A method of overpower protection in a power supply system for driving a light source includes determining a voltage drop across a voltage-controlled resistor (VCR) coupled in series with the light source, calculating a power dissipation of the VCR based on the voltage drop and an output current of the power supply system, determining whether the power dissipation is greater than a power threshold, and in response to determining that the power dissipation is less than or equal to the power threshold, determining that an accumulated energy of the VCR is greater than zero, and decrementing the accumulated energy based on the power threshold and the power dissipation of the VCR.

A light-emitting diode (LED) luminaire comprises an emergency-operated portion comprising a rechargeable battery with a terminal voltage, a self-diagnostic circuit, and a node modulator-demodulator (MODEM). The LED luminaire can auto-switch from a normal power to an emergency power according to availability of the normal power and whether a rechargeable battery test is initiated. The self-diagnostic circuit comprises a clock and is configured to initiate self-diagnostic tests and to auto-evaluate battery performance according to test schedules with the terminal voltage examined and test results stored. The LED luminaire further comprises a remote controller configured to initiate control signals with phase-shift keying (PSK) signals transmitted and to collect test data to and from the node MODEM. The node MODEM is configured to demodulate the PSK signals and to send commands to the self-diagnostic circuit to request responses accordingly.

An LED luminaire emergency driver comprises a rechargeable battery, a charger circuit, an LED driving circuit, and a charging and discharging control circuit. The LED luminaire emergency driver is intended to automatically supply a first supplied voltage to drive LED arrays in an event of a normal power failure. The LED driving circuit is configured to convert a terminal voltage from the rechargeable battery into the first supplied voltage when a line voltage from AC mains is unavailable. The charging and discharging control circuit comprises a relay switch and a transistor circuit assembly configured to sense a charging voltage, to control switching between normal power and an emergency power to operate the LED arrays, and to meet regulatory requirements without operational ambiguity and safety issues.

An LED luminaire emergency driver comprises a rechargeable battery, a charger circuit, an LED driving circuit, and a charging and discharging control circuit. The LED luminaire emergency driver is intended to automatically supply a first supplied voltage to drive LED arrays in an event of a normal power failure. The LED driving circuit is configured to convert a terminal voltage from the rechargeable battery into the first supplied voltage when a line voltage from AC mains is unavailable. The charging and discharging control circuit comprises a relay switch and a transistor circuit assembly configured to sense a charging voltage, to control switching between normal power and an emergency power to operate the LED arrays, and to meet regulatory requirements without operational ambiguity and safety issues.

A driver is configured to provide an output voltage and an output current to a load according to an input voltage. The driver includes a power converter, first and second detecting devices and a controller. The power converter is configured to receive and convert the input voltage to the output voltage and the output current. The first detecting device is configured to detect the input voltage to generate a first signal. The second detecting device is configured to detect the output voltage to generate a second signal, and detect the output current to generate a third signal. The controller is configured to perform a calculation to the second signal and the third signal according to one of lookup tables corresponding to the first signal to generate a power value. An operation method of a driver and a light source system are also disclosed herein.

A driver is configured to provide an output voltage and an output current to a load according to an input voltage. The driver includes a power converter, first and second detecting devices and a controller. The power converter is configured to receive and convert the input voltage to the output voltage and the output current. The first detecting device is configured to detect the input voltage to generate a first signal. The second detecting device is configured to detect the output voltage to generate a second signal, and detect the output current to generate a third signal. The controller is configured to perform a calculation to the second signal and the third signal according to one of lookup tables corresponding to the first signal to generate a power value. An operation method of a driver and a light source system are also disclosed herein.

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.

The lighting device includes a control unit configured to set desired values of drive currents of solid state light sources with different light emission colors. The control unit has a normal mode and a correction mode. The normal mode is a mode of setting the desired values to normal desired values corresponding to instruction values representing a desired color of colors. The correction mode is a mode of setting the desired values to corrected desired values corresponding to corrected instruction values obtained by correcting the instruction values.

A zero-crossing detection circuit coupled to a power factor correction (PFC) controller of a power supply system includes a zener diode configured to generate a zener reference signal, and an operational amplifier coupled to the zener diode and configured to receive the zener reference signal and a feedback signal corresponding to an output current of the power supply system, and to generate a zero-crossing signal to a zero-crossing input of the PFC controller.

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.