An electronic half-bridge ZETA converter may include a transformer, wherein a half-bridge is connected to the primary winding of transformer, and wherein a respective capacitance and a respective diode are associated with the half-bridge switches. Moreover, the converter includes a ZETA converter which is connected to secondary winding of transformer, so that the ZETA converter includes a first inductance, which includes the magnetization inductance of transformer, and a second inductance. Finally, the converter includes a control unit which drives the half-bridge switches with four time intervals that are repeated periodically. Specifically, during the fourth time interval the first and the second switch are opened, so that the capacitance associated with said second switch is charged and the capacitance associated with said first switch is discharged, enabling a zero voltage switching.

A light-emitting diode (LED) lamp comprising a normally-operated portion and an emergency-operated portion is used to replace a luminaire operated only in a normal mode with alternate-current (AC) mains. The normally-operated portion comprises a second driving circuit whereas the emergency-operated portion comprises a rechargeable battery, a first driving circuit, a self-diagnostic circuit, and a control circuit. The LED lamp can auto-switch between the normal mode and an emergency mode according to availability of the AC mains and whether a rechargeable battery test is initiated. The control circuit is configured to produce a pulse train with a predetermined duty cycle to operate the first driving circuit while disabling the second driving circuit to eliminate operational ambiguity during the rechargeable battery test. The self-diagnostic circuit is configured to provide multiple sequences and to auto-evaluate battery performance by sending the pulse train to operate the first driving circuit according to the multiple sequences.

The present invention provides a multi-load control apparatus, a slave circuit and a control method thereof. The multi-load control apparatus includes a master circuit and at least one slave circuit. The master circuit generates at least one pulse width modulation (PWM) signal according to an input signal. The slave circuit controls a power switch according to a corresponding PWM signal. The slave circuit has a primary side circuit and a secondary side circuit. The primary side circuit generates an AC PWM signal according to the corresponding PWM signal. The power switch has a control terminal which is driven according to a floating ground level which is not a constant voltage level. The power switch has a current inflow terminal and a current outflow terminal, which are connected to a corresponding load circuit in series, wherein the series circuit of the power switch and the load circuit receives an AC voltage.

A power converter comprising an inverter for receiving a supply power and providing an alternating output. An output rectifier receives the alternating output and provides a rectified output to a load. An output winding receives the rectified output, and a sensing winding is inductively coupled to the output winding and provides a sensing output. A controller receives the sensing output and provides a control signal to the inverter for controlling the alternating output. A related method of converting power is also provided.

Circuitry 31 for a solid-state lighting arrangement 20 designed for as a replacement for a gas discharge lamp used in a lighting fixture having a ballast. The circuitry 31 unsafe flow of current through the solid-state lighting arrangement 20, under non-operational conditions and during installation of the lighting arrangement, so as to provide compatibility with safety standards for use with discharge lamps.

Circuitry 31 for a solid-state lighting arrangement 20 designed for as a replacement for a gas discharge lamp used in a lighting fixture having a ballast. The circuitry 31 unsafe flow of current through the solid-state lighting arrangement 20, under non-operational conditions and during installation of the lighting arrangement, so as to provide compatibility with safety standards for use with discharge lamps.

Pulse sharing control to enhance performance in multiple output power converters is described herein. During a switching cycle, an energy pulse is provided to more than one port (i.e., output) using pulse sharing transfer. Pulse sharing transfer may enhance performance by reducing audible noise due to subharmonics and by reducing a root mean square current of one or more secondary currents. A primary switch is closed to energize an energy transfer element via a primary current. Energy may be shared among a first load port on a first circuit path via a first secondary current and among a second load port on a second circuit path via a second secondary current.

Pulse sharing control to enhance performance in multiple output power converters is described herein. During a switching cycle, an energy pulse is provided to more than one port (i.e., output) using pulse sharing transfer. Pulse sharing transfer may enhance performance by reducing audible noise due to subharmonics and by reducing a root mean square current of one or more secondary currents. A primary switch is closed to energize an energy transfer element via a primary current. Energy may be shared among a first load port on a first circuit path via a first secondary current and among a second load port on a second circuit path via a second secondary current.

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.