A negative feedback circuit, comprising a node, and a control circuit coupled to the node, wherein the control circuit is configured to provide a stabilizing signal in response to a noise signal coupling to the node from a power rail, and the stabilizing signal is configured to reduce the noise signal at the node and the power rail.

A device may include a light-emitting diode (LED) array including a plurality of LEDs, a rectifier configured to supply an input voltage rectified from an AC voltage to the LED array, an LED driver configured to drain an LED driving current from the LED array, and a current distributor configured to sense a first current passing through at least one first LED from among the plurality of LEDs and supply a second current to at least one second LED from among the plurality of LEDs based on the first current.

A device may include a light-emitting diode (LED) array including a plurality of LEDs, a rectifier configured to supply an input voltage rectified from an AC voltage to the LED array, an LED driver configured to drain an LED driving current from the LED array, and a current distributor configured to sense a first current passing through at least one first LED from among the plurality of LEDs and supply a second current to at least one second LED from among the plurality of LEDs based on the first current.

An LED light fixture includes one or more optical transceivers that have a light support having a plurality of light emitting diodes and one or more photodetectors attached thereto, and a processor in communication with the light emitting diodes and the one or more photodetectors. The processor is constructed and arranged to generate a communication or data transfer signal.

An embodiment LED driver system comprises a power transistor configured to be selectively activated for generating a driving current for an array of LEDs, the power transistor having a first conduction terminal coupled to the array of LEDs and a second conduction terminal coupled to a reference resistor; an operational amplifier having a non-inverting input for receiving a reference voltage, an inverting input coupled to the second conduction terminal of the power transistor, and an output terminal coupled to a first conduction terminal of a transmission gate having a second conduction terminal coupled to a control terminal of the power transistor and a control terminal for receiving an enable signal; and a slew rate control unit configured to control the slew rate of the driving current.

An embodiment LED driver system comprises a power transistor configured to be selectively activated for generating a driving current for an array of LEDs, the power transistor having a first conduction terminal coupled to the array of LEDs and a second conduction terminal coupled to a reference resistor; an operational amplifier having a non-inverting input for receiving a reference voltage, an inverting input coupled to the second conduction terminal of the power transistor, and an output terminal coupled to a first conduction terminal of a transmission gate having a second conduction terminal coupled to a control terminal of the power transistor and a control terminal for receiving an enable signal; and a slew rate control unit configured to control the slew rate of the driving current.

A current to be supplied to a load driven by the current is linearly controlled in accordance with a voltage. A voltage-current converter according to the present invention includes a differential amplifier, a first current mirror, and a voltage setting unit. The differential amplifier receives an input voltage from an input terminal and outputs a voltage in accordance with a difference between the input voltage and a threshold voltage. The first current mirror receives the voltage from the differential amplifier and outputs an output current to an output terminal. The voltage setting unit sets the threshold voltage.

An LED driver circuit controls the currents through a plurality of strings of light-emitting diodes (LEDs), which are connected in series. Each LED string has an associated current regulator. The LED strings are connected between the voltage rail and a reference rail on the output of an AC-to-DC rectifier to receive an unfiltered rectified DC voltage. A first current regulator is active during a first voltage range of the DC voltage to provide a current of a first magnitude to a first LED string only. A second current regulator is active during a second voltage range to provide a current of a second magnitude to the first LED string and to a second LED string. A third current regulator is active during a third voltage range to provide a current of a third magnitude to the first LED string, to the second LED string and to a third LED string.

A circuit comprises an amplifier and a plurality of channels, the plurality of channels including respective transistors. The respective transistors of the channels control respective magnitudes of respective currents of the channels according to an output of the amplifier. The respective transistors of the plurality of channels may be included in an auto-commutated circuit. A first Light Emitting Diode (LED) circuit may be coupled between a power source and a first channel of the plurality of channels. A second LED circuit may be coupled between the first channel and a second channel of the plurality of LED channels. The power source may provide rectified Alternating Current (AC).

The present disclosure provides a technology for precisely controlling an LED driving current using fine current trimming data stored in a memory when driving an LED.