Abstract: Methods and apparatuses for optimizing switching delay in integrated circuits are described. Combinational logic gates are modified with precharge circuitry and instantiated in order to reduce switching transitions of circuit elements in a signal path.

Abstract: A control signal generation circuit includes a voltage detection unit which detects a level of an external voltage and generates first and second detection signals and a control signal control unit which delays a sense amplifier enable signal in response to the first and second detection signals and generates first through third control signals. The enable period of the first and second control signals are controlled based on the levels of the first and second detection signals.

Abstract: A timer circuit is disclosed. The timer, having a delay configured to track inversely with temperature of the memory device, includes a reference signal configured to increase in voltage, as the temperature of the memory device increases. The reference signal may be generated from a current that is derived from a bandgap reference circuit. The timer circuit includes a pull-down path made up of a plurality of selectable pull down transistors which are coupled to the reference signal at the gate. Resistance of the pull-down path is reduced as the reference signal is increased and the reduced resistance of the pull-down path decreases the delay of timer. A plurality of selectable delay elements may be preconfigured to adjust the delay and are coupled to the output path of the current starved inverter.

Abstract: A sensing delay circuit includes a logic element which responds to a test mode signal to transfer a start signal, a delay unit which is configured of a plurality of inverters having MOS transistors with controlled threshold voltage, and receives external voltage as bulk voltage and delays an output signal from the logic element by a predetermined period, and a buffer which responds to an output signal from the delay unit to buffer the output signal from the logic element and output it.

Abstract: A sense amplifier enable signal generator has two stages. Each stage offsets transistor performance variation in the other stage to produce an enable signal output relatively immune from the effects associated with transistor mismatches. In one embodiment, a memory device comprises a plurality of memory cells, sense amplifier circuitry and the enable signal generator. The sense amplifier circuitry is coupled to one or more of the memory cells and senses the state of the one or more memory cells when enabled. The enable signal generator has first and second stages and generates an enable signal applied to the sense amplifier circuitry. The enable signal generator counteracts delay variation when generating the enable signal so that operation of the enable signal generator is substantially unaffected by transistor performance variation in either stage of the enable signal generator.

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 circuit is disclosed for providing highly stable delay time in digital signal processing. The delay circuit includes a preliminary charging/discharging circuit, a signal processing circuit and an output circuit. The preliminary charging/discharging circuit performs charging and discharging operations based on a logic input signal for generating a voltage signal. The signal processing circuit performs signal processing on the voltage signal for generating a first delay signal and a second delay signal. The output circuit performs logic signal processing on the first and second delay signals for generating a logic output signal lagging behind the logic input signal by a delay time. The delay time is independent of any supply voltage. That is, even though the supply voltage is unstable, the delay circuit is capable of generating a stable logic output signal by performing a signal delay process on a logic input signal regardless of the unstable supply voltage.

Abstract: A programmable timing interpolator circuit includes low output impedance buffer circuitry driving a node having a capacitance that varies in response to a programmed delay to be introduced by the interpolator. The low output impedance buffer circuitry receives a subset of course delay signals and, after buffering, provides the buffered course delay signals to fine delay circuitry. The buffer may include two source follower stages coupled to each other. The first source follower stage shifts the level of the received signal down. The second source follower stage shifts the level of the signal from the first source follower stage up. The first and second source follower stages are implemented using NMOS and PMOS technology.

Abstract: A clock skew controller for adjusting a skew between a first clock, which is input to a first clock mesh, and a second clock mesh input to a second clock mesh, includes a pulse generator adapted to output a pulse signal corresponding to a delay time between a first output clock output from the first clock mesh and a second output clock output from the second clock mesh, a pulse width detector adapted to generate a digital signal corresponding to a pulse width of the pulse signal, and a clock delay adjuster adapted to delay one of the first and second clocks by a time corresponding to the digital signal

Abstract: A delay circuit includes a delay time setting circuit to set a delay time of an output signal with respect to an input signal, a first transistor connected to an input terminal of the delay time setting circuit and configured to set a first voltage to the input terminal of the delay time setting circuit and a second transistor connected to an output terminal of the delay time setting circuit and configured to reset the output terminal of the delay time setting circuit to a second voltage and clear the reset of the output terminal of the delay time setting circuit after the first voltage is set.

Abstract: A differential type delay cell includes a differential amplifier and first and second output capacitor circuits. The differential amplifier is configured to amplify a differential input signal to generate an amplified differential output signal at a pair of output nodes of the delay cell. The first and second output capacitor circuits are respectively coupled to a different one of the output nodes, and are configured to have a variable capacitance that varies in response to variation in a power supply voltage.

Abstract: Delay chain circuitry is provided. The delay chain circuitry has a number of delay chain inverters. Each delay chain inverter is connected in series with a load resistor and has an associated capacitor between its input and ground. The electrodes of each capacitor may be formed from metal separated by non-gate-oxide dielectric to maintain accurate capacitor tolerances. A stable current source such as a bandgap reference current source may apply a current to a sensing resistor. The resulting bias voltage is indicative of changes in resistance due to changes in operating temperature. A temperature compensation circuit may use the bias voltage to produce temperature-compensation control signals. The temperature-compensation control signals are applied to the delay chain inverters to adjust their resistances and compensate for temperature-induced changes in the resistances of the load resistors. This ensures that the delay of the delay chain is independent of operating temperature.

Abstract: A delay circuit does not lead to excessive increase in the delay time even if the source voltage drops, and enables to control the delay time from increasing. The delay circuit is designed to delay a logic signal SIN having two logic levels consisting of a low level and a high level, such that the delay times are different for the high and low levels, and the circuit chooses either the low level or the high level and targets a logic level having a shorter delay time. That is, n-MOS transistors N11, N12 and p-MOS transistors P11, P12 are provided as MOS capacitors, so as to change from the off-state to the on-state during the transition period of a signal that appears on each node disposed on a delay path of logic signals. Such a circuit design enables to control source-voltage dependence of delay time so that, even if the source voltage drops, delay times are not increased excessively.

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 current controlled delay circuit is disclosed. Two currents of constant sum are generated to control the delay of the circuit. The circuit includes a differential pair to switch one of the two currents from one leg of the circuit to another leg of the circuit. The circuit includes a cross-coupled pair to switch the other of the two currents from one leg of the circuit to another leg of the circuit. The circuit may include a fixed or variable load.

Abstract: PMOS transistors P1-Pn and PMOS transistors P1?-Pn? are respectively connected in series between a supply voltage terminal VD and output terminals OUTB, while NMOS transistors N1-Nn and NMOS transistors N1?-Nn? are respectively connected in series between the output terminals OUTB and a ground terminal G. Input terminals S1-Sn are respectively connected to the gates of the PMOS transistors P1?-Pn? and NMOS transistors N1-Nn, and they are respectively connected to the gates of the PMOS transistors P1-Pn and NMOS transistors N1?-Nn? through corresponding inverters IV1-IVn.

Abstract: The present invention is a system, circuit and method for low voltage operable, small footprint delay. The delay circuit of the present invention uses an input switching configuration with a limited gate to source conductance to enhance the delay time for any given resistor and capacitor area in an RC network. According to the delay circuit of the present invention, the output of the RC network transitions very slowly in order to achieve a long delay. When the next stage of the delay circuit trips, the limited gate to source conductance is bypassed to allow rapid full rail presetting or resetting on the output of the RC network. This rapid full rail presetting or resetting limits power consumption and rapidly prepares the delay circuit for the next edge transition or cycle. Methods and systems incorporating the delay circuit and techniques of the present invention are also disclosed.

Abstract: A semiconductor integrated circuit comprising a voltage controlled delay cell including a first voltage controlled resistor and a current source transistor of a MOS type differential amplifier circuit, the first voltage controlled resistor functioning as a load resistor, wherein a resistance value of the first voltage controlled resistor is controlled according to a first bias voltage, and a current of the current source transistor is controlled according to a second bias voltage, and a bias circuit including a first replica circuit and a second replica circuit, the first replica circuit having a structure equivalent to that of the voltage controlled delay cell, the second replica circuit having a structure equivalent to a structure in which the first voltage controlled resistor is replaced by a constant resistor, the bias circuit configured to generate and supply the first bias voltage and the second bias voltage to the voltage controlled delay cell.

Abstract: A time delay circuit including a first transistor having a gate, a drain, a source, and a channel between the source and the drain. The input voltage is applied between the gate and drain and the output is taken between the source and drain. The output voltage follows the gate voltage, and the first transistor gate voltage is substantially constant. The time delay circuit also includes a delay element. The output voltage of the first transistor biases the delay element.

Abstract: A synchronized data capture circuit configured to synchronize capturing of data in a first plurality of data signals with a first plurality of timing signals to output a synchronized data capture signal. The synchronized data capture circuit includes a timer generator having a first timer generator output. The timer generator is coupled to receive the first plurality of timing signals and to serially output on the first timer generator output, as a first high frequency timing pulse stream, first timing pulses responsive to timing pulses of the plurality of timing signals. The first high frequency timing pulse stream has a timing pulse stream frequency that is higher than a timing input frequency associated with one of the first plurality of timing signals. The synchronized data capture circuit also includes first plurality of data driver circuits coupled to receive the first plurality of data signals and the plurality of timing signals.

Abstract: A digital phase interpolator including a plurality of delay stages to control delay time of an output signal from first and second input signals having different phase delays. The plurality of delay stages are connected serially, have a same internal structure, determine corresponding axes for interpolation in each stage, and each includes a first inverting section for inverting first and second signal inputs from the previous stage, a phase blender for blending outputs of the first inverting section, a second inverting section for inverting outputs of the first inverting section, and a multiplexer for generating input signals for the next stage in response to a selection signal for determining phase delay time of the output signal of the phase interpolator. Total area and current may be reduced by the present invention because the number of inverters comprising each stage is equal.

Abstract: A variable frequency oscillator provides an output frequency that is adjustable by selectively combining different delay signals from separate signal paths. The present invention's oscillator includes first and second differential signal paths, each exhibiting a different time delay or “phase.” Each signal path includes a series coupling of multiple delay elements, where each delay element comprises a single differential amplifier transistor pair. Each signal path's delay is established by setting the biasing and geometry of the signal paths' differential amplifier transistor pairs. A combiner, separately coupled to each signal path, selectively combines signals from the paths to provide a representative output. This output is also fed back as input to both signal paths. As an example, the combiner may be provided by two non-nested differential amplifier transistor pairs.

Abstract: Circuit for generating an inverse signal of a digital signal with minimal delay difference between the inverse signal and the digital signal. Two inverter circuits (6, 8; 7, 9) have been connected in series. The output signal of the second inverter circuit (7, 9) is the digital signal. An input signal for the first inverter circuit (6, 8) is supplied to a pass-through circuit (13, 14) with threshold action. The signal present between the first (6, 8) and the second (7, 9) inverter circuit is supplied to a control input (16) of the pass-through circuit with threshold action. The signal which is also present between the first (6, 8) and the second (7, 9) inverters appears with some delay at the output (17) of the pass-through circuit with threshold action, which signal is the inverse of the digital signal and at the same time constitutes the output signal of the pass through circuit (13, 14) with threshold action.

Abstract: A system and method for eliminating pulse width variations in digital delay lines partitions a delay line into two substantially identical blocks of delay inverters, inserting a first inverter between the two blocks and a second substantially identical inverter at the output of the second block. The requirement for matching device characteristics at the individual delay inverter level is eliminated and the only requirement is that the parasitic loading of the inverter between the blocks and the inverter on the output of the second block be the same. Consequently, the layout of the delay inverters in a single block may be made in the most efficient manner possible and the same identical layout can be used for the first and second blocks.

Abstract: An apparatus is described comprising a current source and a pair of transistors coupled to the current source. A pair of variable loads are coupled to the pair of transistors such that a first of the pair of transistors drives a first of the pair of variable loads and a second of the pair of transistors drives a second of the pair of variable loads. Each of the pair of variable loads are coupled to a high gain input and a low gain input. Another apparatus is described comprising an oscillator having a high gain input and a low gain input. The oscillator comprises a series of inverters where each inverter output is coupled to the next inverter input in the series. At least one of the inverters comprises a current source and a pair of transistors coupled to the current source.

Abstract: In an high-frequency LSI chip, a clock signal generating circuit which establish accurate synchronism between an input clock signal and an internal clock signal to prevent an input circuit to cause a synchronization shift. The clock signal generating circuit includes an input circuit for amplifying an input signal and outputting an amplified signal as a first internal signal; a variable delay circuit, on the basis of a control signal, for delaying the first internal signal and outputting a delayed signal as a second internal signal; a phase comparator for finding a phase difference between the input signal and second internal signal and outputting a phase difference signal indicative of the phase difference; and a control circuit for generating the control signal on the basis of the phase difference signal. Thereby the influences of a delay caused by the input circuit, which would not be able to be avoided in the prior art, can be avoided and thus the accurate internal clock signal can be generated.

Abstract: A circuit for improving the performance of a charging capacitor inverter used in VCO and similar circuits. The disclosed approach is used to provide both trip point and charging current delay control to reduce the amount of “jitter” associated with the circuit. Trip point delay control is accomplished by adding an in-line transistor, output in a typical charged capacitor inverter, between the charging capacitor and the circuit. The threshold of this transistor is controlled by a dc bias level (control voltage) which allows this transistor to turn “ON” or “OFF” when the node voltage of the capacitor reaches the controllable preset level. Further control of the circuit's delay is obtained by means of circuitry which allows the amount of capacitor charging current to be selected.

Abstract: A bus driver circuit includes a plurality of first MOS transistors connected in series between a data input terminal and a data output terminal, and a plurality of second controlling MOS transistors. Sources of said plurality of first MOS transistors are connected to drains of said plurality of second controlling MOS transistors. Also, gates of said plurality of second controlling MOS transistors to control signal source means for selectively turning ON and OFF said plurality of second controlling MOS transistors. The bus driver circuit thus constructed permits selection of optimal rise-up and fall-down transition period for achieving high speed and efficient data transmission.

Abstract: A programmable delay element includes a current source field-effect transistor (FET), a switch device, a precharge device, and an inverter device. The current source FET gates a programmable, predetermined amount of current. The switch device, which is coupled to the current source FET, receives an input signal having a first and second voltage level. The precharge device precharges the node coupled to the drain of the current source FET when the input signal is at a second voltage level. The inverter device, which is also coupled to the drain of the current source FET, outputs a delayed signal when the input signal is at a first voltage level, the delay of the delayed signal defined by the programmable, predetermined amount of current. The inverter device generates an inverter switch point that is substantially independent of parametric sensitivities, such as temperature variations.

Abstract: In an high-frequency LSI chip, a clock signal generating circuit establishes accurate synchronization between an input clock signal and an internal clock signal to prevent an input circuit from causing a synchronization shift. The clock signal generating circuit includes an input circuit for amplifying an input signal and outputting an amplified signal as a first internal signal; a variable delay circuit, on the basis of a control signal, for delaying the first internal signal and outputting a delayed signal as a second internal signal; a phase comparator for finding a phase difference between the input signal and second internal signal and outputting a phase difference signal indicative of the phase difference; and a control circuit for generating the control signal on the basis of the phase difference signal. Thus, the influences of a delay caused by the input circuit, which would not be avoided in the prior art, can be avoided and the accurate internal clock signal can be generated.

Abstract: A method, and associated apparatus, for eliminating pulse width variations in digital delay lines. The method includes partitioning the delay line into two substantially identical blocks of delay inverters and inserting a first inverter between the two blocks and a second substantially identical inverter at the output of the second block. The requirement for matching device characteristics at the individual delay inverter level is eliminated, and the parasitic loading of the inverter between the blocks and the inverter on the output of the second block is the same. Since the rising edge input to the first block becomes a falling edge input to the second block as it propagates through the delay line, the rising and falling input edges will encounter an identical set of transitions as they propagate through the two blocks.

Abstract: Embodiments of the invention include an integrated circuit output buffer, with a pre-drive stage and an output driver stage, that provides linear performance independent of the load impedance. The output driver stage includes a pull-up resistor arrangement having a plurality of branches connected in parallel and, alternatively at least one pull-down resistor arrangement having a plurality of branches connected in parallel. The branches of the pull-up resistor arrangement include at least one resistor and at least one transistor serially connected between a supply voltage and the output buffer output terminal connectable to the PAD external to the output buffer. The transistor in the pull-up arrangement is connected to both the data terminals from the pre-drive stage and the control bit terminals.

Abstract: A variable delay section comprises a gate element and a plurality of (N) delay elements for delaying the signal change on the output of the gate element. A difference between a first delay provided by n-th delay section and a second delay provided by (n+1)th delay section is constant for any of n's between 1 and N−1. A plurality of variable delay sections are cascaded to form a frequency multiplier, with the output of the last stage variable delay section being fed-back to the input of the first stage variable delay section through a selector. The other input of the selector is connected to the input of the variable delay circuit to allow the internal signal to pass the variable delay sections for K times.

Abstract: A delay circuit having: a first delay inverter having complementarily-connected first p-channel FET and first n-channel FET, one of the first p-channel and first n-channel FETs being provided with a gate length elongated; a second delay inverter having complementarily-connected second p-channel FET and second n-channel FET, one of the second p-channel and second n-channel FETs being provided with a gate length elongated; a NAND gate having a first input to which the input signal is applied and a second input to which the output signal of the second delay inverter is applied; and an inverter to output inverting the output signal of the NAND gate.

Abstract: A VCO (voltage-controlled oscillator) that can realize stable oscillation operation over a broad frequency range with a low level of jitter. The VCO includes a plurality of basic cells having differential input/output, and a center frequency adjustment circuit. The plurality of basic cells are serially connected in a ring. Each basic cell includes a circuit constituted by two delay circuits and an adder circuit, the delay times of the two delay circuits being each independently determined by the center frequency adjustment circuit. The output amplitude of each of the basic cells is controlled to a fixed value. In the adder circuit, the output of one of the delay circuits is multiplied by an addition proportion coefficient, following which the outputs of both delay circuits are added. In this way, the delay time for each basic cell can be set over a broad range.

Abstract: A technique for compensating for supply voltage variations in a delay circuit by utilizing a bias circuit to maintain the delay substantially constant with respect to the supply voltage. The bias circuit generates a bias current having a fixed component and a variable component, in which the variable component varies proportionately to variations in the supply voltage to maintain the delay substantially constant.

Abstract: Phase locked loop integrated circuits include a phase detection circuit, a variable delay device and a delay control circuit. The variable delay device and delay control circuit provide improved characteristics by increasing the signal frequency bandwidth of the delay locked loop integrated circuit in a preferred manner. The phase detection circuit is configured to perform the functions of comparing first and second periodic signals and generating a phase control signal (e.g., VCON1) having a first property (e.g., magnitude) that is proportional to a difference in phase between the first and second periodic signals. The delay control circuit is responsive to the phase control signal VCON1 and generates a delay control signal that is provided to the variable delay device. The delay control circuit may comprise a counter, a first comparator, a second comparator and a shift register. The variable delay device includes a variable delay line and a compensation delay device.

Abstract: Of the MOSFETs used to implement an oscillator circuit or a delay circuit in a semiconductor device, minimally the MOSFETs P12 (N12) used in a part of the circuit that affects the oscillation period or delay time are low-threshold-voltage type MOSFETs.

Abstract: A time delay circuit that produces a constant delay and is independent of supply voltage. The time delay circuit has a current mirror circuit, a voltage shift circuit, an inverter and a capacitor. The inverter will trip at a predetermined voltage level. A capacitor is coupled to the current mirror circuit and to the inverter for generating a portion of the delay time. A voltage shift circuit is coupled to the inverter for approximately mirroring a voltage shift in the current mirror circuit thereby allowing the time delay circuit to be voltage independent.

Abstract: A delay circuit which resists noise present in the power supply or ground includes a waveform modification circuit for varying the rise and fall of inputted pulse signals, and a switch for connecting a power supply and an output terminal when the voltage of the modified waveform exceeds the threshold value related to the power supply voltage. The waveform modification circuit includes a voltage control circuit for varying the output voltage of the waveform modification circuit in accordance with changes in the voltage of the power supply. To reshape a waveform, an input signal is compared with the power supply voltage as a reference value, and the input signal and power supply voltage are switched in accordance with the comparison results. The voltage control circuit changes the output of the waveform modification circuit in accordance with the changes in the reference when noise contained in the power supply voltage is applied to the output of the waveform modification circuit.

Abstract: An apparatus and method for delaying a signal using a variable delay line circuit. A variable delay line circuit includes first and second delay lines, each including a plurality of delay elements. A multiplexer is coupled to respective outputs of the first and second delay lines and selectively couples the output of one of the first or second delay lines to an output of the multiplexer. A control circuit is coupled to the multiplexer and the first and second delay lines, and controls the multiplexer so as to produce a delayed signal at the multiplexer output using one of the first or second delay lines, and changes a delay factor of the other one of the first or second delay lines by varying a resistance and a current of one or more delay elements of the other one of the first or second delay lines.

Abstract: This invention relates to an asymmetrical delay network connected between first and second voltage references and having an input terminal for receiving a trigger signal, and an output terminal. The network is of the type which includes at least one charge control transistor and at least one delay capacitor, connected in series with each other between the first and second voltage references. In particular, the charge control transistor has a control terminal connected to a generator of a constant current, and the output terminal delivers a delay signal which is synchronized to a first edge of the trigger signal. The invention also concerns a constant pulse generator including at least a first and a second of such asymmetrical delay networks.

Abstract: A semiconductor device is provided having an input driver and an output receiver connected by a bus line, the bus line including pulse generating and driver circuitry responsive to threshold levels of voltage change so as to perform high speed switching which compensates for the load of the bus line.

Abstract: A delay element including a stack of p-channel transistors connected in series and a stack of n-channel transistors connected in series with the source of the top p-channel transistor connected to a positive voltage and the source of the bottom n-channel transistor connected to ground. The drain of each n-channel transistor is connected to the drain of a corresponding one of the p-channel transistors and all gates are interconnected and serve as the input to the delay element. The output of the delay element can be any one of the drain connections.

Abstract: A variable delay circuit for controlling delay time includes P channel transistors connected in parallel, with respective source electrodes connected to a power supply, respective drain electrodes connected to an output terminal for providing delayed signal, and respective gate electrodes connected to respective control signal input terminals for receiving control signals. The circuit further includes N channel transistors with respective source electrodes connected to ground, respective drain electrodes connected to the output terminal, and respective gate electrode connected to the respective control signal input terminals. Identical or mutually inverted data signals or control signals are supplied to the respective gate electrodes of the P channel transistors and the respective gate electrodes of the N channel transistors.

Abstract: A reduced area delay circuit and method are disclosed. The delay circuit uses a constant current source and a constant current drain to charge and discharge a capacitor and thus control the delay time of the delay circuit. The constant current source and drain can be implemented using current mirrors formed by configuring MOSFET transistors in a common source configuration. The delay circuit method includes the steps of receiving an input signal, delaying the input signal by using a constant current source or drain in combination with a capacitor, and then buffering the voltage on the capacitor using two inverters. A programmable delay circuit is also disclosed by adding additional pairs of current mirrors to the delay circuit and selectively enabling the pairs to adjust the delay time.

Abstract: The present invention discloses a delay circuit which obtains constant a delay time of delay circuit using an output capacitor by making the resistance of MOS transistor lowest, at the low voltage, middle at the intermediate voltage, and largest at the high voltage, so that the delay time of delay circuit using an output capacitor is kept constant regardless of the change in power source voltage.

Abstract: A delay circuit which employs a Miller effect to delay a signal while driving a subsequent amplifier stage. The Miller effect is dependent upon loading of the circuits on an integrated circuit upon which the delay circuit is implemented, which allows the delay circuit to compensate its delay in relation to other process variation delays present on the integrated circuit. The delay circuit has a first delay stage which delays an input signal and drives a second stage. The delay circuit incorporates a dummy drive stage which adds loading to the first delay stage. In addition, the dummy stage experiences dynamic loading of the delay chain between the first and second stages which allows the coupling of the effect of this dynamic loading back to the first stage through the Miller effect.

Abstract: A ring oscillator having an odd number of single ended stages, each stage including two transistors connected as a current mirror. The stage provides for low-voltage performance and improved process tolerance characteristics.

Abstract: A ring oscillator includes an even-numbered plurality of ring coupled delay stages. Each delay stage includes a differential amplifier, a voltage clamping circuit, and a current source. The differential amplifier receives first and second input signals from a preceding delay stage. The differential amplifier provides a first output signal and a complementary second output signal at first and second nodes, respectively. The voltage clamping circuit is coupled between the first and second nodes to limit a peak-to-peak voltage swing of each of the first and second output signals. The current source is coupled to the differential amplifier and varies a bias current in accordance with a delay bias voltage.