A driving circuit and a method for operating the driving circuit is provided for a lamp, the lamp includes a lighting unit, and a first and a second pair of connection pins for coupling the driving circuit to a power supply unit. The driving circuit includes a pre-heating detection circuit and a protection circuit. The pre-heating detection circuit is coupled to the first pair of connection pins and configured to detect a voltage between the first pair of connection pins and output a reference voltage. The protection circuit includes a switching circuit connected in series with the lighting unit, the protection circuit is configured to compare the reference voltage with an input voltage of the lamp and turn on the switching circuit to light the lighting unit when the input voltage of the lamp is greater than the reference voltage.

A load-switch voltage control circuit includes a power control circuit for controlling a switching element that stabilizes the voltage to a load. The power control circuit determines intervals of conduction for the switching element, that connects a control impedance to the load, for stabilizing the voltage across the load.

An electronic dimming ballast or light emitting diode (LED) driver for driving a gas discharge lamp or LED lamp may be operable to control the lamp to avoid flickering and flashing of the lamp during low temperature or low mercury conditions. Such a ballast or driver may include a control circuit that is operable to adjust the intensity of the lamp. Adjusting the intensity of the lamp may include decreasing the intensity of the lamp. The control circuit may be operable to stop adjustment of the intensity of the lamp if a magnitude of the lamp voltage across the lamp is greater than an upper threshold, and subsequently begin to adjust the intensity of the lamp when the lamp voltage across the lamp is less than a lower threshold. Subsequently beginning to adjust the intensity of the lamp may include subsequently decreasing the intensity of the lamp.

The present invention relates to a LED tube (1) for retrofitting in a fluorescent tube lighting fixture having a preheat phase during which the fluorescent tube lighting fixture is arranged to preheat filaments of a fluorescent tube, the LED tube (1) comprising: an array of LEDs (2), a LED driver (4) for driving the array of LEDs (2), a first pair of contact pins (8, 0) at a first end (12) of the LED tube (1) and a second pair of contact pins (14, 16) at a second end (18) of the LED tube (1) for connecting the LED tube (1) electronically and mechanically to the fluorescent tube lighting fixture, the first pair of contact pins (8, 10) being connected forming a first circuitry, the second pair of contact pins (14, 16) being connected forming a second circuitry, the LED driver (4) being connected between the first circuitry and the second circuitry, and a temperature controlled switch (20) having an open state and a closed state, and being arranged to adapt the closed state when heated, such that a current path between the first circuitry and the second circuitry is obtained, wherein a preheat current passing between the first pair of contact pins (8, 10) during the preheat phase of the fluorescent tube lighting fixture is arranged to heat the temperature controlled switch.

The present technology provides a high-pressure sodium lamp lighting device that reduces occurrence of the acoustic resonance phenomenon. A high-pressure sodium lamp lighting device of one aspect of the present invention comprises a high-pressure sodium lamp of arc length AL within the scope of 142.8 mmAL167 mm. The lighting device also includes an electronic ballast configured to supply a high frequency AC voltage to the high-pressure sodium lamp. A lighting frequency of the electronic ballast is a frequency that avoids a first and a second acoustic resonance occurrence bands f1 kHz and f2 kHz determined based on equations from an arc tube inner diameter D mm of the high-pressure sodium lamp. The equation for f1 is a range of f1min to f1max=(7.4D+130) to (8.3D+156). The equation for f2 is a range of f2 min to f2max=(11.5D+200) to (10.0D+197).

A control algorithm for operating a fluid disinfecting system by UV radiation, wherein the UV radiation is generated by at least one UV lamp including a pair of heating cathodes having a discharge voltage (U.sub.D), the UV lamp is operated by an electronic ballast unit equipped with the control algorithm for adjusting the UV power of the UV lamp by pulse-width-modulation to reduce UV power. The control algorithm decreases the current to a level (I.sub.kmin), increases the voltage amplitude (U) above the discharge voltage (U.sub.D) until a desired UV power level is reached. The pulse width (PW) is decreased with increasing voltage amplitude (U) until PW.sub.min is reached. The decrease in current and the increase in voltage generate an ineffective current-voltage-ratio in which excess current heats the cathode. An electronic ballast equipped with the algorithm and systems equipped with such ballasts are also disclosed.

The present disclosure relates to a starting device for a CDM lamp, comprising: a full-bridge inverter, which at least provides an output as a starting power source to initiate the CDM lamp to work normally; a driving circuit for driving the full-bridge inverter; a single-chip microcomputer, which is connected to the driving circuit; an ignition determining module, one end of which is connected to the full-bridge inverter to sense whether the output of the full-bridge inverter has powered on the CDM lamp, so as to determine whether ignition of the CDM lamp succeeds and then output a result of the determining to the single-chip microcomputer via the other end. The present disclosure provides a novel starting device for a CDM lamp, which facilitates determining whether starting of the CDM lamp succeeds and also facilitates enhancement of successful rate of starting the CDM lamp subsequently.

An electronic ballast with power thermal cutback including an electronic ballast operably connected to provide power to a lamp, the electronic ballast having a PFC converter (HO) operable to receive a PFC input voltage (112) and operable to provide a DC bus voltage on a DC bus (114); a DC/AC converter (120) operable to receive the DC bus voltage from the DC bus (114) and to provide AC power (122) to the lamp (140) at an AC output frequency; a compensator (130) responsive to an electronic ballast condition parameter, the compensator (130) being operable to provide a compensator signal to at least one of the PFC converter (110) and the DC/AC converter (120). At least one of the PFC converter (110) and the DC/AC converter (120) is responsive to the compensator signal to reduce the power to the lamp (140) when the electronic ballast condition parameter passes a threshold.

An electronic dimming ballast or light emitting diode (LED) driver for driving a gas discharge lamp or LED lamp may be operable to control the lamp to avoid flickering and flashing of the lamp during low temperature or low mercury conditions. Such a ballast or driver may include a control circuit that is operable to adjust the intensity of the lamp. Adjusting the intensity of the lamp may include decreasing the intensity of the lamp. The control circuit may be operable to stop adjustment of the intensity of the lamp if a magnitude of the lamp voltage across the lamp is greater than an upper threshold, and subsequently begin to adjust the intensity of the lamp when the lamp voltage across the lamp is less than a lower threshold. Subsequently beginning to adjust the intensity of the lamp may include subsequently decreasing the intensity of the lamp.

An electronic circuit for protecting a load against over-voltage is disclosed. The electronic circuit comprises an input port for receiving a voltage and an output port for feeding the voltage to the load. The electronic circuit further comprises a switching unit arranged to switch on and off the voltage from the input port. Moreover, the electronic circuit comprises a capacitive component arranged to receive the voltage when the switching unit is switched on and is otherwise arranged to feed voltage to the output port. Furthermore, the electronic circuit comprises a comparing unit configured to control the switching unit to be switched off when a value at the output port exceeds a first threshold; and to control the switching unit to be switched on when the value is below a second threshold.