Patents by Inventor Derek Tam
Derek Tam 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: 9252833Abstract: Disclosed are various embodiments for providing a power-efficient driver architecture supporting rail-to-rail operation in full duplex mode. A driver is configured to drive a duplex signal over a transmission medium. A hybrid is configured to recover a received signal from the duplex signal. The received signal is generated by a remote transceiver. The driver is configured to drive the duplex signal based at least in part on the received signal recovered by the hybrid.Type: GrantFiled: May 7, 2012Date of Patent: February 2, 2016Assignee: BROADCOM CORPORATIONInventors: Hui Pan, Yuan Yao, Joseph Aziz, Derek Tam, Xin Wang, Chia-Jen Hsu
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Patent number: 9231655Abstract: A system and method for power control in a physical layer device. Energy savings during an active state can be produced through the monitoring of a received signal level by a receiver in a physical layer device. In one embodiment, based on an indication of the received signal level or other communication characteristic of the transmission medium, a control module can adjust the signal level or amplitude and/or adjust the voltage supply.Type: GrantFiled: April 13, 2012Date of Patent: January 5, 2016Assignee: BROADCOM CORPORATIONInventors: Derek Tam, Xin Wang, Hui Pan, Joseph Aziz
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Patent number: 8977869Abstract: While an IC chip is in idle mode with no power being supplied to the IC chip, the IC chip may be operable to detect a signal pulse received by the IC chip using energy associated with the signal pulse. The IC chip may be operable to control a control signal for a power switch using the energy associated with the signal pulse. The power switch may allow power to be provided to the IC chip based on the control signal. The IC chip may comprise a pulse detector, a latch circuit and an ON/OFF logic circuit within the IC chip. While the IC chip is fully powered and communication with a partner chip is finished, the IC chip may be operable to control the control signal to turn off the power switch for powering down the IC chip based on a turn-off signal.Type: GrantFiled: March 1, 2011Date of Patent: March 10, 2015Assignee: Broadcom CorporationInventors: Jingguang Wang, Derek Tam, Mark Berman, Siavash Fallahi
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Patent number: 8867352Abstract: Systems and methods are used to adjust, e.g., reduce, current driving a transmitter, i.e., to reduce transmitter power consumption, based on an actual value of a received signal from received along a cable. For example, this is very beneficial to an Ethernet system where the received signal is attenuated by the lossy cable. In this case, the transmitter power consumption can be lowered during a normal application where data is transmitted and received through the cable.Type: GrantFiled: April 29, 2010Date of Patent: October 21, 2014Assignee: Broadcom CorporationInventors: Derek Tam, Kevin Tunghai Chan
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Patent number: 8598917Abstract: According to one exemplary embodiment, a transmitter module includes a line drive including a current digital-to-analog converter, where the line driver provides an analog output waveform. The current digital-to-analog converter receives a digitally filtered input waveform including at least two voltage steps. The at least two voltage steps of the digitally filtered input waveform cause a rise time of the analog output waveform to have a reduced dependency on process, voltage, and temperature variations in the line driver, while meeting stringent rise time requirements. The digitally filtered input waveform has an initial voltage level and a final voltage level, where the final voltage level is substantially equal to a sum of the at least two voltage steps of the digitally filtered input waveform.Type: GrantFiled: April 27, 2011Date of Patent: December 3, 2013Assignee: Broadcom CorporationInventors: Andrew Chen, Joseph Aziz, Derek Tam
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Publication number: 20130294294Abstract: Disclosed are various embodiments for providing a power-efficient driver architecture supporting rail-to-rail operation in full duplex mode. A driver is configured to drive a duplex signal over a transmission medium. A hybrid is configured to recover a received signal from the duplex signal. The received signal is generated by a remote transceiver. The driver is configured to drive the duplex signal based at least in part on the received signal recovered by the hybrid.Type: ApplicationFiled: May 7, 2012Publication date: November 7, 2013Applicant: BROADCOM CORPORATIONInventors: Hui Pan, Yuan Yao, Joseph Aziz, Derek Tam, Xin Wang, Chia-Jen Hsu
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Publication number: 20130268782Abstract: A system and method for power control in a physical layer device. Energy savings during an active state can be produced through the monitoring of a received signal level by a receiver in a physical layer device. In one embodiment, based on an indication of the received signal level or other communication characteristic of the transmission medium, a control module can adjust the signal level or amplitude and/or adjust the voltage supply.Type: ApplicationFiled: April 13, 2012Publication date: October 10, 2013Applicant: Broadcom CorporationInventors: Derek Tam, Xin Wang, Hui Pan, Joseph Aziz
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Publication number: 20130182717Abstract: Aspects of a method and system for a power reduction scheme for Ethernet PHYs are provided. An Ethernet PHY in a link partner may disable transmission via a transmit DAC integrated during an inactive connection, 10Base-T autonegotiation operation, and/or active 10Base-T connection with no data packet transmission. The DAC may be a voltage mode or current mode DAC. The PHY or a MAC device may determine when to disable transmission via the DAC. In this regard, the PHY or the MAC device may generate appropriate signals for disabling the transmission. The DAC may be enabled for transmission by the PHY or the MAC device when a connection becomes active or when an active 10Base-T connection is ready to transmit data. Moreover, the PHY may enable transmission via the DAC when operating in a forced 10Base-T mode of operation and the connection to the link partner is active.Type: ApplicationFiled: November 1, 2012Publication date: July 18, 2013Applicant: BROADCOM CORPORATIONInventors: Mark Berman, Manolito Catalasan, Ovidiu Bajdechi, Christopher M. Ward, Bruce H. Conway, Derek Tam, Frank van der Goes
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Patent number: 8325756Abstract: Aspects of a method and system for a power reduction scheme for Ethernet PHYs are provided. An Ethernet PHY in a link partner may disable transmission via a transmit DAC integrated during an inactive connection, 10Base-T autonegotiation operation, and/or active 10Base-T connection with no data packet transmission. The DAC may be a voltage mode or current mode DAC. The PHY or a MAC device may determine when to disable transmission via the DAC. In this regard, the PHY or the MAC device may generate appropriate signals for disabling the transmission. The DAC may be enabled for transmission by the PHY or the MAC device when a connection becomes active or when an active 10Base-T connection is ready to transmit data. Moreover, the PHY may enable transmission via the DAC when operating in a forced 10Base-T mode of operation and the connection to the link partner is active.Type: GrantFiled: April 11, 2007Date of Patent: December 4, 2012Assignee: Broadcom CorporationInventors: Mark Berman, Manolito Catalasan, Ovidiu Bajdechi, Christopher M. Ward, Bruce H. Conway, Derek Tam, Frank Van Der Goes
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Patent number: 8289046Abstract: According to one exemplary embodiment, an active termination circuit includes at least one active termination branch, where the at least one active termination branch includes at least one transistor for providing an active termination output. The at least one active termination branch further includes an amplifier driving the at least one transistor, where the amplifier has a non-inverting input coupled to the active termination output via a feedback network. The amplifier controls a current flowing through the at least one transistor so as to provide the active termination output. The active termination output can be provided at a drain of the at least one transistor, where a source of the at least one transistor is coupled to ground through a degeneration transistor and a tail current sink.Type: GrantFiled: June 30, 2011Date of Patent: October 16, 2012Assignee: Broadcom CorporationInventors: Joseph Aziz, Andrew Chen, Derek Tam, Ark-Chew Wong, Agnes Neves Woo, Marcel Lugthart
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Publication number: 20120223765Abstract: While an IC chip is in idle mode with no power being supplied to the IC chip, the IC chip may be operable to detect a signal pulse received by the IC chip using energy associated with the signal pulse. The IC chip may be operable to control a control signal for a power switch using the energy associated with the signal pulse. The power switch may allow power to be provided to the IC chip based on the control signal. The IC chip may comprise a pulse detector, a latch circuit and an ON/OFF logic circuit within the IC chip. While the IC chip is fully powered and communication with a partner chip is finished, the IC chip may be operable to control the control signal to turn off the power switch for powering down the IC chip based on a turn-off signal.Type: ApplicationFiled: March 1, 2011Publication date: September 6, 2012Inventors: Jingguang Wang, Derek Tam, Mark Berman, Siavash Fallahi
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Patent number: 8228091Abstract: Disclosed is a false-link protection circuit comprising at least one native switch coupled between a communication terminal of a first differential switch and a communication terminal of a second differential switch. The at least one native switch is configured to provide an attenuation path for a pulse link signal received by either communication terminal when the first and second differential switches are in a powered down state. According to one embodiment, a method to attenuate a pulse link signal comprises activating a native switch of a false-link protection circuit by powering down first and second differential switches, receiving a pulse link signal at a communication terminal of one of the first and second differential switches, and attenuating the pulse link signal by diverting it through the false-link protection circuit when the first and second differential switches are in a powered down state.Type: GrantFiled: February 25, 2010Date of Patent: July 24, 2012Assignee: Broadcom CorporationInventors: Ark-Chew Wong, Joseph Aziz, Derek Tam, Kevin Chan
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Patent number: 8183885Abstract: In one embodiment, a circuit for providing a tail current for a line driver includes an adjustable current source. The adjustable current source includes a number of current source cells coupled together in a parallel configuration, where the current source cells are configured to provide the tail current for the line driver in response to a digital control signal. The circuit can further include a digital core coupled to the adjustable current source, where the digital core provides the digital control signal. The digital control signal provides a number of bits, where each bit controls one of the current source cells. In one embodiment, a current source cell can comprise a number of current source sub-cells. The current source cells can be configured to provide the tail current for the line driver in response to the digital control signal when the line driver is operating in a class AB mode.Type: GrantFiled: April 8, 2009Date of Patent: May 22, 2012Assignee: Broadcom CorporationInventors: Joseph Aziz, Andrew Chen, Ark-Chew Wong, Derek Tam
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Patent number: 8148219Abstract: A circuit with dielectric thicknesses is presented that includes a low-pass filter including one or more semiconductor devices having a thick gate oxide layer, while further semiconductor devices of the circuit have thin gate oxide layers. The low-pass filter semiconductor device includes an N-type substrate, a P-type region formed on the N-type substrate, a thick gate oxide layer formed over the P-type region, a P+ gate electrode formed over the thick gate oxide layer and coupled to a first voltage supply line, and P+ pick-up terminals formed in the P-type region adjacent the gate electrode and coupled to a second voltage supply line. The low-pass filter semiconductor device acts as a capacitor, whereby a gate-to-substrate voltage is maintained at less than zero volts to maintain a stable control voltage for the circuit.Type: GrantFiled: June 15, 2009Date of Patent: April 3, 2012Assignee: Broadcom CorporationInventors: Derek Tam, Jasmine Cheng, Jungwoo Song, Takayuki Hayashi
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Publication number: 20110254584Abstract: According to one exemplary embodiment, an active termination circuit includes at least one active termination branch, where the at least one active termination branch includes at least one transistor for providing an active termination output. The at least one active termination branch further includes an amplifier driving the at least one transistor, where the amplifier has a non-inverting input coupled to the active termination output via a feedback network. The amplifier controls a current flowing through the at least one transistor so as to provide the active termination output. The active termination output can be provided at a drain of the at least one transistor, where a source of the at least one transistor is coupled to ground through a degeneration transistor and a tail current sink.Type: ApplicationFiled: June 30, 2011Publication date: October 20, 2011Applicant: BROADCOM CORPORATIONInventors: Joseph Aziz, Andrew Chen, Derek Tam, Ark-Chew Wong, Agnes Neves Woo, Marcel Lugthart
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Publication number: 20110204967Abstract: Disclosed is a false-link protection circuit comprising at least one native switch coupled between a communication terminal of a first differential switch and a communication terminal of a second differential switch. The at least one native switch is configured to provide an attenuation path for a pulse link signal received by either communication terminal when the first and second differential switches are in a powered down state. According to one embodiment, a method to attenuate a pulse link signal comprises activating a native switch of a false-link protection circuit by powering down first and second differential switches, receiving a pulse link signal at a communication terminal of one of the first and second differential switches, and attenuating the pulse link signal by diverting it through the false-link protection circuit when the first and second differential switches are in a powered down state.Type: ApplicationFiled: February 25, 2010Publication date: August 25, 2011Applicant: BROADCOM CORPORATIONInventors: Ark-Chew Wong, Joseph Aziz, Derek Tam, Kevin Chan
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Publication number: 20110199129Abstract: According to one exemplary embodiment, a transmitter module includes a line drive including a current digital-to-analog converter, where the line driver provides an analog output waveform. The current digital-to-analog converter receives a digitally filtered input waveform including at least two voltage steps. The at least two voltage steps of the digitally filtered input waveform cause a rise time of the analog output waveform to have a reduced dependency on process, voltage, and temperature variations in the line driver, while meeting stringent rise time requirements. The digitally filtered input waveform has an initial voltage level and a final voltage level, where the final voltage level is substantially equal to a sum of the at least two voltage steps of the digitally filtered input waveform.Type: ApplicationFiled: April 27, 2011Publication date: August 18, 2011Applicant: Broadcom CorporationInventors: Andrew Chen, Joseph Aziz, Derek Tam
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Patent number: 7982491Abstract: According to one exemplary embodiment, an active termination circuit includes at least one active termination branch, where the at least one active termination branch includes at least one transistor for providing an active termination output. The at least one active termination branch further includes an amplifier driving the at least one transistor, where the amplifier has a non-inverting input coupled to the active termination output via a feedback network. The amplifier controls a current flowing through the at least one transistor so as to provide the active termination output. The active termination output can be provided at a drain of the at least one transistor, where a source of the at least one transistor is coupled to ground through a degeneration transistor and a tail current sink.Type: GrantFiled: April 8, 2009Date of Patent: July 19, 2011Assignee: Broadcom CorporationInventors: Joseph Aziz, Andrew Chen, Derek Tam, Ark-Chew Wong, Agnes Neves Woo, Marcel Lugthart
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Publication number: 20110158137Abstract: Systems and methods are used to adjust, e.g., reduce, current driving a transmitter, i.e., to reduce transmitter power consumption, based on an actual value of a received signal from received along a cable. For example, this is very beneficial to an Ethernet system where the received signal is attenuated by the lossy cable. In this case, the transmitter power consumption can be lowered during a normal application where data is transmitted and received through the cable.Type: ApplicationFiled: April 29, 2010Publication date: June 30, 2011Applicant: Broadcom CorporationInventors: Derek TAM, Kevin Tunghai Chan
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Patent number: 7944251Abstract: According to one exemplary embodiment, a transmitter module includes a line drive including a current digital-to-analog converter, where the line driver provides an analog output waveform. The current digital-to-analog converter receives a digitally filtered input waveform including at least two voltage steps. The at least two voltage steps of the digitally filtered input waveform cause a rise time of the analog output waveform to have a reduced dependency on process, voltage, and temperature variations in the line driver, while meeting stringent rise time requirements. The digitally filtered input waveform has an initial voltage level and a final voltage level, where the final voltage level is substantially equal to a sum of the at least two voltage steps of the digitally filtered input waveform.Type: GrantFiled: March 9, 2009Date of Patent: May 17, 2011Assignee: Broadcom CorporationInventors: Andrew Chen, Joseph Aziz, Derek Tam