A power supply module is applicable to an LED tube lamp adapted to install on a lamp socket, and having an electric shock protection function, the LED tube lamp including a lamp tube, two end caps, each having a first external connection terminal, and each coupled to a respective end of the lamp tube, the first connection terminals of the two end caps for receiving an external signal, and an LED module configured for emitting light. The power supply module includes: a rectifying circuit, coupled to the first external connection terminals of the end caps and the LED module, for rectifying a received signal to produce a rectified signal; a filtering circuit, coupled to the rectifying circuit and the LED module, for filtering the rectified signal to produce a filtered signal; a transistor configured to be switched according to a control signal; an electric shock protection controller for detecting whether an electric shock risk has occurred, and configured to cause a current to be conducted in the detection path for generating the detection result.

A ballast-bypass type LED tube lamp is provided herein, which implements the safety function for protecting the user from electric shock since it conducts only when both ends thereof have been correctly installed into a lamp socket. The ballast-bypass type LED tube lamp includes a lamp tube, two end caps, an LED module and a power supply module. The power supply module includes a detection module for temporarily conducting two detection terminals of the detection module during a detection stage, so that a pulse current is generated when the LED tube lamp is powered on. The detection module performs a detection based on the pulse current, so as to determine whether to conduct or cut off a current path between the first and the second detection terminals after the detection stage.

A circuit for driving an LED lighting device from an AC power source includes a rectifier and one or more strings of LEDs. Each string of LEDs includes multiple LEDs. A controller produces control signals that open and close a set of switches that corresponding with the LED groups. The controller uses a current mirror with a pair of reference branches situated between a reference voltage and ground and between the switches and ground. Each reference branch has a first-in-line resistor between the reference voltage and the current mirror which primarily set the reference current through the controller by having the highest impedances, and the control signals are produced by a set of resistors on one of the branches. Each branch also has a last-in-line resistor between the current mirror and ground with the lowest impedances. The selection of the highest impedances and lowest impedances reduces sensitivity to temperature variations.

An LED tube lamp is disclosed. The LED tube lamp is a ballast-bypass LED tube lamp that includes a lamp tube, two end caps, an LED module, and a power supply module including an electric shock detection circuit. The electric shock detection circuit is capable of forming a current path electrically connected to a power loop of the LED tube lamp for detecting whether a human touches the conductive part of the LED tube lamp when one end of the LED tube lamp has been inserted into a lamp socket.

An apparatus, method and system are disclosed for providing AC line power to lighting devices such as light emitting diodes (LEDs). A representative apparatus comprises: a plurality of LEDs coupled in series to form a plurality of segments of LEDs; first and second current regulators; a current sensor; and a controller to monitor a current level through a series LED current path, and to provide for first or second segments of LEDs to be in or out of the series LED current path at different current levels. A voltage regulator is also utilized to provide a voltage during a zero-crossing interval of the AC voltage. In a representative embodiment, first and second segments of LEDs are both in the series LED current path regulated at a lower current level compared to when only the first segment of LEDs is in the series LED current path.

An LED tube lamp is disclosed. An installation detection circuit is configured in the LED tube lamp configured to receive an external driving signal. The installation detection circuit is configured to detect during one or more pulse signals whether the LED tube lamp is properly installed on a lamp socket, based on detecting a signal generated from the external driving signal. The installation detection circuit includes a switch circuit coupled to the pulse generating circuit, wherein the one or more pulse signals control turning on and off of the switch circuit. The installation detection circuit is further configured to: when it is detected during one or more pulse signals that the LED tube lamp is not properly installed on the lamp socket, control the switch circuit to remain in an off state to cause a power loop of the LED tube lamp to be open; and when it is detected during one or more pulse signals that the LED tube lamp is properly installed on the lamp socket, control the switch circuit to remain in a conducting state to cause the power loop of the LED tube lamp to maintain a conducting state.

Disclosed is a lighting apparatus using an LED as a light source. The lighting apparatus may connect first and second lighting units in series or parallel according to a rectified voltage, change one or more of first and second driving currents corresponding to light emissions of the first and second lighting units, and have the universality for rectified voltages.

A light-emitting diode (LED) tube lamp adapted to install on a lamp socket and configured to receive an external driving signal without the external driving signal passing through a ballast includes a lamp tube, two end caps, each having at least one external connection terminal, a rectifying circuit, for rectifying the external driving signal to produce a rectified signal; a filtering circuit, for filtering the rectified signal to produce a filtered signal; an LED module, disposed on a power loop of the LED tube lamp, coupled to the filtering circuit, and configured for emitting light; a driving circuit coupled between the rectifying circuit and the LED module, and configured to drive the LED module; a mode determination circuit coupled to the rectifying circuit and the driving circuit and configured to detect the voltage level of the rectified signal; a switch circuit; and an installation detection circuit coupled to the mode determination circuit, the switch circuit, and the rectifying circuit; and configured to detect an installation state between the LED tube lamp and a lamp socket based on the voltage level of the rectified signal detected by the mode determination circuit.

A dual-output power adapter for a lighted artificial tree having a plurality of tree portions with light strings having lighting elements. The dual-output power adapter includes a power cord including a first power conductor and a second power conductor, the power cord configured to transmit an input electrical power; a housing configured to receive the first power conductor and a second power conductor; power-converting circuitry in electrical connection with the first power conductor and the second power conductor, the power-converting circuitry configured to convert the input electrical power to a first output electrical power; a first pair of conductors for transmitting the first output electrical power; and a second pair of conductors for transmitting a second output electrical power.

A method and circuit for driving an LED lighting device from an AC power source includes a rectifier and a plurality of strings of LEDs. Each string of LEDs includes a plurality of LEDs. A plurality of switches is controlled by a controller for opening and closing the switches. The controller is adapted to vary the number of strings conducting electricity by applying voltage from the rectifier to arrangements of the plurality of strings of LEDs selected based upon the present voltage of the output of the rectifier and the forward bias voltage of each of the strings of LEDs.