Patents by Inventor Cameron Lacy

Cameron Lacy 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: 10114400
    Abstract: A BGR circuit for sub-1V ICs utilizes a voltage chopping circuit and/or a current chopping circuit and a low-frequency filter to stabilize the output reference voltage that is generated by an op-amp, a current mirror circuit, a CTAT stage, a PTAT stage, and an output stage. The voltage chopping circuit reduces input offset and 1/f noise by periodically alternating (time-averaging) the negative temperature dependent and positive temperature dependent voltages supplied by the CTAT and PTAT stages to the op-amp's input terminals. The current chopping circuit minimizes current variations caused by process-related differences in the current mirror devices by periodically alternating (time-averaging) three balanced currents generated by the current mirror circuit such that each current is transmitted equally to each of the CTAT, PTAT and output stages. The filter serves to maintain loop stability and remove the low frequency noise generated by the applied voltage and/or current chopping operations.
    Type: Grant
    Filed: September 30, 2016
    Date of Patent: October 30, 2018
    Assignee: Synopsys, Inc.
    Inventors: Cameron Lacy, Michael W. Lynch, Sergei Uhanov
  • Publication number: 20180095491
    Abstract: A BGR circuit for sub-1V ICs utilizes a voltage chopping circuit and/or a current chopping circuit and a low-frequency filter to stabilize the output reference voltage that is generated by an op-amp, a current mirror circuit, a CTAT stage, a PTAT stage, and an output stage. The voltage chopping circuit reduces input offset and 1/f noise by periodically alternating (time-averaging) the negative temperature dependent and positive temperature dependent voltages supplied by the CTAT and PTAT stages to the op-amp's input terminals. The current chopping circuit minimizes current variations caused by process-related differences in the current mirror devices by periodically alternating (time-averaging) three balanced currents generated by the current mirror circuit such that each current is transmitted equally to each of the CTAT, PTAT and output stages. The filter serves to maintain loop stability and remove the low frequency noise generated by the applied voltage and/or current chopping operations.
    Type: Application
    Filed: September 30, 2016
    Publication date: April 5, 2018
    Inventors: Cameron Lacy, Michael W. Lynch, Sergei Uhanov
  • Patent number: 8067957
    Abstract: A high-speed universal serial bus (USB) transceiver includes a voltage-mode architecture for generating a USB signal. The voltage mode architecture reduces power consumption by reducing the current requirements for high-speed USB communications. The USB transceiver can include a reference voltage generator, a resistive element, and a switching element for completing and breaking a circuit including the reference voltage generator, the resistive element, and a data pin of a USB port to generate half of the differential USB signal (e.g., the D+ signal). A similar circuit can be used to generate the other half of the differential USB signal (i.e., the D? signal). The resistive element can be a set of parallel resistors in the transceiver, with the set of parallel resistors being specifically selected from a larger population of resistors to provide the specified resistance (45?±10%) in the USB transceiver.
    Type: Grant
    Filed: October 5, 2010
    Date of Patent: November 29, 2011
    Assignee: Synopsys, Inc.
    Inventors: Scott Howe, Dino A. Toffolon, Cameron Lacy, Euhan Chong
  • Publication number: 20110019763
    Abstract: A high-speed universal serial bus (USB) transceiver includes a voltage-mode architecture for generating a USB signal. The voltage mode architecture reduces power consumption by reducing the current requirements for high-speed USB communications. The USB transceiver can include a reference voltage generator, a resistive element, and a switching element for completing and breaking a circuit including the reference voltage generator, the resistive element, and a data pin of a USB port to generate half of the differential USB signal (e.g., the D+ signal). A similar circuit can be used to generate the other half of the differential USB signal (i.e., the D? signal). The resistive element can be a set of parallel resistors in the transceiver, with the set of parallel resistors being specifically selected from a larger population of resistors to provide the specified resistance (45 ?±10%) in the USB transceiver.
    Type: Application
    Filed: October 5, 2010
    Publication date: January 27, 2011
    Applicant: Synopsys, Inc.
    Inventors: Scott Howe, Dino A. Toffolon, Cameron Lacy, Euhan Chong
  • Patent number: 7816942
    Abstract: A high-speed universal serial bus (USB) transceiver includes a voltage-mode architecture for generating a USB signal. The voltage mode architecture reduces power consumption by reducing the current requirements for high-speed USB communications. The USB transceiver can include a reference voltage generator, a resistive element, and a switching element for completing and breaking a circuit including the reference voltage generator, the resistive element, and a data pin of a USB port to generate half of the differential USB signal (e.g., the D+ signal). A similar circuit can be used to generate the other half of the differential USB signal (i.e., the D? signal). The resistive element can be a set of parallel resistors in the transceiver, with the set of parallel resistors being specifically selected from a larger population of resistors to provide the specified resistance (45?±10%) in the USB transceiver.
    Type: Grant
    Filed: January 13, 2010
    Date of Patent: October 19, 2010
    Assignee: Synopsys, Inc.
    Inventors: Scott Howe, Dino A. Toffolon, Cameron Lacy, Euhan Chong
  • Publication number: 20100109706
    Abstract: A high-speed universal serial bus (USB) transceiver includes a voltage-mode architecture for generating a USB signal. The voltage mode architecture reduces power consumption by reducing the current requirements for high-speed USB communications. The USB transceiver can include a reference voltage generator, a resistive element, and a switching element for completing and breaking a circuit including the reference voltage generator, the resistive element, and a data pin of a USB port to generate half of the differential USB signal (e.g., the D+ signal). A similar circuit can be used to generate the other half of the differential USB signal (i.e., the D? signal). The resistive element can be a set of parallel resistors in the transceiver, with the set of parallel resistors being specifically selected from a larger population of resistors to provide the specified resistance (45?±10%) in the USB transceiver.
    Type: Application
    Filed: January 13, 2010
    Publication date: May 6, 2010
    Applicant: Synopsys, Inc.
    Inventors: Scott Howe, Dino A. Toffolon, Cameron Lacy, Euhan Chong
  • Patent number: 7671630
    Abstract: A high-speed universal serial bus (USB) transceiver includes a voltage-mode architecture for generating a USB signal. The voltage mode architecture reduces power consumption by reducing the current requirements for high-speed USB communications. The USB transceiver can include a reference voltage generator, a resistive element, and a switching element for completing and breaking a circuit including the reference voltage generator, the resistive element, and a data pin of a USB port to generate half of the differential USB signal (e.g., the D+ signal). A similar circuit can be used to generate the other half of the differential USB signal (i.e., the D? signal). The resistive element can be a set of parallel resistors in the transceiver, with the set of parallel resistors being specifically selected from a larger population of resistors to provide the specified resistance (45 ?±10%) in the USB transceiver.
    Type: Grant
    Filed: July 29, 2005
    Date of Patent: March 2, 2010
    Assignee: Synopsys, Inc.
    Inventors: Scott Howe, Dino A. Toffolon, Cameron Lacy, Euhan Chong
  • Patent number: 7522659
    Abstract: A Universal Serial Bus (USB) 2.0 transceiver includes a legacy full speed and low speed (FS/LS) USB driver that includes multiple output stages. The multiple output stages are connected in parallel to an output terminal. By sequentially providing the USB data to the multiple output stages, the USB signal at the output terminal will transition between logic states in an incremental fashion as the multiple output stages sequentially switch their individual output states. Consequently, the rise/fall time for the legacy FS/LS USB driver is controlled not by the strength of the inverter transistors in the output stages, but rather by the number of stages and the time interval between application of the USB data to each stage. Therefore, by selecting an appropriate number of output stages and an appropriate timing interval, accurate control over full speed and low speed USB signal rise/fall times can be provided.
    Type: Grant
    Filed: September 19, 2005
    Date of Patent: April 21, 2009
    Assignee: Synopsys, Inc.
    Inventors: Cameron Lacy, Dino A. Toffolon, Scott Howe
  • Publication number: 20070064778
    Abstract: A USB 2.0 transceiver includes a legacy full speed and low speed (FS/LS) USB driver that includes multiple output stages. The multiple output stages are connected in parallel to an output terminal. By sequentially providing the USB data to the multiple output stages, the USB signal at the output terminal will transition between logic states in an incremental fashion as the multiple output stages sequentially switch their individual output states. Consequently, the rise/fall time for the legacy FS/LS USB driver is controlled not by the strength of the inverter transistors in the output stages, but rather by the number of stages and the time interval between application of the USB data to each stage. Therefore, by selecting an appropriate number of output stages and an appropriate timing interval, accurate control over full speed and low speed USB signal rise/fall times can be provided.
    Type: Application
    Filed: September 19, 2005
    Publication date: March 22, 2007
    Applicant: Synopsys, Inc.
    Inventors: Cameron Lacy, Dino Toffolon, Scott Howe
  • Publication number: 20070024327
    Abstract: A high-speed universal serial bus (USB) transceiver includes a voltage-mode architecture for generating a USB signal. The voltage mode architecture reduces power consumption by reducing the current requirements for high-speed USB communications. The USB transceiver can include a reference voltage generator, a resistive element, and a switching element for completing and breaking a circuit including the reference voltage generator, the resistive element, and a data pin of a USB port to generate half of the differential USB signal (e.g., the D+ signal). A similar circuit can be used to generate the other half of the differential USB signal (i.e., the D? signal). The resistive element can be a set of parallel resistors in the transceiver, with the set of parallel resistors being specifically selected from a larger population of resistors to provide the specified resistance (45 ?±10%) in the USB transceiver.
    Type: Application
    Filed: July 29, 2005
    Publication date: February 1, 2007
    Applicant: Synopsys Inc.
    Inventors: Scott Howe, Dino Toffolon, Cameron Lacy, Euhan Chong