Patents by Inventor Thomas L. Hopkins
Thomas L. Hopkins has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 7541745Abstract: A fluorescent lamp assembly includes a fluorescent lamp ballast capable of detecting at least one of a plurality of input signals and generating an output signal. The output signal is associated with a power level that is based on the at least one detected input signal. The fluorescent lamp assembly also includes a fluorescent lamp capable of receiving the output signal and generating light. An intensity of the light is based on the power level associated with the output signal.Type: GrantFiled: November 21, 2007Date of Patent: June 2, 2009Assignee: STMicroelectronics, Inc.Inventor: Thomas L. Hopkins
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Publication number: 20080219480Abstract: An audio selection circuit. The audio selection circuit includes a control/switch circuit having a first input, a second input, and a first output, and a signal detector module configured to detect an audio signal on the second input. If the signal detector detects presence of the audio signal on the second input, the signal detector is configured to transmit a control signal to the control/switch circuit, and the control/switch circuit is configured in response to the control signal to disconnect the first input from the first output and to connect the second input to the first output. Otherwise, the control/switch circuit is configured to connect the first input to the first output and to disconnect the second input from the first output.Type: ApplicationFiled: March 8, 2007Publication date: September 11, 2008Applicant: STMicroelectronics, Inc.Inventor: Thomas L. Hopkins
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Patent number: 7323823Abstract: A fluorescent lamp assembly includes a fluorescent lamp ballast capable of detecting at least one of a plurality of input signals and generating an output signal. The output signal is associated with a power level that is based on the at least one detected input signal. The fluorescent lamp assembly also includes a fluorescent lamp capable of receiving the output signal and generating light. An intensity of the light is based on the power level associated with the output signal.Type: GrantFiled: February 17, 2005Date of Patent: January 29, 2008Assignee: STMicroelectronics, Inc.Inventor: Thomas L. Hopkins
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Patent number: 7242175Abstract: A device and method that determine a freewheeling rotation of an electric motor. The method includes steps of measuring first and second signals from respective first and second windings of an unenergized motor, and determining from the first and second signals whether the unenergized motor is rotating. The method may also include determining from the first and second signals the direction of rotation if the unenergized motor is rotating. The method may further include measuring a third signal from a third winding of the unenergized motor, and determining whether the motor is rotating may include determining that the motor is not rotating if the first, second, and third signals are equal. The first and second signals may each include a respective back voltage.Type: GrantFiled: August 8, 2003Date of Patent: July 10, 2007Assignee: STMicroelectronics, Inc.Inventors: Jianwen Shao, Thomas L. Hopkins
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Patent number: 7233125Abstract: A system controls an induction motor driven by a power inverter circuit. An operational amplifier circuit is operatively connected to the power inverter circuit and operative therewith for sensing DC current and controlling acceleration and deceleration of the induction motor. The operational amplifier circuit includes a first operational amplifier operative in a motoring mode to have a positive polarity output and remain substantially at zero during a regeneration mode. A second operational amplifier circuit is operative in a regeneration mode to have a negative polarity output and remain substantially at zero in a motoring mode.Type: GrantFiled: September 1, 2005Date of Patent: June 19, 2007Assignee: STMicroelectronics, Inc.Inventors: Ramesh T. Ramamoorthy, Thomas L. Hopkins
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Patent number: 6633145Abstract: A system and method of advancing the commutation sequence of a brushless DC motor is provided. The motor having a plurality of coils, each of the coils coupled together at one end to a common center tap and coupled at an opposite end, through a respective coil tap, to both a source voltage and ground via selectively actuateable switches having diodes coupled in parallel therewith. The motor operates in a pulse width modulation (PWM) mode having PWM-on states and PWM-off states. During PWM-off states, a coil tap voltage from the coil tap of a floating phase is provided to a preconditioning circuit. The preconditioning circuit adjusts the floating phase coil tap voltage to compensate for an amount of voltage substantially equal to an amount of voltage by which a voltage at the center tap deviates from zero. The preconditioning circuit further includes sharpening circuitry for amplifying the adjusted floating phase coil tap voltage.Type: GrantFiled: November 20, 2001Date of Patent: October 14, 2003Assignee: STMicroelectronics, Inc.Inventors: Jianwen Shao, Dennis C. Nolan, Kwan A. Haughton, Thomas L. Hopkins
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Publication number: 20030098666Abstract: A system and method of advancing the commutation sequence of a brushless DC motor is provided. The motor having a plurality of coils, each of the coils coupled together at one end to a common center tap and coupled at an opposite end, through a respective coil tap, to both a source voltage and ground via selectively actuateable switches having diodes coupled in parallel therewith. The motor operates in a pulse width modulation (PWM) mode having PWM-on states and PWM-off states. During PWM-off states, a coil tap voltage from the coil tap of a floating phase is provided to a preconditioning circuit. The preconditioning circuit adjusts the floating phase coil tap voltage to compensate for an amount of voltage substantially equal to an amount of voltage by which a voltage at the center tap deviates from zero. The preconditioning circuit further includes sharpening circuitry for amplifying the adjusted floating phase coil tap voltage.Type: ApplicationFiled: November 20, 2001Publication date: May 29, 2003Inventors: Jianwen Shao, Dennis C. Nolan, Kwan A. Haughton, Thomas L. Hopkins
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Patent number: 6547353Abstract: A thermal ink jet printhead system has a printhead with base member and a plurality of ink flow channels formed in the base member that connect to an ink reservoir and terminate in a nozzle through which ink is expelled. A heating element is associated with each ink flow channel. A monolithically integrated multiple output power driver circuit is formed as a semiconductor integrated circuit and connected to each heating element in the printhead. The multiple output driver circuit includes a power MOS transistor connected to each heating element. A reference circuit is operatively connected to each gate of the power MOS transistor and includes a reference transistor having a gate and a reference amplifier that receives as inputs a reference voltage and a source of current. An amplifier output is operatively connected to the gates of the power output transistors and the gate of the reference transistor.Type: GrantFiled: July 27, 1999Date of Patent: April 15, 2003Assignee: STMicroelectronics, Inc.Inventor: Thomas L. Hopkins
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Publication number: 20020033864Abstract: A thermal ink jet printhead system has a printhead with base member and a plurality of ink flow channels formed in the base member that connect to an ink reservoir and terminate in a nozzle through which ink is expelled. A heating element is associated with each ink flow channel. A monolithically integrated multiple output power driver circuit is formed as a semiconductor integrated circuit and connected to each heating element in the printhead. The multiple output driver circuit includes a power MOS transistor connected to each heating element. A reference circuit is operatively connected to each gate of the power MOS transistor and includes a reference transistor having a gate and a reference amplifier that receives as inputs a reference voltage and a source of current. An amplifier output is operatively connected to the gates of the power output transistors and the gate of the reference transistor.Type: ApplicationFiled: July 27, 1999Publication date: March 21, 2002Inventor: THOMAS L. HOPKINS
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Patent number: 6008740Abstract: An electronic speed limit notification system comprises a transmitter for transmitting speed limit information ("SLI"), and a receiver for receiving said transmitted SLI, wherein said receiver can be physically located in a vehicle. The SLI comprises one or more speed limits, wherein each speed limit is the maximum or minimum legal speed for specific vehicles on a specific segment of a specific road traveling in a specific direction.Type: GrantFiled: December 17, 1997Date of Patent: December 28, 1999Assignee: STMicroelectronics, Inc.Inventor: Thomas L. Hopkins
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Patent number: 5898329Abstract: A circuit for producing multiple pulse width modulated outputs. The circuit includes a logic device for each pulse width modulated output. Each of the logic devices includes a first input, a second input, and a clock input, and each of logic device produces a logical high output in response to a logical high at its first input in coincidence with a clock signal at its clock input. The logical high output of the logic device remains high until a logical high is applied at its second input in coincidence with a clock signal at the clock input, whereupon the logic device produces a logical low output. The logical low output of the logic device remains low until a logical high is again applied at its first input in coincidence with a clock signal at the clock input. The circuit includes programmable circuitry for selectively applying logical high and low signals to the first and second inputs of the logic devices.Type: GrantFiled: December 31, 1996Date of Patent: April 27, 1999Assignee: STMicroelectronics, Inc.Inventor: Thomas L. Hopkins
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Patent number: 5770959Abstract: A restart circuit for an electronic device having a first switch, a second switch, an activation device for initiating a restarting operation of the electronic device when at least one of the first switch and the second switch is in a closed position, and a storage device, capable of being read by the electronic device any time after the restarting operation, for storing in digital format the position of the first switch and the second switch during the initiation of the restarting operation.Type: GrantFiled: March 10, 1997Date of Patent: June 23, 1998Assignee: SGS-Thomson Microelectronics, Inc.Inventors: Thomas L. Hopkins, Giorgio Pedrazzini
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Patent number: 5633639Abstract: According to the present invention, a modification of standard successive approximation analog to digital converter circuitry may be utilized to measure an unknown analog value and to produce a digital value after conversion that automatically contains an offset value with respect to a given measurement range. The offset achieved by the successive approximation A/D converter is proportional to an external reference which is used as the reference for the successive approximation A/D converter. The digital value produced according to the present invention is not representative of a raw measurement value but rather is representative of a value with respect to a given measurement range; thus, a digital value of 0 may indicate the minimum value of a given measurement range rather than a value of 0 Ohms, 0 volts, or 0 Amps. This may be expressed in equation form where the desired conversion value is represented by:k(X.sub.unknown -X.sub.offset)where k is a constant, X.sub.Type: GrantFiled: November 30, 1994Date of Patent: May 27, 1997Assignee: SGS-Thomson Microelectronics, Inc.Inventor: Thomas L. Hopkins
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Patent number: 5614902Abstract: According to the present invention, standard analog to digital converter circuitry may be utilized to measure an unknown analog value and to produce a digital value after conversion that automatically contains an offset value with respect to a given measurement range. The digital value produced according to the present invention is not representative of a raw measurement value but rather is representative of a value with respect to a given measurement range; thus, a digital value of 0 may indicate the minimum value of a given measurement range rather than a value of 0 Ohms, 0 volts, or 0 Amps. This may be expressed in equation form where the desired conversion value is represented by:k(X.sub.unknown -X.sub.offset)where k is a constant, X.sub.unknown is the unknown analog value being measured, and X.sub.offset is the offset value. X.sub.offset the offset value may or may not be equal to a reference value.Type: GrantFiled: November 30, 1994Date of Patent: March 25, 1997Assignee: SGS-Thomson Microelectronics, Inc.Inventor: Thomas L. Hopkins