Patents by Inventor Derek Shaeffer
Derek Shaeffer 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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Publication number: 20140260619Abstract: A round-robin sensing device is disclosed. The round-robin sensing device comprises a MEMS device, wherein the MEMS device includes first and second sense electrodes. The round-robin sensing device also comprises a multiplexer coupled to the first and second sense electrodes, at least one sense amplifier coupled to the multiplexer, a demodulator coupled to the at least one sense amplifier, and an integrate and dump circuit coupled to the demodulator. Finally, the round-robin sensing device comprises an analog-to-digital converter (ADC) coupled to the de-multiplexer, wherein the multiplexer, the at least one sense amplifier and the demodulator provide a continuous time sense path during amplification that is resettable and wherein the integrate and dump circuit and the ADC provide a discrete time processing path.Type: ApplicationFiled: August 2, 2013Publication date: September 18, 2014Applicant: InvenSense, Inc.Inventors: Derek SHAEFFER, Stanley WANG
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Publication number: 20140260647Abstract: A pressure sensor is provided which produces a measurement of the displacement and a measurement of a natural frequency of the diaphragm which are then combined to produce a compensated measurement of the displacement of the diaphragm, thereby substantially eliminating the dependence of the compensated displacement measurement on strain.Type: ApplicationFiled: March 3, 2014Publication date: September 18, 2014Applicant: InvenSense, Inc.Inventors: Derek SHAEFFER, Stanley WANG
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Publication number: 20140260713Abstract: A gyroscope system comprises a MEMS gyroscope coupled to a drive system and a sense system. The drive system maintains the MEMS gyroscope in a state of oscillation and the sense system for receiving, amplifying, and demodulating an output signal of the MEMS gyroscope that is indicative of the rate of rotation. The gyroscope system further includes a phase-locked look (PLL) which receives a reference clock (REFCLK) from the drive system and produces a system clock (CLK). Finally, the gyroscope system includes a controller operating on the system clock sets an operating state of the drive system and the sense system and also controls a state of the PLL. One or more system state variables are maintained in a substantially fixed state during a protect mode thereby enabling rapid transitions between a low-power mode and a normal operating mode of the gyroscope system.Type: ApplicationFiled: November 22, 2013Publication date: September 18, 2014Applicant: InvenSense, Inc.Inventors: Derek SHAEFFER, Stanley WANG
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Patent number: 8797090Abstract: A charge pump circuit is disclosed. The charge pump circuit comprises a transfer capacitor receiving a first clock phase and a driving capacitor receiving a second clock phase, the second clock phase opposite to the first clock phase. The circuit includes a first switch coupling an input node to the transfer capacitor. The first switch being controlled by the driving capacitor. The circuit further includes a second switch coupling the input node to the driving capacitor. The second switch being controlled by the transfer capacitor. The circuit also includes a third switch coupling the transfer capacitor to an output node. The third switch being controlled by the driving capacitor. The third switch operating in phase opposition to the first switch. The circuit finally includes a charge storage capacitor coupled to the output node.Type: GrantFiled: March 11, 2013Date of Patent: August 5, 2014Assignee: Invensense, Inc.Inventors: Derek Shaeffer, Baris Cagdaser
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Patent number: 8774738Abstract: Embodiments of the present disclosure provide systems and methods for estimating gain and phase error in a wireless transmitter. Embodiments of the present disclosure provide a gain and phase controller that uses a digital gain and phase estimator to jointly estimate both gain and phase. The forward and feedback signals of a wireless transmitter are digitized using analog to digital (ADC) converters. The digital signals are correlated with each other to dynamically extract gain and phase estimates of the loop. The gain and phase estimates are used to correct gain and phase errors in the wireless transmitter.Type: GrantFiled: April 20, 2012Date of Patent: July 8, 2014Assignee: Broadcom CorporationInventors: Sriraman Dakshinamurthy, Mohamed Mostafa, Derek Shaeffer, Dennis Pu, Peter Capofreddi
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Patent number: 8760392Abstract: The present invention relates to a combination of a 6-axis motion sensor having a 3-axis gyroscope and a 3-axis linear accelerometer, a motion processor and a radio integrated circuit chip (IC), wherein the intelligence in the motion processor enables the communication between the motion sensor, the radio IC and the external network. The motion processor also enables power savings by adaptively controlling the data rate of the motion sensor, depending on the amount or speed of the motion activity.Type: GrantFiled: August 27, 2010Date of Patent: June 24, 2014Assignee: Invensense, Inc.Inventors: Stephen Lloyd, David Sachs, David Devries, Doug Vargha, Derek Shaeffer, Erik Anderson, Kerry Keal, Nathan Royer
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Publication number: 20140167789Abstract: A MEMS capacitive sensing interface includes a sense capacitor having a first terminal and a second terminal, and having associated therewith a first electrostatic force. Further included in the MEMS capacitive sensing interface is a feedback capacitor having a third terminal and a fourth terminal, the feedback capacitor having associated therewith a second electrostatic force. The second and the fourth terminals are coupled to a common mass, and a net electrostatic force includes the first and second electrostatic forces acting on the common mass. Further, a capacitance measurement circuit measures the sense capacitance and couples the first terminal and the third terminal. The capacitance measurement circuit, the sense capacitor, and the feedback capacitor define a feedback loop that substantially eliminates dependence of the net electrostatic force on a position of the common mass.Type: ApplicationFiled: December 19, 2012Publication date: June 19, 2014Applicant: INVENSENSE, INC.Inventors: Baris Cagdaser, Derek Shaeffer, Joseph Seeger
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Publication number: 20140141735Abstract: Systems and methods are provided for a broadband, closed-loop RF transmitter for multi-band applications that employs a single RF path to service multiple bands of operation. Embodiments of the present disclosure implement a broadband impedance matching module, which avoids the need for several costly and complex narrow-band matching networks. In an embodiment, the broadband impedance matching module includes concentric, mutually-coupled inductors. By adding this broadband impedance matching functionality, delay is significantly reduced because a single path can be used to service multiple bands.Type: ApplicationFiled: January 27, 2014Publication date: May 22, 2014Applicant: Broadcom CorporationInventors: Mohamed A. Mostafa, Derek Shaeffer
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Publication number: 20140117966Abstract: A curvature-corrected bandgap reference is disclosed. The curvature-corrected bandgap reference comprises a Brokaw bandgap circuit. The Brokaw bandgap circuit includes an output node providing a reference voltage. The Brokaw bandgap circuit further comprising a first BJT device including a first base terminal coupled to the output node and a first emitter terminal. The first BJT device operates at a first current density that is substantially proportional to absolute temperature. The curvature-corrected bandgap reference also includes a second BJT device including a second base terminal coupled to the output node and a second emitter terminal. The second BJT device operates at a second current density that is substantially independent of temperature. Finally the curvature-corrected bandgap reference includes a correction voltage proportional to a voltage difference of the first and second emitter terminals, wherein the correction voltage substantially cancels a curvature of the reference voltage.Type: ApplicationFiled: December 20, 2012Publication date: May 1, 2014Applicant: INVENSENSE, INC.Inventors: Derek SHAEFFER, Nauman AFZAL
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Patent number: 8639286Abstract: Systems and methods are provided for a broadband, closed-loop RF transmitter for multi-band applications that employs a single RF path to service multiple bands of operation. Embodiments of the present disclosure implement a broadband impedance matching module, which avoids the need for several costly and complex narrow-band matching networks. In an embodiment, the broadband impedance matching module includes concentric, mutually-coupled inductors. By adding this broadband impedance matching functionality, delay is significantly reduced because a single path can be used to service multiple bands.Type: GrantFiled: December 23, 2011Date of Patent: January 28, 2014Assignee: Broadcom CorporationInventors: Mohamed A. Mostafa, Derek Shaeffer
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Patent number: 8567246Abstract: An integrated MEMS device is disclosed. The system comprises a MEMS resonator; and a MEMS device coupled to a MEMS resonator. The MEMS resonator and MEMS device are fabricated on a common substrate so that certain characteristics of the MEM resonator and MEMS device track each other as operating conditions vary.Type: GrantFiled: December 28, 2010Date of Patent: October 29, 2013Assignee: Invensense, Inc.Inventors: Derek Shaeffer, Baris Cagdaser, Chiung C. Lo, Joseph Seeger
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Patent number: 8503952Abstract: A method and apparatus of compensating for an asymmetric frequency response of a radio are disclosed. One method includes estimating a slope control signal, the slope control signal indicating a slope of a frequency response of an amplifier chain of the radio. A difference between gain at positive frequencies and gain at negative frequencies of a complex baseband signal is adjusted with the slope control signal, wherein the complex signal includes an I component and a Q component. The adjusted complex baseband signal is frequency up-converted into a radio signal. The radio signal is amplified by the amplifier chain. The amplified radio signal is transmitted.Type: GrantFiled: April 10, 2008Date of Patent: August 6, 2013Assignee: Broadcom CorporationInventors: Peter Capofreddi, Sriraman Dakshinamurthy, Derek Shaeffer
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Publication number: 20130165058Abstract: Systems and methods are provided for a broadband, closed-loop RF transmitter for multi-band applications that employs a single RE path to service multiple bands of operation. Embodiments of the present disclosure implement a broadband impedance matching module, which avoids the need for several costly and complex narrow-band matching networks. In an embodiment, the broadband impedance matching module includes concentric, mutually coupled inductors. By adding this broadband impedance matching functionality, delay is significantly reduced because a single path can be used to service multiple bands.Type: ApplicationFiled: December 23, 2011Publication date: June 27, 2013Applicant: Broadcom CorporationInventors: Mohamed A. MOSTAFA, Derek Shaeffer
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Publication number: 20130099836Abstract: A system and method in accordance with the present invention provides a gyroscope incorporating an improved PLL technique. The improved PLL auto-corrects its own reference low-frequency noise, thereby eliminating this source of noise, improving the noise performance of the gyroscope and allowing a compact implementation. The net result is a gyroscope with improved bias stability that can meet noise requirements with a smaller footprint.Type: ApplicationFiled: December 22, 2011Publication date: April 25, 2013Applicant: InvenSense, Inc.Inventors: Derek Shaeffer, Ahingsa Soukhaphanith
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Publication number: 20120270511Abstract: Embodiments of the present disclosure provide systems and methods for estimating gain and phase error in a wireless transmitter. Embodiments of the present disclosure provide a gain and phase controller that uses a digital gain and phase estimator to jointly estimate both gain and phase. The forward and feedback signals of a wireless transmitter are digitized using analog to digital (ADC) converters. The digital signals are correlated with each other to dynamically extract gain and phase estimates of the loop. The gain and phase estimates are used to correct gain and phase errors in the wireless transmitter.Type: ApplicationFiled: April 20, 2012Publication date: October 25, 2012Applicant: Broadcom CorporationInventors: Sriraman DAKSHINAMURTHY, Mohamed Mostafa, Derek Shaeffer, Dennis Pu, Peter Capofreddi
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Publication number: 20120242400Abstract: A high-voltage MEMS system compatible with low-voltage semiconductor process technology is disclosed. The system comprises a MEMS device coupled to a high-voltage bias generator employing an extended-voltage isolation residing in a semiconductor technology substrate. The system avoids the use of high-voltage transistors so that special high-voltage processing steps are not required of the semiconductor technology, thereby reducing process cost and complexity. MEMS testing capability is addressed with a self-test circuit allowing modulation of the bias voltage and current so that a need for external high-voltage connections and associated electro-static discharge protection circuitry are also avoided.Type: ApplicationFiled: March 24, 2011Publication date: September 27, 2012Applicant: INVENSENSE, INC.Inventors: Derek SHAEFFER, Baris CAGDASER, Joseph SEEGER
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Publication number: 20120235670Abstract: Described herein are systems, devices, and methods that provide a stable magnetometer. The magnetometer includes a drive element that facilitates flow of a drive current through a node and a sense element operable to detect a magnetic field operating on the drive current. To reduce offset in the detection of the magnetic field, a voltage detector, electrically coupled to the drive element through the node, determines a variation between a node voltage and a target voltage. The voltage detector facilitates suppression of the variation and thereby minimizes the offset in the sense element.Type: ApplicationFiled: March 15, 2012Publication date: September 20, 2012Applicant: INVENSENSE, INC.Inventors: Baris Cagdaser, Derek Shaeffer, Joe Seeger, Chiung C. Lo
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Publication number: 20120176128Abstract: A micromachined magnetic field sensor comprising is disclosed. The micromachined magnetic field comprises a substrate; a drive subsystem, the drive subsystem comprises a plurality of beams, and at least one anchor connected to the substrate; a mechanism for providing an electrical current through the drive subsystem along a first axis; and Lorentz force acting on the drive subsystem along a second axis in response to a magnetic field along a third axis. The micromachined magnetic field sensor also includes a sense subsystem, the sense subsystem comprises a plurality of beams, and at least one anchor connected to the substrate; wherein a portion of the sense subsystem moves along a fourth axis; a coupling spring between the drive subsystem and the sense subsystem which causes motion of the sense subsystem in response to the magnetic field; and a position transducer to detect the motion of the sense subsystem.Type: ApplicationFiled: January 11, 2011Publication date: July 12, 2012Applicant: INVENSENSE, INC.Inventors: Joseph SEEGER, Chiung C. LO, Baris CAGDASER, Derek SHAEFFER
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Publication number: 20120176129Abstract: A micromachined magnetic field sensor is disclosed. The micromachined magnetic field sensor comprises a substrate; and a drive subsystem partially supported by the substrate with a plurality of beams, and at least one anchor; a mechanism for providing an electrical current through the drive subsystem along a first axis; and Lorentz force acting on the drive subsystem along a second axis in response to a magnetic field vector along a third axis. The micromachined magnetic field sensor also includes a position transducer to detect the motion of the drive subsystem and an electrostatic offset cancellation mechanism coupled to the drive subsystem.Type: ApplicationFiled: January 11, 2011Publication date: July 12, 2012Applicant: InvenSense, Inc.Inventors: Joseph SEEGER, Chiung C. LO, Baris CAGDASER, Derek SHAEFFER
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Publication number: 20120086446Abstract: An integrated MEMS device is disclosed. The system comprises a MEMS resonator; and a MEMS device coupled to a MEMS resonator. The MEMS resonator and MEMS device are fabricated on a common substrate so that certain characteristics of the MEM resonator and MEMS device track each other as operating conditions vary.Type: ApplicationFiled: December 28, 2010Publication date: April 12, 2012Applicant: INVENSENSE, INC.Inventors: Derek SHAEFFER, Baris CAGDASER, Chiung C. LO, Joseph SEEGER