Abstract: In a PLL circuit, first an ILFD is connected to an output voltage Vtune from an LPF, thereby causing the ILFD to operate as an oscillator. The ILFD, a DIV, PFD, CP, and LPF form a PLL and thereby locking operations are initiated. When a predetermined time elapses, an output frequency from the ILFD converges into a certain value and the PLL is subjected to a locked state. After the locked state is reached, a sample hold circuit SH holds the output voltage Vtune from the loop filter as of that time and frequency adjustment of the ILFD is completed. Similar frequency adjustment is sequentially performed on other ILFDs.

Abstract: A charge pump includes a current source circuit, a current sink circuit and a switch circuit. The switch circuit is coupled between the current source circuit and the current sink circuit, and is arranged for generating a first current at a first output terminal and generating a second current at a second output terminal according to a first control signal and a second control signal, wherein each of the first current and the second current is generated from the current source circuit.

Abstract: The invention concerns an apparatus comprising an analog circuit and a digital circuit. The analog circuit may be configured to generate an enable signal in response to (i) a comparison of a width of an up pulse and a pre-determined width and (ii) a comparison of a width of a down pulse and the pre-determined width. The up pulse and the down pulse may be generated in response to a comparison of a feedback signal and a reference signal. The enable signal may be active when both the comparisons are within a pre-determined threshold. The digital circuit may be configured to generate an output signal representing a lock status between (i) the feedback signal and (ii) the reference signal. The lock status may be determined (a) during a decision window based on a number of pulses of the reference signal and (b) when the enable signal is active.

Abstract: A drive circuit for a MEMS resonator can include closed loop means for detecting and amplifying a signal of the MEMS resonator, and means for feeding the detected and amplified signal as a feedback signal back to the MEMS resonator. The circuitry also comprises DC bias voltage means for generating for the MEMS resonator a first DC bias voltage, and a second DC bias voltage that is controlled according to measured amplitudes of the MEMS resonator, one of the DC bias voltages being summed into the feedback signal. The circuitry comprises also a start-up circuitry adapted to detect a start-up state, and in response to a detected start-up state change at last one of the DC bias voltages to a predefined level. The state of constant oscillation is achieved reliably and in short time.

Abstract: Various aspects of this disclosure describe switched-capacitor circuits in a PLL. Examples include routing current from a first current source through a capacitor to ground during a first clock phase, routing current from a second current source through the capacitor to ground during a second clock phase, and transferring charge on the capacitor to a loop filter capacitor during a third clock phase. The first current source may generate current responsive to UP error samples from a phase/frequency detector (PFD), and the second current source generates current responsive to DN error samples from the PFD.

Abstract: Some embodiments include apparatus and methods having an input to receive an input signal, additional inputs to receive clock signals having different phases to sample the input signal, and a decision feedback equalizer (DFE) having DFE slices. The DFE slices include a number of data comparators to provide data information based on the sampling of the input signal, and a number of phase error comparators to provide phase error information associated with the sampling of the input signal. The number of phase error comparators of the DFE slices is not greater than the number of data comparators of the DFE slices.

Abstract: An example pulse generation circuit includes a parallel-to-serial circuit configured to convert parallel data to serial data according to parallel clock signal and a serial clock signal, the serial data comprises a sequence of pulses; a clock generator configured to generate a clock signal; and a phase controller configured to generate the serial clock signal from the clock signal based on a phase control signal.

Abstract: A phase locked loop circuit includes a voltage controlled oscillator, VCO, configured to receive an oscillator tuning voltage; a phase detector configured to receive an input signal and a reference signal and generate a phase difference pulse signal that is varied in accordance with the oscillator tuning voltage; a loop filter having an input and an output; and a level shifter circuit coupled to an output of the phase detector and the loop filter input and configured to apply a level shift to the phase difference pulse signal such that the level shift is configured to compensate VCO gain and the loop filter averages the phase difference pulse signal to output an averaged signal to the VCO.

Abstract: A semiconductor device and a layout verification method of a semiconductor device are provided. The layout verification method includes forming a plurality of standard cells each having a first type of a cross coupled structure (XC) and a second type of the XC on a substrate of the semiconductor device, forming a plurality of first inverters in which the first type of the XC is activated in the a plurality of the standard cells and a plurality of second inverters in which the second type of the XC is activated in the a plurality of the standard cells and estimating an electrical characteristic of the first type of the XC or the second type of the XC by measuring a magnitude of a signal delay of the plurality of the first inverters or the plurality of the second inverters.

Abstract: A circuit for clamping current in a charge pump is disclosed. The charge pump includes switching circuitry having a number of switching circuitry transistors. Each of first and second pairs of transistors in the circuit can provide an additional path for current from its associated one of the switching circuitry transistors during off-switching of that transistor so that a spike in current from the switching circuitry transistor is only partially transmitted through a path extending between the switching circuitry transistor and a capacitor of the charge pump.

Abstract: Cycle timing of a charge pump is adapted according to monitoring of operating characteristics of a charge pump and/or peripheral elements coupled to the charge pump. In some examples, this adaptation provides maximum or near maximum cycle times while avoiding violation of predefine constraints (e.g., operating limits) in the charge pump and/or peripheral elements.

Abstract: A device includes a lock detect circuit that is structured and arranged to: convert a reference clock to a reference triangle wave; convert a feedback clock to a feedback triangle wave; determine whether the feedback triangle wave is within a tolerance margin that is defined relative to the reference triangle wave; and generate a determiner output that is a first value when the feedback triangle wave is not within the tolerance margin, and a second value when the feedback triangle wave is within the tolerance margin.

Abstract: A bias circuit is adapted for biasing a to-be-biased transconductance cell such that the to-be-biased transconductance cell has a constant transconductance, and includes a converter and a controller. The converter receives first and second current signals, and generates, based on the first and second current signals, a first voltage signal, a second voltage signal and a bias voltage that is for biasing the to-be-biased transconductance cell. The controller receives the first and second voltage signals from the converter, generates the first and second current signals for the converter based on the first and second voltage signals so as to make a magnitude of the first voltage signal equal a magnitude of the second voltage signal.

Abstract: A semiconductor system may include a first semiconductor device configured to output a command and receive data. The semiconductor system may include a second semiconductor device configured to generate a periodic signal, the periodic signals periodically toggled in response to the command, output the data in response to the periodic signal, and discharge the charges of an internal node if the periodic signal is not toggled during a predetermined section.

Abstract: A loop powered process instrument comprises a control system measuring a process variable and developing a measurement signal representing the process variable. An output circuit, for connection to a remote power source using a two-wire process loop, controls current on the loop in accordance with the measurement signal. A power supply is connected to the output circuit and the control system. The power supply receives power from the two wire process loop and supplies power to the control system. The power supply comprises a voltage regulator receiving loop power and developing a regulated output voltage and an adjustable shunt regulator controlling voltage supplied to the voltage regulator.

Abstract: A wireless communication device has an analog control loop circuitry that generates an analog control signal to adjust a phase of a voltage controlled oscillation signal, in accordance with a phase of a reception signal, a digital control loop circuitry that generates a digital control signal having a frequency determined by a frequency of a reference signal and a predetermined frequency setting code signal and having a phase opposite to a phase of the analog control signal, a voltage controlled oscillator that generates the voltage controlled oscillation signal, on the basis of the analog control signal and the digital control signal, and a data slicer that generates a digital signal obtained by digital demodulation of the reception signal, on the basis of a comparison result of the digital control signal and a predetermined threshold value.

Abstract: A wireless communication device has an analog control loop circuitry that generates an analog control signal to adjust a phase of a voltage controlled oscillation signal, in accordance with a phase of a reception signal, a digital control loop circuitry that generates a digital control signal having a frequency determined by a frequency of a reference signal and a predetermined frequency setting code signal and having a phase opposite to a phase of the analog control signal, a voltage controlled oscillator that generates the voltage controlled oscillation signal, on the basis of the analog control signal and the digital control signal, and a data slicer that generates a digital signal obtained by digital demodulation of the reception signal, on the basis of a comparison result of the digital control signal and a predetermined threshold value.

Abstract: A wireless communication apparatus has an analog control loop circuitry to generate an analog control signal which adjusts a phase of a voltage-controlled oscillation signal, an integrator to integrate the analog control signal, a phase adjuster to adjust a phase of the voltage-controlled oscillation signal, a digital control loop circuitry, in a first mode, to match a frequency of the voltage-controlled oscillation signal to a frequency of the received signal based on an output signal of the phase adjuster, and in a second mode, to generate a digital control signal which is opposite in phase to the analog control signal and has a frequency, a voltage-controlled oscillator to generate the voltage-controlled oscillation signal based on the analog and digital control signals, and a signal switch to supply the analog control signal to the integrator in the first mode and to the voltage-controlled oscillator in the second mode.

Abstract: The present invention discloses a negative charge pump feedback circuit, wherein the feedback circuit is connected between an AND gate and the output terminal of the negative charge pump, and a clock signal is connected to the negative charge pump through the AND gate and under the control of the feedback signal, with the feedback circuit including a switch-capacitor circuit and a comparator; a first terminal of a first capacitor of the switch-capacitor circuit is connected to the output terminal of the negative charge pump through a first switch, and grounded through a second switch; a first terminal of a second capacitor is connected to a second terminal of the first capacitor, grounded though a third switch, and connected to the comparator though a fourth switch; an adjustable capacitor is connected in parallel to both terminals of the second capacitor; a positive-phase input terminal of the comparator is connected to a reference voltage.

Abstract: A square wave generator suitable for use with an electrosurgical device is provided. The square wave generator includes a voltage source configured to output a waveform and a comparator operatively coupled to the voltage source and configured to output energy in the form of a square wave. The generator may also include at least one sensor configured to sense an operational parameter of the energy outputted from the comparator and to provide a sensor signal corresponding thereto and a controller adapted to receive the at least one sensor signal and in response thereto control the voltage source.

Abstract: Provided herein are apparatus and methods for system ready in a clock distribution chip or system. In certain configurations, a communication system includes a clock generation circuit having a divider and phase control circuit to provide output clock signals. The communication system further includes a system ready circuit to provide a system ready signal indicative of whether all of the output clock signals are ready.

Abstract: According to one embodiment, a PLL circuit includes: a phase comparator (13); a pulse width control unit that adjusts a pulse width of comparison results (UP, DN) of the phase comparator (13) and outputs comparison results (UPi, DNi) having a pulse width smaller than that of comparison results (UPp, DNp); a charge pump (14) that outputs a current (Ip) according to the comparison results (UPp, DNp); a charge pump (15) that outputs a current (Ii) according to the comparison results (UPi, DNi); a filter (16) that removes a high-frequency component of a voltage generated based on the current (Ip) and outputs a control voltage (Vp); a filter (17) that outputs, as a control voltage (Vi), a result obtained by integrating the current (Ii); and a voltage control oscillator (18) that generates an oscillating signal having a frequency according to the control voltage (Vp, Vi).

Abstract: Techniques and apparatuses for identifying weak charge pumps and for setting an optimal clock period for charge pumps to minimize variations in a current-voltage characteristic. A current sink which absorbs a specified current is connected to an output node of a charge pump. In one approach, a success or fail status is set for a charge pump by driving it with a specified clock period in a constantly pumping mode and determining if the output voltage reaches a specified output voltage. In another approach, a success or fail status is set for a charge pump by driving it with a specified clock period in a regulation mode and determining if the period in which the output voltage cycles is a specified multiple, e.g., 2×, of a period of the clock signal. In another approach, an optimal clock period is determined.

Abstract: A phase-locked loop (PLL) circuit is disclosed. The PLL circuit includes a detecting circuit configured to detect a phase difference between a digitally controlled oscillator (DCO) clock signal and a reference clock signal, and generate a difference signal based on the detected phase difference; a digitized difference generator, coupled to the detecting circuit, configured to generate a control code based upon the difference signal; and a DCO configured to generate the DCO output signal responsive to the control code of the digitized difference generator; wherein the detecting circuit, the digitized difference generator and the DCO form a closed loop and reduce the phase difference between the DCO output signal and the reference clock signal. An associated method and a circuit are also disclosed.

Abstract: A current generator circuit included in a triangle-wave generator circuit in a control circuit includes plural stages of current mirrors connected in parallel with each other. The plural stages of current mirrors are placed so that the sum of output currents output therefrom becomes an output current of the current generator circuit. A switching element that controls the on/off state of a current in accordance with the amount of load current of a DCDC converter is connected to each of the current mirrors.

Abstract: A method is provided for making a high permittivity dielectric material for use in capacitors. Several high permittivity materials in an organic nonconductive media with enhanced properties and methods for making the same are disclosed. A general method for the formation of thin films of some particular dielectric material is disclosed, wherein the use of organic polymers, shellac, silicone oil, and/or zein formulations are utilized to produce low conductivity dielectric coatings. Additionally, a method whereby the formation of certain transition metal salts as salt or oxide matrices is demonstrated at low temperatures utilizing mild reducing agents. Further, a circuit structure and associated method of operation for the recovery and regeneration of the leakage current from the long-term storage capacitors is provided in order to enhance the manufacturing yield and utility performance of such devices.

Abstract: In one embodiment, a circuit comprises a first load circuit coupled to a first input voltage. A current sinking circuit is coupled to an output of the first load circuit. A second load circuit is coupled to ground. A current sourcing circuit is coupled between a second input voltage and an output of the second load circuit. A charge-recycling circuit is coupled between the output of the first load circuit and the output of the second load circuit to provide current from the current sinking circuit to the output of the current sourcing circuit to reduce current through the current sourcing circuit. The charge-recycling circuit can be a charge pump.

Abstract: A digital phased lock loop includes a digital controlled oscillator configured to produce an output signal at a frequency. A phase comparator compares the output signal, or a signal derived therefrom, with a reference signal to produce a phase error signal. A first loop filter produces a first control signal for the digital controlled oscillator from an output of the phase comparator. A frequency error measuring circuit coupled to the output of the phase comparator produces a frequency error signal. A second loop filter produces a second control signal for the digital controlled oscillator from an output of the frequency error measuring circuit. A circuit combines the first and second control signals and provides the combined control signals to the digital controlled oscillator.

Abstract: A charge pump circuit includes a capacitor, a current source circuit coupled to the capacitor for providing a charging current and a discharging current to the capacitor. The current source circuit includes a switch transistor with a gate terminal for receiving a control signal, a current source transistor having a source terminal coupled to a drain of the switch transistor, and a feedthrough suppression capacitor coupled between a gate terminal of a gate terminal of the switch transistor and a gate terminal of the current source transistor. The feedthrough suppression capacitor is configured to lower a feedthrough effect.

Abstract: An improved clock data recovery circuit is provided which provides lower bit error rates and faster locking times. In an embodiment, the circuit includes a voter having one or more voter inputs. The voter may generate up votes indicative of a recovered clock having a negative phase offset relative to a given voter input, or down votes indicative of the recovered clock having a positive phase offset. The circuit may include a comparator configured to output a phase adjustment signal and a tie signal. The circuit may further include an M-depth shift register and a multiplexer configured to select either the phase adjustment signal or an output from the shift register as a multiplexer output. The circuit may further include a flip-flop that generates a phase adjustment output signal. The shift register may receive the phase adjustment output signal at a data input of the shift register.

Abstract: A frequency synthesizing module includes an operating circuit, for generating a control voltage according to a reference signal and a feedback signal; a controllable oscillating circuit, configured for generating an oscillating signal according to the control voltage and a first control signal, comprising a first oscillating circuit with a first frequency gain, and a second oscillating circuit with a second frequency gain; a feedback circuit, for generating the feedback signal according to the oscillating signal and a second control signal; a control circuit, for generating the first control signal and the second control signal; wherein the control circuit adjusts the first control signal by a first value and adjusts the second control signal by a second value to estimate the first frequency gain of the first oscillating circuit; wherein the first value is proportional to the second value.

Abstract: A phase-locked loop (PLL) includes a time to voltage converter to convert a phase error between a reference signal and a feedback signal of the PLL to one or more voltage signals. An oscillator-based analog to digital converter (ADC) receives the one or more voltage signals and controls one or more oscillators according to the voltages. The oscillator-based ADC determines a digital value corresponding to the phase error based on the frequencies of the one or more oscillators.

Abstract: Phase-locked loop circuitry to generate an output signal, the phase-locked loop circuitry comprising oscillator circuitry, switched resistor loop filter, coupled to the input of the oscillator circuitry (which, in one embodiment, includes a voltage-controlled oscillator), including a switched resistor network including at least one resistor and at least one capacitor, wherein an effective resistance of the switched resistor network is responsive to and increases as a function of one or more pulsing properties of a control signal (wherein pulse width and frequency (or period) are pulsing properties of the control signal), phase detector circuitry, having an output which is coupled to the switched resistor loop filter, to generate the control signal (which may be periodic or non-periodic). The phase-locked loop circuitry may also include frequency detection circuitry to provide a lock condition of the phase-locked loop circuitry.

Abstract: A driver may provide a transition of a switch between an on state and an off state in two stages. In the first stage, the voltage slew rate of the voltage at an output terminal of the switch may be controlled. In the second stage, the current gradient of the switch may be controlled. The transition between the first stage and the second stage may be made based on the value of the voltage at the output terminal of the switch.

Abstract: A charge pump includes a switching circuit, a constant current source, a constant current sink, an adaptive current source, and an adaptive current sink. The switching circuit generates an output voltage at an output node according to an up control signal and a down control signal. The constant current source supplies a first current to the switching circuit. The constant current sink draws a second current from the switching circuit. The adaptive current source supplies a third current to the switching circuit. The adaptive current sink draws a fourth current from the switching circuit. The third current and the fourth current are adjustable according to the up control signal and the down control signal.

Abstract: A boost circuit includes a power rail to provide a supply voltage, a switch transistor controlling output of a boosted signal from a source of the switch transistor, and a timing and voltage control circuit configured to generate an equalization (EQ) signal to be applied to a gate of the switch transistor. The EQ waveform has a level being an EQ high level, an EQ low level lower than the EQ high level, or an EQ clamped level between the EQ low level and the EQ high level.

Abstract: A novel and useful 60 GHz frequency generator based on a third harmonic extraction technique which improves system level efficiency and performance. The frequency generator employs a third harmonic boosting technique to increase the third harmonic at the output of the oscillator. The oscillator generates both ˜20 GHz fundamental and a significant amount of the third harmonic at ˜60 GHz and avoids the need for a frequency divider operating at 60 GHz. The undesired fundamental harmonic at ˜20 GHz is rejected by the good fundamental harmonic rejection ratio (HRR) inherent in the oscillator buffer stage while the ˜60 GHz component is amplified to the output. The fundamental harmonic is further suppressed by active cancellation by properly combining the two outputs. The oscillator fabricated in 40 nm CMOS exhibits a phase noise of ?100 dBc/Hz at 1 MHz offset from a 60 GHz carrier and have a tuning range of 25%.

Abstract: A circuit for clamping current in a charge pump is disclosed. The charge pump includes switching circuitry having a number of switching circuitry transistors. Each of first and second pairs of transistors in the circuit can provide an additional path for current from its associated one of the switching circuitry transistors during off-switching of that transistor so that a spike in current from the switching circuitry transistor is only partially transmitted through a path extending between the switching circuitry transistor and a capacitor of the charge pump.

Abstract: A device and method for measuring jitter includes a capacitive element capable of being selectively charged, wherein the selection is made by a received signal from which an accumulated jitter value is to be determined. An analog-to-digital converter is coupled to the capacitive element to determine a voltage across the capacitive element after a number of cycles of the received signal. A determination module is coupled to the analog-to-digital converter to output the accumulated jitter value of the received signal using the voltage, wherein the accumulated jitter value is accumulated over the number of cycles.

Abstract: A clock data recovery circuit is configured to receive an input data signal formed of a series of input data pieces synchronized with a reference clock signal, and to generate a regenerated clock signal. The clock data recovery circuit includes a regenerated clock generating circuit; a latch circuit; a comparison circuit; a logical sum signal generating circuit; and a charge pump.

Abstract: The phase-locked loop (PLL) presented herein controls the phase of the output of the PLL. To that end, the PLL includes an oscillator that generates an output signal at an output of the PLL responsive to a comparison between a reference signal input to the PLL and a feedback signal derived from the output signal. To control the phase of the output signal, a modulation signal is applied to one input of the oscillator, separate from the reference signal input, where the modulation signal comprises one or more pulses having a total area defined based on the desired phase shift. To maintain the desired phase shift at the output of the PLL, the PLL also sets a time relationship between the reference signal and the feedback signal based on the desired phase shift.

Abstract: A clock generating apparatus includes an oscillator and a frequency synthesizer. The oscillator is utilized for generating a reference clock signal. The frequency synthesizer is coupled to the oscillator and utilized for synthesizing a target clock signal in accordance with the reference clock signal and a frequency division factor that has been adjusted or compensated, and outputting the target clock signal as an output of the clock generating apparatus.

Abstract: A level shifter circuit for level shifting voltages of signals crossing multiple circuit domains includes an input stage and a driver stage. The input stage receives an oscillating signal generated by a ring oscillator and generates an inverted oscillating signal. The differential oscillating signals are provided to the driver stage, which level shifts a voltage level of the oscillating signal to a level of a supply voltage of the ring oscillator.

Abstract: A phase-locked loop circuit includes a phase detector, a charge pump, a capacitor, and a capacitor multiplier. The phase detector receives a reference frequency and a feedback frequency to generate a up/down signal. The charge pump, which includes a positive node and a negative node, receives the up/down signal to generate a first current. The capacitor is coupled to the negative node. The capacitor multiplier, coupled to the negative node, generates a second current which is the first current divided by a first scaling number.

Abstract: An integrated circuit device includes a driver circuit (100) having a pull-up network with a first pull-up transistor (108) coupled to a second pull-up transistor (110) at a first node (VP), and a pull-down network coupled to the pull-up network including a first pull-down transistor (112) coupled to a second pull-down transistor (114) at a second node (VN). A first bias switch (116) is coupled to the first node. A second bias switch (118) is coupled to the second node. A control circuit (104) is coupled to operate the first and second bias switches. The first bias switch is operated to reduce a voltage at the first node during a pull-down cycle of the driver circuit and the second bias switch is operated to reduce a voltage at the second node during a pull-up cycle of the driver circuit.

Abstract: An apparatus for driving LED display includes a plurality of phase locked loop circuits. Each of the phase locked loop circuits includes a divider configured to receive the voltage controlled output signal and generate the feedback signal, a memory configured to generate a modulation profile codes and a sigma delta block. The divider receives a randomized numbers so as to change a dividing ratio over a modulation period. The sigma delta block includes at least one sigma delta modulator and at least one gain block. The sigma delta block is configured to receive the modulation profile codes and generate the randomized numbers to the divider. Each of the at least one gain block is configured to generate a value that is multiplied to at least one of the at least one sigma delta modulator so as to change a spread spectrum modulation depth.

Abstract: A wireless communication device for communicating in the near-field via active load modulation. The device including an antenna configured to receive a magnetic field, a recovery device configured to recover a clock from the magnetic field, and a multiplexer configured to receive the recovered clock and a reference clock, and to output one of the recovered clock and the reference clock based on a current operational state of the wireless communication device, The wireless communication device further including a shunt regulator configured to produce the active load modulation by modulating an impedance of the wireless communication device, a phase-locked loop (PLL) configured to receive one of the recovered clock and the reference clock and to utilize the received clock to control the active load modulation, and a driver configured to contribute to the active load modulation by adjusting an amplitude of a voltage across the antenna.

Abstract: A circuit includes first and second capacitances arranged on a first path that connects first and second terminals; a first switch arranged between the first capacitance and the second capacitance; a second switch arranged on a second path that connects a reference voltage section and a first node formed between the first capacitance and the first switch; a third switch arranged on a third path that connects the section and a second node formed between the second capacitance and the first switch; a first resistance arranged on a fourth path that connects the first node and a third node formed between the first terminal and the first capacitance; a second resistance arranged on a fifth path that connects the second node and a fourth node formed between the second terminal and the second capacitance; a fourth switch on the fourth path; and a fifth switch on the fifth path.

Abstract: A circuit may include a phase detector circuit, a charge pump circuit, a delay circuit, and a multiplexer circuit. The phase detector circuit may be configured to output a comparison signal based on a comparison of a phase of an inversion of a first clock signal and a phase of a multiplexer signal. The charge pump may be configured to integrate the comparison signal and to output a control voltage based on the integration of the comparison signal. The delay circuit may be configured to receive a second clock signal, to delay the second clock signal based on the control voltage, and to output the delayed second clock signal. The second clock signal may be a divided version of the first clock signal. The multiplexer circuit may be configured to output the multiplexer signal based on the delayed second clock signal.

Abstract: A charge pump circuit and a phase lock loop circuit (PLL) having the same are provided. A main voltage divider and an assistant voltage divider configured in the charge pump circuit generate a voltage division within a predetermined time of activating the charge pump circuit. Therefore, when the charge pump circuit initiates operating, a voltage of a control end of a main switch set configured in the charge pump circuit is set to be the voltage division. The voltage of the control end is gradually decreased from the voltage division to a stable voltage according to a first current and a second current flowing through the main switch set. Accordingly, it can decrease the time from initiating operation of the pump circuit to stabilizing the voltage of the control end, thereby it can increase the working efficiency of the PLL.