Abstract: Described herein are a method and apparatus for a selective SYSREF (SYStem REFerence signal) scheme that is driven by an external SYSREF source for a system that may include, for example, analog blocks, such as analog-to-digital converters (ADCs), digital-to-analog converters (DACs), radio frequency (RF) arrays, as well as digital blocks, which may include JESD serializer/deserializer (SERDES) Transport and Link Layer circuitry, all of which can be operating at different clock frequencies. In one aspect, synchronization of the components is achieved when an internal SYSREF for the analog blocks is keyed off the external SYSREF, but the internal SYSREF pulse used by the digital blocks is programmatically keyed off one of the periodic internal SYSREF pulses. Additionally, a mechanism is provided for synchronization of the programmatically selected internal SYSREF across different clock domains in the digital blocks.

Abstract: Aspects of the disclosure are directed to adaptively delaying an input signal. In accordance with one aspect, an apparatus includes a plurality of delay units, wherein each of the plurality of delay units includes a substantially similar output load characteristic; a plurality of buffer units, wherein each of the plurality of buffer units is coupled to one of the plurality of delay units; wherein a quantity of the plurality of delay units equals a quantity of the plurality of buffer units; an additional delay unit coupled to a delay unit output of one of the plurality of delay units; and a one-hot decoder coupled to each of the plurality of buffer units, the one-hot decoder configured to enable one and only one of the plurality of buffer units.

Abstract: Digital controlled delay lines are provided. A digital controlled delay line includes a plurality of delay cells coupled in a chain forming a propagation path to propagate an input signal and to delay the input signal by a delay time. The propagation path is formed when a single delay cell is operated in a feedback mode, the delay cells previous to the single delay cell in the chain are operated in a propagation mode, a subsequent delay cell following the single delay cell in the chain is operated in a standby mode, and the delay cells following the first subsequent delay cell in the chain are operated in an idle mode.

Abstract: Programmable delay circuits are described herein according to embodiments of the present disclosure. In one embodiment, a delay circuit comprises a plurality of delay stages coupled in series. Each of the delay stages comprises a delay gate on a forward path of the delay circuit, wherein the delay gate is configured to pass or block a signal on the forward path depending on a logic state of a respective select signal. Each of the delay stages also comprises a multiplexer on a return path of the delay circuit, wherein the multiplexer is configured to pass a signal on the return path or route the signal on the forward path to the return path depending on the logic state of the respective select signal. Output logic states of the delay gates and the multiplexers may remain static during a change in the delay setting of the delay circuit to reduce glitch.

Abstract: A delay time adjusting circuit is described, in which a reference signal circuit generates at least one reference signal to an A/D conversion circuit, an input signal circuit generates an input signal to the A/D conversion circuit, the A/D conversion circuit compares the input signal with the at least one reference signal to output a digital signal to a digital logic chip, and the digital logic chip determines a delay time based on the digital signal. In this way, the delay time can be determined digitally, and an adjusting accuracy of the delay time can be increased; and also, the delay time can be adjusted through changing the level of the input signal, thus reducing circuit losses and costs.

Abstract: A delay circuit includes a first flip flop (FF), a transistor connected to the FF, a first resistor capacitor circuit (RCC) coupled to the transistor and between a voltage and a ground, a first comparator for comparing an output of the first RCC and a voltage reference, gate logic coupled to the input line and to an output of the first FF and to a second FF, a second transistor coupled to the second FF, a second RCC coupled to the second transistor and between the voltage and ground, a second comparator for comparing an output of the second RCC and the voltage reference and coupled to the first FF, and output logic coupled to the first and second comparators.

Abstract: A digitally controlled delay device includes at least one delay generating gate device, whose propagation delay is controlled by limiting operating current by means of a tail transistor that is controlled by its gate voltage, a gate control voltage control means for controlling the current limiting transistor gate voltage, and a bank of digitally controlled MOSFET transistors in parallel configuration, and the digital control is adapted to switch the transistors to off and to diode mode connection, current feeding means to feed current through the bank of MOSFET transistors, and the voltage over the bank of parallel transistors is used for gate source control voltage of the tail transistors.

Abstract: Techniques and mechanisms for operating an integrated circuit to communicate via a hardware interface for the integrated circuit, wherein a pinout with the hardware interface is based on the configuration. In an embodiment, the integrated circuit receives a first plurality of signals via the hardware interface, and sequentially latches a second plurality of signals based on the first plurality of signals. In another embodiment, some or all of the second plurality of signals are variously latched by the integrated circuit in an order which is based on the first configuration.

Abstract: A method and system in accordance with the present invention provides for a method and circuit for oversampling using a delay element in which input clock signals and input data signals are affected by phase and time delays to provide for the circuit generating samples providing a greater granularity of detail over a period, thereby reducing error probabilities.

Abstract: Various embodiments of a method of configuring a delay circuit for generating a plurality of delays in a delay line and a delay circuit configurable for generating plurality of delays are provided. The method includes determining, through a control circuit coupled with a delay line set, a first number of delay steps corresponding to an intrinsic delay of a delay line from among a plurality of delay lines of the delay line set. The intrinsic delay is a minimum delay contributed by the delay line. The method also includes determining, through the control circuit, a second number of delay steps to provide a delay through the delay line based on the first number of delay steps. The method further includes configuring, through a configuration circuit coupled with the delay line set, the delay line for generating the delay corresponding to the second number of delay steps through the delay line.

Abstract: In a solid-state imaging device, each of a plurality of switches is connected between a pulse output terminal of each delay unit and a pulse input terminal of the next-stage delay unit. Each of a plurality of switches is connected between the pulse output terminal and the pulse input terminal of each delay unit. A plurality of switches is turned on and a plurality of switches is turned off in conjunction with an oscillation operation, and a plurality of switches is turned off and a plurality of switches is turned on in conjunction with a holding operation.

Abstract: A structure for performing cross-chip communication with mesochronous clocks. The structure includes: a data delay line; a remote clock delay line; a structure that captures at least one value of a state of a delayed remote clock signal on the remote clock delay line; and a control that influences a delay associated with the data delay line and the remote clock delay line.

Abstract: According to an aspect of the embodiment, a driver outputs a driver current to a reception LSI, and a receiver included in the reception LSI receives an analog voltage signal corresponding to a value of the driver current as a receiver input. An A/D converter converts the voltage signal of the receiver input to a digital value, and transmits the digital value to a driver current controller in a transmission LSI. The driver current controller adjusts a number of PMOS driving stages in the driver or a number of NMOS driving stages in the driver, to make the digital value of the voltage signal of the receiver input belong to a predetermined range.

Abstract: A method for source synchronous communication. The method includes dynamically adjusting a delay that is applied to a data signal and a remote clock signal until a delayed remote clock signal is synchronized with a local clock signal, and capturing data from a delayed data signal associated with the delay in a local domain.

Abstract: A device for detecting an approach or a touch related to at least one sensor element, in particular in an electrical appliance, the device comprising an input side and an output side, between which a first signal path with a first input and a first output and a second signal path with a second input and a second output are arranged, wherein the first signal path comprises a delay device with a delay, the delay device configured to delay a digital first input signal at the first input into a digital first output signal at the first output, wherein the delay is dependent on a capacitance value resulting from the approach or the touch related to the sensor element, and wherein the second signal path comprises an XOR-element, which is configured to generate an edge in a digital second output signal at the second output, when the digital first output signal outputted by the delay device exhibits an edge.

Abstract: A method and circuit for generating an adjustable delay signal is presented, wherein the delay can be linear and monotonic with high resolution delay steps. The circuit utilizes one or more serially coupled delay cells and a load cell. Each delay cell comprises an inverter, a nor-multiplexer, and a programmable capacitor, wherein a first control signal is used to control the operation of the nor-multiplexer and a second control signal is used to control capacitance of the programmable capacitor. Values of the first and the second control signals are selected based on any desired range of total delay time and any desired delay time for a specific application of the circuit.

Abstract: A delay circuit of a semiconductor device increases its delay time as an external voltage increases. The delay circuit can also ensure a desired delay time according to an external voltage, without additional delay circuits. The delay circuit of the semiconductor device includes a first delay unit, and a second delay. The second delay unit has a propagation delay characteristic different from that of the first delay unit with respect to variation of a power supply voltage, wherein the first delay unit is supplied with a first power supply voltage independent of variation of an external voltage, and the second delay unit is supplied with a second power supply voltage dependent on the variation of the external voltage.

Abstract: A delay circuit and method of operation has a plurality of series-connected stages including a first stage and a last stage that provides the delayed signal. Each of the series-connected stages has a plurality of series-connected transistors having an outermost transistor and an innermost transistor and one or more or none of a plurality of intervening transistors. Each of the plurality of series-connected transistors is connected in series to a respective different load stack. An input signal that is coupled to the first stage is propagated repeatedly between the first stage, intervening stages if any, and a last stage. The first stage has a signal input, one or more feedback inputs, and at least two output terminals.

Abstract: Disclosed herein is a delay circuit for performing one of a charge and a discharge in two stages, and delaying a signal, the delay circuit including an output section configured to output a delayed signal; two power supplies; and a delay inverter; wherein the delay inverter has a first transistor and a second transistor of an identical channel type for one of a first charge and a first discharge, the first transistor and the second transistor being connected in series with each other between the output section and one power supply, and the delay inverter has a third transistor of a different channel type from the first transistor and the second transistor for one of a second charge and a second discharge, the third transistor being connected in parallel with one of the first transistor and the second transistor.

Abstract: A voltage-controlled oscillation circuit (15) includes a plurality of independent ring oscillation circuits different in the number of stages; and a selector (22) selectively outputting as a feedback clock signal (FB) an output of one of the ring oscillation circuits, so that any of the outputs of the independent ring oscillation circuits is always outputted as the feedback clock signal, which makes it possible to output the feedback clock signal keeping a proper duty ratio even when the operating speed is high, allowing arbitrary adjustment of the delay time before an input signal (DLLI) is outputted.

Abstract: An apparatus for the controlled delay of an input signal includes a signal input for receiving an input signal. The input signal is supplied to a delay line with a multiplicity of delay elements. Outputs of the delay elements allow respective differently delayed phase signals to be tapped off. Furthermore, a register line with a multiplicity of register elements is provided. The register elements are each associated with one of the delay elements. Each of the register elements has a reset input and a clock input. The reset inputs are coupled to the signal input. The outputs of the delay elements are each coupled to the clock input of the register element associated therewith.

Abstract: A delay circuit acquiring an output signal delayed from an input signal, comprising: a switched capacitor group that includes a plurality of switched capacitor units, wherein each of the plurality of switched capacitor units has a charging MOS transistor and a discharging MOS transistor, and a capacitive element which is connected to sources of the charging and the discharging MOS transistors; and a switching control unit that performs on/off control of the charging and the discharging of the MOS transistors, to cause each of the capacitive elements to be charged in sequence based on the input signal, and that, upon causing the each of the capacitive elements to be charged in sequence based on the input signal, causes the capacitive element charged last time to be discharged, to allow the output signal to be output in sequence.

Abstract: A configurable delay chain with switching control. The configurable delay chain includes a plurality of delay elements. A switch circuit is included and is coupled to the delay elements and configured to select at least one of the plurality of delay elements to create a delay signal path. The delay signal path has an amount of delay in accordance with a number of delay elements comprising the delay signal path. An input is coupled to a first delay element of the delay signal path to receive an input signal and an output is coupled to the switch circuit and is coupled to the delay signal path to receive a delayed version of the input signal after propagating through the delay signal path. A plurality of turnoff devices are coupled to inputs of the delay elements and coupled to the switch circuit, wherein the switch circuit activates at least one turnoff device of at least one unused delay element that is not on the delay signal path.

Abstract: Certain exemplary embodiments can provide a system, which can comprise a circuit adapted to cause an actuation of an output device according to a control output. The control output can be generated comprising a control signal, the control signal extracted from a sequence of clock pulses. The sequence of clock pulses can comprise the control signal.

Abstract: A clock synchronization system and method avoids output clock jitter at high frequencies and also achieves a smooth phase transition at the boundary of the coarse and fine delays. The system may use a single coarse delay line configured to generate two intermediate clocks from the input reference clock and having a fixed phase difference therebetween. The coarse delay line may have a hierarchical or a non-hierarchical structure. A phase mixer receives these two intermediate clocks and generates the final output clock having a phase between the phases of the intermediate clocks. The coarse shifting in the delay line at high clock frequencies does not affect the phase relationship between the intermediate clocks fed into the phase mixer. The output clock from the phase mixer is time synchronized with the input reference clock and does not exhibit any jitter or noise even at high clock frequency inputs.

Abstract: Improvement of quantization errors that arise in a delay line with finite resolution. A direct digital synthesizer (DDS), which contains a numerically controlled oscillator (NCO) and a digital-to-phase converter (DPC), is placed in the feedback loop of a phase locked loop (PLL). The DDS is used as a fractional divider of the voltage controlled oscillator (VCO) frequency, such that the reference frequency of the DDS is made variable. Alignment of the edges provided by the DDS delay line may then be adjusted. Mismatch errors in the DDS delay line are reduced by utilizing independently tunable delay elements.

Abstract: A delay locked loop for generating an internal clock signal locked to an external clock signal includes: a phase detector for detecting a phase difference between the external clock signal and the internal clock signal; a delay unit controller for generating a control signal and a selection signal in response to an output signal of the phase detector; a variable delay device (VDD), responsive to the control signal and a selection signal, to produce a delayed version of the external clock signal on a VDD output line, the variable delay device being configured such that, if the external clock signal undergoes a change from a first frequency to a second frequency significantly different than the first frequency, then a resultant load on the VDD output line nonetheless remains substantially the same.

Abstract: Delay line circuits include a plurality of delay cells connected in series. The delay cells respectively include a first to a third logic gate. The first logic gate, in response to a selection signal, generates a first signal based on an input signal. The second logic gate generates a second signal based on the input signal in response to the selection signal. The third logic gate generates a third signal based on either a return signal or an output signal of the second logic gate.

Abstract: A hierarchical and modular clock programmable delay circuit structure is described that can achieve almost unlimited fine resolution and unlimited delay range. The same circuit may also be applied to critical circuits that require fine adjustment in timing applications. The modular design allows the circuit and its layout to be synthesized by software to achieve desired delay resolution and range. Constant capacitive load of internal node enhances the linearity of achieved delay by digital controls.

Abstract: A delay circuit comprises: N-stage circuits having a first circuit to an N-th circuit connected in cascade, the input signal being input to the first circuit and a transmission signal delayed by a (k-1)-stage (where 2?k?N) circuit is input to a k-th circuit for sequential transmission; a common delay circuit for delaying the transmission signal of each stage commonly; and path control means for controlling a path of an i-th (1?i?N) circuit so that during a predetermined period from an edge timing of a signal input to the i-th circuit to an edge timing of the transmission signal delayed by the common delay circuit through the i-th circuit, the common delay circuit is connected to a signal path, and during the other period, the common delay circuit is disconnected from the signal path, wherein the delayed signal passing through the common delay circuit N times is generated.

Abstract: A time-to-digital converter (TDC), a system-on-chip including a TDC, a method of phase detection for use in synthesizing a clock signal and a non-linearity corrector for a TDC. In one embodiment, the TDC includes a chain of delay elements configured to receive a clock signal and generate delayed clock signals. Each one of the delay elements includes: (1) a non-inverting buffer configured to delay the clock signal by about twice a delay of an inverter to provide a buffer-delayed clock signal and (2) a first transmission gate coupled to the non-inverting buffer and configured to delay the clock signal by about the delay of an inverter to provide a first gate-delayed clock signal.

Abstract: Circuits and methods for generating multi-phase clock signals using digitally-controlled hierarchical delay units (HDs) are provided. A plurality of serially-coupled HDs outputs clock signals that are phase-shifted relative to a reference clock signal. Each HD includes either one or two variable delay lines that provide coarse phase adjustment of an associated input signal. Each HD also includes one or more phase mixers that provide fine phase adjustment of the input signal.

Abstract: A delay control circuit capable of controlling a delay time is disclosed. The delay control circuit includes a delay detecting circuit, a first pulse generator, a counter control circuit and a counter. The delay detecting circuit delays an input signal by a first time in response to an output signal and compares the input signal and the delayed input signal to generate a first signal. The first pulse generator generates a second signal in response to the input signal. The counter control circuit generates a count-up signal and a count-down signal in response to the first signal and the second signal. The counter generates the output signal in response to the count-up signal and the count-down signal to divide the first time by 2n intervals, wherein n is a positive integer.

Abstract: High resolution digital delay circuits and methods are provided. A multiplexer receives the outputs of first and second delay elements. At least the second delay element is adjustable using a digital control signal. The multiplexer and the first delay element form a first delay loop. The multiplexer, the first delay element and the second delay element form a second delay loop. A logic circuit monitors the number of times (M) that a signal cycles through the first loop. After M reaches a predetermined value (i.e., when the signal is delayed by a predetermined delay), the multiplexer receives a control signal that causes the second loop to close. A signal cycles through the second loop, which provides additional delay. Preferably, the signal cycles through the second loop only once. Generally, this causes the resolution of the delay circuit to be proportional to the minimum delay adjustment of the second delay element.

Abstract: A semiconductor integrated circuit that has an output circuit in which an output-stage operating voltage lower than a power supply voltage is applied to an output stage is provided. Even when the power supply voltage is lowered, a sufficient output signal amplitude can be obtained. An increase in circuit scale can be prevented and the power consumption can be reduced. An output-stage operating voltage supply source, including an N-channel MOS transistor having a first threshold voltage, applies an operating voltage lower than a power supply voltage to the output stage of the output circuit. A drive-circuit operating voltage supply source, including an N-channel MOS transistor having a second threshold voltage lower than the first threshold voltage, applies a drive-circuit operating voltage higher than the output-stage operating voltage to a drive circuit.

Abstract: Circuits and methods for generating multi-phase clock signals using digitally-controlled hierarchical delay units (HDs) are provided. A plurality of serially-coupled HDs outputs clock signals that are phase-shifted relative to a reference clock signal. Each HD includes either one or two variable delay lines that provide coarse phase adjustment of an associated input signal. Each HD also includes one or more phase mixers that provide fine phase adjustment of the input signal.

Abstract: A set of interconnected delay stages, such as a voltage-controlled oscillator, has switch-controlled load circuitry connected to each output of each delay stage in the oscillator ring. In one embodiment, for each delay stage output, the switch-controlled load circuitry includes a switch, a transistor, and a current source. The switch is connected between the corresponding delay stage output and the transistor gate, the current source is connected between a power supply and the transistor drain, and the transistor source is connected to ground. In such a configuration, the transistor's gate-to-source capacitance can be applied to the corresponding delay stage output by closing the switch, for example, for lower-frequency operations. In addition, the output impedance of the current source decouples the capacitive load from the power supply, thereby substantially shielding the oscillator ring from noise in the power supply.

Abstract: High resolution digital delay circuits and methods are provided. A multiplexer receives the outputs of first and second delay elements. At least the second delay element is adjustable using a digital control signal. The multiplexer and the first delay element form a first delay loop. The multiplexer, the first delay element and the second delay element form a second delay loop. A logic circuit monitors the number of times (M) that a signal cycles through the first loop. After M reaches a predetermined value (i.e., when the signal is delayed by a predetermined delay), the multiplexer receives a control signal that causes the second loop to close. A signal cycles through the second loop, which provides additional delay. Preferably, the signal cycles through the second loop only once. Generally, this causes the resolution of the delay circuit to be proportional to the minimum delay adjustment of the second delay element.

Abstract: A pulse width control system includes a serial transmission line for receiving serial data signals and a differential pair having a first transistor and a second transistor. The first and second transistors are connected to the transmission line for respectively producing a positive data signal and a negative data signal. The first and second transistors are respectively controlled by a first control signal and a second control signal, with a differential data signal being produced by subtracting the negative data signal from the positive data signal. First and second delay control cells are connected to the first and second transistors for respectively delaying the first and second control signals. Delay times caused by the first and second delay control cells to delay the first and second control signals are adjusted to ensure that all data pulses of the differential data signal have uniform width.

Abstract: A mixer circuit arrangement 30 comprises a complementary transconductor circuit 31 and a mixer stage 32. The complementary transconductor circuit 31 includes two paths in parallel between a positive supply voltage VDD and ground G and is connected directly between the voltage supply terminals VDD and G. The first path includes a P-type MOS transistor TP1 and an N-type MOS transistor TN1 connected in series. Similarly, the second path includes a P-type MOS transistor TP2 and an N-type MOS transistor TN2 connected in series. The gate electrodes of the P-type transistors TP1 and TP2 are connected to a voltage bias Vbp via high value bias resistors Rb, and the gate electrodes of the N-type transistors TN1 and TN2 are connected to a second voltage bias Vbn via high value bias resistors Rb. The mixer stage 32 is connected between the output of the complementary transconductor circuit 31 and a load, the load also being connected to one of the supply terminals.

Abstract: Circuits and methods for generating multi-phase clock signals using digitally-controlled hierarchical delay units (HDs) are provided. A plurality of serially-coupled HDs outputs clock signals that are phase-shifted relative to a reference clock signal. Each HD includes either one or two variable delay lines that provide coarse phase adjustment of an associated input signal. Each HD also includes one or more phase mixers that provide fine phase adjustment of the input signal.

Abstract: A variable-delay signal generator circuit includes a delay chain and an interpolator circuit. The delay chain produces multiple multi-phase signals, where each of the multi-phase signals represents a delayed version of an input event signal. Each of the multi-phase signals is separated from consecutive signals by a first phase increment. The interpolator circuit includes multiple interpolator blocks, where each block receives a multi-phase signal. The interpolator circuit interpolates between consecutive interpolator blocks, to produce an output signal that represents a modified-delay version of the input event signal. The output signal is delayed to one of multiple phase delays that exist between consecutive multi-phase signals, inclusive. To produce the output signal, a variable current source within each interpolator block is adjusted, based on a current source select signal. The current source select signal is produced by a bias circuit, which includes a split current source.

Abstract: A ring oscillator circuit, such as a VCO, with a relatively high level of noise rejection for noise originating from both the voltage supply and ground. The ring oscillator circuit is composed of a plurality of differential delay circuits, each differential delay circuit generating a differential output signal that is a delayed (and preferably inverted) version of a differential input signal. ‘Each differential delay circuit includes first and second input transistors for receiving the differential input signal. Each differential delay circuit also includes first and second load transistors coupled in parallel with the respective first and second input transistors. Each differential delay circuit further includes a first current source coupled between the first input transistor and a first power supply terminal (e.g.

Abstract: A delay circuit including a delay section having two or more predetermined delay stages is disclosed. Each predetermined delay stage adds a predetermined delay time to an input signal. The delay circuit also includes selecting switch sections. At least one of the selecting switch sections includes: a buffer section for receiving a delayed input signal from one of the delay stages and a selecting section means directly connected to the buffer section for activating the buffer section to establish a delay path, wherein an output signal from the delay path has a desired delay time.

Abstract: Disclosed is a clock period sensing circuit in which it is possible to broaden the operating range of phase adjustment and frequency multiplier circuits, etc., by performing coarse period adjustment in advance. A plurality of delay sensing circuits having slightly overlapping operating ranges and different centers of operation are connected in parallel with respect to a an input clock signal, which is passed through the delay sensing circuits. The period of the clock is sensed coarsely in short periods using a signal which identifies delay sensing circuits through which the clock signal has passed and delay sensing circuits through which the clock signal has not passed.

Abstract: A transition delay circuit having an input terminal and an output terminal is disclosed. According to one embodiment, the transition delay circuit also includes a first MOS capacitor, a second MOS capacitor, and a delay circuit. The first MOS capacitor includes a first terminal connected to the input terminal of the transition delay circuit and a second terminal that is connected to the output terminal of the transition delay circuit. The second MOS capacitor includes a first terminal connected to the input terminal of the transition delay circuit and a second terminal that is connected to the output terminal of the transition delay circuit. The second MOS capacitor has a different polarity than the first MOS capacitor. The delay circuit includes a first terminal connected to the input terminal of the transition delay circuit and a second terminal that is connected to the output terminal of the transition delay circuit.

Abstract: A digitally programmable delay circuit is provided, which includes a control input and a plurality of delay stages coupled in series with one another to form a delay line. Each stage has a previous stage input, a previous stage output, a next stage input and a next stage output. The next stage output and the next stage input are coupled to the previous stage input and the previous stage output, respectively, of a next one of the delay stages in the delay line. The previous stage input is coupled to the next stage output. The previous stage input and the next stage input are selectively coupled to the previous stage output based on the control input.

Abstract: A delay device has multiplexers connected in series in a differential configuration. First connections of the multiplexers are connected to the output of an upstream multiplexer. Second inputs of the multiplexers are connected to the input connection to which the signal that is to be delayed can be supplied. A control signal controls the switch position of one of the multiplexers such that its output is connected to the input of the delay device. All the other multiplexers are in the other switch position. This results in the delay device producing a specific delay time. When used in a delay control loop, this results in a jitter-free output signal, even if the operating conditions are fluctuating.

Abstract: A delay circuit has a delay that is consistent under varying process and temperature conditions. The delay through a delay path is controlled by inserting resistors on the pull-up and pull-down paths of the delaying inverters. Each resistor has a resistance value that is determined by a varying a number of enabled similarly-sized transistors coupled in parallel across the resistor, rather than by varying the size of a single transistor. In one embodiment, a first transistor in each resistor is always enabled, while additional transistors are enabled using select signals. In one embodiment, the select signals are provided by configuration memory cells in a PLD. Other embodiments include additional delay paths and a multiplexer circuit that selects one of the delay paths. The described delay circuit is particularly useful in a DLL trim unit, where variations between resistors can cause jitter and locking problems in the DLL.

Abstract: A ring oscillator circuit, such as a VCO, with a relatively high level of noise rejection for noise originating from both the voltage supply and ground. The ring oscillator circuit is composed of a plurality of differential delay circuits, each differential delay circuit generating a differential output signal that is a delayed (and preferably inverted) version of a differential input signal. Each differential delay circuit includes first and second input transistors for receiving the differential input signal. Each differential delay circuit also includes first and second load transistors coupled in parallel with the respective first and second input transistors. Each differential delay circuit further includes a first current source coupled between the first input transistor and a first power supply terminal (e.g.