Charge pump circuit, PLL circuit with charge pump circuit, and semiconductor integrated circuit with charge pump circuit

A phase-locked loop circuit having a phase comparator for comparing phases of reference and output signals with each other, a charge pump circuit for receiving first and second control signals from the phase comparator and providing corresponding signals, a low-pass filter for filtering an output of the charge pump circuit into a VCO input signal, and a voltage-controlled oscillator for generating a signal whose frequency is determined by the VCO input signal, wherein the charge pump circuit comprises:

• a first transistor connected to a first power source line and having a control electrode to receive said first control signal;
• a second transistor connected to a second power source line and having a control electrode to receive said second control signal;
• a third transistor and a current source connected in series between the first and second transistors, a node between the third transistor and the current source providing a signal, which is passed through a low-pass filter to provide said VCO input signal;
• and
• a control voltage generator for generating a control voltage according to the VCO input signal and applying the control voltage to a control electrode of the third transistor.

A semiconductor integrated circuit having a multiplexer for multiplexing low-speed parallel data composed of a plurality of bits into high-speed serial data, a clock generator for receiving a reference clock signal and generating a clock signal for the multiplexer, a demultiplexer for demultiplexing high-speed serial data into low-speed parallel data composed of a plurality of bits, and a clock recovery circuit for receiving the high-speed serial data and generating a clock signal for the demultiplexer, wherein the clock recovery circuit includes a phase-locked loop circuit having a phase comparator for comparing the phases of reference and output signals with each other, a charge pump circuit for receiving first and second control signals from the phase comparator and providing corresponding signals, a low-pass filter for filtering an output of the charge pump circuit into a VCO input signal, and a voltage-controlled oscillator for generating a signal whose frequency is determined by the VCO input signal, wherein the charge pump circuit comprises:

• a first transistor connected to a first power source line and having a control electrode to receive said first control signal;
• a second transistor connected to a second power source line and having a control electrode to receive said second control signal;
• a third transistor and a current source connected in series between the first and second transistors, a node between the third transistor and the current source providing a signal, which is passed through a low-pass filter to provide said VCO input signal;
• and
• a control voltage generator for generating a control voltage according to the VCO input signal and applying the control voltage to a control electrode of the third transistor.