An LED tube lamp includes a first rectifying circuit, a second rectifying circuit, an LED lighting module, a mode determination circuit and a mode switching circuit. The first rectifying circuit is coupled to a first pin and second pin and is configured to rectify an external driving signal transmitted from the first pin and/or the second pin. The second rectifying circuit is coupled to a third pin and a fourth pin and is configured to rectify the external driving signal with the first rectifying circuit. The filter circuit is coupled to the first rectifying circuit and configured to filter the rectified signal. The LED lighting module has a driving circuit and an LED module, and is coupled to the filter circuit and is connected to receive the filtered signal. The mode determination circuit is configured to generate a first determined result signal based on the external driving signal. The mode switching circuit is coupled to the filter circuit and the driving circuit, and is configured to determine whether to perform a first driving mode or a second driving mode based on the first determined result signal. The driving circuit receives a filtered signal from the filtering circuit and drives the LED module light when performing the first driving mode, and the filtered signal bypasses at least a component of the driving circuit to drive the LED module to light when performing the second driving model.

A linear light-emitting diode (LED)-based solid-state lamp comprises an LED driving circuit, LED arrays, at least one rectifier, and an electric current flow control module. The LED driving circuit comprises a control loop compensation device with a control loop correction signal to precisely control an electric current to flow into the LED arrays. The electric current flow control module uses the control loop correction signal in a way that it detects and determines if the linear LED-based solid-state lamp is operated in a normal mode or in an electric shock hazard mode. When an electric shock hazard is identified, the electric current flow control module shuts off a return current flow from the LED arrays to reach the at least one rectifier, thus eliminating an overall through-lamp electric shock current. The scheme can effectively prevent a through-lamp electric shock from occurring during relamping or maintenance.

A load control device may be configured to control an electrical load, such as a lighting load. The load control device may include a first terminal adapted to be coupled to an alternating-current (AC) power source, and a second terminal adapted to be coupled to the electrical load. The load control device may include a bidirectional semiconductor switch, a filter circuit, and a control circuit. The bidirectional semiconductor switch may be coupled in series between the first terminal and the second terminal, and be configured to provide a phase-control voltage to the electrical load. The filter circuit may be coupled between the first terminal and the second terminal. The control circuit may be configured to render the bidirectional semiconductor switch conductive and non-conductive to control an amount of power delivered to the electrical load, and be configured to adjust the impedance and/or filtering characteristics of the filter circuit.

A light-emitting diode (LED) tube lamp with overcurrent and/or overvoltage protection capabilities includes a lamp tube, a first rectifying circuit, a filtering circuit, an LED lighting module, and a protection circuit. The lamp tube has pins for receiving an external driving signal. The first rectifying circuit is for rectifying the external driving signal to produce a rectified signal. The filtering circuit is for filtering the rectified signal to produce a filtered signal. The LED lighting module includes an LED module, wherein the LED lighting module is configured to receive the filtered signal to produce a driving signal, and the LED module is for receiving the driving signal for emitting light. The protection circuit is configured to determine whether to enter a protection state, wherein upon entering the protection state, the protection circuit works to limit or restrain the level of the filtered signal.

An LED tube lamp includes a lamp tube, having a first pin and a second pin for receiving an external driving signal; a first rectifying circuit for rectifying the external driving signal; a filtering circuit for producing a filtered signal; an LED lighting module configured for emitting light; and a ballast-compatible circuit, coupled to the first rectifying circuit, and containing a metallic electrode, a bimetallic strip, and a heating filament in an inert gas. A spacing is configured between the bimetallic strip and the metallic electrode, and the bimetallic strip includes two metallic strips with different temperature coefficients. When the external driving signal is initially input at the first pin and second pin, the ballast-compatible circuit will be in an open-circuit state, until entering a conduction state, which allows a current to flow through the LED lighting module thus allowing the LED tube lamp to emit light.

A power supply system includes a converter configured to generate a drive signal based on a rectified input signal for powering a light source, a ripple control system including a voltage-controlled resistor (VCR) coupled to a secondary-side of the converter and configured to dynamically adjust a resistance of the VCR to compensate for ripples in the drive signal, and a controller configured to sense an output voltage of the converter, to calculate a voltage drop across the VCR, and to generate a feedback signal to control the drive signal of the converter based on the sensed output voltage and the calculated voltage drop.

A multi-mode control scheme for an LED lamp system uses the detected firing angle of an AC input voltage waveform to select from multiple regulation modes. In operation, a current controller compares the detected firing angle to one or more specified thresholds and selects the appropriate regulation scheme based on the comparison result. When the detected firing angle is less than a first firing angle threshold, the controller employs a current shaping regulation mode. When the detected firing angle is greater than a second firing angle threshold, the controller employs a switching cycle-I_Peak modulation regulation mode. And when the detected firing angle is greater than the first firing angle threshold and less than the second firing angle threshold, the controller employs a hybrid regulation mode.

The invention provides a lighting controller, comprising: a detector adapted to detect a voltage of a power source, said power source is for providing power to a lighting unit via a lighting driver; a controlling unit, coupled to the lighting driver and adapted for controlling the driver to deliver a constant power to the lighting unit regardless of the power source is being consumed, before the detected voltage drops below a first threshold, and controlling the driver to deliver a gradually reduced power to the lighting unit after the detected voltage drops below the first threshold. Wherein the controlling unit is further adapted for switching an up-converter between the power source and the driver to boost the output voltage from the power source to the driver, in a first condition; and bypassing said up-converter, in a second condition, and implementing said step of controlling the driver; wherein said first condition comprises operating in high occupancy periods, and said second condition comprises operating in low occupancy periods

Methods and systems for controlling current provided to one or more LEDs for a period of time after power supplied to the LED driver is shut down are described herein. By controlling current through the one or more LEDs after shutdown, the light emitted from the one or more LEDs transitions to zero at a predictable rate with a predictable lag time. An LED based illumination system includes an energy storage element and a controlled luminous drawdown module electrically coupled between one or more LEDs and an electrical power converter employed to control current provided to the one or more LEDs during normal operation. The controlled luminous drawdown module senses a reduction in voltage at the output of the electrical power converter and operates to control current flow through one or more LEDs of the LED string until electrical energy stored in the electrical storage element is depleted.

A LED circuit comprises a current drive circuit for driving a current through the parallel combination of a LED arrangement and an output capacitor. An override arrangement overrides the current level setting to a default current level during start-up, and the override arrangement is disabled when a current flow is sensed by a sensor. The current setting of the driver is ignored until a threshold current is sensed through the LED arrangement. The delay associated with initial start-up charging of the output capacitor is thereby avoided.