Patents by Inventor Janardhanan S. Ajit
Janardhanan S. Ajit 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: 7746124Abstract: A method of providing bias voltages for input output connections on low voltage integrated circuits. As integrated circuit voltages drop generally so does the external voltages that those circuits can handle. By placing input and output devices, in series, external voltages can be divided between the devices thereby reducing junction voltages seen by internal devices. By using external voltages as part of a biasing scheme for integrated circuit devices, stress created by the differential between external voltages and internal voltages can be minimized. Additionally device wells can be biased so that they are at a potential that is dependant on the external voltages seen by the low voltage integrated circuit.Type: GrantFiled: May 15, 2009Date of Patent: June 29, 2010Assignee: Broadcom CorporationInventor: Janardhanan S. Ajit
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Publication number: 20090224821Abstract: A method of providing bias voltages for input output connections on low voltage integrated circuits. As integrated circuit voltages drop generally so does the external voltages that those circuits can handle. By placing input and output devices, in series, external voltages can be divided between the devices thereby reducing junction voltages seen by internal devices. By using external voltages as part of a biasing scheme for integrated circuit devices, stress created by the differential between external voltages and internal voltages can be minimized. Additionally device wells can be biased so that they are at a potential that is dependant on the external voltages seen by the low voltage integrated circuit.Type: ApplicationFiled: May 15, 2009Publication date: September 10, 2009Applicant: Broadcom CorporationInventor: Janardhanan S. Ajit
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Patent number: 7292072Abstract: A method of providing bias voltages for input output connections on low voltage integrated circuits. As integrated circuit voltages drop generally so does the external voltages that those circuits can handle. By placing input and output devices, in series, external voltages can be divided between the devices thereby reducing junction voltages seen by internal devices. By using external voltages as part of a biasing scheme for integrated circuit devices, stress created by the differential between external voltages and internal voltages can be minimized. Additionally device wells can be biased so that they are at a potential that is dependant on the external voltages seen by the low voltage integrated circuit.Type: GrantFiled: July 14, 2005Date of Patent: November 6, 2007Assignee: Broadcom CorporationInventor: Janardhanan S. Ajit
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Patent number: 7268595Abstract: A system and method for compensating for process, voltage, and temperature variations in a circuit is provided. A system includes an inverter having an input port, and an output port, and is configured to (i) receive an input signal, (ii) delay the received input signal, and (iii) provide the delayed signal to the inverter output port. The system also includes a logic device including at least two input ports and an output port. A first of the at least two input ports is configured to receive the delayed signal. Finally, the system includes a charge storing device having a first end coupled, at least indirectly, to a second of the at least two input ports and a second end coupled to a logic device common node. The charge storing device is configured to (i) receive the input signal and (ii) sense a rate of change in voltage of the received input signal, the sensed voltage being representative of a corresponding current.Type: GrantFiled: January 10, 2006Date of Patent: September 11, 2007Assignee: Broadcom CorporationInventor: Janardhanan S. Ajit
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Patent number: 7138847Abstract: A method of providing bias voltages for input output connections on low voltage integrated circuits. As integrated circuit voltages drop generally so does the external voltages that those circuits can handle. By placing input and output devices, in series, external voltages can be divided between the devices thereby reducing junction voltages seen by internal devices. By using external voltages as part of a biasing scheme for integrated circuit devices, stress created by the differential between external voltages and internal voltages can be minimized. Additionally device wells can be biased so that they are at a potential that is dependant on the external voltages seen by the low voltage integrated circuit.Type: GrantFiled: December 2, 2004Date of Patent: November 21, 2006Assignee: Broadcom CorporationInventor: Janardhanan S. Ajit
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Patent number: 7138836Abstract: A method of preventing Hot Carrier Injection in input/output connections on low voltage integrated circuits. As integrated circuit voltages drop generally so does the external voltages that those circuits can tolerate. By placing input/output devices, in series, external voltages can be divided between the devices thereby reducing junction voltages seen by internal devices. A circuit for preventing Hot Carrier Injection in these input/output devices comprises comparing an input voltage to a reference voltage, and if conditions that would produce Hot Carrier Injection are present (e.g. when input voltage is greater than reference voltage), slowing the turn-on of one of the series connected input/output devices, thereby reducing the voltage from the drain-to-source of another series connected input/output device.Type: GrantFiled: December 3, 2002Date of Patent: November 21, 2006Assignee: Broadcom CorporationInventors: Janardhanan S. Ajit, Laurentiu Vasiliu
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Patent number: 7123460Abstract: Methods and systems for protecting integrated circuits from power-on sequence currents and for biasing transistors in paths susceptible to power-on sequence damage are provided. The system includes a plurality of protection circuits coupled between a first circuit input and a second circuit input. Each protection circuit includes a switch and a voltage sensors. When the voltage amplitude of a first voltage source coupled to the protection circuit exceeds a first threshold and the voltage amplitude of a second voltage source coupled to the protection circuit is below a second threshold, the switch is closed, coupling the first circuit input to the second circuit input. When the voltage amplitude of the first voltage source exceeds the first threshold and the voltage amplitude of the second voltage source exceeds the second threshold, the switch is open, decoupling the first circuit input from the second circuit input.Type: GrantFiled: November 22, 2004Date of Patent: October 17, 2006Assignee: Broadcom CorporationInventor: Janardhanan S. Ajit
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Patent number: 7112998Abstract: A system and method for level shifting a core, lower voltage in a one-stage level shift device to produce a higher, driving voltage. The system includes a first device that optimally functions with a first voltage and that outputs the first voltage. The system also includes a one-stage level shift device that receives the first voltage and shifts the first voltage to a second voltage without an intermediate voltage, the second voltage being higher than the first voltage. The system also includes a second device that receives the second voltage to optimally function. In some cases, the first voltage can be a periodic wave such that the higher voltage is produced with one portion of the level shift device during a first portion of the wave and another portion of the level shift device during a second portion of the wave.Type: GrantFiled: March 3, 2005Date of Patent: September 26, 2006Assignee: Broadcom CorporationInventor: Janardhanan S. Ajit
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Patent number: 7002379Abstract: An apparatus for providing bias voltages for input/output (I/O) connections on low voltage integrated circuits. In one embodiment, the invention comprises an I/O pad, a pull-down transistor device that has a protective transistor coupled to said I/O pad, and a pull-up transistor device that has a second protective transistor, coupled to said I/O pad. A first switch coupled to the first protective transistor is responsive to a first supply voltage, a second supply voltage, and a reference voltage. Likewise, a second switch coupled to the second protective transistor is responsive to the first supply voltage and the reference voltage. A first self-bias circuit is also coupled to the first switch, wherein said the self-bias circuit uses a voltage at said I/O pad to bias the first protective transistor when both of the first and second supply voltages are powered off.Type: GrantFiled: October 18, 2004Date of Patent: February 21, 2006Assignee: Broadcom CorporationInventor: Janardhanan S. Ajit
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Patent number: 6985015Abstract: A method of providing bias voltages for input output connections on low voltage integrated circuits. As integrated circuit voltages drop generally so does the external voltages that those circuits can handle. By placing input and output devices, in series, external voltages can be divided between the devices thereby reducing junction voltages seen by internal devices. By using external voltages as part of a biasing scheme for integrated circuit devices, stress created by the differential between external voltages and internal voltages can be minimized. Additionally device wells can be biased so that they are at a potential that is dependant on the external voltages seen by the low voltage integrated circuit.Type: GrantFiled: December 3, 2004Date of Patent: January 10, 2006Assignee: Broadcom CorporationInventor: Janardhanan S. Ajit
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Patent number: 6985014Abstract: A system and method for compensating for process, voltage, and temperature variations in a circuit is provided. A system includes an inverter having an input port, and an output port, and is configured to (i) receive an input signal, (ii) delay the received input signal, and (iii) provide the delayed signal to the inverter output port. The system also includes a logic device including at least two input ports and an output port. A first of the at least two input ports is configured to receive the delayed signal. Finally, the system includes a charge storing device having a first end coupled, at least indirectly, to a second of the at least two input ports and a second end coupled to a logic device common node. The charge storing device is configured to (i) receive the input signal and (ii) sense a rate of change in voltage of the received input signal, the sensed voltage being representative of a corresponding current.Type: GrantFiled: November 14, 2002Date of Patent: January 10, 2006Assignee: Broadcom CorporationInventor: Janardhanan S. Ajit
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Patent number: 6949964Abstract: A method of providing bias voltages for input output connections on low voltage integrated circuits. As integrated circuit voltages drop generally so does the external voltages that those circuits can handle. By placing input and output devices, in series, external voltages can be divided between the devices thereby reducing junction voltages seen by internal devices. By using external voltages as part of a biasing scheme for integrated circuit devices, stress created by the differential between external voltages and internal voltages can be minimized. Additionally device wells can be biased so that they are at a potential that is dependant on the external voltages seen by the low voltage integrated circuit.Type: GrantFiled: July 16, 2003Date of Patent: September 27, 2005Assignee: Broadcom CorporationInventor: Janardhanan S. Ajit
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Patent number: 6940334Abstract: Methods and systems for protecting integrated circuits (“ICs”) from power-on sequencing problems provide an interim voltage during power-on sequences in order to prevent over-voltage conditions across IC terminals. Voltages at first and second terminals of a circuit are monitored and an interim voltage to the second terminal is provided when the voltage at the first terminal exceeds a first threshold and a voltage at the second terminal is below a second threshold. The interim voltage protects the circuit from excessive voltage differences across the first and second terminals during power-on sequences, and is deactivated during normal operation so as not to draw excessive current. The method/system helps to insure that multi-supply dependent logic and/or other circuitry does not receive inappropriate voltage levels, and thus helps to insure that lower voltage level based circuitry is not damaged during power-up, transients, and/or glitches.Type: GrantFiled: December 22, 2003Date of Patent: September 6, 2005Assignee: Broadcom CorporationInventor: Janardhanan S. Ajit
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Patent number: 6930528Abstract: Methods and systems for controlling delay relatively independent of process, supply-voltage, and/or temperature (“PVT”) variations include sensing an output signal after a number of inverters and activating different numbers of transistors and/or adjusting strength of transistors in a delay path to compensate for PVT variations. In an embodiment, a waveform is received, delayed, and output to an output terminal using at least one relatively low-power device. Supplemental output power is provided by at least one relatively high-power device until the output waveform exceeds a threshold.Type: GrantFiled: September 13, 2004Date of Patent: August 16, 2005Assignee: Broadcom CorporationInventor: Janardhanan S. Ajit
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Patent number: 6914456Abstract: A method of providing bias voltages for input output connections on low voltage integrated circuits. As integrated circuit voltages drop generally so does the external voltages that those circuits can handle. By placing input and output devices, in series, external voltages can be divided between the devices thereby reducing junction voltages seen by internal devices. By using external voltages as part of a biasing scheme for integrated circuit devices, stress created by the differential between external voltages and internal voltages can be minimized. Additionally device wells can be biased so that they are at a potential that is dependant on the external voltages seen by the low voltage integrated circuit.Type: GrantFiled: December 19, 2002Date of Patent: July 5, 2005Assignee: Broadcom CorporationInventor: Janardhanan S. Ajit
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Patent number: 6914466Abstract: An input circuit has hysteresis to mitigate the effects of input noise. The input circuit receives an analog input signal and determines whether the unregulated analog input signal is a high or a low voltage. The input circuit outputs a regulated low voltage (i.e., “0”) for a low input signal, and outputs a regulated high voltage (i.e., “1”) for a high input signal. The low-to-high transition occurs at a higher voltage than a high-to-low transition, which mitigates noise on the input signal. Furthermore, the comparator includes a feedback path from an output of the comparator to an input of the comparator. The feedback path causes some delay in any output voltage transition (i.e. high-to-low output transition or low-to-high transition), which further enhances the hysteresis effect and improves noise immunity. An embodiment of the circuit interfaces with high voltage (e.g., 5V) input signals and outputs low voltage (e.g., 1.2V) output signals.Type: GrantFiled: May 14, 2004Date of Patent: July 5, 2005Assignee: Broadcom CorporationInventor: Janardhanan S. Ajit
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Patent number: 6906552Abstract: A system and method for level shifting a core, lower voltage in a one-stage level shift device to produce a higher, driving voltage. The system includes a first device that optimally functions with a first voltage and that outputs the first voltage. The system also includes a one-stage level shift device that receives the first voltage and shifts the first voltage to a second voltage without an intermediate voltage, the second voltage being higher than the first voltage. The system also includes a second device that receives the second voltage to optimally function. In some cases, the first voltage can be a periodic wave such that the higher voltage is produced with one portion of the level shift device during a first portion of the wave and another portion of the level shift device during a second portion of the wave.Type: GrantFiled: August 26, 2002Date of Patent: June 14, 2005Assignee: Broadcom CorporationInventor: Janardhanan S. Ajit
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Patent number: 6864737Abstract: Methods and systems for limiting power supply and ground bounce enables control of the output current drive dependent on the changes in supply (VDD and GND) levels. This is made possible by making the gate drive of the output driver PMOS and NMOS dependent on the VDD and GND swings. When the VDD or GND increases above normal operating levels, the gate drive of the output driver PMOS is reduced and when the GND or VDD reduces below normal operating levels, the gate drive of the output driver NMOS is reduced. This leads to reduced current flow between the supplies and the pad thereby reducing the VDD and GND bounce problem.Type: GrantFiled: June 14, 2004Date of Patent: March 8, 2005Assignee: Broadcom CorporationInventor: Janardhanan S. Ajit
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Patent number: 6859069Abstract: Methods and systems for sensing load conditions and for adjusting output current drive according to the sensed load conditions to maintain one or more signal characteristics within a desired range. Load conditions are sensed by monitoring one or more signal characteristics that are affected by load conditions, such as voltage changes with respect to time. Output current drive is then adjusted, as needed, to maintain the one or more desired signal characteristics. In an embodiment, rising and/or falling edge slopes are monitored. For example, a dV/dt may be monitored. The dV/dt can be monitored by coupling a capacitance to the output signal, generating a current with the capacitance, and generating a voltage from the current. The voltage is generally proportional to the dV/dt. Depending upon the load conditions, a supplemental current is generated and/or adjusted and added to the output signal to maintain the desired signal characteristics within a desired range.Type: GrantFiled: November 12, 2003Date of Patent: February 22, 2005Assignee: Broadcom CorporationInventor: Janardhanan S. Ajit
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Patent number: 6859074Abstract: An apparatus for providing bias voltages for input/output (I/O) connections on low voltage integrated circuits. In one embodiment, the invention comprises an I/O pad, a pull-down transistor device that has a protective transistor coupled to said I/O pad, and a pull-up transistor device that has a second protective transistor, coupled to said I/O pad. A first switch coupled to the first protective transistor is responsive to a first supply voltage, a second supply voltage, and a reference voltage. Likewise, a second switch coupled to the second protective transistor is responsive to the first supply voltage and the reference voltage. A first self-bias circuit is also coupled to the first switch, wherein said the self-bias circuit uses a voltage at said I/O pad to bias the first protective transistor when both of the first and second supply voltages are powered off.Type: GrantFiled: July 14, 2003Date of Patent: February 22, 2005Assignee: Broadcom CorporationInventor: Janardhanan S. Ajit