Abstract: A broadband multi-phase output delay locked loop (DLL) circuit can be operated in a wide range of frequencies and generate various phases. Unlike conventional voltage control delay lines in which delay cells are connected in series, the DLL circuit utilizes a delay matrix in which a resistant network is used so that the number of delay cells connected in series is reduced, various phases can be outputted, and a delay interval error (phase error) due to the resistant network is minimized. The current of the delay cells is controlled so that the delay cells in the delay matrix can operate in a wide range of frequencies, and load capacitance values of capacitors connected in parallel in the delay cells can be controlled.

Abstract: A clock synchronization circuit and a clock synchronization method which generate an internal clock synchronized to an external clock is presented. The circuit and method include a clock enable control circuit generating a clock enable control signal controlled by a power supply voltage and a power-down signal. The circuit and method also include a clock generating circuit receiving an input clock which selectively generates an internal clock synchronized to an external clock using the input clock using the clock enable control signal. Whereupon, a locking failure can be prevented by performing a phase update operation selectively in accordance with whether the power supply voltage is varied or not in the power-down mode. Furthermore, current consumption can be reduced by controlling phase update time in accordance with a variable magnitude of the power supply voltage.

Abstract: A circuit, delay-locked loop, memory device, system and method of synchronizing a clock are described. A circuit generally includes a delay line configured to delay an external clock signal to produce a substantially in-phase output clock signal, a main loop configured to control delay through the delay line, and a secondary loop configured to adjust delay through the main loop. The clock synchronization method generally includes adjusting a delay along a delay line in response to a first phase difference between an input clock to the delay line and a shared clock signal delayed by a shared dynamic I/O model of an output driver. The method further includes adjusting the shared dynamic I/O model in response to a second phase difference between an output clock signal and the shared clock signal.

Abstract: A delay locked loop that controls a delay time period by using a shifter and an adder includes a master delay locked loop and a slave delay locked loop. The master delay locked loop outputs a first digital value corresponding to one clock cycle of a first input clock signal. The slave delay locked loop receives the first digital value and delays a second input clock signal for a time period smaller than the one clock cycle of the first input clock signal. The slave delay locked loop includes a shifter, an operator, and a variable delay circuit. The shifter shifts the first digital value to generate a second digital value. The operator adds or subtracts an offset value to or from the second digital value to generate a third digital value, wherein the offset value varies according to a process, a voltage, and a temperature (PVT). The variable delay circuit delays the second input clock signal for a time period corresponding to the third digital value.

Abstract: Method and apparatus for generating system clock synchronization pulses using a Phase Locked Loop (PLL) lock detect signal are provided. The method includes utilizing a clock lock detect signal indicative that a system clock is synchronized with an internal clock, and determining an initial count value. Then, start counting beginning at a first rising edge of the system clock after the clock lock detect signal is generated, the counting starting with the initial count value. The method further includes generating a synchronization pulse (syncnp) when the counting ends, where the syncnp indicates the beginning of the next system clock cycle, and continue generating syncnps separated by one system clock cycle so as to continue indicating the beginning of the next system clock cycle. The method further guarantees stopping the syncnp generation when the lock detect is inactive indicating that the internal clock and the system clock are not synchronized.

Abstract: A delay-locked loop includes a phase detector, a shift register, a digital low pass filter, a digital to analog converter, a bias circuit, and a delay circuit. The phase detector generates a lagging signal and a leading signal corresponding to a phase difference between an input clock signal and a feedback clock signal. The shift register outputs a digital data according to the lagging signal and the leading signal. The digital low pass filter generates a selecting signal according to the digital data. The bias circuit generates a first control voltage and a second control voltage in response to the bias voltage converted from the selecting signal. The delay circuit generates the feedback clock signal corresponding to the first control voltage and the second control voltage.

Abstract: A delay adjustor for adjusting the delay time of a signal, the adjustor comprising: a first capacitance unit and a variable capacitance unit serially coupled to the first capacitor wherein the capacitance of the variable capacitance unit is adjusted according to a first control signal and the variable capacitance unit comprises a plurality of second capacitors and at least a first switch coupled to the at least one capacitor of the second capacitors.

Abstract: A delay apparatus, and a delay locked loop circuit and a semiconductor memory apparatus using the same are provided. A delay locked loop circuit includes a register controlled delay part that delays a plurality of clocks input during an initial operation by delay amounts among initial delay amounts to be varied, which are set according to initial state setting signals, and increases or decreases the set delay amounts according to a phase detecting signal after the initial operation, a phase comparator that compares a phase of any one of the plurality of clocks and a phase of any one of the plurality of clocks delayed by the register controlled delay part and outputs the phase detecting signal, and an initial state setting unit that generates the initial state setting signals.

Abstract: A semiconductor memory device has a DLL circuit capable of suppressing EMI without distorting a DLL clock required in high-speed operation. The semiconductor memory device includes a delay locked loop (DLL) circuit configured to be responsive to a system clock to output a DLL clock having a phase that is changed when electromagnetic interference (EMI) is detected, for the DLL clock to have frequencies within a delay locking range, and a data output circuit configured to output data in synchronization with the DLL clock.

Abstract: A phase shift circuit that includes two, rather than four, delay chains and corresponding selectors is described. This provides a significant area savings and reduces the intrinsic delay of the phase shift circuit, which is particularly beneficial for embodiments in which there is no intrinsic delay matching. In one implementation, the phase shift circuit includes a first delay circuit and a matching delay circuit. The first delay circuit provides a first delay that includes a first intrinsic delay and a first intentional delay. The delay matching circuit provides a matching delay that matches the first intrinsic delay. In one implementation, the phase shift circuit also includes a second delay circuit to provide a second delay that includes a second intrinsic delay and second intentional delay, where the second intrinsic delay matches the first intrinsic delay and the second intentional delay is half as long as the first intentional delay.

Abstract: A power-down mode control apparatus includes an internal power-down control block configured to receive a locking completion signal and to generate an internal power-down signal, which is toggled for a predetermined time; a noise check block configured to check occurrence/non-occurrence of noise on the basis of a phase detection signal and to generate a plurality of power-down selection signals in response to the locking completion signal and the internal power-down signal; and a power-down enter control block configured to generate a plurality of power-down enter signals, which instruct individual circuits to enter a power-down mode in response to a reference clock signal, the plurality of power-down selection signals, a power-down mode signal, and the internal power-down signal.

Abstract: Phase detection circuitry in a delay-locked loop compares a periodic input signal to a feedback signal. The phase detection circuitry generates a delay signal that controls delays of the delay circuits. Two or more output signals of the delay circuits are transmitted to an input of the phase detection circuitry. The delay-locked loop can be configured so that the period of the periodic input signal divided by a delay of one of the delay circuits equals a non-integer rational number when the phase and frequency of the periodic input signal are constant. A frequency multiplier can be coupled to the delay circuits to generate a periodic output signal. The periodic output signal has an average frequency that is a product of the frequency of the periodic input signal multiplied by a fractional non-integer number when the phase and frequency of the periodic input signal are constant.

Abstract: A delay locked loop circuit includes a delay locking unit configured to output a first internal clock and a second internal clock, a rising edge of which is synchronized with that of the first internal clock by delaying a compensated external clock for compensating a skew of a semiconductor memory device; a duty ratio compensation unit configured to generate the compensated external clock by compensating a duty ratio of an external clock of the semiconductor memory device and to compensate duty ratios of the first and second internal clocks; and a clock control unit configured to control an activation state of the second internal clock after the duty ratio compensation of the external clock.

Abstract: A delay line including a phase detector having two inputs and one output. The first input of the phase detector is connected to an input of the delay line. The second input of the phase detector is connected to an output of the delay line. The output of the phase detector is connected to a control circuit which controls current flow at a control node to produce a control voltage at the node. A voltage-controlled delay unit is responsible to the control voltage to control a delay applied to a signal at an input of the delay line.

Abstract: A delayed locked loop (DLL) circuit for reducing power consumption in updating a delay value of an external clock after locking. The DLL circuit includes a phase comparator for comparing a phase of a feedback clock and a phase of an external clock, and a delay unit for delaying an external clock in response to a comparison signal from the phase comparison. A replica unit receives the delayed external clock and outputs the feedback clock. A toggling controller disables toggling of the delayed external clock that is inputted to the replica unit for a predetermined time at a regular interval after locking.

Abstract: A delay time adjusting method adjusts a delay time of an input signal so that a phase of the input signal and a phase of an output signal match each other. The delay time adjusting method comprises the step of delaying the phase of the output signal until a phase difference between the phase of the input signal and the phase of the output signal becomes N periods, where N is an integer other than zero.

Abstract: The invention relates to frequency adjustment of electronic signals. The method comprises the steps of providing an output signal of a frequency generator with a first frequency as input signal for a signal delay element providing an edge of said input signal of said signal delay element; delaying said input signal by adding a delay to each cycle of said input signal until the delayed output signal of the signal delay element is aligned to an edge of said input signal.

Abstract: A reference circuit and method for mitigating switching jitter and delay-locked loop (DLL) using same are provided. The reference circuit and method determine a number of steps of a fine delay line (FDL) that are equivalent to a step of a coarse delay line (CDL). Switching jitter of the DLL is reduced since the delay of the step of the CDL that is switched when on an underflow or overflow condition of the FDL is detected is equivalent to the delay of the provided number of steps of the FDL.

Abstract: An operation mode setting apparatus includes an operation mode setting control unit that discriminates the phase of a reference clock from the phase of a feedback clock and generates a locking suspension signal, and an operation mode setting unit that generates a locking completion signal in response to a pulse signal and a phase comparison signal under the control of a reset signal and the locking suspension signal.

Abstract: Provided are a DLL circuit having a coarse lock time adaptive to a frequency band of an external clock signal and a semiconductor memory device having the DLL circuit. The DLL circuit includes a delay circuit, a replica circuit, and a phase detector. The phase detector generates a first comparison signal used by the delay circuit to delay an external clock signal in units of a first cell delay time or a second comparison signal used by the delay circuit to delay the external clock signal in units of a second cell delay time. The DLL circuit delays the external clock signal by the cell delay time adaptive to the frequency band of the external clock signal, and thus can perform an accurate and rapid coarse lock operation for the entire frequency band.

Abstract: The present invention relates to a delay-locked loop-based multiphase clock generator that generates a plurality of multiphase clocks from an input clock signal using a voltage controlled delay line including a plurality of dummy cells. The delay-locked loop-based multiphase clock generator includes an anti-harmonic lock circuit that receives an input clock and a reference clock of multiple clocks, determines whether a pulse signal derived from the input clock is within a normal locking range of the reference clock, and outputs a compulsory control signal to compulsorily control an output signal of a phase detector if it is determined that the pulse signal is not within the normal locking range.

Abstract: A delay locked loop (DLL) circuit includes a basic loop, a coarse loop, a delay model and a fine loop. The basic loop generates a plurality of first clock signals, based at least in part on an input clock signal, a feedback clock signal and a fine loop output signal. The first clock signals respectively have a phase difference. The coarse loop generates a plurality of output clock signals, based at least in part on the input clock signal, the feedback clock signal and the first clock signals. The plurality of output clock signals respectively have a phase difference. The delay model generates the feedback clock signal by delaying one of the output clock signals by a first time period. The fine loop generates the fine loop output signal, based at least in part on the input clock signal and the feedback clock signal.

Abstract: A delayed locked loop supports increased operation frequency in a semiconductor memory device. An output driver for use in a delay locked loop includes a first driving block for receiving an output from the delay locked loop to generate a first DLL clock for outputting read data corresponding to a read command, and a second driving block for receiving an output from the delay locked loop to generate a second DLL clock for reducing current consumption during a write operation, wherein the first driving block has larger delay amount than the second driving block.

Abstract: A method and apparatus is presented for debugging and testing a memory controller. In one embodiment, a testing interface is presented for performing stuck-at testing. In a second embodiment, a testing interface is presented for observing clock timing in a memory controller.

Abstract: A DLL circuit comprising: delay circuits which output first and second delayed clock signals obtained by delaying the reference clock signal by a delay times selected according to control signals; an interpolation circuit which interpolates a phase difference between the delayed clock signals to output an internal clock signal; an output circuit which generates a predetermined signal; a dummy output circuit which has the same transmission characteristics as the output circuit and outputs a feedback clock signal having the same phase as the predetermined signal; a phase comparison circuit which compares phases of the reference clock signal and the feedback clock signal; delay control circuits which controls the control signals in a direction where both phases are equal; wherein the delay time of the second delayed clock signal is larger than the first delayed clock signal by an amount equivalent to one cycle of the reference clock signal.

Abstract: A phase shift circuit that includes two, rather than four, delay chains and corresponding selectors is described. This provides a significant area savings and reduces the intrinsic delay of the phase shift circuit, which is particularly beneficial for embodiments in which there is no intrinsic delay matching. In one implementation, the phase shift circuit includes a first delay circuit and a matching delay circuit. The first delay circuit provides a first delay that includes a first intrinsic delay and a first intentional delay. The delay matching circuit provides a matching delay that matches the first intrinsic delay. In one implementation, the phase shift circuit also includes a second delay circuit to provide a second delay that includes a second intrinsic delay and second intentional delay, where the second intrinsic delay matches the first intrinsic delay and the second intentional delay is half as long as the first intentional delay.

Abstract: A DLL circuit includes a first delay line circuit, a first phase comparison circuit, a control circuit, and a first selecting circuit. The first delay line circuit can change a delay amount and provide a delay to a first clock signal. The first phase comparison circuit can detect a phase difference between the first clock signal and an output signal of the first delay line circuit, and a phase difference between a test clock signal of which frequency is lower than the first clock signal and an output signal of the first delay line circuit or a signal after dividing the output signal. The control circuit controls a delay amount of the first delay line circuit according to the detection result of the first phase comparison circuit.

Abstract: A digital DLL circuit includes: a first register configured to hold a first delay specifying value to specify a delay of a rising edge side of a signal; a second register configured to hold a second delay specifying value to specify a delay of a falling edge side of a signal; and a digitally-controlled variable delay circuit configured to be allowed to individually control delays of a rise side and a fall side of a signal. The digital DLL circuit further includes a control circuit configured to implement control so that a rise-side delay and a fall-side delay by the variable delay circuit are kept at the first delay specifying value of the first register and the second delay specifying value of the second register, respectively.

Abstract: A method and apparatus is provided for controlling a delay line for achieving power reduction. The device comprises a delay lock loop to provide an output signal based upon a phase difference between a reference signal and a feedback signal, said delay lock loop comprising at least one delay circuit comprising a plurality of logic gates configured to provide for substantially uniform degradation of a plurality of NAND gates in a static state.

Abstract: A delay locked loop is disclosed which includes a clock selector for selecting and outputting any one of normal-phase and reverse-phase external clocks in response to a clock selection information signal, a first delay line for delaying an output signal from the clock selector by a predetermined amount of time, a second delay line for delaying an inverted version of an output signal from the first delay line by a predetermined amount of time, and a phase mixer for mixing a phase of the output signal from the first delay line and a phase of an output signal from the second delay line and outputting an internal clock having a corrected duty cycle as a result of the mixing.

Abstract: An output circuit includes a detector receiving a parallel data signal, detecting a level change degree for the parallel data signal between a first time point and a second time point, and outputting a select signal according to the level change degree; a delay adjusting device receiving and differentially delaying the parallel data signal into a first and a second delayed parallel data signals with a first and a second delay time, respectively; and a first multiplexer electrically connected to the detector and the delay adjusting device, and selecting one of the first and the second delayed parallel data signals to be outputted in response to the select signal.

Abstract: A semiconductor memory device includes a phase comparator, a delay chain, a delay controller, a fine delay chain, a delay model, a locking state detector, and a fine delay controller. The phase comparator compares a phase of a reference clock with that of a feedback clock. The delay chain delays and outputs the reference clock. The delay controller controls a delay value of the delay chain in response to the comparison result of the phase comparator. The fine delay chain outputs a delay value of a clock outputted from the delay chain. The delay model delays a clock to a modeled delay value to provide a delayed clock as the feedback clock. The locking state detector generates a locking variation signal corresponding to a phase difference between the reference clock and the feedback clock. The fine delay controller controls a fine adjustment value of the fine delay chain.

Abstract: A delay circuit includes a delay device, to which an input signal is supplied. A first phase-shifted signal can be generated by the delay device, which is delayed by a first delay time with respect to the input signal, and a second phase-shifted signal can be generated, which is delayed by a second delay time with respect to the input signal. The delay device is configured such that the first and second phase-shifted signal can be generated in inverted fashion with respect to one another at an output terminal of the delay device after a delay of the input signal by a delay time.

Abstract: A DLL circuit has an input circuit configured to generate a synchronization reference signal on the basis of an input signal, a first delay unit configured to delay the synchronization reference signal, a timing offset circuit configured to adjust a synchronization position of the synchronization reference signal delayed by the first delay unit to generate a signal to be synchronized, a phase comparison circuit configured to compare phase of the synchronization reference signal with that of the signal to be synchronized, a first control circuit configured to select an output signal of the first delay unit on the basis of a comparison result of the phase comparison circuit, a second delay unit configured to delay the synchronization reference signal or the signal to be synchronized and a second control circuit configured to select an output signal of the second delay unit in the case where the comparison result of the phase comparison circuit is within a predetermined range.

Abstract: The invention provides a logic circuit to identify time difference between signals having a variation in delay, and an integrated circuit which can evaluate variations in delay among internal signals. By using a logic circuit which outputs different number of pulse depending on a relationship of delay when a first signal and a second signal which are a pair of digital signals having a time difference are inputted, variations in delay of internal signals of an integrated circuit can be evaluated. Specifically, an output signal is generated by a logical operation of values of the first signal and second signal in a period in which the first signal is High and the second signal is Low, and values of a first signal and a second signal immediately before them by using a latch circuit. Further, by using a delay circuit which can set a delay time of an input signal, time difference between signals can be evaluated quantitatively.

Abstract: A delay locked loop circuit includes a phase detector configured to compare a phase of a reference clock signal with a phase of an output clock signal and to output a comparison signal, a control voltage generator configured to output a control voltage based on the comparison signal, a voltage controlled delay line comprising a plurality of delay elements and configured to delay the reference clock signal based on the control voltage and to output the output clock signal, and a control voltage initializer configured to generate digital codes based on characteristics of the voltage controlled delay line and to generate an initial control voltage based on the digital codes.

Abstract: Methods, devices, and systems are disclosed for a delay locked loop. A delay locked loop may comprise a delay line configured to receive a reference clock signal and output a delayed clock signal. The delay locked loop may also comprise a feedback loop including a frequency divider operably coupled to the delayed clock signal and configured to generate a frequency divided clock signal. Furthermore, the delay locked loop may include a phase detector configured to receive the reference clock signal and the frequency divided clock signal having a frequency less than that of the reference clock signal. Additionally, the phase detector may be configured to measure a phase difference of the reference clock signal and the frequency divided clock signal upon receipt of an active edge of the frequency divided clock signal.

Abstract: Circuits, methods and systems are disclosed providing clock synchronization circuits for synchronized clock distribution for a plurality of devices in a semiconductor device. The clock synchronization apparatus includes an independent synchronization circuit and a dependent synchronization circuit. The independent synchronization circuit may provide synchronized clock distribution for a first destination while the dependent synchronization circuit may provide synchronized clock distribution to a second destination. A method for synchronized clock distribution to a plurality of destinations is also described.

Abstract: The clock generator for semiconductor memory apparatus which includes: a first divider configured to divide a frequency of a first internal clock generated by using an external clock; a first delay unit configured to delay an output of the first divider by first delay time; a second divider configured to divide a frequency of an output of the first delay unit; a second delay unit configured to delay the output of the second divider by second delay time; a phase comparator configured to compare a phase of the output of the first divider with a phase of the output of the second delay unit and output a result of the comparison; and a delay time setting unit configured to set the first delay time on the basis of the output of the phase comparator.

Abstract: A delay locked loop circuit includes a phase detecting unit for detecting a phase difference between a reference clock signal and a feedback clock signal, and for producing a phase difference detection signal, a code generating unit for producing a digital code signal according to the phase difference detection signal, a control current generating unit for generating a control current using the digital code signal, and a current controlled delay line for producing the feedback clock signal by delaying the reference clock signal by a delay time varied by the control current.

Abstract: A method and apparatus for controlling a power-down mode of a delay locked loop (DLL), in which the apparatus includes a first switch unit, a DLL, and a second switch unit. The first switch unit transfers a first clock signal in response to a clock input enable signal. The DLL receives the first clock signal through the first switch unit to generate a second clock signal and is turned off by a power-down signal that is generated from the first clock signal latched by the first switch unit. The second switch unit transfers the second clock signal in response to a clock output enable signal. In a power-down mode, the clock input enable signal is deactivated in response to a clock enable signal and the clock output enable signal is deactivated after a predetermined number of clock cycles that are necessary for the latched first clock signal to be completely transferred through the delay cells of the DLL to an output terminal of the DLL.

Abstract: Timing test circuits, including programmable strobe and clock generators, may include at least two DLLs having differing numbers of delay elements thereby producing many timing signals having various phase relationships. A detector circuit can generate many different timing intervals as may be defined by independently selected events in signals arising from both of the DLLs.

Abstract: A DLL circuit of a semiconductor memory apparatus includes a frequency sensing unit that generates and outputs a high frequency signal and a low frequency signal on the basis of a CAS latency signal. A clock dividing unit divides the frequency of an internal clock by a predetermined value and generates a divided clock in response with whether the high frequency signal is enabled or the low frequency signal is enabled. A phase sensing unit that switches a reference clock and a comparison clock, compares the phases thereof in accordance with whether the high frequency signal is enabled or the low frequency signal is enabled, selectively switches first and second phase control signals generated on the basis of the comparison result, and outputs the switched signals.

Abstract: A DLL of a memory device having a normal mode and a power down mode includes a clock buffer for buffering an external clock signal to output an internal clock signal. A power down mode controller generates a power down mode control signal to define the normal mode or the power down mode in response to a clock enable signal. A source clock generation unit receives the internal clock signal to generate a DLL source clock signal under the control of the power down mode control signal. A phase update unit performs a phase update operation based on the DLL source clock signal to output a DLL clock signal.

Abstract: System and method for generating multiple local oscillator signals comprising a first-stage phase-locked loop (PLL) having an input to receive a first reference signal input and having an output to transmit a second reference signal, wherein the second reference signal is an integer or fractional multiple of the first reference signal; and a plurality of second-stage PLLs, each second-stage PLL having an input coupled to the output of the first-stage PLL and receiving the second reference signal, and each second-stage PLL having an output for transmitting a local oscillator signal, wherein each of the local oscillator signals is an integer multiple of the second reference signal.

Abstract: The present invention provides a way of hysteretic switching for efficiently reducing the heavy switching between two adjacent coarse intervals. The present invention disposes a number of fine intervals to cover a range which is larger than the length of one coarse interval. Each coarse interval comprises some extra fine intervals which are exceeded the boundary of the coarse intervals in one side. The heavy switching will be postponed until the extra fine intervals are used up. In the meantime, the fine calibration unit records the number of extra fine interval which be used. An extra-boundary value will be recorded in the fine calibration unit for determining an initial fine interval in another coarse interval if the heavy switching occurs. It should be noted that the extra-boundary value could be a positive or minus value corresponding to which a forward coarse interval or a backward coarse interval the reference signal drifts into.

Abstract: A circuit comprises a digital phase locked loop for generating a synchronization signal and a voltage regulator for providing regulated output voltage responsive to the synchronization signal from the digital phase locked loop.

Abstract: A delay lock clock synthesizer comprises: an adjustable delay circuit for receiving an input clock and for generating an output clock having a phase offset controlled by a control signal; a phase detector for detecting a phase difference between the input clock and the output clock and for generating a phase error signal representing the phase difference; a summing circuit for summing the phase error signal and a phase offset signal into a modified phase error signal; and a filter for filtering the modified phase error signal to generate the control signal to control the adjustable delay circuit.

Abstract: A delay locked loop includes an auxiliary phase shifter for controlling a phase blending point after the delay locked loop is initially locked, thereby reducing jitter. A control circuit directs a phase blender to detect the point where two delayed signals are phase-blended, and directs the auxiliary phase shifter to select between a delayed clock signal and a received clock signal. When the point where the two delayed signals are phase-blended is in-between first edges of the two delayed signals, the control circuit directs the auxiliary phase shifter to transmit the received clock signal without delaying the clock signal. When the point where the two delayed signals are phase-blended is close to at least one of the first edges of the two delayed signals, the control circuit directs the auxiliary phase shifter to delay the clock signal by a predefined time. As a result, bang-bang jitter in the delay locked loop is reduced.

Abstract: Disclosed are current sink and source circuits, a charge pump that incorporates them, and a phase locked loop that incorporates the charge pump. The current sink and source circuits each have a current mirror that biases a transistor connected to an output node. These circuits each further have a two-stage feedback amplifier to sense the current mirror drain voltage and to control the transistor gate voltage in order to stabilize the current mirror drain voltage independent of output voltage at the output node. The amplifier also increases output resistance at the output node. This configuration allows for a wide operation voltage range and ensures good circuit performance under a very low power supply. A charge pump that incorporates these circuits generates highly matched charging and discharging currents. A PLL that incorporates this charge pump exhibits minimal bandwidth shifts and minimal locking speed and jitter performance degradation.