Abstract: A voltage control oscillator includes: a voltage-current converter circuit that converts an inputted voltage to a current according to the value of the voltage; a current mirror circuit; a ring oscillator including differential inverters connected in multiple stages; an inverting amplifier; and a buffer. The ring oscillator outputs, from each of the differential inverters, a signal amplitude-limited by a current converted by the voltage-current converter circuit and the current mirror circuit and a voltage applied from the inverting amplifier and the ring oscillator outputs an oscillatory frequency in response to the output signal.

Abstract: An apparatus comprising a transconductance control circuit, a boost control circuit, a current computation circuit and an oscillator circuit. The transconductance control circuit may be configured to generate a current control signal in response to (i) a voltage control signal and (ii) a plurality of range control signals. The boost control circuit may be configured to generate a current boost signal in response to a reference current signal and an enable signal. The current computation circuit may be configured to generate a first control signal and a second control signal in response to the current boost signal and the current control signal. The oscillator circuit may be configured to generate an output signal oscillating at a particular frequency in response to the first control signal and the second control signal.

Abstract: The invention provides a delay line circuit. The delay line circuit includes a delay line section and a feedback selection section. The delay line section receives an input clock signal and a feedback clock signal and delays one of the input clock signal and the feedback clock signal to generate an output clock signal, wherein the delay line section includes a plurality of delay units coupled in series. The feedback selection section is coupled to the delay line section and feedbacks the output clock signal to one of the delay units to serve as the feedback clock signal based on a selection signal. Wherein, one of the input clock signal and the feedback clock signal is delayed by a specific number of the delay units based on the selection signal to changes the frequency of the output clock signal.

Abstract: A method establishes an initial voltage in a ring oscillator and a logic circuit of an integrated circuit device. Following this, the method enables the operating state of the ring oscillator. After enabling the operating state of the ring oscillator, the method steps up to a stressing voltage in the ring oscillator. The initial voltage is approximately one-half the stressing voltage. The stressing voltage creates operating-level stress within the ring oscillator. The method measures the operating-level frequency within the ring oscillator using an oscilloscope (after stepping up to the stressing voltage).

Abstract: LC tank and ring-based VCOs are disclosed that each include a differential pair of transistors for steering a tail current generated by a current source responsive to a bias voltage. A biasing circuit generates the bias voltage such that a transconductance for the transistors in the differential pairs is inversely proportional to a resistance.

Abstract: A negative resistance device for a multiphase oscillator is disclosed. The negative resistance device is coupled to taps of the multiphase oscillator so that it injects no energy into the oscillator when the oscillator is most sensitive to noise, thereby decreasing the phase noise of the oscillator. The negative resistance device also guarantees the direction of movement of a traveling wave past the taps of the multiphase oscillator.

Abstract: A circuit includes a first path including a first transistor and a first current source. The first transistor is responsive to a tuning voltage. The circuit also includes a tuning voltage range extension circuit responsive to the tuning voltage. The tuning voltage range extension circuit is configured to selectively change current supplied by the first path as the tuning voltage exceeds a capacity threshold of the first transistor.

Abstract: A random number generation system comprising one or more ring oscillators configured to generate entropy due to accumulated phase drift. A random number generator can include a ring oscillator configured to switch between a first state in which a signal of the ring oscillator oscillates between logic levels, and a second state in which the signal at least partially settles to one of the logic levels. The random number generator can also include a counter configured to measure a count of pulses of the signal and a whitener mechanism configured to receive the signal from the ring oscillator, latch a logic level of the signal from the ring oscillator, latch the count of pulses from the counter, and generate a random number based on the logic level and the count of pulses. Corresponding methods may also be performed.

Abstract: An oscillator includes: inverters that are connected in a loop shape and of which the number is an odd number greater than or equal to three; and a delay section that delays change in a voltage which is input to one inverter of the odd number of inverters. The one inverter is a schmitt trigger inverter. The schmitt trigger inverter includes a current source, and a resistor in which current supplied by the current source flows. A hysteresis width of the schmitt trigger inverter depends on the current which flows in the resistor.

Abstract: An injection-locked oscillator circuit includes a master oscillator, a slave oscillator, and an injection lock control circuit. The slave oscillator is decoupled from the master oscillator (for example, due to an unlock condition). When the slave is free running, its oscillating frequency is adjusted (for example, as a function of a supply voltage). After an amount of time, the slave is to be relocked to the master (for example, due the unlock condition no longer being present). The slave oscillating frequency is made to be slightly lower than the master oscillating frequency. The slave is then only recoupled to the master upon detection of an opposite-phase condition between the master oscillator output signal and the slave oscillator output signal. By only recoupling the slave to the master during opposite-phase conditions, frequency overshoots in the slave oscillating frequency are avoided that may otherwise occur were the recoupling done during in-phase conditions.

Abstract: A ring oscillator including a plurality of buffer units, each of which has a cross-coupled structure, for generating clock signals using a bias voltage having a predetermined voltage level applied thereto, wherein the clock signals have a swing width corresponding to the bias voltage.

Abstract: A single-staged balanced-output inductor-free oscillator and method thereof are provided. In one implementation an apparatus includes a first network comprising a first amplifier configured in a self feedback topology via a first feedback network for generating a first end of an output signal; a second network comprising a second amplifier configured in a self feedback topology via a second feedback network for generating a second end of the output signal; and a cross-coupling network for cross-coupling the first end and the second end of the output signal, wherein the first network and the second network share a common supply current and the first feedback network and the second feedback network are configured in a cross-controlling topology.

Abstract: A semiconductor integrated circuit capable of reliably detecting oscillation stop of a vibrator-type oscillation circuit and reliably restarting the oscillation circuit when oscillation stop is detected is provided. The semiconductor integrated circuit includes one or more main oscillation circuits configured to generate a main clock signal by a vibrator, a ring oscillator configured to always operate independently of the main oscillation circuit, a main clock detection circuit configured to monitor the main clock signal on the basis of an output clock signal of the ring oscillator and to determine an operation state of the main oscillation circuit, and an switch circuit configured to switch a combination of elements making up the main oscillation circuit in response to a detection result of the main clock detection circuit.

Abstract: An integrated circuit comprising oscillator circuitry is arranged to generate a clock signal for functional logic module of the integrated circuit. The oscillator circuitry comprises a plurality of propagation paths, and is arranged to apply a transition signal to inputs of the plurality of propagation paths, and to cause the output clock signal to transition based on a propagation of the transition signal through a determined set of the propagation paths.

Abstract: Circuits, apparatuses, and methods are disclosed for oscillators. In one such example oscillator circuit, a plurality of delay stages are coupled in series. A variable delay circuit stage is coupled to the plurality of delay stages and is configured to delay a signal through the variable delay circuit stage by a variable delay. The variable delay increases responsive to a rising magnitude of a supply voltage provided to the variable delay circuit stage.

Abstract: A ring oscillator is disclosed. The ring oscillator includes a first tri-path inverter, a second tri-path inverter and a third tri-path inverter. The second tri-path inverter is connected to the first tri-path inverter. The third tri-path inverter is connected to the first and second tri-path inverters to provide feedback for oscillations.

Abstract: A PLL circuit includes a phase detector, a loop filter (LF), a voltage-controlled oscillator (VCO), and a frequency divider. The phase detector compares a phase of a signal Fs which is input from outside with a phase of a signal Fo/N which is input from the frequency divider. The loop filter generates a signal Vin by removing alternating current components from a signal input from the phase detector. The voltage-controlled oscillator outputs a signal Fo based on the signal Vin input from the loop filter. The frequency divider converts the signal Fo output from the voltage-controlled oscillator into Fo/N (frequency division by N), and outputs it to the phase detector.

Abstract: A variable-capacitance device includes a first capacitance element coupled between a first power supply terminal and an output terminal, a capacitance selection switch that is turned on and off in accordance with a capacitance switching signal, a second capacitance element coupled in parallel to the first capacitance element and in series to the capacitance selection switch, and an error correction circuit configured to operate such that in a state in which the capacitance selection switch is in an OFF state, in response to a charge reset signal that causes a voltage at the output terminal to be reset to a reset voltage, the error correction circuit substantially eliminates a difference between the voltage at the output terminal and a voltage at a capacitance switching node at which the second capacitance element is coupled to the capacitance selection switch.

Abstract: A device may include an oscillator to generate a clock signal based on first and second control signals. The oscillator may include a first buffer stage a second buffer stage. The first buffer stage may output a first signal that is based on an output of the second buffer stage and the first control signal. The second buffer stage may output the clock signal. The clock signal may be based on the first signal and the second control signal.

Abstract: A device (1) for generating a random bit sequence has a digital ring oscillator circuit (2) having at least one first feedback path (R8) and one second feedback path (R14). To this end, a changeover is performed between the feedback paths (R8, R14) at times which can be predetermined, and a random signal (OS) having a random level history can be tapped at an output node (4) of the ring oscillator circuit (2).

Abstract: A wide frequency, low voltage oscillator includes multiple delay elements, in which each delay element includes two inverters coupled through a latching element into a differential-type configuration. Two current-source PMOS devices bias the latching element in a high-gain region at low-voltage. By coupling these current-source PMOS devices into the delay elements, the start-up voltage of the latching element is reduced. Each delay element is also biased using a replica bias circuit that scales the supply/control voltage of the oscillator and provides the scaled supply/control voltage to control the lower rail of oscillation amplitude. By coupling the replica bias circuit to the lower rail, the lower rail of the oscillation amplitude follows the changes to the supply/control voltage.

Abstract: A level shifter for a set of at least three phase-shifted signals is disclosed. The level shifter comprises an odd plural number of inverters arranged in a ring. A supply terminal of each inverter is coupled to a supply rail via a respective switching device, which is controlled by the phase-shifted signals.

Abstract: The present invention provides an oscillator which is based on a 6T SRAM for measuring the Bias Temperature Instability. The oscillator includes a first control unit, a first inverter, a second control unit, and a second inverter. The first control unit is coupled with the first inverter. The second control unit is coupled with the second inverter. The first control unit and the second control unit is used to control the first inverter and the second inverter being selected, biased, and connected respectively, so that the NBTI and the PBTI of the SRAM can be measured separately, and the real time stability of the SRAM can be monitored immediately.

Abstract: A voltage controlled oscillator including a control signal adjuster and ring-connected delay cells is disclosed. The control signal adjuster receives a first control signal to generate a second control signal boosted from the first control signal when the first control signal is lower than a transistor threshold voltage. The ring-connected delay cells are controlled by the first and second control signals both to generate an oscillation signal. Each of the delay cells has a first set of current generation transistors and a second set of current generation transistors. Each transistor of the first set of current generation transistors has a control terminal receiving the first control signal while each transistor of the second set of current generation transistors has a control terminal receiving the second control signal. The first and second sets of current generation transistors collectively output an oscillation signal with unchanged frequency of associated input signal.

Abstract: Electronic circuitry comprising operational circuits of active switching type requiring timing signals, and conductive means for distributing said timing signals to the operational circuits, wherein the timing signal distribution means includes a signal path that has different phases of a drive signal are supplied via active means at different positions about the signal path where that path exhibits endless electro-magnetic continuity without signal phase inversion or has interconnections with another signal path having different substantially unidirectional signal flow where there is no endless electromagnetic continuity between those signal paths and generally has non-linear associated circuit means where the signal path is of a transmission line nature.

Abstract: Reducing a gain of a VCO, which may be used in a serdes system, includes using an oscillator replicating the VCO. The oscillator frequency varies according to PVT conditions of circuit elements of the oscillator, which affect a speed of the circuit elements. A first circuit receives an output of the oscillator to produce a current that varies inversely proportionally to the oscillator frequency. A second circuit injects the current into a power supply line of the VCO. Thus, high VCO frequencies can be attained. By reducing the gain of the VCO, thermal noise contribution of the loop resistor and the loop capacitor required for desired loop bandwidth are reduced. During fast corner conditions, minimal current is injected into the VCO. During slow corner conditions, high current is injected into the VCO. These help keep VCTRL of the PLL loop close to a mid-rail operating region.

Abstract: A wideband phase modulator comprises a multiphase generator, a phase selector, and a phase adjuster. The wideband phase modulator is configured to receive an N-bit digital phase-modulating signal comprising a timed sequence of N-bit phase-modulating words, where N is a positive integer representing the bit resolution of the N-bit digital phase-modulating signal. The multiphase generator generates a plurality of coarse carrier phases, all having the same carrier frequency but each offset in phase relative to the other. The M most significant bits of the N-bit phase-modulating words are used to form M-bit phase select words that control the output phase of the phase selector. The phase adjuster performs a precision rotation operation, whereby a selected coarse carrier phase is adjusted so that the phase of the resulting final precision phase-modulated signal more closely aligns with a desired precision phase.

Abstract: Described herein is the method and apparatus for determining frequency of an oscillator coupled with one or more analog devices, and for determining within-die or across-die variations in an analog property associated with the one or more analog devices, the determining based on the oscillator frequency. The analog property includes output signal swing, bandwidth, offset, gain, and delay line linearity and range. The one or more analog devices include input-output (I/O) buffer, analog amplifier, and delay line. The method further comprises updating a simulation model file based on the determining of the within-die and/or across-die variations of the analog property.

Abstract: A VCO circuit includes: a control portion to which a first voltage is inputted and from which a second voltage corresponding to the first voltage is outputted; a current source portion to which the second voltage is inputted and from which a current corresponding to the second voltage is outputted; and an oscillator circuit to which the current is inputted and from which a signal with a frequency in accordance with the current is outputted. The control portion includes an adjusting circuit which changes the second voltage in conjunction with fluctuation of a power supply voltage. Accordingly, fluctuation of the frequency Fo of an output signal of the VCO circuit can be suppressed even when the power supply voltage of the VCO circuit fluctuates.

Abstract: In one embodiment, a voltage-controlled oscillator (VCO) is provided that includes: a plurality of differential inverters coupled to form a loop, each differential inverter having a differential pair of transistors configured to steer a tail current from a current source, the current source sourcing the tail current responsive to a bias voltage, wherein each transistor in the differential pair couples to a power source through a corresponding switching-capacitor circuit; and a bias circuit configured to generate the bias voltage such that a transconductance for each transistor in the differential pairs is proportional to a factor that is a function of a ratio of transistor widths within the bias circuit.

Abstract: A differential ring oscillator includes a plurality of delay stages connected in a ring. At least one of the delay stages includes: a current source, arranged to generate a bias current according to a coarse tuning signal; a latching circuit arranged to generate a differential output signal to a next delay stage according to a differential input signal from a previous delay stage; a capacitive array arranged to provide a first capacitance according to a fine tuning signal; and a varactor device arranged to provide a second capacitance according to a controllable signal for locking an oscillating frequency of the differential ring oscillator to a target frequency. The coarse tuning signal and fine tuning signal are arranged for adjusting the oscillating frequency of the differential ring oscillator to, respectively, reach a predetermined frequency range including the target frequency and to approach the target frequency in the predetermined frequency range.

Abstract: An object is to provide a method for preventing the occurrence of variations in time resolution by providing a calibration process to a TDC at the time of start up and further preventing the increase in circuit scale by reducing the redundancy of delay elements. A calibration of a multiphase oscillator TDC and a vernier TDC is carried out at the time of power-on. In the calibration, a timing input to be input to the vernier TDC is selected from output signals of DCCO based on a reference clock. Also, data is defined as an output signal which is adjacent to the output signal of DCCO mentioned above and proceeds in phase, and the delay therebetween is derived. By repeating it to all of the output signals, the one cycle of the output signal of DCCO is derived.

Abstract: A reference voltage generation circuit has: a first PN junction element; a second PN junction element having a higher forward direction voltage than the first PN junction element; a first differential amplifier inputting an anode of the first PN junction element and a first connection node between a first and a second resistor disposed in series between a first output of the first differential amplifier and a first potential, and generating a first output voltage at the first output; and a second differential amplifier inputting an anode of the second PN junction element and a second connection node between a fourth and a third resistor disposed in series between a second output of the second differential amplifier and the first output of the first differential amplifier, and generating a reference voltage at the second output. A resistance ratio between the third and the fourth resistors is variable.

Abstract: A method and apparatus for sensing analyte. The method includes the steps of sensing one or more parameters in reaction to the presence of one or more analytes and outputting a current therefrom in accordance with level of the sensed parameter by each of a plurality of sensors, each of the plurality of sensors being provided in one or more sensor array columns, receiving an output current from one of the plurality of sensors from each of the plurality of sensor arrays by a Voltage Controlled Oscillator (VCO) arranged in a VCO array. The method further includes the steps of generating an output oscillation frequency by each VCO in accordance with the level of the received output current, and counting a number of oscillations over a predetermined time received from each of the plurality of VCOs in the VCO array by a plurality of counters arranged in a counter array.

Abstract: A gated voltage-controlled oscillator receives a gating signal and outputs an oscillating signal having a frequency corresponding to the gating signal. The gated voltage-controlled oscillator includes a delay unit, having a first terminal and a second terminal, and a multiplexer, having a first input terminal, a second input terminal, a select terminal and an output terminal. The first input terminal and the select terminal are coupled to the gating signal. The second input terminal is coupled to the first terminal of the delay unit. The output terminal outputs the oscillating signal and is coupled to the second terminal of the delay unit. The delay unit delays the oscillating signal and outputs the delayed oscillating signal into the second input terminal. The multiplexer outputs a signal of the first input terminal or the second input terminal according to the gating signal.

Abstract: A device may include an oscillator to generate a clock signal based on first and second control signals. The oscillator may include a first buffer stage a second buffer stage. The first buffer stage may output a first signal that is based on an output of the second buffer stage and the first control signal. The second buffer stage may output the clock signal. The clock signal may be based on the first signal and the second control signal.

Abstract: An oscillator is provided and includes a resistance unit, a capacitance unit, a first inverter and a second inverter. The resistance unit is serially connected between a first reference point and a second reference point. The capacitance unit is coupled between the first reference point and an output point, and includes capacitors. One terminal of each of the capacitors is coupled to the output point, and the other terminal of each of the capacitors is coupled to the first reference point or a reference ground according to a control signal. The input terminal of the first inverter is coupled to the first reference point, and the output terminal of the first inverter is coupled to the second reference point. The input terminal of the second inverter is coupled to the output terminal of the first inverter, and the output terminal of the second inverter is coupled to the output point.

Abstract: An oscillator circuit includes a circuit loop and multiple current sources. The circuit loop includes an output having the oscillating signal. The multiple current sources are turned on independently of a phase of the oscillating signal. The current sources control magnitudes of both charging current and discharging current at nodes of the circuit loop, including the output. Relative magnitudes of different current sources determine a frequency of the oscillating signal.

Abstract: A ring oscillator circuit for measurement of negative bias temperature instability effect and/or positive bias temperature instability effect includes a ring oscillator having first and second rails, and an odd number (at least 3) of repeating circuit structures. Each of the repeating circuit structures in turn includes an input terminal and an output terminal; a first p-type transistor having a gate, a first drain-source terminal coupled to the first rail, and a second drain source terminal selectively coupled to the output terminal; a first n-type transistor having a gate, a first drain-source terminal coupled to the second rail, and a second drain source terminal selectively coupled to the output terminal; and repeating-circuit-structure control circuitry. The ring oscillator circuit also includes a voltage supply and control block.

Abstract: Apparatus and methods are provided for oscillators having adjustable gain. An exemplary oscillator module comprises a first node for a first voltage, a control node for a control signal, and oscillator circuitry coupled to the first node and the control node. The oscillator circuitry generates an output signal with a first oscillation frequency based on the first voltage, and in response to the control signal being asserted, the oscillator circuitry generates the output signal with a second oscillation frequency based on the first voltage. The second oscillation frequency is greater than the first oscillation frequency.

Abstract: A system including a plurality of amplifiers configured to generate a clock signal having a frequency. The clock signal is input to a processor. The amplifiers are connected in series. An output of a last one of the amplifiers is fed back to an input of a first one of the amplifiers. Each of the amplifiers has a transconductance. A frequency adjustment module is configured to adjust, based on an activity level of the processor, the frequency of the clock signal by adjusting the transconductance of the amplifiers.

Abstract: A circuit interconnection structure for synchronizing a network of oscillators placed on a semiconductor substrate. One such structure comprises a first synchronizing circuit electrically coupled to a second synchronizing circuit through tunable delay circuits. Also disclosed are methods to tune oscillators placed in different regions of a circuit having multiple clock domains by estimating the relative slack of a first group of signals within the circuit with regard to the period of a first clock domain, and estimating the relative slack of the second group of signals within the circuit with regard to the period of second clock domain, wherein the estimating is performed at process and operational corners that cover the variability of the circuit at different speed conditions, then calculating tuning values for the oscillator delays for each region such that the oscillator delay slack matches the worst relative slack of the signals of the same region.

Abstract: An apparatus for sensing analyte is provided. The apparatus may include a plurality of sensor array columns, each sensor array column including a plurality of sensors, each sensor being adapted for sensing one or more parameters in reaction to the presence of one or more analytes and output a current therefrom in accordance with level of the sensed parameter, a Voltage Controlled Oscillator (VCO) array including a plurality of VCOs, each VCO adapted to receive an output current from one of the plurality of sensors from each of the plurality of sensor arrays and for and generating an output oscillation frequency in accordance with the level of the received output current, and a counter array including a plurality of counters, each counter adapted to receive an output from a corresponding VCO and count a number of oscillations over a predetermined time.

Abstract: An oscillating apparatus includes: a transfer gate including a P-channel transistor and a N-channel transistor; a first inverter for inverting an output signal of the transfer gate and outputting the inverted output signal of the transfer gate; a second inverter for inverting the output signal of the first inverter and outputting the inverted output signal of the first inverter; a third inverter for inverting the output signal of the first inverter and outputting the inverted output signal of the first inverter; a fourth inverter for inverting the output signal of the third inverter and outputting the inverted output signal of the third inverter to an input-terminal of the transfer gate; a first capacitor connected between an output-terminal of the transfer gate and an output-terminal of the second inverter; and a second capacitor connected between the output-terminal of the transfer gate and a reference potential node.

Abstract: Leakage inversion systems and methods are described. A leakage inverter can be configured to transition a signal, wherein a leakage characteristic impacts a transition of the signal. The leakage inverter can be included in an oscillating ring path that outputs an indication of the impacts the leakage characteristic has on a transition of a signal. A leakage inverter can include a leakage transistor coupled in series between a pull up transistor and a pull down transistor, wherein leakage in the leakage transistor impacts at least one transition of the signal. A pull down transition delay can be asymmetric (e.g., fast/slow, short/long, etc.) with respect to a pull up transition delay. Asymmetry can be associated with an effect of the leakage current on a transition of the signal. Results can be utilized in a variety of different analysis (e.g., analyze manufacturing process compliance and defects, leakage current power consumption, etc.).

Abstract: Power consumption in an oscillator formed of a chain of two inverters in series, with resistive feedback from the output of the first inverter to its input, and capacitive feedback from the output of the second inverter to the input of the first inverter is lowered by reducing the supply voltage to the two inverters and reducing the voltage swing at the input to the first inverter. The supply voltage is reduced by adding one or more diodes, or other voltage reducing elements or means for reducing the voltage, between the power and ground rails of the power source and the power and ground inputs of the two inverters, and the voltage swing is reduced by selecting the feedback capacitor.

Abstract: An electrical circuit includes a first transistor having a first source, a first drain, and a first gate, whereby the first transistor receives an input voltage through the first gate. An output voltage terminal outputs voltage from the first transistor and is connected to the first drain. A second transistor includes a second source, a second drain, and a second gate, whereby the second transistor receives a bias voltage through the second gate, and wherein the first source is connected to the second drain. A first capacitor is connected to the first source, the second source, and the second drain. An inductor is connected to the first drain. A second capacitor is connected in parallel with the inductor and further connected to the first drain.

Abstract: A frequency generator is provided which is embodied in an integrated circuit manufactured at a process node below 100 nm. The frequency generator comprises a current starved oscillator configured to generate an output frequency signal in dependence on a voltage of a bias signal and a self-biased current generator configured to generate the bias signal, wherein the self-biased current generator comprises a first transistor and a second transistor connected in series. The bias signal is taken from a midpoint between the first transistor and the second transistor, and respective gates of the first and second transistors are connected to keep said first and second transistors in a cut-off state. Accordingly the self-biased current generator operates in a deep sub-threshold state and a current of said bias signal is dependent on a leakage current in the first and second transistors.

Abstract: Reducing a gain of a VCO, which may be used in a serdes system, includes using an oscillator replicating the VCO. The oscillator frequency varies according to PVT conditions of circuit elements of the oscillator, which affect a speed of the circuit elements. A first circuit receives an output of the oscillator to produce a current that varies inversely proportionally to the oscillator frequency. A second circuit injects the current into a power supply line of the VCO. Thus, high VCO frequencies can be attained. By reducing the gain of the VCO, thermal noise contribution of the loop resistor and the loop capacitor required for desired loop bandwidth are reduced. During fast corner conditions, minimal current is injected into the VCO. During slow corner conditions, high current is injected into the VCO. These help keep VCTRL of the PLL loop close to a mid-rail operating region.

Abstract: An apparatus for generating a random bit sequence has a ring oscillator which includes inverting digital devices and on which an oscillator signal can be tapped. An intermediate storage element monitors and stores fluctuating levels of the oscillator signal. At least two controllable switch devices for simultaneously exciting at least two harmonic wave edges of the ring oscillator are provided in a signal path of the ring oscillator. The phasing of the two harmonic wave edges and a potential convergence thereof are subject to statistical fluctuations, which are used as a basis for the random bit generation. A corresponding random number generator can be used in particular as an FPGA for security applications, such as cryptographic methods. The apparatus has substantially digital components, which are easy to produce in a standardized manner. A dedicated regulating circuit is not necessary. The apparatus is also robust toward exterior influences.