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.

Disclosed is a driving circuit for a Light Emitting Diode (LED) lamp, the LED lamp containing the driving circuit and a method for operating the driving circuit. The driving circuit includes: three alternating voltage input terminals, including two alternating voltage input terminals for receiving an alternating voltage and one common terminal, the two alternating voltage input terminals are controlled so that at least one alternating voltage input terminal receives the alternating voltage from a power supply; a constant current control circuit receiving the alternating voltage through at least one alternating voltage input terminal and outputting a constant direct current to an LED load, the constant current control circuit includes a constant current control chip having a maximum on-time pin; and a three-stage dimming detection control circuit including a variable control resistor for three-stage dimming control, and is controlled by the alternating voltage received by at least one alternating voltage input terminal so that the variable control resistor is connected to the maximum on-time pin with different resistance values, and the constant current control chip outputs three different current levels according to a resistance value of the connected variable control resistor.

Disclosed is a driving circuit for a Light Emitting Diode (LED) lamp, the LED lamp containing the driving circuit and a method for operating the driving circuit. The driving circuit includes: three alternating voltage input terminals, including two alternating voltage input terminals for receiving an alternating voltage and one common terminal, the two alternating voltage input terminals are controlled so that at least one alternating voltage input terminal receives the alternating voltage from a power supply; a constant current control circuit receiving the alternating voltage through at least one alternating voltage input terminal and outputting a constant direct current to an LED load, the constant current control circuit includes a constant current control chip having a maximum on-time pin; and a three-stage dimming detection control circuit including a variable control resistor for three-stage dimming control, and is controlled by the alternating voltage received by at least one alternating voltage input terminal so that the variable control resistor is connected to the maximum on-time pin with different resistance values, and the constant current control chip outputs three different current levels according to a resistance value of the connected variable control resistor.

The invention relates to an incorporation of a current limiting/regulating circuit on a luminaire board for ensuring that the luminaire board will automatically operate at its desired current after a replacement. Since the current control at the luminaire board causes an initial mismatch between the current supply of the driver and the demand of the luminaire board, the driver output voltage will drift towards the maximum output voltage of the driver. When the maximum output voltage is reached, the driver is configured to operate in constant-voltage (CV) mode, sense the output current and reduce its output current to the same value as consumed by current-controlled luminaire board. Alternatively, the driver may gradually reduce the setpoint of the output current until it just leaves the CV mode and stay at that setpoint. In this way, the driver will automatically operate at the correct current of a newly installed luminaire board without any action from the user.

The invention relates to an incorporation of a current limiting/regulating circuit on a luminaire board for ensuring that the luminaire board will automatically operate at its desired current after a replacement. Since the current control at the luminaire board causes an initial mismatch between the current supply of the driver and the demand of the luminaire board, the driver output voltage will drift towards the maximum output voltage of the driver. When the maximum output voltage is reached, the driver is configured to operate in constant-voltage (CV) mode, sense the output current and reduce its output current to the same value as consumed by current-controlled luminaire board. Alternatively, the driver may gradually reduce the setpoint of the output current until it just leaves the CV mode and stay at that setpoint. In this way, the driver will automatically operate at the correct current of a newly installed luminaire board without any action from the user.

The present embodiment relates to a communication protocol between an MCU and an LED driving circuit for LED driving. The MCU may define and use an SPI protocol including ID setting, a command, configuration data, etc.

The present embodiment relates to a communication protocol between an MCU and an LED driving circuit for LED driving. The MCU may define and use an SPI protocol including ID setting, a command, configuration data, etc.

A device and a method for providing an electrical current to an electrical load is disclosed. In particular, the device comprises a memory storage device for storing a plurality of ideal voltage waveforms; an electronic controller arranged in data communication with the memory storage device, the electronic controller operable to select one of the plurality of ideal voltage waveforms to compute a reference voltage and a switching period based on a predetermined rule; and an electronic switch arranged to receive the switching period to switch the electronic switch between an on state and an off state, wherein the electrical current is calculated based on a function of the reference voltage and the switching period of the electronic switch.

Methods and systems are provided for a light-emitting diode (LED) drive circuit of an optical probe. As an example, a method for an optical probe including an LED in an LED drive circuit comprises reducing power consumption of the LED drive circuit by adjusting a drive voltage of the LED drive circuit based on one or more LED drive circuit characteristics and one or more LED drive circuit operating parameters. In this way, the LED drive circuit may be efficiently operated.