Abstract: An LED driver that is operable with two different types of power source originally designed for a high-intensity discharge lamp. The LED driver directs current of an input power provided by the power source down a first current path if it is determined that the power source comprises a functional ignitor. The LED driver directs current of an input power provided by the power source down a second current path if it is determined that the 5 power source does not comprise a functional ignitor.

Abstract: A device for determining a type of a power source for powering a LED lighting unit, wherein one possible type comprises a ballast originally designed for a high intensity discharge lamp and repurposed for use with an LED lighting unit. The power source type determiner monitors at least one electrical parameter of either a load or the power source itself after a power drawn by the load whose characteristic is set to a critical value. A value of the electrical parameter is used to identify a type of the power source. A value of the electrical parameter is the pulse generated by the traditional ballast for gas discharge lamp, which pulse is detected to determine the type of the power source.

Abstract: An LED driver that is operable with two different types of power source originally designed for a high-intensity discharge lamp. The LED driver directs current of an input power provided by the power source down a first current path if it is determined that the power source comprises a functional ignitor. The LED driver directs current of an input power provided by the power source down a second current path if it is determined that the 5 power source does not comprise a functional ignitor.

Abstract: A device for determining a type of a power source for powering a LED lighting unit, wherein one possible type comprises a ballast originally designed for a high intensity discharge lamp and repurposed for use with an LED lighting unit. The power source type determiner monitors at least one electrical parameter of either a load or the power source itself after a power drawn by the load whose characteristic is set to a critical value. A value of the electrical parameter is used to identify a type of the power source.

Abstract: A retrofit Light Emitting Diode, LED, lighting device for connection to a ballast, wherein said ballast is arranged to be connected to a mains voltage and arranged to provide for a ballast current, wherein said LED lighting device is arranged to detect a dip in said mains voltage using a zero current detector.

Abstract: A retrofit Light Emitting Diode, LED, lighting device for connection to a ballast, wherein said ballast is arranged to be connected to a mains voltage and arranged to provide for a ballast current, wherein said LED lighting device is arranged to detect a dip in said mains voltage using a zero current detector.

Abstract: A retrofit lamp is to be used with a ballast. A shunt switch is provided in parallel with an output load and is adapted to shunt input terminals of the lamp using pulse width control so as to tune the current through the lighting element. This current control is used to enable compatibility with different ballasts and to provide dimming control. A detection circuit is used to detect an abnormal drive condition of the retrofit lamp and the pulse width control of the shunt switch can then be overridden by holding the shunt switch at a stable state for a certain duration. This prevents overload conditions and avoids DC signals in the event of component failures.

Abstract: A retrofit lamp is to be used with a ballast. A shunt switch is provided in parallel with an output load and is adapted to shunt input terminals of the lamp using pulse width control so as to tune the current through the lighting element. This current control is used to enable compatibility with different ballasts and to provide dimming control. A detection circuit is used to detect an abnormal drive condition of the retrofit lamp and the pulse width control of the shunt switch can then be overridden by holding the shunt switch at a stable state for a certain duration. This prevents overload conditions and avoids DC signals in the event of component failures.

Abstract: A method for driving and dimming an HID lamp (2), the method comprising the steps of: providing a controllable HBCF current source stage (20); using the HBCF current source stage (20) to generate commutating DC lamp current (I) having alternating current direction; supplying the HBCF current source stage (20) with an intermediate voltage (Vo). In normal mode, the commutating DC lamp current (I) is generated with a predetermined nominal current magnitude (IN) while the intermediate voltage (Vo) has a predetermined nominal level (VN). In a dim mode, the commutating DC lamp current (I) is generated with a current magnitude lower than said nominal current magnitude (IN) while the intermediate voltage (Vo) has a level (VH) higher than said nominal level (VN).

Abstract: The invention relates to a circuit for operating a high pressure discharge lamp La. The circuit comprises input terminals for connecting to a source of supply voltage; first capacitive means C1 coupled to the input terminals and second capacitive means C2 coupled to the input terminals parallel to the first capacitive means C1. A switchable element D1 is provided between the first and second capacitive means C1, C2 for blocking a current with which the second capacitive means C2 in use charge the first capacitive means C1. Output terminals for connection of the high pressure discharge lamp La and the inductive means are provided and a commutator BR coupled to said input terminal and to said output terminals for supplying an alternating current to the high pressure discharge lamp La when the lamp is connected to said output terminals. The circuit comprises a pulse supply for supplying to the output terminals a current pulse in a later part of a half period of the alternating current.