Abstract: A phase-locked loop includes a processing unit, a voltage-controlled oscillator, and a control unit. The processing unit generates a control voltage to a node according to a phase difference between a reference clock and a first feedback clock. The voltage-controlled oscillator generates the first feedback clock according to a voltage of the node. The control unit deactivates the voltage-controlled oscillator and provides a start voltage to the node in a power-down mode, and activates the voltage-controlled oscillator to generate the first feedback clock according to the voltage of the node in a power-on mode. The control unit stops providing the start voltage in the power-on mode.

Abstract: A kick back compensated charge pump circuit with kicker capacitor is disclosed. The charge pump circuit comprises a pump up circuit that comprises a first PMOS transistor and a second PMOS transistor in a cascode configuration and coupled to a first kicker capacitor. The charge pump circuit also comprises a pump down circuit that comprises a first NMOS transistor and a second NMOS transistor in a cascode configuration and coupled to a second kicker capacitor. The kicker capacitors increase the speed of the charge pump circuit by charging and discharging a gate to source capacitance (CGS) of the pump up circuit and of the pump down circuit of the charge pump circuit.

Abstract: A charge-pump includes a first charge-pump sub-circuit having a control terminal that communicates with a first bias voltage line. A first charge-pump mirror sub-circuit regulates current on the control terminal. A first capacitance and a first ripple reducing sub-circuit communicate with the first bias voltage line. A second charge-pump sub-circuit and a second charge-pump mirror sub-circuit communicate with a second bias voltage line. A second capacitance and a second ripple reducing sub-circuit communicate with the second bias voltage line. An output communicates with the first and second charge-pump sub-circuits.

Abstract: A circuit, with applications to phase-locked loops and frequency synthesis, where a divider circuit shuffles between dividing the output of a voltage-controlled oscillator by N or N+1, where N is an integer, and where a phase frequency detector provides three logic signals to a charge pump so that one of three values of current may be sourced to a loop filter, with the result that the circuit behaves as a conventional phase-lockup loop fictitious divider circuit that is capable of dividing the output of the voltage-controlled oscillator by a non-integral value.

Abstract: The invention concerns a controllable current source or “charge pump” (12) in an integrated circuit, comprising two supply terminals (K1, K2) for the application of two supply potentials (V1, V2) as well as an output terminal (Kout) for the delivery of an output current, connected via a first controllable current path (T1) with the first supply terminal (K1), and via a second controllable current path (T2) with the second supply terminal (K2). In order to improve the current source (12) with regard to the quality of the output signal, it is provided according to the invention that the controllable current source (12) furthermore has a replica (T1?, T2?) of the current paths (T1, T2) in their non-controlled state, of which a replica output terminal (Kout?) is connected via a current mirror (T5 to T8) with the output terminal (Kout).

Abstract: The phase locked loop (PLL) with adjustable phase shift is described. The PLL includes a voltage controlled oscillator which is capable of generating multiple phase shifted output signals, and multiple phase detectors capable of determining the phase differences between the output signals and a reference clock. The PLL further includes a weighting device capable of weighting the phase differences and generating a control signal for the voltage controlled oscillator.

Abstract: In one embodiment, a circuit comprises at least first and second circuit stages, at least one level shifting circuit, and a control circuit. The first circuit stage is configured and arranged to produce a reference voltage at the at least one first output during each first phase of at least first and second phases, and to produce an output signal at the at least one first output that is responsive to an input signal at the at least one first input during each second phase of the at least first and second phases. The at least one level shifting circuit comprises at least one capacitor and at least one switch and is coupled between the first circuit stage and the second circuit stage.

Abstract: A delay amount variable circuit (8) adapted to change a delay amount according to a ZQ calibration result is inserted in a path of a DQ replica system. The delay amount of the path of the DQ replica system is variable and is adjusted so as to make constant a timing skew difference between a DQ buffer system and the DQ replica system. The ZQ calibration result changes depending on variations in temperature, voltage, and manufacture. Therefore, by obtaining the delay amount corresponding to these variations, there are obtained a DLL circuit with high accuracy that can make the skew difference constant, and a semiconductor device incorporating such a DLL circuit.

Abstract: A phase locked loop (PLL), including a phase-frequency detector receiving two clock signals and outputting a phase detection signal corresponding to the phase difference between the two clock signals is provided. A controller receives the phase detection signal and generates a first control signal and a second control signal according to the phase detection signal, an oscillator receiving the first control signal and outputting a first output clock signal with a folded period corresponding to the first control signal and a loop divider receiving the second control signal and the first output clock signal dividing the frequency of the first output clock signal by an integer unfolding divisor corresponding to the second control signal and outputting a second output clock signal coupled to the phase-frequency detector. The PLL eliminates unlocked frequencies for all process imperfections, has decreased circuit area and provides a broad output bandwidth.

Abstract: The invention relates to a phase-locked loop circuit (1) in a radio transceiver for the detection of the linear operation of a first voltage controlled oscillator (2), which comprises a frequency divider (8), a reference oscillator (10), a phase detector (12) to compare the phases of the reference oscillator (10) with a divided frequency of the frequency divider (8), and a charge pumping means (14) connected to the phase detector (12) and is characterized in that the connection (13) between the phase detector (12) and the charge pumping means (14) has at least one branch-off line (15) connected to at least one filtering means (22), whose output voltage is related to the linear operation of the voltage controlled oscillator (2).

Abstract: A loop filter (30) includes a first capacitor (31) provided between an input terminal for a current signal and a reference voltage, a switched capacitor circuit (32) provided between the input terminal and the first capacitor (31) and a second capacitor (33) provided in parallel to the first capacitor (31) and the switched capacitor circuit (32). In the switched capacitor circuit (32), when a third capacitor (321) is connected to the first capacitor (31), a fourth capacitor (322) is connected to the second capacitor (33). In the loop filter (30) having the above-described configuration, a capacitance value of the second capacitor (33) is set to be larger than respective capacitance values of the third and fourth capacitors (321 and 322).

Abstract: A system clock signal generator circuit comprising a first PLL circuit that is frequency and phase locked to a wobble signal; a frequency and phase comparator for comprising a first output signal from the first PLL circuit with a system clock signal as frequency divided by M and for outputting a second output signal based on the differences in frequency and in phase; a PLL filter for providing a predetermined cutoff to the second output signal to output a third output signal; a pulse width modulating circuit for generating a pulse wave, the carrier frequency of which is a second reference clock signal, and for outputting a fourth output signal obtained by modulating the pulse width of the pulse wave by the third output signal; a low pass filter for smoothing the fourth output signal to output a fifth output signal; a VCO circuit the control voltage of which is the fifth output signal; a first frequency divider circuit for frequency dividing an output signal of the VCO circuit by N to output a system clock sig

Abstract: An audio amplifier with an integrated asymmetric charge pump is provided. The audio amplifier receives VDD and VSS as power supply signals. The integrated charge pump is arranged to provide VSS from VDD, such that VSS is a negative voltage that is lower in magnitude than VDD.

Abstract: A charge pump (140) having a differential current amplifier with a current source (151) that sources output current (155) in response to a first bias point (141), and a current sink (152) that sinks current in response to a second bias point (142) is provided. The charge pump includes a first level translator (131) that monitors a high range of an output voltage (156) of the differential current amplifier and self-adjusts the first bias point to extend the output voltage to a higher range, and a second level translator (132) that monitors a low range of the output voltage of and self-adjusts the second bias point to extend the output voltage to a lower range. The charge pump keeps the output current constant between the higher range and the lower range. A sensing transistor increases an output impedance of the differential current amplifier and reduces output loading.

Abstract: According to the present invention, there is provided a semiconductor device including: a phase locked loop circuit having, a phase frequency detector which receives a reference signal and a frequency-divided signal, and outputs a phase difference detection signal by performing phase comparison, a charge pump which receives the phase difference detection signal and outputs a charge pump signal by converting a voltage change into a current change, a loop filter which receives the charge pump signal, and outputs a control voltage by passing components having frequencies not more than a predetermined frequency, a voltage controlled oscillator which outputs a frequency signal having a frequency based on the control voltage, and a frequency divider which receives the frequency signal, and outputs the frequency-divided signal by dividing the frequency; a mask signal generator which generates a mask signal masking a timing at which the phase frequency detector compares phases of the frequency-divided signal and the

Abstract: Disclosed is a booster circuit comprising a voltage detection circuit for outputting a decision output signal for detecting a boosted voltage and controlling a voltage boosting operation, an oscillation circuit, and a plurality of charge pump circuits. The oscillation circuit includes an odd number of stages of control-type inverters. When the decision output signal from the voltage detection circuit indicates the voltage boosting operation (oscillation), the odd number of stages of inverters constitute a closed path. Oscillation outputs from outputs of the control-type inverters are thereby extracted, respectively. When the decision output signal indicates a stop of the voltage boosting operation (stop of the oscillation), output values of the control-type inverters are not inverted and held, and the oscillation is thereby stopped. The charge pump circuits receive output signals from the control-type inverters as clock signals, respectively, and operate.

Abstract: This invention provides a charge pump circuit used in phase-locked loop (PLL) having the function of power management for portable application. According to different applications, power management adjusts the power consumption modes of this PLL that will also correspond to different jitter degree. There are three kinds of modes contained in the PLL: the first mode is normal mode having the larger power consumption and smaller jitter, second mode is low power mode having moderate power consumption and moderate jitter, and third mode is the traditional mode having the smaller power consumption and the larger jitter.

Abstract: A methodology is disclosed that enables the delay stages of an analog delay locked loop (DLL) or phase locked loop (PLL) to be programmed according to the operating condition, which may depend on the frequency of the input reference clock. The resulting optimized delay stages allow for a broad frequency range of operation, fast locking time over a wide range of input clock frequencies, and a lower current consumption at high clock frequencies. Better performance is achieved by allowing the number of analog delay stages active during a given operation to be flexibly set. The deactivation or turning off of unused delay stages conserves power at higher frequencies. The high frequency range of operation is increased by using a flexible number of delay stages for various input clock frequencies. Because of the rules governing abstracts, this abstract should not be used to construe the claims.

Abstract: A charge pump circuit is disclosed, including: a dummy current path comprising a first junction node; a normal current path comprising a second junction node; a switch, coupled between the dummy current path and the normal current path; wherein when the switch is closed a first voltage is at the first junction node and the second junction node, and when the switch is open a second voltage is at the first junction node; and a comparator, for comparing the first voltage and the second voltage to balance a current mismatch of the charge pump circuit. The disclosed charge pump circuit can be implemented in a phase locked loop system.

Abstract: A charge pump for use in a Phase Locked Loop/Delay Locked Loop minimizes static phase error through the use of an operational amplifier. The operational amplifier also mitigates the effects of low power supply voltage.

Abstract: An improved burst mode receiver includes a digital phase detector, receiving an incoming signal. The receiver also includes a charge pump, receiving pulse signals from the digital phase detector to compare the incoming clock phase to the local generated clock phase and to control the charge pump, a loop filter, receiving a charge value from the charge pump and producing a control signal and a local clock generator, receiving the control signal, producing a recovered clock and supplying the recovered clock to the digital phase detector.

Abstract: An amplitude modulator is provided, which has a first supply connection for supplying a supply potential and a second supply connection for supplying a ground potential. An amplifier stage with a push-pull output stage has a signal input for supplying a signal, and has a single-pole output for emitting a single-ended signal. In order to supply the push-pull output stage, the amplifier stage is connected in a supply path between the first and the second supply connection. A first controllable voltage source and a second controllable voltage source are also provided, whose control inputs are connected to a connection for control purposes by means of a differential modulation signal, and are connected between the amplifier stage and the first supply connection, or the amplifier stage and the second supply connection. Amplitude modulation is thus achieved by modulation of the supply voltage or of the supply current to the push-pull output stage.

Abstract: A nonvolatile semiconductor memory device includes a memory cell array of a plurality of memory cells; and a voltage generating circuit for generating a programming voltage to be applied to the memory cells. The voltage generating circuit includes a first voltage generating unit for generating a negative voltage through a first charge pump; and a second voltage generating unit for generating a positive voltage through a second charge pump. During an accelerated programming operation, the first voltage generating unit increases a pumping efficiency of the first charge pump using an external power supply voltage, and the second voltage generating unit directly outputs the external power supply voltage.

Abstract: A power supply, and a method of controlling the power supply, in which more or less power capacity of the power supply is activated depending on the state of a digital data signal on a data bus. The power supply has a control circuit which detects the number of “zero” bits present on the data bus, and responsively activates one or more of a plurality of power supply circuits such as charge pump circuits. The outputs of the charge pump circuits are mutually connected to a driver adapted to program memory cells of a flash memory circuit.

Abstract: The present invention provides a voltage generating circuit and a control method thereof which is capable of preventing an increase in the occupied area and suitable for raising the voltage of the power supply in a wide range.

Abstract: A constant current output charge pump includes a switch module configured to compare a reference voltage with a load voltage and output a switch signal, a voltage margin control module configured to compare a first voltage and a second voltage with an output voltage and output a voltage margin control signal, a clock control module, a charge pump module, a current control module and a load module. The clock control module is configured to capture the switch signal and the voltage margin control signal and output a first clock signal and a second clock signal according to a system to the charge pump module for charging the input voltage.

Abstract: A phase detector generates a phase dependent control signal according to the phase relationship between a first and second clock signal. The phase detector includes first and second phase detector circuits receiving the first and second clock signals and generating select signals having duty cycles corresponding to the phase relationship between the clock edges of the first and second clock signals. The phase detector also includes a charge pump that receives select signals from the phase detector circuits and produces an increasing or decreasing control signal when the first and second clock signals do not have the predetermined phase relationship, and a non-varying control signal when the first and second clock signals do have the predetermined phase relationship. The control signal may be used to adjust the delay value of a voltage-controlled delay circuit in order to adjust the phase relationship between the first and second clock signals to have a predetermined phase relationship.

Abstract: An improved clock recovery system, phase-locked loop, and phase detector are provided as well as a method for generating charge pump signals. The clock recovery system includes a phase-locked loop. The phase-locked loop includes a phase detector and a voltage-controlled oscillator. The phase detector generates pump signals that change linearly with respect to differences between phases of an incoming signal and a clocking signal. The oscillator is coupled to receive the pump signals and produce a clocking signal at a frequency not exceeding the frequency of the incoming signal. For example, the oscillator can produce clocking signals at one-half the frequency of the incoming signal, where the incoming signal is preferably a maximum bit rate of a data signal from which the clock signal is recovered. The phase detector can include a first flip-flop and second flip-flop.

Abstract: A charge pump for use in a Phase Locked Loop/Delay Locked Loop. The charge pump includes a pull-up circuit a pull-down circuit and a reference current source. The reference current source includes a number of select transistors and a number of mirror master transistors. The mirror master transistors are coupled to slave transistors in either of the pull-up circuit and the pull-down circuit.

Abstract: A phase locked loop (PLL) with phase rotation spreading includes a phase detector, a charge pump, a filter, a voltage controlled oscillator (VCO) and a selector. The phase detector receives a reference clock signal and a feedback clock signal to thereby produce an error signal. The charge pump converts the error signal into a current signal. The filter converts the current signal into a voltage signal. The VCO produces N clock signals with a same frequency in accordance with the voltage signal, where the N clock signals have phases ?0 to ?N?1 respectively, and ?j indicates a lead of over ?j+1, for j=0, 1, . . . , N?2. The selector selects one from the N clock signals in accordance with a predetermined sequence to thereby produce a target clock signal, and finely adjusts a frequency of the target clock signal for a spreading operation.

Abstract: A system and method for effectively utilizing a dual-mode phase-locked loop to support a data transmission procedure includes a voltage controlled oscillator that generates a receiver clock signal in response to VCO input control signals. A binary phase detector generates a BPD output signal during a BPD mode by comparing input data and the receiver clock signal. In addition, a lock-assist circuit generates a PFD output signal during a PFD mode by comparing a reference signal and a divided receiver clock signal. A loop filter performs a BPD transfer function to generate a VCO input control signal from the BPD output signal during the BPD mode. The same loop filter also performs a PFD transfer function to generate the VCO input control signal from the PFD output signal during the PFD mode.

Abstract: A digital phase locked circuit provides an output clock signal whose phase is synchronous with the phase of an input clock signal under a desired level of a phase absorption characteristic even if the input clock signal is supplied in a burst fashion. A phase comparing part compares the phase of the output clock signal with the phase of the input clock signal. A phase comparison result detecting part outputs an INC/DEC request signal for controlling a division operation based on a phase comparison signal. An execution rate computing part computes a phase difference between the input clock signal and the output clock signal based on the INC/DEC request signal and outputs an execution rate corresponding to the phase difference. A clock generating part controls a division operation for the master clock signal in accordance with the INC/DEC request signal and changes phase absorption speed of the output clock signal in accordance with the execution rate.

Abstract: Charge pump circuitry is provided that is insensitive to charge sharing and current mismatch effects. The charge pump circuitry has an output node at which a charge pump output voltage is provided. A first current source charges the output node to increase the output voltage or a second current source discharge the output node to decrease the output voltage. The charge pump circuitry uses a unit-gain op-amp circuit to prevent charge sharing effects from affecting the output voltage when switching between discharging and charging operations. A low-pass filter is used to reduce feedback noise on the output node. A replica feedback circuit prevents current mismatch between the currents produced by the first and second current sources. The first and second current sources may be formed using programmable transistors that are adjusted by static control signals provided by programmable elements to further minimize current mismatch.

Abstract: Provided are a semiconductor memory device having a source synchronous interface capable of reducing jitter while minimizing overhead and a clocking method thereof. The semiconductor memory device comprises a phase locked loop (PLL) circuit receiving a first external clock signal for a command and address signal and generating a first internal clock signal, a first delay locked loop (DLL) circuit receiving a second external clock signal for predetermined bits of data and the first internal clock signal and generating a second internal clock signal locked to the second external clock signal, and a second DLL circuit receiving a third external clock signal for the remaining bits of the data and the first internal clock signal and generating a third internal clock signal locked to the third external clock signal.

Abstract: In a symmetrical phase-lock loop (PLL) device, first (I1P1, I1P2) and second (I2P1, I2P2) pairs of switches are disposed between (i) first and second outputs of a symmetrical time/voltage conversion block and (ii) first and second inputs of a voltage processing block. In addition, third (I3P1, I3P2) and fourth (I4P1, I4P2) pairs of switches are disposed upstream of the first and second inputs of the phase comparator (PC).

Abstract: A charge pump includes first and second pairs of differential transistors. Each transistor includes control, first, and second terminals. First and second charge pump drivers communicate with the control terminal of one of the first pair of differential transistors and one of the second pair of differential transistors, respectively. Third and fourth charge pump drivers communicate with the control terminal of the other of the first pair of differential transistors and the other of the second pair of differential transistors, respectively. The first through fourth charge pump drivers include respective pairs of differential transistors that receive control signals from respective control circuits.

Abstract: A phase-locked loop and method are disclosed. One method embodiment includes providing a dual-path filter of a phase-locked loop, the dual-path filter consisting of passive components, and summing control signals in the dual-path filter using the passive components.

Abstract: A dual differential sawtooth signal generator includes a first sawtooth voltage generator that has a first capacitor and a second capacitor that are alternately charged with a feedback control source current from a low voltage reference voltage level. A second sawtooth voltage generator has a first discharge capacitor and a second discharge capacitor that are alternately discharged with a feedback control sink current from a high voltage reference voltage level. The output signals of the two sawtooth voltage generators are compared to control a phase frequency comparator that provides signals to control a dual charge pump that provides the feedback control source current and that provides the feedback control sink current.

Abstract: A clock and data recovery circuit having parallel dual path is disclosed, which includes a phase detecting circuit, a first charge pump, a proportional load circuit, a second charge pump, an integration load circuit, and a voltage control oscillating circuit. The phase detecting circuit respectively compares a phase difference between a data signal and a plurality of clock signals to generate two proportional control signal and two integration control signal for respectively controlling the first charge pump and the second charge pump to generate a first current and a second current. The proportional load circuit and the integration load circuit respectively receive the first current and the second current to output a proportional voltage and an integration voltage. The voltage control oscillating circuit adjusts the phase and frequency of the plurality of clock signals in response to the proportional voltage and the integration voltage.

Abstract: Adverse effects of switching noise produced by a charge pump circuit on a displayed image are prevented. In a synchronizing separation circuit 18, a synchronizing signal is separated from a video signal. The separated synchronizing signal is subjected to ½ frequency division in a flip-flop 20 to obtain a clock signal having a period which is two times as much as one horizontal period, and this clock signal is utilized to control switching of the charge pump circuit. As a result, a timing at which each switch in the charge pump is changed over can be set in a period close to a horizontal synchronizing signal without a video signal, thereby preventing noise from affecting the video signal.

Abstract: An anti-gate leakage programmable capacitor including at least one capacitor having a first terminal coupled to a first node and a second terminal, a second node, and a control circuit which selectively couples the second terminal of the capacitor to the second node or which drives the second terminal to the same voltage as the first node. In one embodiment, the programmable capacitor includes multiple capacitors, an amplifier having an input coupled to the first node and an output, and a switch circuit coupled to the second node, to each second terminal of each capacitor and to the amplifier output. The switch circuit selectively switches each second terminal of each capacitor between the amplifier output and the second node. The switch circuit may include pairs of switches each controlled by a corresponding select signal to selectively switch a corresponding capacitor between the reference node and the output of the amplifier.

Abstract: A method and apparatus for capacitance multiplication using two charge pumps. A first charge pump (206) provides a current signal (I216) that is first conducted by a resistor (310) of an RC network and then split into three current paths prior to being conducted by a capacitor of the RC network. A first current path provides current to the capacitor (306) of the RC network from node (320). A second current path multiplies the current conducted by capacitor (306) by a first current multiplication factor. A third current path provides current to a second charge pump, which multiplies the current from the first charge pump by a second current multiplication factor that has a fractional value with an inverse magnitude sign relative to the first current multiplication factor. The combination of the second and third current paths effectively multiplies the capacitance magnitude of capacitor (306).

Abstract: A phase locked loop (PLL) integrated circuit includes a voltage-controlled oscillator (VCO) configured to generate a clock signal at an output terminal thereof. The VCO is further configured to improve the frequency response of the PLL by varying a capacitance of the output terminal concurrently with changing a frequency of the clock signal. The VCO may include a control signal generator, which is configured to generate a plurality of control signals in response to UP and DOWN pumping signals, and an oscillator, which is configured to generate the clock signal in response to the plurality of control signals. The oscillator may be a ring oscillator, which is responsive to the plurality of control signals.

Abstract: A charge-pump circuit includes: MOS transistors connected in series and having one end to which a system ground power supply voltage is supplied; and a discharge transistor. The discharge transistor has one end connected to a node which is connected to the MOS transistors, and the system ground power supply voltage is supplied to the other end of the discharge transistor. The MOS transistors are implemented by a triple-well structure formed in a p-type semiconductor substrate. When a normal operation is performed, the MOS transistors are turned ON and the discharge transistor is turned OFF. When a discharge operation is performed, the MOS transistors are turned OFF and the discharge transistor is turned ON, and a current path is formed by parasitic bipolar transistor elements.

Abstract: An integrated circuit device includes a fast-locking phase locked loop (PLL). This PLL includes a phase-frequency detector and first and second charge pumps, which are responsive to first and second control signals generated by the phase-frequency detector. The first and second charge pumps have different current sourcing characteristics when the first control signal is active and different current sinking characteristics when the second control signal is active.

Abstract: A phase-locked loop includes a voltage-controlled oscillator and a charge-pump loop filter. The voltage-controlled oscillator includes a varactor having a first set of capacitor cells configured to adjust a capacitance based on a first control voltage, and a second set of capacitor cells configured to adjust a capacitance based on a second control voltage. The charge-pump loop filter receives a first and a second update signal, each having at least one state based on a phase difference between a first clock and a second clock, and comprises a first component and a second component. The first component is configured to adjust, during an update period, a voltage across an impedance from a reference level based on the states of the first and second update signals and to return the voltage across the impedance to the reference level prior to an end of the update period, wherein the voltage across the impedance comprises the first control voltage.

Abstract: In one embodiment, the present invention provides a phase-locked loop comprising a charge-pump loop filter and a phase detector system. The charge-pump loop filter is configured to provide a control voltage having a voltage level based on a state of a first control signal and on a state of a second control signal. The phase detector system is configured to receive a first clock, a second clock, and a control signal defining a plurality of states including a first state and a second state. The phase detector system is further configured to provide the first control signal and the second control signal each having a state based on a phase difference between the first and second clocks when the control signal has the first state, and to provide the first control signal and second control signal each having a state asynchronously controlled by the control signal when the control signal has the second state.

Abstract: The smart charge-pump circuits basically include a high-performance charge-pump circuit as well as a smart lock-in circuit. After the smart charge-pump circuit sensors an initial condition and responds accordingly, it will begin to operate fully as a high performance charge-pump.

Abstract: A charge pump and loop filter circuit of a phase locked loop includes a resistor, first and second capacitors, first and second input current sources for supplying first and second currents to the circuit, a first output current source for outputting the first current from the circuit, and a second output current source for receiving the second current from the circuit. The charge pump also contains a plurality of up pulse switches and down pulse switches for controlling current flow through the circuit such that only a fraction of the current that flows through the resistor flows into and out of the first capacitor for charging and discharging the first capacitor. The size of the first capacitor can be reduced accordingly based on the amount of current used to charge and discharge the first capacitor.

Abstract: Operation noise and charge error of a charge pump circuit are reduced, thereby the jitter characteristics and the spectrum characteristics of a PLL circuit are improved, and further a time period elapsed until the PLL circuit is locked is shortened. The charge pump circuit 36 receives a control signal depending on an output of a phase comparison circuit 34 from a control circuit 35, and comprises a first P-channel MOS transistor P1, a second P-channel MOS transistor P2 and a third P-channel MOS transistor P3, and a first N-channel MOS transistor N1, a second N-channel MOS transistor N2 and a third N-channel MOS transistor N3, and a first current source 61, a second current source 62, a third current source 63 and a fourth current source 64.