Abstract: An apparatus and method are provided to re-configure an existing low-jitter phase locked loop (PLL) circuit for fast start-up during system wake-up. During system start-up, a feed-back path of the PLL is disconnected to independently control the VCO frequency. This independently controlled VCO then injects energy into a resonator (e.g., a crustal oscillator) for its fast start-up. Once a resonance frequency of the resonator is detected and an oscillation builds up in the resonator, a VCO control voltage is stored. The PLL feedback is then restored and the stored VCO control voltage is applied to perform phase-locking operation. Since the PLL control voltage is already set to the desired operating point, the PLL lock time is very small.

Abstract: Techniques for radiofrequency (RF) touch and gesture recognition are disclosed. In the illustrative embodiment, RF transmitters and receivers are connected to data lines and gate lines of a display. RF signals sent on one data or gate line may be scattered to a different data or gate line based on the presence of a nearby object, such as a finger. The amount of scattering on different data or gate lines can be used to determine a location of one or more objects.

Abstract: A reference sampling Type-I fractional-N PLL directly samples the reference clock and therefore does not use a reference buffer. Here, a phase-detector is a passive sampling switch which neither consumes any power nor generates any noise. Therefore, all the major contributors of in-band phase-noise are eliminated by the reference sampling Type-I fractional-N divider. A double sampling phase-detector with a switched-capacitor passive voltage interpolator circuit is used to achieve fractional-N output. To achieve a high resolution of the voltage interpolator or the switched capacitor, a sigma-delta modulator is used.

Abstract: A reference sampling Type-I fractional-N PLL directly samples the reference clock and therefore does not use a reference buffer. Here, a phase-detector is a passive sampling switch which neither consumes any power nor generates any noise. Therefore, all the major contributors of in-band phase-noise are eliminated by the reference sampling Type-I fractional-N divider. A double sampling phase-detector with a switched-capacitor passive voltage interpolator circuit is used to achieve fractional-N output. To achieve a high resolution of the voltage interpolator or the switched capacitor, a sigma-delta modulator is used.

Abstract: An apparatus injects a start clock to a crystal at the beginning to increase an overall start up speed of the crystal. The apparatus relies on an impedance change inside the crystal itself instead of searching for a synchronization on the yet small crystal oscillation. The apparatus includes an oscillator (separate from the crystal) to search for the crystal's resonance frequency by detecting the crystal's impedance change. Once the frequency of the oscillator matches the crystal's resonance, there is significant change in the crystal's impedance. Using that information, the apparatus can lock the oscillator frequency at the crystal resonance frequency and inject the clock with high efficiency.

Abstract: An apparatus injects a start clock to a crystal at the beginning to increase an overall start up speed of the crystal. The apparatus relies on an impedance change inside the crystal itself instead of searching for a synchronization on the yet small crystal oscillation. The apparatus includes an oscillator (separate from the crystal) to search for the crystal's resonance frequency by detecting the crystal's impedance change. Once the frequency of the oscillator matches the crystal's resonance, there is significant change in the crystal's impedance. Using that information, the apparatus can lock the oscillator frequency at the crystal resonance frequency and inject the clock with high efficiency.

Abstract: A sub-sampler phase locked loop (SSPLL) system having a frequency locking loop (FLL) and a phase locked loop (PLL) is disclosed. The FLL is configured to detect frequency variations between a phase locked loop (PLL) output signal and a reference frequency and automatically generate a pulsed correction signal upon the detected frequency variations and apply the pulsed correction signal to a voltage controlled oscillator (VCO) control voltage. The PLL is configured to generate the PLL output signal based on the VCO control voltage.

Abstract: A quadrature based voltage controlled oscillator (VCO) local oscillator (LO) system is disclosed. The system includes a phase detector, a quadrature phase VCO, a quadrature control path, an in-phase control path, and an in-phase VCO. The phase detector is configured to compare and generate phase error between a reference clock and an in-phase VCO output. The quadrature control path configured to generate a quadrature control voltage based on a quadrature VCO output and the in-phase VCO output. The quadrature phase VCO configured to generate the quadrature VCO output based on the quadrature control voltage and the generated phase error. The in-phase control path configured to generate an in-phase control voltage based on the quadrature VCO output and the in-phase VCO output. The in-phase VCO is configured to generate the in-phase VCO output based on the in-phase control voltage and the generated phase error. An all digital dual mode phase locked/phase tracking loop LO generate system is also disclosed.

Abstract: A quadrature based voltage controlled oscillator (VCO) local oscillator (LO) system is disclosed. The system includes a phase detector, a quadrature phase VCO, a quadrature control path, an in-phase control path, and an in-phase VCO. The phase detector is configured to compare and generate phase error between a reference clock and an in-phase VCO output. The quadrature control path configured to generate a quadrature control voltage based on a quadrature VCO output and the in-phase VCO output. The quadrature phase VCO configured to generate the quadrature VCO output based on the quadrature control voltage and the generated phase error. The in-phase control path configured to generate an in-phase control voltage based on the quadrature VCO output and the in-phase VCO output. The in-phase VCO is configured to generate the in-phase VCO output based on the in-phase control voltage and the generated phase error. An all digital dual mode phase locked/phase tracking loop LO generate system is also disclosed.

Abstract: A sub-sampler phase locked loop (SSPLL) system having a frequency locking loop (FLL) and a phase locked loop (PLL) is disclosed. The FLL is configured to detect frequency variations between a phase locked loop (PLL) output signal and a reference frequency and automatically generate a pulsed correction signal upon the detected frequency variations and apply the pulsed correction signal to a voltage controlled oscillator (VCO) control voltage. The PLL is configured to generate the PLL output signal based on the VCO control voltage.

Abstract: A time-based decision feedback equalizer (TB-DFE) circuit may include a voltage-to-time converter configured to convert a communication signal into a time-based signal. A timing of when an edge of the time-based signal occurs is indicative of a voltage level of the communication signal. The circuit may include a plurality of delay circuits arranged to process the time-based signal in series to generate a delay data signal. The delay circuits may adjust the timing of when the edge of the time-based signal occurs, and a corresponding time delay introduced by each of the delay circuits may be based on a respective weighting factor applied to one or more samples of an output digital signal previously generated by the TB-DFE circuit. A phase detector may compare a timing of an edge of the delay data signal with a reference clock signal and generate the output digital signal based on the comparison.

Abstract: A time-based decision feedback equalizer (TB-DFE) circuit may include a voltage-to-time converter configured to convert a communication signal into a time-based signal. A timing of when an edge of the time-based signal occurs is indicative of a voltage level of the communication signal. The circuit may include a plurality of delay circuits arranged to process the time-based signal in series to generate a delay data signal. The delay circuits may adjust the timing of when the edge of the time-based signal occurs, and a corresponding time delay introduced by each of the delay circuits may be based on a respective weighting factor applied to one or more samples of an output digital signal previously generated by the TB-DFE circuit. A phase detector may compare a timing of an edge of the delay data signal with a reference clock signal and generate the output digital signal based on the comparison.

Abstract: In one example, an oscillator circuit includes: a master oscillator comprising a master LC tank coupled to a master active circuit, the master LC tank including a primary winding of a transformer and a capacitance; a slave oscillator comprising a slave LC tank coupled to a slave active circuit, the slave LC tank including a secondary winding of the transformer and a capacitance; and a first pair of coupling transistors and a second pair of coupling transistors each coupling the master oscillator to the slave oscillator. Gates of the first pair of coupling transistors are coupled to the master oscillator through a switch. Gates of the second pair of coupling transistors are coupled to the master oscillator through respective ninety-degree phase shifters and the switch.

Abstract: An integrated circuit includes a number of pads. The integrated circuit further includes a cascode transistor having an open drain connection to a first one of the pads. A bias generator circuit is included in the integrated circuit. The bias generator circuit has an output connected to a gate terminal of the cascode transistor. In a first mode of operation, the bias generator outputs a bias signal that is derived from an integrated circuit supply voltage present at a second one of the pads. However, in a second mode of operation provided when the integrated circuit supply voltage is not present, the bias generator generates the bias signal derived from a voltage present at the first one of the pads.

Abstract: An integrated circuit includes a number of pads. The integrated circuit further includes a cascode transistor having an open drain connection to a first one of the pads. A bias generator circuit is included in the integrated circuit. The bias generator circuit has an output connected to a gate terminal of the cascode transistor. In a first mode of operation, the bias generator outputs a bias signal that is derived from an integrated circuit supply voltage present at a second one of the pads. However, in a second mode of operation provided when the integrated circuit supply voltage is not present, the bias generator generates the bias signal derived from a voltage present at the first one of the pads.