摘要:
A 3-way halogen lamp selectively generates a first light level, second light level, and third light level based on whether a first terminal on the lamp base and a second terminal on the lamp base are connected to a power supply. A controller housed entirely within the based detects whether the first and second terminals are connected to the power supply, and generates a control signal as a function thereof. A switching circuit housed entirely within the base is operated by the control signal to provide a voltage load signal having a particular RMS voltage. A single filament halogen capsule is attached to the base and connected to the switching circuit for receiving the voltage load signal and generating the first light level, second light level, and third light level when the voltage signal has a first RMS voltage, a second RMS voltage, and a third RMS voltage, respectively.
摘要:
A method for converting a line voltage to an RMS load voltage in a lamp includes providing a control circuit which includes a switch and a microcontroller that operates the switch to establish an RMS load voltage for the lamp. The load voltage of the lamp is sensed and the sensed load voltage is compared in the microcontroller to a reference RMS voltage. Operation of the switch is adjusted in response to the comparison so that the RMS load voltage is substantially constant at the reference RMS voltage over a first operating range of the line voltage and so that the RMS load voltage decreases with decreasing line voltage at non-zero line voltages less than the first operating range.
摘要:
A lamp contains a voltage conversion circuit that converts a line voltage to an RMS load voltage and includes a switch and a microcontroller that operates the switch to define the RMS load voltage. The microcontroller senses a load voltage of the lamp, compares the sensed load voltage to a reference RMS voltage, and operates the switch in response to the comparison so that the RMS load voltage is substantially constant at the reference RMS voltage over an operating range of the line voltage and so that the RMS load voltage decreases with decreasing line voltage at line voltages less than the operating range. The operating range of the line voltage is defined to have a minimum that is a non-zero line voltage at which a load current is a predetermined maximum. The voltage conversion circuit may be a phase clipping circuit or a pulse width modulation circuit.
摘要:
A phase-control power controller converts a line voltage to an RMS load voltage and includes a phase-control clipping circuit that clips a load voltage to provide the RMS load voltage. The power controller may be in a base of a lamp and connected to a lamp terminal. The phase-clipping circuit establishes a phase conduction angle that determines the RMS load voltage for the lamp and includes a transistor switch and a microcontroller that operates the transistor switch, where ON/OFF periods of the transistor switch define the phase conduction angle. The microcontroller senses a load voltage at the lamp terminal, compares the sensed load voltage to a reference RMS voltage, and adjusts the ON/OFF periods of the transistor switch in response to the comparison to cause the load voltage to approach the reference RMS voltage. The circuit may be used for reverse, forward, or forward/reverse hybrid phase clipping.
摘要:
A method of operating a power controller that converts a line voltage to an RMS load voltage includes a soft start in which a duty cycle of a pulse width modulation circuit is gradually increased to a steady state value that defines the RMS load voltage. The controller has a circuit with a time-based signal source that triggers conduction independently of line voltage magnitude and a transistor switch whose gate receives signals from the time-based signal source to trigger the circuit. When starting the power controller, a microcontroller increases the duty cycle of the pulse width modulation circuit in plural steps to provide the soft start.
摘要:
An incandescent halogen lamp used in connection with a vehicle headlamp system in which stray light attributable to reflection off of internal lamp components is reduced while the structural integrity of the lamp is maintained. The halogen lamp includes two filaments, several lead wires, and a support bridge all sealed within a glass envelope. Each filament is connected at its outermost end to a flattened end portion of a lead wire which extends along the length of the filament from near the support bridge to the upper end of the filament. The flattened outer ends of the lead wires have a narrow profile that is in alignment with the direction of illumination of light from their respective filaments. This arrangement reduces the surface area that could otherwise interfere with light emitted by the filaments, and thereby reduces the overall stray light produced by the lamp. The flattened outer ends can have a roughened surface to further help reduce the amount of light reflected off the lead wires.
摘要:
A lamp contains a voltage conversion circuit that converts a line voltage to an RMS load voltage and includes a switch and a microcontroller that operates the switch to define the RMS load voltage. The microcontroller senses a load voltage of the lamp, compares the sensed load voltage to a reference RMS voltage, and operates the switch in response to the comparison so that the RMS load voltage is substantially constant at the reference RMS voltage over an operating range of the line voltage and so that the RMS load voltage decreases with decreasing line voltage at line voltages less than the operating range. The operating range of the line voltage is defined to have a minimum that is a non-zero line voltage at which a load current is a predetermined maximum. The voltage conversion circuit may be a phase clipping circuit or a pulse width modulation circuit.
摘要:
A phase-control power controller that converts a line voltage to an RMS load voltage includes a fixed phase forward/reverse hybrid phase-control clipping circuit that performs phase-control clipping of a load voltage to provide an RMS load voltage. A conduction angle of the phase-control clipping circuit is defined by a time-based pulse source that triggers conduction in the phase-control clipping circuit independently of line voltage magnitude during time periods that span polarity changes of the load voltage and that are separated by intervals when conduction is not triggered. The phase-control clipping circuit includes a transistor switch whose gate receives positive polarity signals from the time-based pulse source to trigger conduction of the phase-control clipping circuit. The power controller may be in a voltage conversion circuit that converts a line voltage at a lamp terminal to the RMS load voltage usable by a light emitting element of the lamp.
摘要:
A method of operating a lamp that has a power controller connected between a terminal and a light emitting element that converts the line voltage to an RMS load voltage. An input to an analog control block is provided in the controller that is independent of a change in magnitude of the line voltage. A trigger signal from the analog control block is provided at a first frequency by charging and discharging a capacitor in the analog control block that receives the input. An initial condition of the analog control block is resetted periodically. A sync signal synchronizes the trigger signal with a waveform of the line voltage. A load voltage is clipped based on the synchronized trigger signal to define the RMS load voltage.
摘要:
A lamp includes a voltage controller that converts a line voltage to a desired RMS load voltage. The voltage controller is entirely within a lamp base and uses pulse width modulation to define the RMS load voltage. The voltage controller has a feed-back circuit that adjusts the RMS load voltage to a desired voltage based on a comparison to a preset reference. The voltage converter also includes a switching transistor that pulse width modulates lamp current and that is responsive to the feed-back circuit. The feed-back circuit may be included in a microcontroller that has a time-based signal source that triggers the transistor, a comparator that compares the load voltage to a reference, and a program that adjusts the time-based signal source based on the comparison so as to provide the desired RMS load voltage.