Abstract: An igniter circuit (10) for an HID lamp (11) has a DC input (VBUS) for coupling to a source of DC voltage, and an output (23, 24) for coupling to the HID lamp. A resonant ignition circuit (12) operating at a controlled resonant frequency is coupled to the DC input for producing successive bursts of voltage having a frequency equal to the resonant frequency and having an amplitude that increases with time. The resonant ignition circuit (12) feeds the bursts of voltage across the output of the igniter until an HID lamp coupled thereto reaches breakdown.

Abstract: An igniter circuit (10) for an HID lamp (11) has a DC input (VBUS) for coupling to a source of DC voltage, and an output (23, 24) for coupling to the HID lamp. A resonant ignition circuit (12) operating at a controlled resonant frequency is coupled to the DC input for producing successive bursts of voltage having a frequency equal to the resonant frequency and having an amplitude that increases with time. The resonant ignition circuit (12) feeds the bursts of voltage across the output of the igniter until an HID lamp coupled thereto reaches breakdown.

Abstract: A startup circuit (30) for a power supply (44), has an input (31) for connecting to a source of high voltage thereto, and an output rail (33) for feeding rectified voltage to the power supply. A first energy storage device (35) is coupled to the output rail for storing energy when voltage is first applied to the input, and a second energy storage device (37) is coupled to an output of the power supply for storing energy when a voltage appearing at the output of the power supply reaches substantially steady state. A switching circuit (36, 50) is coupled to the first energy storage device and the second energy storage device and is responsive to the first energy storage device having sufficient energy for transferring the energy to the second energy storage device and disconnecting the first energy storage device from the output rail.

Abstract: A startup circuit (30) for a power supply (44), has an input (31) for connecting to a source of high voltage thereo, and an output rail (33) for feeding rectified voltage to the power supply. A first energy storage device (35) is coupled to the output rail for storing energy when voltage is first applied to the input, and a second energy storage device (37) is coupled to an output of the power supply for storing energy when a voltage appearing at the output of the power supply reaches substantially steady state. A switching circuit (36, 50) is coupled to the first energy storage device and the second energy storage device and is responsive to the first energy storage device having sufficient energy for transferring the energy to the second energy storage device and disconnecting the first energy storage device from the output rail.

Abstract: A controller for reducing acoustic noise produced during use of a leading edge dimmer, includes a leading edge controller responsive to an input voltage fed thereto for producing a control signal upon detection of a leading edge, and a linear switch coupled to the leading edge controller and responsive to the control signal for linearly switching the input voltage so that a rate of rise of the leading edge is decreased. A trailing-edge controller may be coupled to a leading-trailing edge detector and responsive to detection of a trailing edge dimmer for disabling the leading edge controller and decreasing a rate of decline of the trailing edge of the input voltage.

Abstract: A controller for reducing acoustic noise produced during use of a leading edge dimmer, includes a leading edge controller responsive to an input voltage fed thereto for producing a control signal upon detection of a leading edge, and a linear switch coupled to the leading edge controller and responsive to the control signal for linearly switching the input voltage so that a rate of rise of the leading edge is decreased. A trailing-edge controller may be coupled to a leading-trailing edge detector and responsive to detection of a trailing edge dimmer for disabling the leading edge controller and decreasing a rate of decline of the trailing edge of the input voltage.