A power supply using a microcontroller for circuit protection and an LED lighting system using the power supply are disclosed. A power supply according to embodiments of the present invention includes a floating converter and at least a first reference voltage source connected to a negative output terminal of the floating converter. A microcontroller is connected to the first reference voltage source and to a control input of the floating converter, which may be a floating buck converter. In some embodiments, a second reference voltage source is connected to the microcontroller. A voltage divider and/or a comparator can be used to provide one or both voltage reference sources.

A load control device for controlling the intensity of a lighting load, such as a light-emitting diode (LED) light source, may include a power converter circuit operable to receive a rectified AC voltage and to generate a DC bus voltage, a load regulation circuit operable to receive the bus voltage and to control the magnitude of a load current conducted through the lighting load, and a control circuit operatively coupled to the load regulation circuit for pulse width modulating or pulse frequency modulating the load current to control the intensity of the lighting load to a target intensity. The control circuit may control the intensity of the lighting load by pulse width modulating the load current when the target intensity is above a predetermined threshold and control the intensity of the lighting load by pulse frequency modulating the load current when the target intensity is below the predetermined threshold.

A light source lighting circuit comprises a first lighting circuit for receiving current from the electric power supply line and supplying drive current to a first light source and a second lighting circuit for receiving the current from the electric power supply line and supplying drive current to a second light source. When a state of the drive current flowing to the first light source shows an abnormality, or when state of the drive current flowing to the second light source shows an abnormality, the first lighting circuit stops operation. When a state of the drive current flowing to the second light source shows an abnormality, or when a state of the drive current flowing to the first light source shows an abnormality, the second lighting circuit stops operation.

The present invention discloses a switching regulator capable of reducing current ripple and a control circuit thereof. The switching regulator includes a buck power stage circuit and a control circuit. The control circuit includes an operation signal generation circuit and a current source circuit for reducing current ripple. The current source circuit is coupled to the operation signal generation circuit and the buck power stage circuit, for operating a ripple reduction switch therein according to an operation signal, to convert the output voltage to a load voltage between a load node and a reference node, and to reduce a current ripple of the output current, so as to generate a load current which is supplied to a load circuit, wherein the load circuit is coupled between the load node and the reference node, and the current source circuit is coupled between the output node and the load node.

A self-healing overtemp circuit is described and illustrated comprising a temperature sensing circuit, a voltage sensing circuit, and optionally, a current sensing circuit. The self-healing overtemp circuit is designed to ramp down power in an LED lighting system (or other electrical circuit) in response to a sensed or impending thermal runaway (and optionally, overcurrent) event. Said thermal runaway and overcurrent events may be a result of failure of one or more components (e.g., driver, active cooling means) of the lighting system. The self-healing overtemp circuit further comprises means of restoring power to said LEDs in a manner that avoids (i) a perceivably bright flash of light or (ii) increased risk of component failure.

An LED tube lamp is disclosed. The LED tube lamp includes a lamp tube, a first external connection terminal and a second external connection terminal coupled to the lamp tube and for receiving an external driving signal, a rectifying circuit coupled to the first external connection terminal and the second external connection terminal and configured to rectify the external driving signal to produce a rectified signal, a filtering circuit coupled to the rectifying circuit and configured to filter the rectified signal to produce a filtered signal, an LED module coupled to the filtering circuit and configured to receive the filtered signal for emitting light; and a conduction-delaying circuit coupled to the rectifying circuit and comprising a conduction-delaying device, wherein the conduction-delaying circuit is configured such that when the external driving signal is initially input to the LED tube lamp, the conduction-delaying device is in an open-circuit state, and then the conduction-delaying device will enter a conducting state when voltage across the conduction-delaying device exceeds the conduction-delaying device's trigger voltage value, wherein the conducting state of the conduction-delaying device causes the LED module to conduct current for emitting light.

An anti-flicker and anti-glow switchable load apparatus to be installed in the light socket of a commonly powered electronic switching device, such as a motion activated light switch. An energy efficient light bulb or lamp, such as a cathode fluorescent lamp or light emitting diode is then screwed into the apparatus. A first embodiment of the present invention includes a switchable light source, a switchable load, a controller, and a voltage sensor. When the present invention in the first embodiment detects a higher voltage, thus indicating the lamp has been switched from the “off” state to the on state, the switchable load is disconnected, and the current is re-routed to pass through the energy efficient lamp.

An over-voltage protection circuit for executing an over-voltage protection for a LED module of an electronic device. The over-voltage protection circuit includes a control unit and an over-voltage detection module, a trigger module and an adjustment module. The LED module includes a positive input port. The over-voltage detection module detects a voltage of the positive input port of the LED module and produce a detection voltage proportional to the voltage of the positive input port. The control unit controls the LED module to work or do not work according to the detection voltage. The trigger module produces corresponding trigger signals according to a 2D signal or a 3D signal output by a 2D/3D signal port. The adjustment module adjusts the proportion between the detection voltage and the voltage of the positive input port according to the trigger signal.

A fluorescent lamp replacement may include one or more LED drivers and lamps in various embodiments, as well as a shock hazard/pin safety circuit. The present invention provides a fluorescent lamp replacement that, for example, powers an LED and/or OLED and/or QD lamp from a fluorescent fixture, including operating 5 and being powered by electronic ballasts. In some embodiments, a fluorescent lamp replacement includes a number of pins configured to electrically connect to a fluorescent lamp fixture, at least one non-fluorescent light source, a transistor between at least one of the pins and the at least one non-fluorescent light source, and a shock hazard protection circuit configured to disable the transistor to limit current flowing through at least some of the pins.

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.