Patents by Inventor Krishnaswamy Thiagarajan

Krishnaswamy Thiagarajan 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: 9667300
    Abstract: A frequency synthesizer that includes a reference frequency scaler and a phase locked loop (PLL) coupled to the reference frequency scaler. The reference frequency scaler is configured to generate a first reference frequency and a second reference frequency. The PLL is configured to generate a first output frequency based on the first reference frequency during a first timeslot and a second output frequency based on the second reference frequency during a second timeslot. The PLL comprises a loop filter that includes a first switch connected in series to a first capacitor and configured to close during the first timeslot and a second switch connected in series to a second capacitor and configured to open during the first timeslot.
    Type: Grant
    Filed: June 29, 2015
    Date of Patent: May 30, 2017
    Assignee: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Jagdish Chand Goyal, Krishnaswamy Thiagarajan, Jayawardan Janardhanan, Srikanth Manian
  • Patent number: 9509323
    Abstract: A fractional-N frequency synthesizer that suppresses integer boundary spurs. A frequency synthesizer includes a fractional-N phase locked loop (PLL) and a reference frequency scaler. The reference frequency scaler is coupled to a reference clock input of the PLL, the reference frequency scaler includes a programmable frequency divider, and a programmable frequency multiplier connected in series with the programmable frequency divider. Each of the divider and multiplier is configured to scale a reference frequency provided to the PLL by a programmable integer value.
    Type: Grant
    Filed: May 12, 2015
    Date of Patent: November 29, 2016
    Assignee: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Krishnaswamy Thiagarajan, Jagdish Chand Goyal, Srikanth Manian, Debapriya Sahu
  • Patent number: 9450546
    Abstract: According to an aspect of present disclosure, a set of power amplifiers are used to amplify power of a signal for transmission. The signal powers from a set of power amplifiers are coupled to set of primary windings which are commonly coupled to a secondary winding such that the powers on the primary windings are additive in the secondary winding. A current path on the primary side is provided for flow of a current that is induced on at least one primary winding when a power amplifier coupled to that primary winding is in “off” state. As a result, the induced current is prevented from flowing in to the power amplifier that are in “on” state. Further, the current path isolates the power amplifiers from each other thereby enabling the power amplifiers to operate at the rated efficiency. In one embodiment, the current path is provided using a resistor network.
    Type: Grant
    Filed: January 27, 2014
    Date of Patent: September 20, 2016
    Assignee: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Apu Sivadas, Alok Joshi, Krishnaswamy Thiagarajan, Rakesh Kumar
  • Publication number: 20160126895
    Abstract: An I converter outputs I sign data and I magnitude data based on received I data. A Q converter outputs Q sign data and Q magnitude data based on received Q data. An I clock generates an I phase based ort the I sign data. A Q clock generates a Q phase based on the Q sign data. An I modulator generates an I magnitude pulse stream based on the I magnitude data. A Q modulator generates a Q magnitude pulse stream based on the Q magnitude data. A digital logic component generates an output signal based on the I phase, the I magnitude pulse stream, the Q phase and the Q magnitude pulse stream. A power amplifier generates an amplified signal based on the output signal.
    Type: Application
    Filed: October 30, 2014
    Publication date: May 5, 2016
    Inventors: Gireesh Rajendran, Rakesh Kumar, Alok Prakask Joshi, Subhashish Mukherjee, Krishnaswamy Thiagarajan, Apu Sivadas
  • Publication number: 20150381190
    Abstract: A frequency synthesizer that includes a reference frequency scaler and a phase locked loop (PLL) coupled to the reference frequency scaler. The reference frequency scaler is configured to generate a first reference frequency and a second reference frequency. The PLL is configured to generate a first output frequency based on the first reference frequency during a first timeslot and a second output frequency based on the second reference frequency during a second timeslot. The PLL comprises a loop filter that includes a first switch connected in series to a first capacitor and configured to close during the first timeslot and a second switch connected in series to a second capacitor and configured to open during the first timeslot.
    Type: Application
    Filed: June 29, 2015
    Publication date: December 31, 2015
    Inventors: Jagdish Chand GOYAL, Krishnaswamy THIAGARAJAN, Jayawardan JANARDHANAN, Srikanth MANIAN
  • Publication number: 20150326236
    Abstract: A fractional-N frequency synthesizer that suppresses integer boundary spurs. A frequency synthesizer includes a fractional-N phase locked loop (PLL) and a reference frequency scaler. The reference frequency scaler is coupled to a reference clock input of the PLL, the reference frequency scaler includes a programmable frequency divider, and a programmable frequency multiplier connected in series with the programmable frequency divider. Each of the divider and multiplier is configured to scale a reference frequency provided to the PLL by a programmable integer value.
    Type: Application
    Filed: May 12, 2015
    Publication date: November 12, 2015
    Applicant: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Krishnaswamy THIAGARAJAN, Jagdish Chand GOYAL, Srikanth MANIAN, Debapriya SAHU
  • Publication number: 20150214907
    Abstract: According to an aspect of present disclosure, a set of power amplifiers are used to amplify power of a signal for transmission. The signal powers from a set of power amplifiers are coupled to set of primary windings which are commonly coupled to a secondary winding such that the powers on the primary windings are additive in the secondary winding. A current path on the primary side is provided for flow of a current that is induced on at least one primary winding when a power amplifier coupled to that primary winding is in “off” state. As a result, the induced current is prevented from flowing in to the power amplifier that are in “on” state. Further, the current path isolates the power amplifiers from each other thereby enabling the power amplifiers to operate at the rated efficiency. In one embodiment, the current path is provided using a resistor network.
    Type: Application
    Filed: January 27, 2014
    Publication date: July 30, 2015
    Applicant: Texas Instruments Incorporated
    Inventors: APU SIVADAS, Alok Joshi, Krishnaswamy Thiagarajan, Rakesh Kumar
  • Patent number: 8611445
    Abstract: A wireless transceiver includes a receiver and a transmitter, the receiver and transmitter implemented to have multiple receive and transmit channels respectively, to provide multiple-input multiple-output (MIMO) capability. In an embodiment, the transceiver is implemented to include two transmit channels and two receive channels. Some blocks/circuitry of each of the receive and transmit channels are implemented with reduced area and current consumption, with a corresponding increase in noise. In a single-input single-output (SISO) mode of operation, the receiver combines the output of both the receive channels to compensate for the increase in noise due to the implementation with smaller area and lower current consumption. Similarly, the transmitter combines the output of both the transmit channels to compensate for the increase in noise. The transceiver operates with no signal degradation in SISO mode, and with a small degradation in signal quality in the MIMO mode.
    Type: Grant
    Filed: September 29, 2010
    Date of Patent: December 17, 2013
    Assignee: Texas Instruments Incorporated
    Inventors: Gireesh Rajendran, Anand Kannan, Krishnaswamy Thiagarajan
  • Patent number: 8325752
    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: Grant
    Filed: July 29, 2008
    Date of Patent: December 4, 2012
    Assignee: Texas Instruments Incorporated
    Inventors: Gireesh Rajendran, Apu Sivadas, Rittu Kulwant Sachdev, Krishnaswamy Thiagarajan
  • Patent number: 8203384
    Abstract: An amplifier has first and second differential outputs connected to first and second ends of one side of a balun. A second side of the balun, inductively coupled to the first side of the balun, has a center tap that is electrically coupled to a conductive path to a power supply reference node for the amplifier.
    Type: Grant
    Filed: February 1, 2011
    Date of Patent: June 19, 2012
    Assignee: Texas Instruments Incorporated
    Inventors: Krishnaswamy Thiagarajan, Gireesh Rajendran, Subhashish Mukherjee, Apu Sivadas
  • Patent number: 8195109
    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: Grant
    Filed: March 23, 2010
    Date of Patent: June 5, 2012
    Assignee: Texas Instruments Incorporated
    Inventors: Gireesh Rajendran, Apu Sivadas, Subhashish Mukherjee, Krishnaswamy Thiagarajan
  • Publication number: 20120076241
    Abstract: A wireless transceiver includes a receiver and a transmitter, the receiver and transmitter implemented to have multiple receive and transmit channels respectively, to provide multiple-input multiple-output (MIMO) capability. In an embodiment, the transceiver is implemented to include two transmit channels and two receive channels. Some blocks/circuitry of each of the receive and transmit channels are implemented with reduced area and current consumption, with a corresponding increase in noise. In a single-input single-output (SISO) mode of operation, the receiver combines the output of both the receive channels to compensate for the increase in noise due to the implementation with smaller area and lower current consumption. Similarly, the transmitter combines the output of both the transmit channels to compensate for the increase in noise. The transceiver operates with no signal degradation in SISO mode, and with a small degradation in signal quality in the MIMO mode.
    Type: Application
    Filed: September 29, 2010
    Publication date: March 29, 2012
    Applicant: TEXAS INSTRUMENTS INCORPORATED
    Inventors: Gireesh Rajendran, Anand Kannan, Krishnaswamy Thiagarajan
  • 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: 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