摘要:
High resolution output drivers having a relatively small number of sub-driver branches or slices each having nominal impedances substantially larger than a quantization step and that incrementally differ from one another by an impedance step substantially smaller than a quantization step. In one implementation, such “differential” or “non-uniform” sub-driver slices implement respective elements of an n choose k equalizer, with each such differential sub-driver slice being implemented by a uniform-element impedance calibration DAC. In another implementation, each component of a uniform-slice equalizer is implemented by a differential-slice impedance calibration DAC, and in yet another implementation, each component of a differential-slice equalizer is implemented by a differential-slice impedance calibration DAC. In an additional set of implementations, equalization and impedance calibration functions are implemented bilaterally in respective parallel sets of driver branches, rather than in the nested “DAC within a DAC” arrangement of the hierarchical implementations. Through such bilateral arrangement, multiplication of the equalizer and calibrator quantizations is avoided, thereby lowering the total number of sub-driver slices required to meet the specified ranges and resolutions.
摘要:
High resolution output drivers having a relatively small number of sub-driver branches or slices each having nominal impedances substantially larger than a quantization step and that incrementally differ from one another by an impedance step substantially smaller than a quantization step. In one implementation, such “differential” or “non-uniform” sub-driver slices implement respective elements of an n choose k equalizer, with each such differential sub-driver slice being implemented by a uniform-element impedance calibration DAC. In another implementation, each component of a uniform-slice equalizer is implemented by a differential-slice impedance calibration DAC, and in yet another implementation, each component of a differential-slice equalizer is implemented by a differential-slice impedance calibration DAC. In an additional set of implementations, equalization and impedance calibration functions are implemented bilaterally in respective parallel sets of driver branches, rather than in the nested “DAC within a DAC” arrangement of the hierarchical implementations. Through such bilateral arrangement, multiplication of the equalizer and calibrator quantizations is avoided, thereby lowering the total number of sub-driver slices required to meet the specified ranges and resolutions.
摘要:
A differential amplifier with adaptive biasing and offset cancellation is disclosed. In one particular exemplary embodiment, the differential amplifier may comprise a first electrical path comprising a first transistor and a first resistance element, and a second electrical path comprising a second transistor and a second resistance element, where the first and the second electrical paths are coupled to a voltage source on one end and to a current source on the other end. The differential amplifier may further comprise a first adjustable current source coupled between the voltage source and a first node located between the first transistor and the first resistance element, and a second adjustable current source coupled between the voltage source and a second node located between the second transistor and the second resistance element, wherein the first and second adjustable current sources provide biasing currents for the two electrical paths.
摘要:
A differential amplifier with adaptive biasing and offset cancellation is disclosed. In one particular exemplary embodiment, the differential amplifier may comprise a first electrical path comprising a first transistor and a first resistance element, and a second electrical path comprising a second transistor and a second resistance element, where the first and the second electrical paths are coupled to a voltage source on one end and to a current source on the other end. The differential amplifier may further comprise a first adjustable current source coupled between the voltage source and a first node located between the first transistor and the first resistance element, and a second adjustable current source coupled between the voltage source and a second node located between the second transistor and the second resistance element, wherein the first and second adjustable current sources provide biasing currents for the two electrical paths.
摘要:
A circuit includes a frequency synthesizer, N phase mixers coupled to the frequency synthesizer, a plurality of receivers, and a calibration circuit. The frequency synthesizer is to receive a reference clock signal and is to output a primary clock signal. A respective phase mixer in the N phase mixers is to output a respective secondary clock signal having a corresponding phase. A respective receiver in the plurality of receivers is coupled to two of the N phase mixers, and at a respective time is to receive data in accordance with the respective secondary clock signal from one of the two phase mixers coupled to the respective receiver. The calibration circuit is to calibrate a secondary clock signal output by a respective phase mixer in the N phase mixers by adjusting the phase of the secondary clock signal of the respective phase mixer.
摘要:
An integrated circuit includes samplers, a phase error determination circuit, and periodic signal generators. The samplers generate respective sampled signals by sampling respective input signals in response to respective periodic signals. The input signals have a common phase error. The phase error determination circuit receives the sampled signals from the samplers. The phase error determination circuit generates a representation of the common phase error of the input signals in response to sampled signals received in a set-up mode in which the samplers sample respective input signals having a common bit pattern. The periodic signal generators generate the periodic signals differing in phase from one another by defined phase differences in the set-up mode and subject the periodic signals to a common phase shift in a normal mode in response to the representation of the common phase error. The common phase shift matches the common phase error of the input signals.
摘要:
A communication channel includes a first component having a transmitter coupled to a normal signal source, and a second component having a receiver coupled to a normal signal destination. A communication link couples the first and second components. Calibration logic provides for setting an operation value for a parameter of the communication channel, such as by executing an exhaustive calibration sequence at initialization of the link. A tracking circuit, including a monitoring function, tracks drift in the parameter by monitoring a feedback signal that has a characteristic that correlates with drift in the communication channel, and updates, or indicates the need for updating of, the operation value of the parameter in response to the monitoring function.
摘要:
Clocking circuitry includes a first clock generator to generate a first clock signal and having a first duty cycle correction input, and a second clock generator to generate a second clock signal and having a second duty cycle correction input. Some embodiments have more than two clock generators. A multiplexer selects between the clock signals from the clock generators. The multiplexer has a first input coupled to the first clock signal and has a second input coupled to the second clock signal, and has a clock output coupled to a clock input of a duty cycle circuit. The duty cycle circuit receives the selected clock signal from the multiplexer and generates a duty cycle correction signal.
摘要:
A system that adjusts the timing of write operations at a memory controller is described. This system operates by observing timing drift for read data at the memory controller, and then adjusting the timing of write operations at the memory controller based on the observed timing drift for the read data.
摘要:
A PLL/DLL circuit is current self-biased responsive to a current Ild provided from a voltage regulator to a VCO or VCDL. Bias current Ibias, which is proportional to Ild, is provided to components of the PLL/DLL, such as a charge pump or loop resistor, from an interconnect coupled to the voltage regulator. In an embodiment of the present invention, a component of the PLL/DLL includes a bias-generating device, such as a MOSFET p-type transistor having a drain coupled to the interconnect. In an embodiment of the present invention, a voltage regulator includes an AMP having a bias-generating device, such as a p-type transistor, acting as a current source, having a source coupled to Vdd and a drain coupled to the interconnect. The gate of the bias-generating device is coupled to the gate of four other p-type devices. Each of the four p-type devices has a source coupled to Vdd. The drains of the first and second p-type transistors are coupled to an output providing Ild. A negative input of the AMP (“INM”) is coupled to the gate of a first n-type transistor and a positive input of the AMP (“INP”) is coupled to the gate of a second n-type transistor. The drains of the first and second n-type transistors are coupled to the drains of the second and third p-type transistors. The sources of the first and second n-type transistors are coupled to the drain of a third n-type transistor. The source of the third n-type transistor is coupled to ground and the gate is coupled to a fourth n-type transistor. The drain of the fourth n-type transistor is coupled to the drain of the fourth p-type transistor and the source of the fourth n-type transistor is coupled to ground.