摘要:
Methods and apparatus relate to a bidirectional differential interface having a voltage-mode transmit driver architecture formed of multiple selectively enabled slices for coarse output resistance impedance matching. In an illustrative example, the transmit driver may include a programmable resistance for fine-tuning to impedance match the output resistance for transmit operation. During receive operation, protective voltage may be proactively applied to gates of drive transistors, for example, to minimize voltage stresses applied by external signal sources. Some implementations may automatically float the sources of the drive transistors, for example, to prevent back-feeding externally driven signal currents during receive mode operations. The transmit driver may have programmable voltage swing on, for example, the upper and/or lower bounds to enhance compatibility. A programmable common mode voltage node may be selectively applied, for example, through common mode resistors for receive mode operations. Various embodiments may reduce pin count for high speed bidirectional I/O.
摘要:
A phase locked loop (PLL) circuit includes a voltage controlled oscillator (VCO), a first loop circuit, and a second loop circuit. The first loop circuit includes a first loop filter configured to receive a first signal based on a feedback signal from the VCO and provide a first VCO frequency control signal to the VCO. The second loop circuit includes a compensation circuit configured to receive a reference signal and the first signal, and provide a second VCO frequency control signal to the VCO.
摘要:
An example automatic gain control (AGC) circuit includes a base current-gain circuit having a programmable source degeneration resistance responsive to first bits of an AGC code word. The AGC circuit further includes a programmable current-gain circuit, coupled between an input and an output of the base current-gain circuit, having a programmable current source responsive to second bits of the AGC code word. The AGC circuit further includes a bleeder circuit, coupled to the output of the base current-gain circuit, having a programmable current source responsive to logical complements of the second bits of the AGC code word. The AGC circuit further includes a load circuit coupled to the output of the base current-gain circuit.
摘要:
Apparatus and associated methods relate to automatically generating a data structure representation of an on-chip inductive-capacitive (LC) tank circuit by determining parasitic inductances in each of the segments of conductive paths that connect a main inductor to one or more selectable VCO components such as capacitors and varactors, for example. In an illustrative example, one or more of the selectable VCO components may be arranged, when selected, to form a parallel resonant LC tank with the main inductor. A method may include defining nodes ai terminating each of the segments along the conductive paths between the main inductor terminals and a drive circuit. By modelling the paths as multi-port inductors and transformers, resonant frequency of the VCO may be more accurately predicted by simulation.
摘要:
An apparatus relating to on-chip noise measurement is disclosed. In such an apparatus, an asynchronous comparator receives a first input and a second input to provide a digital output. A threshold voltage generator receives a first periodic signal and a second periodic signal to provide the second input as an analog voltage responsive to the first and second periodic signals. A sampling circuit is coupled to receive the digital output signal and a third periodic signal. The sampling circuit is configured to sample the digital output signal using the third periodic signal to provide a sampled signal of the digital output signal. A processor is coupled to receive a delay signal and the sampled signal to determine a noise measurement signal for the first input signal.
摘要:
An example automatic gain control (AGC) circuit includes a base current-gain circuit having a programmable source degeneration resistance responsive to first bits of an AGC code word. The AGC circuit further includes a programmable current-gain circuit, coupled between an input and an output of the base current-gain circuit, having a programmable current source responsive to second bits of the AGC code word. The AGC circuit further includes a bleeder circuit, coupled to the output of the base current-gain circuit, having a programmable current source responsive to logical complements of the second bits of the AGC code word. The AGC circuit further includes a load circuit coupled to the output of the base current-gain circuit.
摘要:
In an example, a phase-locked loop (PLL) circuit includes an error detector operable to generate an error signal; an oscillator operable to provide an output signal having an output frequency based on the error signal and a frequency band select signal, the output frequency being a frequency multiplier times a reference frequency; a frequency divider operable to divide the output frequency of the output signal to generate a feedback signal based on a divider control signal; a sigma-delta modulator (SDM) operable to generate the divider control signal based on inputs indicative of an integer value and a fractional value of the frequency multiplier, the SDM responsive to an order select signal operable to select an order of the SDM; and a state machine operable to, in an acquisition state, generate the frequency band select signal and set the order of the SDM.
摘要:
A phase locked loop (PLL) circuit includes a voltage controlled oscillator (VCO), a first loop circuit, and a second loop circuit. The first loop circuit includes a first loop filter configured to receive a first signal based on a feedback signal from the VCO and provide a first VCO frequency control signal to the VCO. The second loop circuit includes a compensation circuit configured to receive a reference signal and the first signal, and provide a second VCO frequency control signal to the VCO.
摘要:
An example sigma delta modulator (SDM) circuit includes a floor circuit, a subtractor having a first input coupled an input of the floor circuit and a second input coupled to an output of the floor circuit, and a multi-stage noise shaping (MASH) converter having a programmable order. The MASH converter includes an input coupled to an output of the subtractor. The SDM further includes a programmable delay circuit having an input coupled to the output of the floor circuit, and an adder having a first input coupled to an output of the MASH converter and a second input coupled to an output of the programmable delay circuit.
摘要:
A method relates generally to data reception for any of a plurality of data rates. In such a method, information and phases of a clock signal are obtained by a decision feedback equalizer. The information is equalized using the phases of the clock signal with the decision feedback equalizer to provide equalized sample streams. The equalized sample streams and the phases of the clock signal are provided to a selection circuit block. A first and a second phase of the phases are swapped, along with swapping a first and a second equalized sample stream corresponding to the first phase and the second phase, responsive to a data rate of the plurality of data rates.