Abstract: An active protection circuit for a MOSFET isolated switched power supply system operates to control the switching of the MOSFET isolation switches. A monitoring circuit operates to sense and turn off the isolation switch of the currently active power supply if it senses reverse current flowing through the switch. Simultaneously, a controller receives indication that the active power supply is out of specification, and actively switches the system voltage source to the other power supply. The controller actively ensures that the isolation switch of the out-of-specification power supply remains off until it determines otherwise.

Abstract: Disclosed is a switching array for the switching of electrical signals from any input to any output. Large arrays are built upon a recursive use of small arrays that are connected such that several paths are available for the routing of each signal. The resultant arrays may be fault tolerant in that the failure of a single switch does not impede the ability for the system to make connections from one point to another.

Abstract: Disclosed is a serial communications protocol for connecting a master and a plurality of slaves using three communication lines. The protocol establishes a method for communication between the master and any slave. Any device on the communication bus may initiate the communication. A method of arbitrating any bus collisions is also given.

Abstract: A DC—DC voltage converter has a controller, two switches, a transformer and two rectifying diodes. The transformer has a first winding, a second winding and a center tap. Input voltage is connected between the center tap and ground. An anode of each diode is connected to the outer ends of the two windings and the cathodes of the two diodes are connected together to provide a positive output with respect to ground. Each switch is connected between an outer end of one winding and ground. The controller generates control signals to turn the switches on and off for limited periods of time in phase opposition to alternately connect the outer ends of the first and second winding to ground to cause current to flow alternatively in one of the windings and induce a voltage in the other winding that is additive to the input voltage, thereby providing an output voltage greater than the input voltage.

Abstract: Techniques are provided for simultaneously ascertaining the status of a plurality of devices coupled to a data bus. A master device transmits at least one status request message over the data bus to a plurality of slave devices. In response, the plurality of slave devices transmit to the master device a status indicator message including a plurality of status indicators indicating statuses of the plurality of slave devices. The master device receives the status indicator message and ascertains the status of at least some of the plurality of slave devices by examining the status indicators. The status request message and/or status indicator message may be a message defined according to a protocol associated with the data bus. The data bus may, for example, be a serial data bus such as an I2C bus.

Abstract: Techniques are provided for simultaneously addressing multiple devices on a data bus, such as by transmitting over a data bus a single message that is received and processed by multiple devices on the bus. Multiple devices may be simultaneously addressed using the standard bus architecture and protocol, without affecting the operation of other devices on the bus. In particular, a master device may address a first subset of the plurality of devices on the bus using a primary address shared by the first subset of the plurality of devices. The master device may address a second subset of the plurality of devices using a secondary address shared by the second subset of the plurality of devices. The second subset is a subset of the first subset. The master device may then transmit information over the bus to the second subset of the plurality of devices.

Abstract: An active protection circuit for a MOSFET isolated switched power supply system operates to control the switching of the MOSFET isolation switches. A monitoring circuit operates to sense and turn off the isolation switch of the currently active power supply if it senses reverse current flowing through the switch. Simultaneously, a controller receives indication that the active power supply is out of specification, and actively switches the system voltage source to the other power supply. The controller actively ensures that the isolation switch of the out-of-specification power supply remains off until it determines otherwise.

Abstract: A three-axis algebraic model is used to numerically compensate for magnetic errors in measured magnetic field values in an electronic compass for any orientation of the compass. This model is based on physical principles and uses a linear algebra approach that facilitates computation of the parameters needed for compensation. During a calibration procedure of the electronic compass, magnetic and gravity fields are measured in three axes at each of a variety of combinations of orientations and azimuths. This set of measured magnetic and gravity fields is used to calculate a matrix compensation coefficient and a vector compensation coefficient using a system of equations. These compensation coefficients are stored and then used during normal operations of the electronic compass to correct all subsequently measured magnetometer data to obtain corrected values for the Earth's magnetic field, from which the correct azimuth can be calculated.

Abstract: A three-axis physical model is used to numerically compensate for errors in measured magnetic field values in an electronic compass for operation at any orientation. This compensation method generates certain quantities that characterize the magnetic field of the Earth in the vertical plane. These quantities are used to monitor the accuracy of the electronic compass during normal operation by comparing their current values either with values obtained during the calibration procedure or with values obtained from historical averages. Significant departure from the calibration values or from the historical averages indicates a probable loss of accuracy of the compass, and the user is so alerted.

Abstract: A DC-DC voltage converter comprises a controller, two switches, a transformer and two rectifying diodes. The transformer has a first winding, a second winding and a center tap. Input voltage in connected between the center tap and ground. An anode of each diode is connected to the outer ends of the two windings and the cathodes of the two diodes are connected together to provide a positive output with respect to ground. Each switch is connected between an outer end of one windings and ground. The controller generates control signals to turn the switches on and off for limited periods of time in phase opposition to alternately connect the outer ends of the first and second winding to ground to cause current to flow alternatively in one of the windings and induce a voltage in the other winding that is additive to the input voltage, thereby providing an output voltage greater than the input voltage.

Abstract: A dual power source system includes a first power source and a second power source operably coupled with an electrical device, as well as a switching mechanism capable of selecting between the first and second power sources. An uninterruptible power supply (UPS) is place in line with one of the first and second power sources leading to the electrical device. Sense circuitry is capable of identifying a power failure condition in either the first or second power sources. A controller utilizes signals from the sense circuitry to selectively switch between the first and second power sources while configuring the UPS in a manner of providing for a plurality of operational states that accommodate the electrical device with operational power despite any combination of power failures in the first and second power sources.

Abstract: A power system has a first power supply operatively connect in parallel to a second power supply. The output of the first power supply is connected to the input of a switching device, such as a mosfet. The output of the switching device is the output of the power system. A measuring device, such as a differential amplifier measures the polarity between the input and output of the switching device. A controller connected to the switching device permits the switching device to conduct current if a first polarity is present between the input and the output. The controller interrupts current flow if a second polarity is present between the input and the output.

Abstract: An active protection circuit for a MOSFET isolated switched power supply system operates to control the switching of the MOSFET isolation switches. A monitoring circuit operates to sense and turn off the isolation switch of the currently active power supply if it senses reverse current flowing through the switch. Simultaneously, a controller receives indication that the active power supply is out of specification, and actively switches the system voltage source to the other power supply. The controller actively ensures that the isolation switch of the out-of-specification power supply remains off until it determines otherwise.

Abstract: A power system has a first power supply operatively connect in parallel to a second power supply. The output of the first power supply is connected to the input of a switching device, such as a mosfet. The output of the switching device is the output of the power system. A measuring device, such as a differential amplifier measures the polarity between the input and output of the switching device. A controller connected to the switching device permits the switching device to conduct current if a first polarity is present between the input and the output. The controller interrupts current flow if a second polarity is present between the input and the output.

Abstract: A three-axis algebraic model is used to numerically compensate for magnetic errors in measured magnetic field values in an electronic compass for any orientation of the compass. This model is based on physical principles and uses a linear algebra approach that facilitates computation of the parameters needed for compensation. During a calibration procedure of the electronic compass, magnetic and gravity fields are measured in three axes at each of a variety of combinations of orientations and azimuths. This set of measured magnetic and gravity fields is used to calculate a matrix compensation coefficient and a vector compensation coefficient using a system of equations. These compensation coefficients are stored and then used during normal operations of the electronic compass to correct all subsequently measured magnetometer data to obtain corrected values for the Earth's magnetic field, from which the correct azimuth can be calculated.

Abstract: A three-axis physical model is used to numerically compensate for errors in measured magnetic field values in an electronic compass for operation at any orientation. This compensation method generates certain quantities that characterize the magnetic field of the Earth in the vertical plane. These quantities are used to monitor the accuracy of the electronic compass during normal operation by comparing their current values either with values obtained during the calibration procedure or with values obtained from historical averages. Significant departure from the calibration values or from the historical averages indicates a probable loss of accuracy of the compass, and the user is so alerted.

Abstract: A DC-DC voltage converter comprises a controller, two switches, a transformer and two rectifying diodes. The transformer has a first winding, a second winding and a center tap. Input voltage in connected between the center tap and ground. An anode of each diode is connected to the outer ends of the two windings and the cathodes of the two diodes are connected together to provide a positive output with respect to ground. Each switch is connected between an outer end of one windings and ground. The controller generates control signals to turn the switches on and off for limited periods of time in phase opposition to alternately connect the outer ends of the first and second winding to ground to cause current to flow alternatively in one of the windings and induce a voltage in the other winding that is additive to the input voltage, thereby providing an output voltage greater than the input voltage.

Abstract: A method and apparatus for controlling the speed of a voltage-controlled fan by locking the pulse-width modulated speed control voltage to a tachometer signal of the fan is presented. By triggering the off time of the PWM pulse to the detection of the tachometer signal and ensuring the off time is less than one tachometer period, no phase and frequency information is lost.

Abstract: A golf putting aid device for remotely retrieving and placing a golf ball on a green, and for marking the location of the ball after reaching the green. The device comprises an essentially circular housing having a primary recess for capturing and temporarily holding the golf ball. A secondary recess is provided for securing the device to a hand held shaft, such as for convenience the hand grip of a putter. The device includes a mechanical mechanism that includes a pair of cooperating pivotal members, that are reversely pivotal during capture and releasing of the golf ball, and a fixed, contact activating latching member. One of the pivotal member mounts a magnet for depositing and picking up a magnetizible ball marker.

Abstract: A system and method for injecting and canceling a bias voltage in an attenuated circuit is presented. The attenuated circuit is disposed within a tri-state logic-level measurement apparatus. The bias voltage is provided to ensure that when the measurement apparatus is floating, it floats at the tri-state voltage. In one embodiment, a summing network is connected to an attenuator, a first voltage generator which provides a bias voltage and a second voltage generator which provides a cancellation voltage. In another embodiment, a FET amplifier is provided in place of the summing network.