Patents by Inventor Gireesh Rajendran

Gireesh Rajendran 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).

  • Patent number: 8121558
    Abstract: A local oscillator (LO) generator architecture using a wide tuning range oscillator is disclosed. In one embodiment, a wide tuning oscillator based LO generator system includes a wide tuning range oscillator for generating a signal with a first initial frequency or a second initial frequency in response to a control voltage, a first frequency controlling circuit for converting the first initial frequency of the signal into a final frequency, and a second frequency controlling circuit for converting the second initial frequency of the signal into the final frequency.
    Type: Grant
    Filed: May 12, 2008
    Date of Patent: February 21, 2012
    Assignee: Texas Instruments Incorporated
    Inventors: Gireesh Rajendran, Nir Tal, Ashish Lachhwani
  • Publication number: 20120019324
    Abstract: An amplifier includes a first pair of transistors (the first pair) that defines a first output, each transistor of the first pair having a gate coupled to a first input terminal; a second pair of transistors (the second pair) that defines a second output, each transistor of the second pair having a gate coupled to a second input terminal; a first capacitor coupled to the second output terminal and to the gate of a first transistor of the first pair; a second capacitor coupled to the second output terminal and to the gate of a second transistor of the first pair; a third capacitor coupled to the first output terminal and to the gate of a third transistor of the second pair; and a fourth capacitor coupled to the first output terminal and to the gate of a fourth transistor of the second pair.
    Type: Application
    Filed: September 28, 2011
    Publication date: January 26, 2012
    Applicant: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Rakesh KUMAR, Gireesh RAJENDRAN, Rittu Sachdev SINGH
  • Patent number: 8049562
    Abstract: An amplifier includes a first pair of transistors (the first pair) that defines a first output, each transistor of the first pair having a gate coupled to a first input terminal; a second pair of transistors (the second pair) that defines a second output, each transistor of the second pair having a gate coupled to a second input terminal; a first capacitor coupled to the second output terminal and to the gate of a first transistor of the first pair; a second capacitor coupled to the second output terminal and to the gate of a second transistor of the first pair; a third capacitor coupled to the first output terminal and to the gate of a third transistor of the second pair; and a fourth capacitor coupled to the first output terminal and to the gate of a fourth transistor of the second pair.
    Type: Grant
    Filed: January 7, 2010
    Date of Patent: November 1, 2011
    Assignee: Texas Instruments Incorporated
    Inventors: Rakesh Kumar, Gireesh Rajendran, Rittu Sachdev Singh
  • Publication number: 20110243120
    Abstract: A single-antenna solution is provided for near-field and far-field communication in wireless devices. In an embodiment, a first transceiver block generates a first transmit signal to be transmitted using radiative techniques. A second transceiver block generates a second transmit signal to be transmitted using inductive coupling. The first and second transceiver blocks are coupled to a same antenna for transmitting the first transmit signal using radiative coupling, and the second transmit signal using inductive coupling. The first transceiver block and the second transceiver block operate according to time division multiplexing, and in an embodiment corresponding to an FM transceiver and an NFC transceiver.
    Type: Application
    Filed: April 5, 2010
    Publication date: October 6, 2011
    Inventors: Brian Paul Ginsburg, Gangadhar Burra, Assaf Sella, Subhashish Mukherjee, Gireesh Rajendran, Yogesh Darwhekar, Apu Sivadas
  • Publication number: 20110237206
    Abstract: A switched power amplifier contained in a circuit is implemented to receive a single-ended input signal and generate a single-ended output signal, the single-ended output signal being a power-amplified version of the single-ended input signal. The switched power amplifier provides high efficiency.
    Type: Application
    Filed: March 23, 2010
    Publication date: September 29, 2011
    Inventors: Gireesh Rajendran, Apu Sivadas, Subhashish Mukherjee, Krishnaswamy Thiagarajan
  • Publication number: 20110207420
    Abstract: An active filter circuit includes an inductance-capacitance (LC) circuit (110) for wireless frequency input, a bi-directional mixer (120) and a filter impedance (130) series-coupled across at least part of the LC circuit (110), and another mixer (420) coupled to at least some portion of the LC circuit. Other circuits, processes, receivers, transmitters and transceivers are disclosed.
    Type: Application
    Filed: April 9, 2010
    Publication date: August 25, 2011
    Applicant: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Gireesh Rajendran, Ashish Lachhwani, Rakesh Kumar
  • Publication number: 20110187463
    Abstract: Oscillator circuit for radio frequency transceivers. An oscillator circuit includes a first oscillator that generates a signal having a first frequency and a second oscillator that generates a signal having a second frequency. The oscillator circuit includes a mixer that is responsive to the signal having the first frequency and the signal having the second frequency to provide a signal having a third frequency and one or more frequency components. The oscillator circuit includes a filter that is responsive to the signal from the mixer to attenuate the one or more frequency components and provide a signal having a desired frequency. The oscillator circuit includes a correction circuit to correct a drift in at least one of the first frequency and the second frequency by controlling the second frequency, thereby correcting the drift in the third frequency and the desired frequency.
    Type: Application
    Filed: February 4, 2010
    Publication date: August 4, 2011
    Applicant: Texas Instruments Incorporated
    Inventors: Gireesh Rajendran, Debapriya Sahu, Alok Prakash Joshi, Ashish Lachwani
  • Publication number: 20110171994
    Abstract: Multi-mode transceiver and a circuit for operating the multi-mode transceiver. A multi-mode transceiver includes a first circuit that is configurable to operate as one of a transmitter and a receiver in a first mode, and a second circuit that is configurable to operate as one of the transmitter and the receiver in a second mode. The multi-mode transceiver includes a first element coupled to the first circuit. The multi-mode transceiver includes a second element coupled to the first element and one or more ports. The multi-mode transceiver also includes a first switch, coupled to the second element and to the second circuit, that is configurable to operate the transceiver in at least one of the first mode and the second mode in conjunction with the first element and the second element.
    Type: Application
    Filed: January 8, 2010
    Publication date: July 14, 2011
    Applicant: Texas Instruments Incorporated
    Inventors: Gireesh RAJENDRAN, Timothy Don DAVIS, Apu SIVADAS, Michel FRECHETTE, Thiagarajan KRISHNASWAMY, Salvatore PENNISI, Rakesh KUMAR, Bijit Thakorbhai PATEL, Subhashish MUKHERJEE, Debapriya SAHU
  • Publication number: 20110163808
    Abstract: An amplifier includes a first pair of transistors (the first pair) that defines a first output, each transistor of the first pair having a gate coupled to a first input terminal; a second pair of transistors (the second pair) that defines a second output, each transistor of the second pair having a gate coupled to a second input terminal; a first capacitor coupled to the second output terminal and to the gate of a first transistor of the first pair; a second capacitor coupled to the second output terminal and to the gate of a second transistor of the first pair; a third capacitor coupled to the first output terminal and to the gate of a third transistor of the second pair; and a fourth capacitor coupled to the first output terminal and to the gate of a fourth transistor of the second pair.
    Type: Application
    Filed: January 7, 2010
    Publication date: July 7, 2011
    Applicant: Texas Instruments Incorporated
    Inventors: Rakesh Kumar, Gireesh Rajendran, Rittu Sachdev Singh
  • Publication number: 20110102088
    Abstract: Low noise amplifier circuit. The low noise amplifier circuit includes an amplifier that amplifies an input to provide an output. The amplifier is coupled to an input terminal. The circuit also includes a device in a cascode connection with the amplifier. The circuit further includes a tuning circuit coupled to the device to phase shift the output. Further, the circuit includes a feedback circuit that is responsive to a phase-shifted output to enhance gain of the amplifier. The feedback circuit is coupled to the tuning circuit and the amplifier.
    Type: Application
    Filed: November 5, 2009
    Publication date: May 5, 2011
    Applicant: Texas Instruments Incorporated
    Inventors: Gireesh RAJENDRAN, Ashish LACHHWANI, Rakesh KUMAR
  • Publication number: 20110039511
    Abstract: A low-power receiver front-end includes a transconductance amplifier that produces a single-ended current signal in response to a single-ended voltage signal. An output of the transconductance amplifier is provided to an LC tuned circuit. At resonance, the LC tuned circuit generates a differential current signal in response to the single-ended current signal. Single-ended current signals corresponding to the resonant frequency of the LC tuned circuit are converted into differential signals. Further, the LC tuned circuit amplifies the differential current signals by an associated quality factor. Further, a mixer is coupled to an output of the LC tuned circuit. The mixer generates IF signals in response to the differential current signals.
    Type: Application
    Filed: August 13, 2009
    Publication date: February 17, 2011
    Applicant: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Gireesh Rajendran, Ashish Lachwani, Rittu Kulwant Sachdev, Rakesh Kumar
  • Publication number: 20100075724
    Abstract: A method, system, and apparatus of a DC current based on chip RF power detection scheme for a power amplifier are disclosed. In one embodiment, a method includes generating a scaled current from an other current associated with power amplifier, transforming the scaled current (e.g., the scaled current may be scaled to the other current value) into a digital signal and using the digital signal to set a radio frequency power value of an antenna of the antenna module. The method may include transforming the scaled current into a voltage signal. The method may also include transforming the voltage signal into the digital signal. The method may also include generating a current mirror from a low dropout regulator.
    Type: Application
    Filed: September 22, 2008
    Publication date: March 25, 2010
    Inventors: APU SIVADAS, Gireesh Rajendran, Ashish Lachhwani, David Cohen
  • Publication number: 20100027568
    Abstract: A circuit for sharing Tx/Rx ports of a CMOS based time multiplexed transceiver includes a Low Noise Amplifier (LNA) and a Power amplifier (PA), and deploys a single RF choke shared between the LNA and PA. The circuit selectively functions as a PA cascode or a LNA input device. In one form the circuit uses MOS transistors configured for use in one of Blue tooth, WLAN and TDMA applications, taking advantage of source-drain symmetry of the MOS transistors. The circuit may include a DC path and be used in WLAN applications, wherein the sharing of the single choke is enabled by one switch in the DC path. As described, the single RF choke is disposed outside of the LNA and the PA. The circuit supports high out powers and causes reduced signal loss due to just one LC tank as opposed to two LC tanks present in the prior art.
    Type: Application
    Filed: July 29, 2008
    Publication date: February 4, 2010
    Inventors: Gireesh Rajendran, Apu Sivadas, Rittu Kulwant Sachdev, Krishnaswamy Thiagarajan
  • Publication number: 20090289721
    Abstract: An electronic circuit comprising a transistor-based RF (radio frequency) power amplifier (112) having balanced outputs (172, 176), a transistor-based receiver RF amplifier (116) having balanced inputs (152, 156) ohmically connected to said balanced outputs (172, 176) respectively of said RF power amplifier (112), and a balun (114) having a primary (182, 186) and a secondary (188), said primary (182, 186) having primary connections and a supply connection (185) of said primary (182, 186) intermediate said primary connections and said primary connections ohmically connected both to said balanced outputs (172, 176) of said RF power amplifier (112) respectively and to said balanced inputs (152, 156) of said receiver RF amplifier, thereby to switchlessly couple RF between the balun (114) and the RF power amplifier (112) and switchlessly couple RF between the balun (114) and the receiver RF amplifier (116). Other electronic circuits, processes, devices and systems are disclosed.
    Type: Application
    Filed: May 5, 2009
    Publication date: November 26, 2009
    Applicant: Texas Instruments Incorporated
    Inventors: Gireesh Rajendran, Apu Sivadas, Subhashish Mukherjee
  • Publication number: 20090280752
    Abstract: A local oscillator (LO) generator architecture using a wide tuning range oscillator is disclosed. In one embodiment, a wide tuning oscillator based LO generator system includes a wide tuning range oscillator for generating a signal with a first initial frequency or a second initial frequency in response to a control voltage, a first frequency controlling circuit for converting the first initial frequency of the signal into a final frequency, and a second frequency controlling circuit for converting the second initial frequency of the signal into the final frequency.
    Type: Application
    Filed: May 12, 2008
    Publication date: November 12, 2009
    Inventors: Gireesh Rajendran, Nir Tal, Ashish Lachhwani
  • Publication number: 20090201088
    Abstract: According to an aspect of the present invention, the magnitude and phase angle of looking-in impedance driven by an amplifier are computed in digital domain during normal operation within a module containing the amplifier. In an embodiment, the computed magnitude and phase angle are used for impedance matching at a node driven by the amplifier. As a result, impedance matching may be obtained even in situations when the impedance changes during operation.
    Type: Application
    Filed: February 10, 2009
    Publication date: August 13, 2009
    Applicant: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Apu Sivadas, Gireesh Rajendran, Subhashish Mukherjee
  • Patent number: 6876223
    Abstract: EMI caused on a sensitive pin by large electric current flowing through a load pin when driving a high load is reduced or substantially eliminated. An equal amount of current, but in opposite direction, is caused to be flown in another pin (“third pin”) located close to the load pin. As a result, the EMI caused by the third pin cancels the EMI generated by the load pin. During a discharge phase, a fourth pin carries and equal amount of current, but in opposite direction, to that in the load pin. The third and fourth pins may be formed by power supply pin and ground pin. A control path may avoid a path from the third pin to the fourth pin during both the charging and discharging phases. In addition, the high load may be driven by a programmable driver which uses an amount of current proportionate to the extent of load, thereby avoiding parasitic currents. EMI is further reduced as a result.
    Type: Grant
    Filed: July 25, 2002
    Date of Patent: April 5, 2005
    Assignee: Texas Instruments Incorporated
    Inventors: Gireesh Rajendran, Anil Kumar, Debapriya Sahu, Srinivasan Venkatraman
  • Publication number: 20040017671
    Abstract: EMI caused on a sensitive pin by large electric current flowing through a load pin when driving a high load is reduced or substantially eliminated. An equal amount of current, but in opposite direction, is caused to be flown in another pin (“third pin”) located close to the load pin. As a result, the EMI caused by the third pin cancels the EMI generated by the load pin. During a discharge phase, a fourth pin carries and equal amount of current, but in opposite direction, to that in the load pin. The third and fourth pins may be formed by power supply pin and ground pin. A control path may avoid a path from the third pin to the fourth pin during both the charging and discharging phases. In addition, the high load may be driven by a programmable driver which uses an amount of current proportionate to the extent of load, thereby avoiding parasitic currents. EMI is further reduced as a result.
    Type: Application
    Filed: July 25, 2002
    Publication date: January 29, 2004
    Applicant: Texas Instruments Incorporated
    Inventors: Gireesh Rajendran, Anil Kumar, Debapriya Sahu, Srinivasan Venkatraman