The present disclosure is for a light-emitting diode light string control system, which comprises: a switching unit having a power input end, a power output end connected to the light string, and a controlled end. A control unit is connected to the controlled end of the switching unit. A second power-generating unit is also connected to the light-emitting diode light string. The light-emitting control command sent by the control unit is in a carrier wave mode to realize brightness variation of the light string, which saves costs and simplifies the control circuit. A short-circuit protection unit is employed to provide fast and reliable response in real time.

A lamp has a safety circuit connected to first and second electrical connection terminals. A test is used to detect if the first and second electrical connection terminals are both connected to external power without an interfering impedance such a human body, and only then enable operation of the lamp. A time for the test is different from a time when another lamp in the system applies a test.

A lighting device circuit comprising: a reference LED string, a mirror LED string coupled in parallel to the reference LED string, an operational amplifier based current mirror circuit coupled to the reference LED string and to the mirror LED string, and a window comparator circuit that includes only a single input that is coupled to a fault sense node. The fault sense node directly connects to a drain node of a transistor within the operational amplifier based current mirror and a LED within the mirror LED string.

A lighting device circuit comprising: a reference LED string, a mirror LED string coupled in parallel to the reference LED string, an operational amplifier based current mirror circuit coupled to the reference LED string and to the mirror LED string, and a window comparator circuit that includes only a single input that is coupled to a fault sense node. The fault sense node directly connects to a drain node of a transistor within the operational amplifier based current mirror and a LED within the mirror LED string.

An LED component comprises a plurality of fused light-emitting diodes (LEDs) (e.g., micro-transfer printable or micro-transfer printed LEDs). Each fused LED comprises an LED with first and second LED electrical connections for providing power to the LED and a fuse with first and second fuse electrical connections. The first LED electrical connection is electrically connected to the first electrode. The first fuse electrical connection is electrically connected to the second LED electrical connection and the second fuse electrical connection is electrically connected to the second electrode. A fused LED source wafer comprises an LED wafer having a patterned sacrificial layer forming an array of sacrificial portions separated by anchors and a plurality of fused LED components, each fused LED component disposed entirely on or over a corresponding sacrificial portion. A light-emission system comprises a system substrate and a plurality of fused LED components disposed on or over the system substrate.

An LED component comprises a plurality of fused light-emitting diodes (LEDs) (e.g., micro-transfer printable or micro-transfer printed LEDs). Each fused LED comprises an LED with first and second LED electrical connections for providing power to the LED and a fuse with first and second fuse electrical connections. The first LED electrical connection is electrically connected to the first electrode. The first fuse electrical connection is electrically connected to the second LED electrical connection and the second fuse electrical connection is electrically connected to the second electrode. A fused LED source wafer comprises an LED wafer having a patterned sacrificial layer forming an array of sacrificial portions separated by anchors and a plurality of fused LED components, each fused LED component disposed entirely on or over a corresponding sacrificial portion. A light-emission system comprises a system substrate and a plurality of fused LED components disposed on or over the system substrate.

A lamp has a safety circuit connected to first and second electrical connection terminals. A test is used to detect if the first and second electrical connection terminals are both connected to external power without an interfering impedance such a human body, and only then enable operation of the lamp. A time for the test is different from a time when another lamp in the system applies a test.

Lighting fixtures are provided. In one example implementation, a lighting fixture can include a housing, one or more drivers, and means for securing the one or more drivers to the housing to decrease thermal resistance between one or more of the drivers and the housing. The lighting fixture can also include an LED system comprising a light engine having a plurality of LED devices. The plurality of LED devices can be arranged on an LED board of the light engine such that a first portion of the LED board has a first density of LED devices and a second portion of the LED board has a second density of LED devices. The first density can be different than the second density.

A lamp control device includes a lamp including an LED module which has a plurality of LED channels; and a controller configured to detect respective feedback voltages of the plurality of LED channels, and determine, when at least any one feedback voltage among the feedback voltages is retained to be lower than a predetermined reference voltage and a generation count of an over voltage protection signal reaches a predetermined reference count, an LED channel corresponding to the feedback voltage, as an open.

The present disclosure relates to a fail-safe LED system including an LED circuit arrangement. The LED circuit arrangement includes a plurality of LED strings arranged in parallel with respect to each other. The LED circuit arrangement is supplied with electrical current from a constant current power supply. The fail-safe LED system includes structure for detecting a in at least one of the LED strings a failure that causes increased current to pass through remaining operational LED strings of the plurality of LED strings. The fail-safe LED system also includes a current correction string arranged in parallel with respect to the plurality of LED strings. When activated in response to the detection of a failure, the current correction string accommodates current from the constant current power supply such that the current passing through each operational LED string is reduced to a corrected current level.