Abstract: A temperature-compensated crystal oscillator includes a mode selector circuit 100, a control logic serial•interface 200, a PROM circuit 300, an oscillation control circuit 400 and an oscillation circuit 500, and has, as terminals, a power terminal (VCC/CLK) 11, an input terminal (VC/DATA/PE) 12, an output terminal (OUT) 13 and a ground terminal (GND) 14. The mode selector circuit 100 switches the crystal oscillator to an emulation mode when a first signal in which a power voltage and a clock signal supplied through the power terminal 11 are superimposed, is inputted from the power terminal and a second signal having a predetermined pattern is inputted from the input terminal 12.

Abstract: A first order function generation circuit receives a signal from a temperature sensor circuit, and generates a first order function control signal V1 that is affected by the ambient temperature. A fourth order and fifth order approximation function generation circuit receives signals from the temperature sensor circuit and from the third order approximation function generation circuit, and generates a fourth and fifth order approximation function control signal V45 that is affected by the ambient temperature. A peak change point adjustment circuit outputs a signal to adjust the value of a peak change point temperature Ti for the third order approximation function generation circuit, the first order generation function circuit and the fourth order and fifth order approximation function generation circuit. A temperature compensation circuit adds together control signals V0, V1, V3 and V5, and outputs the resultant signal Vc.

Abstract: The object of the present invention is to provide a crystal oscillator with one IC capable of effectively responding to specifications or a frequency of an installed set, an output terminal of the oscillator 1 is connected to an input terminal of the inverter 2, an output terminal of which is connected to the first resistor 7 and one terminal of the second resistor 8, the other terminal of the first resistor 7 is connected to one terminal of the first capacitor 9 and an input terminal of the first transistor 3, the other terminal of the first capacitor 9 is connected to one terminal of the first switch 11, and the other terminal of the first switch 11 is grounded, the other terminal of the second resistor 8 is connected to one terminal of the second capacitor 10 and an input terminal of the second transistor 4, the other terminal of the second capacitor 10 is connected to one terminal of the second switch 12, and the other terminal of the second switch 12 is grounded, an output terminal of the first transisto

Abstract: An oscillator starting control circuit capable of shortening a starting time and stably controlling the starting time, and furthermore, stabilizing an oscillating frequency after starting an oscillating circuit. An oscillating circuit (1) is a crystal oscillating circuit in which an input and an output of an inverter (14) are connected to both ends of a crystal oscillator (15) and both ends of a resistor (16), the input is connected to a drain of an MOS variable capacity (10), the output is connected to a drain of an MOS variable capacity (11), a source of the MOS variable capacity (10) is connected to a fixed capacity (12), a source of the MOS variable capacity (11) is connected to a fixed capacity (13), and the other ends of the fixed capacities (12, 13) are connected to a GND.

Abstract: A temperature-compensated crystal oscillator includes a mode selector circuit 100, a control logic serial•interface 200, a PROM circuit 300, an oscillation control circuit 400 and an oscillation circuit 500, and has, as terminals, a power terminal (VCC/CLK) 11, an input terminal (VC/DATA/PE) 12, an output terminal (OUT) 13 and a ground terminal (GND) 14. The mode selector circuit 100 switches the crystal oscillator to an emulation mode when a first signal in which a power voltage and a clock signal supplied through the power terminal 11 are superimposed, is inputted from the power terminal and a second signal having a predetermined pattern is inputted from the input terminal 12.

Abstract: A first order function generation circuit receives a signal from a temperature sensor circuit, and generates a fist order function control signal V1 that is affected by the ambient temperature. A fourth order and fifth order approximation function generation circuit receives signals from the temperature sensor circuit and from the third order approximation function generation circuit, and generates a fourth and fifth order approximation function control signal V45 that is affected by the ambient temperature. A peak change point adjustment circuit outputs a signal to adjust the value of a peak change point temperature Ti for the third order approximation function generation circuit, the first order generation function circuit and the fourth order and fifth order approximation function generation circuit. A temperature compensation circuit adds together control signals V0, V1, V3 and V5, and outputs the resultant signal Vc.

Abstract: The object of the present invention is to provide a crystal oscillator with one IC capable of effectively responding to specifications or a frequency of an installed set, an output terminal of the oscillator 1 is connected to an input terminal of the inverter 2, an output terminal of which is connected to the first resistor 7 and one terminal of the second resistor 8, the other terminal of the first resistor 7 is connected to one terminal of the first capacitor 9 and an input terminal of the first transistor 3, the other terminal of the first capacitor 9 is connected to one terminal of the first switch 11, and the other terminal of the first switch 11 is grounded, the other terminal of the second resistor 8 is connected to one terminal of the second capacitor 10 and an input terminal of the second transistor 4, the other terminal of the second capacitor 10 is connected to one terminal of the second switch 12, and the other terminal of the second switch 12 is grounded, an output terminal of the first transisto

Abstract: There is provided a temperature-compensated crystal oscillator for reducing a voltage noise of a cubic function control voltage controlling an output frequency of an oscillation circuit. A temperature-compensated crystal oscillator includes a quartz vibrator, an amplifier having an oscillation frequency controller, and a temperature compensation circuit of a crystal oscillation frequency, wherein a reference voltage for a compensation voltage of the temperature compensation circuit is generated using a forward voltage of a diode.

Abstract: In a voltage controlled oscillator including an amplifier, a feedback circuit and a crystal oscillator, two MOS transistors M1, M2 are connected for use as variable capacity elements for the frequency adjustment of the voltage controlled oscillator. Drains of the MOS transistors M1, M2 are respectively connected to an XT terminal and an XTB terminal of the crystal oscillator. Sources of the MOS transistors M1, M2 are made common and connected to a grounding terminal via a capacitor C3. Gates of the MOS transistors M1, M2 are made common, and an added voltage signal of a temperature compensating signal voltage and an external frequency control signal voltage is applied to the common gate terminals of the MOS transistors to thereby perform the frequency control of the oscillator.

Abstract: It is an object to provide an oscillator starting control circuit capable of shortening a starting time and stably controlling the starting time, and furthermore, stabilizing an oscillating frequency after starting an oscillating circuit. [Means for Resolution] An oscillating circuit (1) is a crystal oscillating circuit in which an input and an output of an inverter (14) are connected to both ends of a crystal oscillator (15) and both ends of a resistor (16), the input is connected to a drain of an MOS variable capacity (10), the output is connected to a drain of an MOS variable capacity (11), a source of the MOS variable capacity (10) is connected to a fixed capacity (12), a source of the MOS variable capacity (11) is connected to a fixed capacity (13), and the other ends of the fixed capacities (12, 13) are connected to a GND.

Abstract: With first, second and third current exchanger circuits cascaded, a current in proportion to a difference between an ambient temperature Ta and a reference temperature Tr is input to the first current exchanger circuit. The first current exchanger circuit supplies a current in proportion to the square of Ta?Tr to the second current exchanger circuit, the second current exchanger circuit supplies a current in proportion to the fourth power of Ta?Tr to the third current exchanger circuit, and the third current exchanger circuit outputs a current in proportion to the fifth power of Ta?Tr. Each of the first, second and third current exchanger circuits has a configuration which does not require a high supply voltage enough to drive a series circuit of three or more diodes.

Abstract: A voltage controlled oscillator enables controlling the MOS transistor threshold voltage independently of the temperature compensation control signal and external voltage frequency control signal. The voltage controlled oscillator has a crystal oscillator and a load capacitance is parallel connected to a crystal oscillator. The load capacitance includes a first MOS transistor comprising a gate terminal and a source/drain terminal formed by shorting the source and drain, and a second MOS transistor comprising a gate terminal and a source/drain terminal formed by shorting the source and drain. First and second control signal generating circuits supply respective control signals to the source/drain terminals and gate terminals of the first and second MOS transistors.

Abstract: In a voltage controlled oscillator including an amplifier, a feedback circuit and a crystal oscillator, two MOS transistors M1, M2 are connected for use as variable capacity elements for the frequency adjustment of the voltage controlled oscillator. Drains of the MOS transistors M1, M2 are respectively connected to an XT terminal and an XTB terminal of the crystal oscillator. Sources of the MOS transistors M1, M2 are made common and connected to a grounding terminal via a capacitor C3. Gates of the MOS transistors M1, M2 are made common, and an added voltage signal of a temperature compensating signal voltage and an external frequency control signal voltage is applied to the common gate terminals of the MOS transistors to thereby perform the frequency control of the oscillator.

Abstract: With first, second and third current exchanger circuits cascaded, a current in proportion to a difference between an ambient temperature Ta and a reference temperature Tr is input to the first current exchanger circuit. The first current exchanger circuit supplies a current in proportion to the square of Ta−Tr to the second current exchanger circuit, the second current exchanger circuit supplies a current in proportion to the fourth power of Ta−Tr to the third current exchanger circuit, and the third current exchanger circuit outputs a current in proportion to the fifth power of Ta−Tr. Each of the first, second and third current exchanger circuits has a configuration which does not require a high supply voltage enough to drive a series circuit of three or more diodes.