Abstract: A method for powering a load by a light source driving circuit is disclosed. The method includes: acquiring a first sensing signal indicative of an average current flowing through the load; generating a first temperature detecting signal indicative of an ambient temperature of the light source driving circuit; and adjusting the average current flowing through the load based on the first temperature detecting signal and the first sensing signal to make the average current flowing through the load to be inversely proportional to the ambient temperature of the light source driving circuit if the ambient temperature of the light source driving circuit is between a first temperature threshold and a second temperature threshold.

Abstract: A motor drive control device includes a three-phase rectifier; a boosting circuit including a reactor, a switching element, and a backflow preventing element and boosts a direct-current bus voltage supplied from the three-phase rectifier; a smoothing capacitor; an inverter circuit; a boosting control unit; an inverter control unit; and a circuit protecting unit suppresses a ripple current flowing through the smoothing capacitor. In the circuit protecting unit, a correlation of an on-duty ratio of the switching element included in the boosting circuit, the output power of the inverter circuit, and an estimated ripple current are set. On the basis of the on-duty ratio of the switching element, output power of the inverter circuit, and the correlation, the circuit protecting unit determines an estimated ripple current flowing through the smoothing capacitor. When the estimated ripple current exceeds a preset threshold, the circuit protecting unit suppresses the ripple current.

Abstract: Illumination devices (10), systems and methods that convert an alternating current (AC) supply (14) to a direct current (DC) for powering a plurality of light emitting diodes (LEDs) are disclosed. An illumination device (10) comprises a full wave rectifier (12) for converting the AC supply into a direct current (DC). A current limiting diode (CLD) module (16), comprising at least two CLDs coupled in parallel, is coupled in series to an output of the full wave rectifier and a light emitting diode (LED) module (18) comprising a plurality of LEDs is coupled in series between an output of the CLD module (16) and the full wave rectifier (12).

Abstract: A zero-voltage switching type electronic ballast for a fluorescent lamp includes a pair of capacitors connected in series between first and second nodes of a DC power source; a pair of switching devices whose current passages are connected in series between the first and second nodes of the DC power source; a load resonant circuit portion having a serial resonant circuit between the connection node of the pair of capacitors and the connection node of the pair of switching devices, and a discharge lamp; capacitors each connected in parallel to the current passage of the switching devices; a driving transformer having a secondary side which includes first and second windings each connected to the respective switching devices and having opposite polarities, and a third winding having the same polarity as the first winding and connected between the connection node of the pair of switching devices and the load resonant circuit, and a primary side having a fourth winding to which a switching control signal of a pre

Abstract: In a power source circuit, an AC voltage of a commercial AC power source is full-wave-rectified by a diode bridge and divided into two 1/2 voltages by two capacitors connected to the output terminals of the diode bridge. A half-bridge inverter operation is performed by a smoothing capacitor and first and second reverse-conductive switches connected in parallel with the output terminals of the diode bridge via inductors, respectively. A power from the capacitors is temporarily stored in the inductors, and the first and second reverse-conductive switches are operated, thereby performing two boosting chopper operations.

Abstract: In electronic flash apparatus having a flash trigger switch and a flash termination switch, an RC network is provided to apply current to the control electrode of the flash termination switch when the flash trigger switch is in a conductive state.