A light source device that supplies a constant current to a diode load that includes a plurality of light-emitting elements connected in series. The light source device includes a power supply circuit connected to the diode load and a peak current limiting circuit connected in series to the diode load. The peak current limiting circuit includes a current detector that is connected in series to the diode load and a current-regulating circuit that controls a current to the diode load by a detection voltage of the current detector. Further, the current detector has a series circuit including a resistor and a coil.

A light source device that supplies a constant current to a diode load that includes a plurality of light-emitting elements connected in series. The light source device includes a power supply circuit connected to the diode load and a peak current limiting circuit connected in series to the diode load. The peak current limiting circuit includes a current detector that is connected in series to the diode load and a current-regulating circuit that controls a current to the diode load by a detection voltage of the current detector. Further, the current detector has a series circuit including a resistor and a coil.

The present disclosure provides systems, methods and apparatuses for inducing a desired biological response in an organism through the use of one or more repetitive signals from one or a series of LED lights designed to emit the signal with multiple pulsed components. Each component of the signal contains a one or more light color spectrum or wavelength that is within 50 nm of the peak absorption of a photon receptor of the organism corresponding to the desired biological response. Each component has a repetitive ON duration with an OFF duration and an intensity where the relationship between the ON duration and OFF duration of the first component and the second component induces the desired response in the organism through the stimulation or excitation of a molecule associated with a photoreceptor and the reset of the molecule.

A serial LED driver with a built-in calibratable parameter transmits a grayscale vector, a calibration parameter matrix or an appropriate current value vector and includes: a nonvolatile memory receiving and storing the calibratable parameter; a calibration matrix processing unit reads elements corresponding to the LED lamp bead and being pre-stored in the calibration parameter matrix of the nonvolatile memory, receives the grayscale vector, and performs matrix computation according to the grayscale vector and the calibration parameter matrix to generate a new grayscale vector; and a pulse width modulation circuit, which outputs a constant current to the LED lamp bead according to the first new grayscale vector to adjust the LED lamp bead; or outputs another corresponding constant current to adjust the LED lamp bead according to the new grayscale vector and the appropriate current value vector corresponding to the LED lamp bead and being pre-stored in the nonvolatile memory.

A serial LED driver with a built-in calibratable parameter transmits a grayscale vector, a calibration parameter matrix or an appropriate current value vector and includes: a nonvolatile memory receiving and storing the calibratable parameter; a calibration matrix processing unit reads elements corresponding to the LED lamp bead and being pre-stored in the calibration parameter matrix of the nonvolatile memory, receives the grayscale vector, and performs matrix computation according to the grayscale vector and the calibration parameter matrix to generate a new grayscale vector; and a pulse width modulation circuit, which outputs a constant current to the LED lamp bead according to the first new grayscale vector to adjust the LED lamp bead; or outputs another corresponding constant current to adjust the LED lamp bead according to the new grayscale vector and the appropriate current value vector corresponding to the LED lamp bead and being pre-stored in the nonvolatile memory.

A two-wire load control device (such as, a dimmer switch) for controlling the amount of power delivered from an AC power source to an electrical load (such as, a high-efficiency lighting load) includes a thyristor coupled between the source and the load, a gate coupling circuit coupled between a first main load terminal and the gate of the thyristor, and a control circuit coupled to a control input of the gate coupling circuit. The control circuit generates a drive voltage for causing the gate coupling circuit to conduct a gate current to thus render the thyristor conductive at a firing time during a half cycle of the AC power source, and to allow the gate coupling circuit to conduct the gate current at any time from the firing time through approximately the remainder of the half cycle, where the gate coupling circuit conducts approximately no net average current to render and maintain the thyristor conductive.

System and method for controlling one or more light emitting diodes. For example, the system includes: a power supply controller configured to receive a cathode voltage from a cathode of a diode, the diode including an anode configured to receive a rectified voltage generated by a rectifying bridge, the power supply controller being further configured to generate a first signal based at least in part on the cathode voltage; and a driver configured to receive the first signal and generate a second signal based at least in part on the first signal, the driver being further configured to output the second signal to a gate terminal of a transistor, the transistor including a source terminal coupled to the driver and a first resistor, the transistor further including a drain terminal coupled to the one or more light emitting diodes and an output capacitor connected to the cathode of the diode.

System and method for controlling one or more light emitting diodes. For example, the system includes: a power supply controller configured to receive a cathode voltage from a cathode of a diode, the diode including an anode configured to receive a rectified voltage generated by a rectifying bridge, the power supply controller being further configured to generate a first signal based at least in part on the cathode voltage; and a driver configured to receive the first signal and generate a second signal based at least in part on the first signal, the driver being further configured to output the second signal to a gate terminal of a transistor, the transistor including a source terminal coupled to the driver and a first resistor, the transistor further including a drain terminal coupled to the one or more light emitting diodes and an output capacitor connected to the cathode of the diode.

Examples are disclosed that relate to monitoring an emission state of light sources. One example provides a light emitting circuit comprising a power source, one or more light sources connected to an output of the power source, and a control circuit comprising a pulsed voltage source and a control transistor configured to regulate a current through the light sources based upon an output of the pulsed voltage source. The light emitting circuit further comprises a monitor transistor comprising a gate connected to an output of the light sources such that a voltage at the output of the light sources controls an output of the monitor transistor, and a monitor transistor detector connected to the output of the monitor transistor. The monitor transistor detector is configured to monitor a state of the one or more light sources based upon a state of the output of the monitor transistor.

Examples are disclosed that relate to monitoring an emission state of light sources. One example provides a light emitting circuit comprising a power source, one or more light sources connected to an output of the power source, and a control circuit comprising a pulsed voltage source and a control transistor configured to regulate a current through the light sources based upon an output of the pulsed voltage source. The light emitting circuit further comprises a monitor transistor comprising a gate connected to an output of the light sources such that a voltage at the output of the light sources controls an output of the monitor transistor, and a monitor transistor detector connected to the output of the monitor transistor. The monitor transistor detector is configured to monitor a state of the one or more light sources based upon a state of the output of the monitor transistor.