Unitrode Corporation

Other

John A O'Connor

John P Bazinet

Robert A Mammano

Robert Allan Neidorff

Mark G Jordan

Thomas W Byrne

James R Garrett

Winthrop H McClure

Dhaval B Dalal

John H Ziegler

David S Zendzian

Disclosed is a pivotable signpost support device. The device includes a signpost support that is vertically aligned with a ground post support, wherein the signpost support is disposed above the ground post support that is affixed to a ground post. The signpost support and the ground post support are secured between first vertical support and a second vertical support. The signpost support is pivotally secured to the first and second vertical supports by means of a pivot bolt having a die spring at an end thereof, so that it can pivot forward and backward relative to the first and second vertical supports. The pivot bolt can tighten the die spring so as to keep the signpost support in an upright position but allowing the signpost support to fall into a collapsed position.

Pivotable signpost support device

An adjustable mirror assembly. The adjustable mirror assembly includes one or more mirrors that are affixed to a front portion of a vehicle and configured to view the underside of the vehicle. The mirrors allow for both vertical movement and horizontal and vertical angular adjustment. Thus, the mirrors can have a field of view of the underside of the vehicle, which may include a blade for grading road and ground surfaces. In one embodiment, the mirrors are controllable from a control box positioned within the vehicle by a vehicle operator. Further, one or more light sources can be activated to illuminate a desired area for improved vision in low and no light conditions.

Adjustable mirror assembly

A brushless DC motor controller including a track and hold circuit responsive to the voltage at the motor centertap terminal and the voltage across at least one motor winding in order to determine the position of the rotor by detecting zero crossings of the back EMF of the unenergized winding in a manner having reduced susceptibility to noise. In one embodiment, the output of the track and hold circuit is interpolated to reduce the effects of pulse width modulation noise on rotor position detection. The drive signals controlling a plurality of electronically controlled switches which effect energization of the windings are chopped in order to control the speed of the motor. In one embodiment, the switch connected to a positive voltage is chopped when the sensed back EMF is positive and the switch connected to the negative voltage is chopped when the sensed back EMF is negative. Also provided is a PWM disable circuit for selectively disabling a PWM signal used to chop the drive signals in order to further reduce the effects of noise on rotor position detection.

Brushless DC motor controller

A power factor correction controller is disclosed which extracts RMS information from a rectified AC input line voltage signal using a sample and hold analog to digital conversion approach. The controller then processes a digital word representing the RMS information through the application of a programmable mathematical function. The result is converted to analog form and provided as an input to an analog multiplier. The controller also monitors the output load power of an isolated boost converter circuit and linearly reduces the overlap delay time of a MOSFET transition switch when the load power decreases.

Controller for isolated boost converter with improved detection of RMS

A circuit breaker IC adapted for controlling an external NMOS switch coupled between a supply voltage and a load referenced to ground, with the circuit breaker being isolated from ground. With this arrangement, the voltage across the circuit breaker is limited, thereby permitting use of a low voltage integrated circuit fabrication process. The circuit breaker includes a sensor for sensing load current through the switch and providing an output signal indicative of the load current, a charge pump providing a supply voltage and an amplifier responsive to the sensor output signal and to the charge pump supply voltage for providing a drive signal to control the switch.

Floating positive circuit breaker

An integrated circuit controller for a switching power converter implementing feed-forward and synchronization features. The controller IC has pins which permit dual functionality. The feed-forward feature is implemented with a supply voltage from an unregulated auxiliary winding which additionally powers the controller. The synchronization feature is implemented by coupling an external synchronization signal to a feedback pin of the controller IC to which a feedback signal from the output of the converter is also coupled.

Controller having feed-forward and synchronization features

A battery charger/monitor circuit for charging and/or monitoring a plurality of series-connected cells, including a voltage sensor for sensing the voltage across each of the cells to provide a high cell voltage signal proportional to the highest voltage across any of the cells and a low cell voltage signal proportional to the lowest voltage across any of the cells. The circuit is operable in a monitor mode or a charge mode. In the monitor mode, the cells are disconnected from a load if the low cell voltage signal decreases to a first predetermined level. The circuit includes a controller which provides a control signal in response to the high cell voltage signal, the low cell voltage signal and a current sense signal, for controlling the charging of the cells. In the charge mode, the cells receive a constant charge current until the high cell voltage signal reaches a second predetermined level, after which the voltage across the cell charged to the highest voltage is held substantially constant, causing the charge current to be reduced.

Voltage sensor for detecting cell voltages

A synchronous step-down DC to DC converter includes a bootstrap capacitor monitored by a controller for maintaining a desired bootstrap voltage to drive a high side NMOS switch. The controller temporarily increases the duty cycle of the low side NMOS switch when the bootstrap voltage decreases below a predetermined level to maintain a minimum level of charge on the bootstrap capacitor.

DC/DC converter having a bootstrapped high side driver

This invention relates to a contoured neck pillow. The invention consists of a central pad of polyurethane foam having a compression of about seven pounds, which is relatively softer and more elastic than a surrounding ring of polyurethane foam having a compression of about fifteen to twenty pounds. Two convoluted foam sections enclose the ring and pad, and are in turn encased within a protective cover.

Contoured symmetrical differential-elasticity neck pillow

A switching regulator having improved dynamic response to load variations includes a load compensation circuit coupled to the output terminal. The load compensation circuit supplies current to a load coupled to the output terminal when the output voltage is less than a first predetermined level and/or diverts current away from the load when the output voltage is greater than a second predetermined level. The load compensation circuit operates in this manner until the output voltage is between the first and second predetermined levels. The load compensation circuit responds faster to load variations than the switching regulator to accommodate sudden changes in the load demand.

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Merrimack, NH, United States of America

John A O'Connor