Temperature compensated oscillator, method of controlling temperature compensated oscillator, and wireless communication device

A temperature compensated oscillator that has a voltage controlled oscillation circuit whose output signal oscillation frequency changes according to supplied voltage and a temperature compensation circuit that outputs temperature compensation voltage for keeping said output signal oscillation frequency constant based on temperature, the temperature compensated oscillator comprising:

• a filter circuit that removes noise contained in said temperature compensation voltage that has a plurality of stages of low-pass filters having capacitance elements connected in parallel to resistor elements via a switching circuit, and
• a power control circuit that controls power supply at least to said voltage controlled oscillation circuit and said temperature compensation circuit, respectively, said switching circuit switching connection locations of one end of all of said capacitance elements between a temperature compensation voltage output side of each corresponding resistor element and a temperature compensation voltage input side of a resistor element closest to said temperature compensation circuit among all of said resistor elements, and said power control circuit controlling said switching circuit to connect one end of all of said capacitance elements to the temperature compensation voltage input side of the resistor element closest to said temperature compensation circuit when power supply to said voltage controlled oscillation circuit is started and to said temperature compensation voltage output side of each corresponding resistor element after a specified time period has passed.

A temperature compensated oscillator that has a voltage controlled oscillation circuit whose output signal oscillation frequency changes according to supplied voltage and a temperature compensation circuit that outputs temperature compensation voltage for keeping said output signal oscillation frequency constant based on temperature, the temperature compensated oscillator comprising:

• an output switching circuit that switches between a first mode where the output voltage follows said temperature compensation voltage, and a second mode where the output voltage is maintained at said temperature compensation voltage of the mode switching time;
• a filter circuit that removes noise contained in said temperature compensation voltage output via said output switching circuit;
• and
• a power control circuit that controls power supply at least to said voltage controlled oscillation circuit and said temperature compensation circuit, respectively, said power supply circuit switching said output switching circuit to said first mode when power supply to said temperature compensation circuit is started, and to said second modewhen power supply to said temperature compensation circuit is stopped.

A temperature compensated oscillator that has a voltage controlled oscillation circuit whose output signal oscillation frequency changes according to supply voltage, a temperature compensation circuit that outputs temperature compensation voltage for keeping the output signal oscillation frequency constant based on temperature, a voltage control circuit that outputs frequency control voltage for making the output signal oscillation frequency the frequency to be set based on an externally supplied frequency control signal, and an adder that outputs said temperature compensation voltage and said frequency control voltage added together, the temperature compensated oscillator comprising:

• a first filter circuit that removes noise contained in said temperature compensation voltage;
• a switching circuit connected in parallel with said first filter circuit;
• a second filter circuit that removes noise contained in said frequency control voltage;
• and
• a power control circuit that controls power supply at least to said voltage controlled oscillation circuit and said temperature compensation circuit, respectively, said power control circuit turning on said switching circuit for a specified period of time when power supply to said voltage controlled oscillation circuit is started.

A temperature compensated oscillator that has a voltage controlled oscillation circuit whose output signal oscillation frequency changes according to supplied voltage, a temperature compensation circuit that outputs temperature compensation voltage for keeping said output signal oscillation frequency constant based on temperature, a voltage control circuit that outputs frequency control voltage for making said output signal oscillation frequency the frequency to be set based on the externally supplied frequency control signal, and an adder that outputs said temperature compensation voltage and said frequency control voltage added together, the temperature compensated oscillator comprising:

• a first filter circuit that removes noise contained in said temperature compensation voltage and that is a low-pass filter having capacitance elements connected in parallel to resistor elements;
• a second filter circuit that removes noise contained in said frequency control voltage;
• a power control circuit that controls power supplied at least to said voltage controlled oscillation circuit and said temperature compensation circuit, respectively;
• and
• a switching circuit that switches connection locations of one end of all of said capacitance elements between a temperature compensation voltage output side and a temperature compensation voltage input side, said power control circuit using said switching circuit to connect one end of said capacitance elements to the temperature compensation voltage input side of said resistor elements when power supply to said voltage controlled oscillation circuit is started, and to the temperature compensation voltage output side of said resistor elements after a specified time period has passed.

A temperature compensated oscillator that has a voltage controlled oscillation circuit whose output signal oscillation frequency changes according to supplied voltage, a temperature compensation circuit that outputs temperature compensation voltage for keeping said output signal oscillation frequency constant based on temperature, a voltage control circuit that outputs frequency control voltage for making said output signal oscillation frequency the frequency to be set based on the externally supplied frequency control signal, and an adder that outputs said temperature compensation voltage and said frequency control voltage added together, the temperature compensated oscillator comprising:

• a first filter circuit that removes noise contained in said temperature compensation voltage and that is a low-pass filter having a plurality of stages having capacitance elements connected in parallel to resistor elements;
• a second filter circuit that removes noise contained in said frequency control voltage;
• a power control circuit that controls power supply at least to said voltage controlled oscillation circuit and said temperature compensation circuit, respectively;
• and
• a switching circuit that switches connection locations of one end of all said capacitance elements between a temperature compensation voltage output side of each corresponding resistor element and a temperature compensation voltage input side of a resistor element closest to said temperature compensation circuit among all of said resistor elements, said power control circuit controlling said switching circuit to connect one end of said capacitance elements to the temperature compensation voltage input side of said resistor element closest to said temperature compensation circuit when power supply to the voltage controlled oscillation circuit is started, and to the temperature compensation voltage output side of each corresponding resistor element after a specified time period has passed.

A temperature compensated oscillator that has a voltage controlled oscillation circuit in which output signal oscillation frequency changes according to supplied voltage, a temperature compensation circuit that outputs temperature compensation voltage for keeping said output signal oscillation frequency constant based on temperature, a voltage control circuit that outputs frequency control voltage for making said output signal oscillation frequency the frequency to be set based on the externally supplied frequency control signal, and an adder that outputs said temperature compensation voltage and said frequency control voltage added together, the temperature compensated oscillator comprising:

• an output switching circuit that switches between a first mode where the output voltage follows said temperature compensation voltage, and a second mode where the output voltage is maintained at said temperature compensation voltage of a mode switching time;
• a first filter circuit that removes noise contained in said temperature compensation voltage output via said output switching circuit;
• a second filter circuit that removes noise contained in said frequency control voltage;
• and
• a power control circuit that controls power supply at least to said voltage controlled oscillation circuit and said temperature compensation circuit, respectively, said power control circuit switching said output switching circuit to said first mode when power supply to the temperature compensation circuit is started, and to said second mode when power supply to said temperature compensation circuit is stopped.

A method of controlling a temperature compensated oscillator that has a voltage controlled oscillation circuit whose output signal oscillation frequency changes according to supplied voltage, and a temperature compensation circuit that outputs temperature compensation voltage for keeping said output signal oscillation frequency constant based on temperature, the method comprising:

• switching between a first mode where the output voltage follows said temperature compensation voltage, and a second mode where the output voltage is maintained at said temperature compensation voltage of the mode switching time, using an output switching circuit;
• removing noise contained in said temperature compensation voltage output via said output switching circuit using a filter circuit;
• and
• controlling power supply to at least said voltage controlled oscillation circuit and said temperature compensation circuit, respectively, using a power control circuit, said power control circuit switching said output switching circuit to said first mode when power supply to said temperature compensation circuit is started, and switching said output switching circuit to said second mode when power supply to said temperature compensation circuit is stopped.

A method of controlling a temperature compensated oscillator that has a voltage controlled oscillation circuit whose output signal oscillation frequency changes according to supplied voltage, a temperature compensation circuit that outputs temperature compensation voltage for keeping said output signal oscillation frequency constant based on temperature, a voltage control circuit that outputs frequency control voltage for making said output signal oscillation frequency the frequency to be set based on the externally supplied frequency control signal, and an adder that outputs said temperature compensation voltage and said frequency control voltage added together, the method comprising:

• removing noise contained in said temperature compensation voltage using a first filter circuit;
• removing noise contained in said frequency control voltage using a second filter circuit;
• and
• controlling power supply at least to said voltage controlled oscillation circuit and said temperature compensation circuit, respectively, using a power control circuit, said power control circuit turning on a switching circuit connected in parallel with said first filter circuit for a specified time period when power supply to said voltage controlled oscillation circuit is started.

A method of controlling a temperature compensated oscillator that has a voltage controlled oscillation circuit whose output signal oscillation frequency changes according to supplied voltage, a temperature compensation circuit that outputs temperature compensation voltage for keeping said output signal oscillation frequency constant based on temperature, a voltage control circuit that outputs frequency control voltage for making said output signal oscillation frequency the frequency to be set based on externally supplied frequency control signals, and an adder that outputs said temperature compensation voltage and said frequency control voltage added together, the method comprising:

• switching between a first mode where the output voltage follows said temperature compensation voltage, and a second mode where the output voltage is maintained at said temperature compensation voltage of a mode switching time, using an output switching circuit;
• removing noise contained in said temperature compensation voltage output via said output switching circuit using a first filter circuit;
• removing noise contained in said frequency control voltage using a second filter circuit;
• and
• controlling power supply at least to said voltage controlled oscillation circuit and said temperature compensation circuit, respectively, using a power control circuit, said power control circuit switching said output switching circuit to said first mode when power supply to the temperature compensation circuit is started, and switching said output switching circuit to said second mode when power supply to said temperature compensation circuit is stopped.