摘要:
A power supply for a Xenon lamp of a projection television includes a pulse-width-modulator that is included in a power regulating outer feedback loop and in a current-mode inner feedback loop. A current sensing transformer, responsive to a current in a chopper arrangement of the power supply, generates a signal that is coupled to a lowpass filter. The filter generates a ramping portion of each pulse of a control signal that is coupled to a current sensing terminal of the pulse-width-modulator. A switch operating synchronously with a horizontal sync signal is coupled across a capacitor of the lowpass filter to completely discharge the capacitor prior to the beginning of each ramping portion.
摘要:
An arrangement is disclosed for controlling the power applied to two remote loads energized from a common ac line. An example is a circuit for controlling fan speed and lamp brightness, both loads being installed in a common ceiling fixture, and requiring only a two conductor interconnection to a wall mounted control circuit. An exemplary control circuit employs two conventional controllers, each having a bidirectional, semiconductor switch, (e.g., a triac) having a manually adjustable conduction duty cycle for power control. The control circuit includes shunt and series diodes for mutual isolation of the controllers and for allocating one controller to one load and the other controller to the other load. The arrangement simplifies installation costs in requiring only a two conductor control connection, and is economic in its selection of components for the control function.
摘要:
In a motor control circuit for an electronically commutated reversible motor used in a ceiling fan, a control is used to reduce the voltage supplied to the motor for variable speed or torque operation. At the same time, a substantially smooth control voltage, dependent on the variable voltage supplied to the motor, is produced. This control voltage, which is used to enhance the adjustment rate, is applied to control a pulse width modulator, which produces output pulses which also control the flow of energy to the motor. When the control voltage reaches a value slightly past the desired minimum speed or torque setting, a signal is generated to change the direction of motor rotation. Means are provided to delay the actual reversal to protect the power switches in the control circuit. When power is first applied, the initial direction of motor rotation is set by a switch on the ceiling fan. The control circuit permits control of motor reversal from a wall location. The control circuitry is designed for use in a maximally integrated ECM control circuit. The invention also concerns a method of controlling an ECM, including reversal, and reversal combined with torque or speed control.
摘要:
The present invention relates to a pulse generator for use at a selected frequency near 100 Khz and having a predetermined duty cycle (typically 20%). The pulse generator is designed for integrated circuit fabrication using a CMOS process. The design utilizes a ring oscillator whose frequency is varied by external adjustment of a single resistance and which utilizes a gating stage responsive to electrical conditions in at least two stages of the ring oscillator to establish the desired duty cycle. The duty cycle may also be adjusted, as by the inclusion of optional stages in the ring oscillator. The design features a low power consumption, and high temperature stability of frequency and duty cycle.
摘要:
A lighting unit is described utilizing an energy efficient metal vapor arc lamp as the main source of light supplemented by a standby filamentary light source producing light when the arc lamp is being started, the filament thereof serving as a resistive ballast for the arc lamp under normal operation. The lighting unit is designed as a more efficient replacement for the incandescent lamp. The lighting unit includes a rectifier for conversion of 60 hertz ac to dc, and a dc energized operating network, including a ferrite transformer and a transistor switch. The operating network produces an output adapted to each operating state of the arc lamp, including the provision of a high ignition potential, a power boost for the lamp during the glow to arc transition, warm-up and ballasting provisions, and means for sustaining the arc during transients which reduce the line voltage. The filamentary light source provides useful standby illumination while the arc lamp is being started, the amount being reduced to a low value as the arc lamp approaches normal light output.
摘要:
An energy efficient lighting unit is described designed for functional similarity to the incandescent light used in the home. The light unit utilizes a metal vapor arc lamp as the main source of light supplemented by a standby filamentary light source. The lighting unit includes means for converting 60 hertz ac to dc, and a dc energized operating network comprising an inverter operating at above audible frequencies (e.g. 30-40 KHz). The operating network produces a sequence for the arc lamp and the standby filamentary light source appropriate to each operating state of the arc lamp.
摘要:
The present invention relates to a threshold amplifier suited to integrated circuit fabrication of a process employing CMOS technology. The threshold amplifier is designed to sense current producing a first or a second logic level as a function of a current threshold. The amplifier comprises a p-channel device and a n-channel device serially connected across the bias supply. The gate to source voltages of the two devices are respectively controlled by a diode connected p-channel device similarly serially connected across the bias supply with a diode connected n-channel device, the source of the latter being returned to ground via a current carrying resistance also in the second series path. The output level which is taken at the drain inter-connection between the devices in the first series path depends on the relative conductivity of the two devices which is in turn affected by the induced voltage drop in the source connected resistance in the second series path. The threshold voltage may be controlled by the geometry ratio between the n-channel devices, and the current setting in the second series path.
摘要:
The present invention relates to a lighting unit having low and high light levels and employing an efficient arc lamp as the source of light during the high level setting. The unit employs a filamentary light source for the production of light during low light level operation, the filament acting as a resistive ballast for the arc lamp during high level operation. Practical embodiments operate in a conventional three-way light socket with the sequences being off, low, high and low, and off, low, high, and high.
摘要:
A smoke detector comprising a smoke detection cell of the ionization type and an electrical network which provides for ac operation of the detection cell. The impedance of the smoke detection cell is very high (40,000 megohms) and changes in the presence of airborne combustion products. The network senses the impedance change by a measurement of the current through the chamber assuming an ac source under a short circuit load condition, a technique facilitating the use of bipolar transistors.
摘要:
The present invention relates to an AM-FM receiver of the superheterodyne variety having a novel bias supply circuit wherein a common filter capacitor may be used for the bias supply, the AGC function in AM operation, and the AFC function in FM operation. The B+ bias is supplied through a controllable current source which adjusts the bias in accordance with the detector output. In the FM mode setting, automatic frequency control of the local oscillator is provided by bias adjustment. In the AM mode setting, automatic gain control of the IF amplifier and of the AM section of the tuner is provided by bias adjustment. The invention has preferred application to integrated circuit fabrication.
摘要翻译:本发明涉及一种具有新型偏置电源电路的超外差种类的AM-FM接收机,其中公共滤波电容器可用于偏置电源,AM操作中的AGC功能和FM操作中的AFC功能。 B +偏压通过可控电流源提供,可根据检测器输出调节偏置。 在FM模式设置中,通过偏置调整提供本地振荡器的自动频率控制。 在AM模式设置中,通过偏置调整提供了IF放大器和调谐器的AM部分的自动增益控制。 本发明优选应用于集成电路制造。