Patents by Inventor Apu Sivadas
Apu Sivadas 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).
-
Publication number: 20150214907Abstract: 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: ApplicationFiled: January 27, 2014Publication date: July 30, 2015Applicant: Texas Instruments IncorporatedInventors: APU SIVADAS, Alok Joshi, Krishnaswamy Thiagarajan, Rakesh Kumar
-
Patent number: 9083075Abstract: A device includes multiple transceivers, a coupling block and an antenna. The transceivers operate according to time-division multiple access (TDMA) techniques. The coupling block is designed to enable the multiple transceivers to transmit or receive corresponding signals using the antenna. The multiple transceivers include a first transmitter and a second transmitter. The first transmitter is connected to the antenna via a first coupling network. The second transmitter is connected to the antenna via a series connection of a second coupling network and at least a portion of the first coupling network. Other transmitters are connected to the antenna via a series arrangement of at least a portion of the first coupling network and corresponding coupling networks.Type: GrantFiled: August 4, 2011Date of Patent: July 14, 2015Assignee: TEXAS INSTRUMENTS INCORPORATEDInventors: Alok Prakash Joshi, Gireesh Rajendran, Apu Sivadas
-
Publication number: 20150194944Abstract: Exemplary embodiments are related to wideband matching devices. A device may include a primary winding including a first plurality of inductors in series and a first switch coupled to the primary winding and configured to tune the primary winding to a frequency band of a plurality of frequency bands. The device may also include a secondary winding including a second plurality of inductors in series and a second switch coupled to the secondary winding and configured to tune the secondary winding to the frequency band.Type: ApplicationFiled: January 9, 2014Publication date: July 9, 2015Applicant: QUALCOMM INCORPORATEDInventors: Alok Joshi, Gireesh Rajendran, Apu Sivadas
-
Patent number: 8824977Abstract: A circuit includes an antenna, and a pair of transceivers. A first transceiver in the pair is connected to the antenna via a first pair of feed-points, and is designed to transmit and receive signals in a first band of frequencies. A second transceiver in the pair is connected to the antenna via a second pair of feed-points, and is designed to transmit and receive signals in a second band of frequencies. The first band and the second band are non-overlapping frequency bands. The first pair of feed-points is located at a voltage null point of the antenna with respect to the second pair of feed-points. The second pair of feed-points is located at a voltage null point of the antenna with respect to the first pair of feed-points. The first transceiver and the second transceiver are, thus, enabled to simultaneously transmit and/or receive corresponding signals using the same antenna.Type: GrantFiled: April 11, 2011Date of Patent: September 2, 2014Assignee: Texas Instruments IncorporatedInventors: Gireesh Rajendran, Apu Sivadas, Yogesh Darwhekar, Vivek Dham
-
Patent number: 8725088Abstract: 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: GrantFiled: April 5, 2010Date of Patent: May 13, 2014Assignee: Texas Instruments IncorporatedInventors: Brian Paul Ginsburg, Gangadhar Burra, Assaf Sella, Subhashish Mukherjee, Gireesh Rajendran, Yogesh Darwhekar, Apu Sivadas
-
Patent number: 8483627Abstract: 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: GrantFiled: May 5, 2009Date of Patent: July 9, 2013Assignee: Texas Instruments IncorporatedInventors: Gireesh Rajendran, Apu Sivadas, Subhashish Mukherjee
-
Patent number: 8412136Abstract: 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: GrantFiled: February 10, 2009Date of Patent: April 2, 2013Assignee: Texas Instruments IncorporatedInventors: Apu Sivadas, Gireesh Rajendran, Subhashish Mukherjee
-
Publication number: 20130034088Abstract: A device includes multiple transceivers, a coupling block and an antenna. The transceivers operate according to time-division multiple access (TDMA) techniques. The coupling block is designed to enable the multiple transceivers to transmit or receive corresponding signals using the antenna. The multiple transceivers include a first transmitter and a second transmitter. The first transmitter is connected to the antenna via a first coupling network. The second transmitter is connected to the antenna via a series connection of a second coupling network and at least a portion of the first coupling network. Other transmitters are connected to the antenna via a series arrangement of at least a portion of the first coupling network and corresponding coupling networks.Type: ApplicationFiled: August 4, 2011Publication date: February 7, 2013Applicant: TEXAS INSTRUMENTS INCORPORATEDInventors: Alok Prakash Joshi, Gireesh Rajendran, Apu Sivadas
-
Patent number: 8325752Abstract: 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: GrantFiled: July 29, 2008Date of Patent: December 4, 2012Assignee: Texas Instruments IncorporatedInventors: Gireesh Rajendran, Apu Sivadas, Rittu Kulwant Sachdev, Krishnaswamy Thiagarajan
-
Patent number: 8326371Abstract: 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: GrantFiled: September 22, 2008Date of Patent: December 4, 2012Assignee: Texas Instruments IncorporatedInventors: Apu Sivadas, Gireesh Rajendran, Ashish Lachhwani, David Cohen
-
Publication number: 20120258660Abstract: A circuit includes an antenna, and a pair of transceivers. A first transceiver in the pair is connected to the antenna via a first pair of feed-points, and is designed to transmit and receive signals in a first band of frequencies. A second transceiver in the pair is connected to the antenna via a second pair of feed-points, and is designed to transmit and receive signals in a second band of frequencies. The first band and the second band are non-overlapping frequency bands. The first pair of feed-points is located at a voltage null point of the antenna with respect to the second pair of feed-points. The second pair of feed-points is located at a voltage null point of the antenna with respect to the first pair of feed-points. The first transceiver and the second transceiver are, thus, enabled to simultaneously transmit and/or receive corresponding signals using the same antenna.Type: ApplicationFiled: April 11, 2011Publication date: October 11, 2012Applicant: TEXAS INSTRUMENTS INCORPORATEDInventors: Gireesh Rajendran, Apu Sivadas, Yogesh Darwhekar, Vivek Dham
-
Patent number: 8249524Abstract: A near field communication (NFC) transceiver contains a transmitter portion to generate a transmit wireless signal, and a receiver portion to receive and process a receive wireless signal. The circuit further contains a shunt capacitor, a switch, and an antenna interface to couple the transmitter portion and the receiver portion to an antenna designed to communicate with external antennas by inductive coupling. The switch couples the shunt capacitor in parallel with the antenna in one operational mode, and decouples the shunt capacitor from the antenna in another operational mode. Transmit and receive performance of the NFC transceiver are enhanced as a result.Type: GrantFiled: September 10, 2010Date of Patent: August 21, 2012Assignee: Texas Instruments IncorporatedInventors: Yogesh Darwhekar, Alok Prakash Joshi, Gireesh Rajendran, Subhashish Mukherjee, Apu Sivadas
-
Patent number: 8203384Abstract: 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: GrantFiled: February 1, 2011Date of Patent: June 19, 2012Assignee: Texas Instruments IncorporatedInventors: Krishnaswamy Thiagarajan, Gireesh Rajendran, Subhashish Mukherjee, Apu Sivadas
-
Patent number: 8195109Abstract: 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: GrantFiled: March 23, 2010Date of Patent: June 5, 2012Assignee: Texas Instruments IncorporatedInventors: Gireesh Rajendran, Apu Sivadas, Subhashish Mukherjee, Krishnaswamy Thiagarajan
-
Publication number: 20120064826Abstract: A near field communication (NFC) transceiver contains a transmitter portion to generate a transmit wireless signal, and a receiver portion to receive and process a receive wireless signal. The circuit further contains a shunt capacitor, a switch, and an antenna interface to couple the transmitter portion and the receiver portion to an antenna designed to communicate with external antennas by inductive coupling. The switch couples the shunt capacitor in parallel with the antenna in one operational mode, and decouples the shunt capacitor from the antenna in another operational mode. Transmit and receive performance of the NFC transceiver are enhanced as a result.Type: ApplicationFiled: September 10, 2010Publication date: March 15, 2012Applicant: TEXAS INSTRUMENTS INCORPORATEDInventors: Yogesh Darwhekar, Alok Prakash Joshi, Gireesh Rajendran, Subhashish Mukherjee, Apu Sivadas
-
Publication number: 20110243120Abstract: 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: ApplicationFiled: April 5, 2010Publication date: October 6, 2011Inventors: Brian Paul Ginsburg, Gangadhar Burra, Assaf Sella, Subhashish Mukherjee, Gireesh Rajendran, Yogesh Darwhekar, Apu Sivadas
-
Publication number: 20110237206Abstract: 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: ApplicationFiled: March 23, 2010Publication date: September 29, 2011Inventors: Gireesh Rajendran, Apu Sivadas, Subhashish Mukherjee, Krishnaswamy Thiagarajan
-
Publication number: 20110171994Abstract: 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: ApplicationFiled: January 8, 2010Publication date: July 14, 2011Applicant: Texas Instruments IncorporatedInventors: Gireesh RAJENDRAN, Timothy Don DAVIS, Apu SIVADAS, Michel FRECHETTE, Thiagarajan KRISHNASWAMY, Salvatore PENNISI, Rakesh KUMAR, Bijit Thakorbhai PATEL, Subhashish MUKHERJEE, Debapriya SAHU
-
Publication number: 20100075724Abstract: 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: ApplicationFiled: September 22, 2008Publication date: March 25, 2010Inventors: APU SIVADAS, Gireesh Rajendran, Ashish Lachhwani, David Cohen
-
Publication number: 20100027568Abstract: 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: ApplicationFiled: July 29, 2008Publication date: February 4, 2010Inventors: Gireesh Rajendran, Apu Sivadas, Rittu Kulwant Sachdev, Krishnaswamy Thiagarajan