably conduct the bypass current around the at least one of the light-emitting devices responsive to a control voltage applied to a control node and a compensation circuit coupled to the control node and configured to vary the control voltage responsive to a temperature and/or total string current.

Abstract: A lighting apparatus includes a string with a plurality of serially-connected light emitting device sets, each set comprising at least one light emitting device. The apparatus further includes at least one controllable bypass circuit configured to variably bypass current around at least one light emitting device of a set of the plurality of light emitting device sets responsive to a control input. The control input may include, for example, a temperature input, a string current sense input and/or an adjustment input. The control input may be varied, for example, to adjust a color point of the string.

Abstract: A lighting control circuit comprises a dimming level detection circuit, a waveform generator and a comparator circuit. The dimming level detection circuit is configurable to generate a first voltage level signal corresponding to a selected one of at least two different types of dimming signals selected from among an AC phase cut dimming signal, a DC voltage level dimming signal or a PWM dimming signal. The waveform generator is configured to output a periodic waveform. The comparator circuit is configured to compare the periodic waveform with the first voltage level signal to generate an output waveform having a duty cycle corresponding to a dimming level of the one of the at least two different input dimming signals and a frequency corresponding to the frequency of the periodic waveform. Also, methods of controlling lighting.

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.