An expander circuit may be configured to control a plurality of driver circuits for driving light emitting diodes (LEDs). The expander circuit may comprise a bus interface circuit configured to receive control signals from a processor over a communication bus, and a plurality of modulation signal generators configured to generate modulation signals based on the control signals. The expander circuit may be configured to provide the modulation signals to the plurality of driver circuits for driving the LEDs.

A two-stage driver supplies current to a light emitting diode (LED) load. The two-stage driver includes a first stage and a second stage. The first stage has a first flyback converter. The first stage is configured to receive a non-regulated voltage input and to generate a substantially constant bulk voltage across a first-stage output filter capacitor. The second stage has a second flyback converter. The second stage is configured to receive the bulk voltage from the first stage. The second stage is further configured to generate a desired current through the LED load. The second stage is electrically isolated from the first stage such that the LED load does not share a common ground reference with the non-regulated voltage input to the first stage.

UV hard-surface disinfection system that is able to disinfect the hard surfaces in a room, while minimizing missed areas due to shadows by providing multiple UV light towers that can be placed in several areas of a room such that shadowed areas are eliminated and that can be transported by a cart that is low to the ground such that the towers may be loaded and unloaded easily by a single operator. The system is able to be controlled remotely, such that during activation of the system, no operator is present, and to automatically cut power to all towers in the event that a person enters the room.

A solid state light source driver circuit that operates in either a buck convertor or a boost convertor configuration is provided. The driver circuit includes a controller, a boost switch circuit and a buck switch circuit, each coupled to the controller, and a feedback circuit, coupled to the light source. The feedback circuit provides feedback to the controller, representing a DC output of the driver circuit. The controller controls the boost switch circuit and the buck switch circuit in response to the feedback signal, to regulate current to the light source. The controller places the driver circuit in its boost converter configuration when the DC output is less than a rectified AC voltage coupled to the driver circuit at an input node. The controller places the driver circuit in its buck converter configuration when the DC output is greater than the rectified AC voltage at the input node.

A method for controlling an amount of power delivered to an electrical load may include controlling an average magnitude of a load current towards a target load current that ranges from a maximum-rated current to a minimum-rated current in a normal mode, and controlling the average magnitude of the load current below the minimum-rated current in a burst mode. The burst mode may include at least one burst-mode period that comprises a first time period associated with an active state and a second time period associated with an inactive state. During the burst mode, the method may include regulating a peak magnitude of the load current towards the minimum-rated current during the active state, and stopping the generation of at least one drive signal during the inactive state to control the average magnitude of the load current to be less than the minimum-rated current.

Methods and apparatus for implementing a control apparatus for a light fixture for externally controlling the current to the LED light emitter of a landscape LED light fixture. In an exemplary embodiment a control apparatus for controlling current to an LED light source in a landscape lighting device includes an LED driver, a user control with a control setting indicator, and a driver housing including setting indicators.

Methods and apparatus for implementing a control apparatus for a light fixture for externally controlling the current to the LED light emitter of a landscape LED light fixture. In an exemplary embodiment a control apparatus for controlling current to an LED light source in a landscape lighting device includes an LED driver, a user control with a control setting indicator, and a driver housing including setting indicators.

A micro light-emitting diode (μLED) array system can include an image post processor configured to translate received image data to pulse width modulation (PWM) and/or analog current control data, an input frame buffer configured to receive the control data, a plurality of individually controllable μLEDS of a μLED array, a return frame buffer that receives data indicating a μLED electrical output characteristic including an output current, and compare circuitry configured to compare image data from the input and return frame buffers, and transfer comparison data to the image post processor, the image post processor configured to alter individual μLED control data based on the comparison data.

The invention provides an LED drive power supply and a controller thereof. The controller comprises a ground terminal, a sampling terminal, and a power supply terminal. The ground terminal and an output ground of a power supply module have different potentials. A drain of a power switching transistor is coupled to a positive output terminal of the power supply module, a source of the power switching transistor and the sampling terminal are coupled to a first terminal of a sampling resistor, and a second terminal of the sampling resistor is coupled to the ground terminal. The controller further includes a logic control circuit determining whether a sampling voltage input by the sampling terminal is zero; a driver generating a first driving signal to the power switching transistor; and a bias circuit configured to receive a power supply voltage.

The invention provides an LED drive power supply and a controller thereof. The controller comprises a ground terminal, a sampling terminal, and a power supply terminal. The ground terminal and an output ground of a power supply module have different potentials. A drain of a power switching transistor is coupled to a positive output terminal of the power supply module, a source of the power switching transistor and the sampling terminal are coupled to a first terminal of a sampling resistor, and a second terminal of the sampling resistor is coupled to the ground terminal. The controller further includes a logic control circuit determining whether a sampling voltage input by the sampling terminal is zero; a driver generating a first driving signal to the power switching transistor; and a bias circuit configured to receive a power supply voltage.