A harmonics correction circuit is implemented as an independent device (such as a SiP or ASIC), and includes (1) a first node, (2) a second node, (3) a first current path extending from the first node to the second node, (4) a second current extending from the first node to ground, (5) a third current path extending from the first node to the second node, (6) a sense resistor electrically connected to the second node and to ground, (7) a differential circuit (e.g., a differential amplifier or other type of operational amplifier (“op-amp”)) that has a first input, a second input, and an output, (8) a transistor comprising a gate that is electrically connected to the output of the differential circuit, a drain that is electrically connected to the third current path, and a source that is electrically connected along the third current path.

An LED tube lamp includes a lamp tube, an LED module, a power supply module, a micro switch, and an actuator. The lamp tube has pins for receiving an external driving signal. The power supply module is configured for supplying power to the LED module. The micro switch is coupled to the power supply module. And the actuator is configured to cause the micro switch to change to a closed-circuit position to allow the power supply module to supply power to the LED module for emitting light. When the LED tube lamp is properly installed into a lamp holder, the micro switch closes to electrically connect the power supply module to an external driving signal.

The invention provides an automotive lighting unit for detecting electrical characteristics of light emitter diode component. At least one light emitter diode light source is selectively disposed on any one of at least one circuit channel of at least one drive power loop. At least one circuit breaker comprises at least one circuit switch corresponding to the at least one drive power loop, and is disposed on the circuit channel with the at least one light emitter diode light source. The at least one circuit channel is controlled by the at least one circuit switch to turn in a state of isolating from a drive power. An ammeter connection line is connected with the two sides one of the at least one light emitter diode light source.

The invention provides an automotive lighting unit for detecting electrical characteristics of light emitter diode component. At least one light emitter diode light source is selectively disposed on any one of at least one circuit channel of at least one drive power loop. At least one circuit breaker comprises at least one circuit switch corresponding to the at least one drive power loop, and is disposed on the circuit channel with the at least one light emitter diode light source. The at least one circuit channel is controlled by the at least one circuit switch to turn in a state of isolating from a drive power. An ammeter connection line is connected with the two sides one of the at least one light emitter diode light source.

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 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.

The present document relates to the compensation of voltage variations within power converters. A driver circuit for a solid state light source is described. The driver circuit comprises a switched-mode power converter comprising a switch; wherein the switched-mode power converter is configured to convert an input voltage at an input of the switched-mode power converter into an output voltage at an output of the switched-mode power converter. Furthermore, the driver circuit comprises current sensing means configured to determine a sensed current signal indicative of a current through the switch; and voltage sensing means configured to determine a sensed voltage signal indicative of the input voltage. In addition, the driver circuit comprises a control unit configured to determine a gate control signal for putting the switch into an off-state, based on the sensed current signal and based on the sensed voltage signal.

An 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; an LED lighting module coupled to the first external connection terminal and configured to receive a signal for emitting light, the signal derived from the first external driving signal; and a ballast interface circuit coupled between the first external connection terminal and the LED lighting module. The ballast interface circuit may be configured such that when the external driving signal is initially input at the first external connection terminal and second external connection terminal, the ballast interface circuit will initially be in an open-circuit state, which prevents the LED tube lamp from emitting light, until the ballast interface circuit enters a conduction state, which conduction state allows a current input at the first external connection terminal/second external connection terminal to flow through the LED lighting module and thereby allows the LED tube lamp to emit light

The present disclosure relates generally to systems and methods for transient response improvements in electrical circuits. More particularly, the present disclosure relates to systems and methods for suppressing overshoot currents and overshoot durations in circuits using switching regulators, such as driver circuits for LED applications. Embodiments of the invention relate to an LED driver that utilizes transient suppression systems and method for LED applications.