Piezoelectric vibration circuit

Abstract

Provides piezoelectric oscillation circuits that can obtain stable oscillation characteristics over a wide range of power supply voltages and can adjust the oscillation output amplitude. The circuit includes: a stabilized power supply (6) that stabilizes the voltage fluctuation of the DC voltage supplied from the DC power supply VDD; an oscillation circuit section (1) that uses a crystal vibrator (X1) as an oscillation source; ), using the output signal of the oscillating circuit part (1) as an input, connecting a multi-stage inverter circuit in series, and connecting a depletion-type MOS transistor on the last stage inverter circuit; the output amplification of the output of the amplifying buffer circuit (4) The circuit (5) is characterized in that it has: an output level adjustment circuit, which is composed of a plurality of MOS switches (Msw1~Msw3) and resistance elements (RD1~RD3), and can change the Nch-transistors constituting the output amplifier circuit (5). (M9) gate voltage to adjust the output level; storage circuit (11), storing data for selecting any one of a plurality of MOS switches; decoder (12), according to the data stored in the storage circuit (11) An analog signal input to the MOS switch is generated.

Description

technical field [0001] The invention relates to a piezoelectric oscillating circuit, which is especially suitable for a low-power consumption temperature-compensated crystal oscillator (TCXO) and the like. Background technique [0002] In recent years, there has been a strong demand for downsizing and weight reduction of portable devices used in mobile communications such as mobile phones, and quartz oscillator circuits used as frequency references for these portable devices have also been required to be downsized. [0003] FIG. 8 is a circuit diagram showing an example of a circuit configuration of a conventional crystal oscillation circuit. [0004] In this FIG. 8, X1 is a quartz vibrator, Rf is a high-frequency resistor, C1 and C2 are capacitors for oscillation, 1 is an oscillation amplifier circuit, 2 is a first snubber circuit (primary snubber circuit), and 3 is a second snubber circuit ( Second stage buffer circuit), 4 is the third buffer circuit (third stage buffer c...

AI Technical Summary

Problems solved by technology

[0017] However, in recent years, there have been various demands for temperature-compensated crystal oscillators (TCXOs) used as reference oscillation sources for mobile phones. In order to satisfy low power consumption, it is necessary to suppress the oscillation output voltage amplitude low, and to It is necessary to increase the output amplitude of the IC that drives the post-stage of the TCXO, and it is necessary to optimize the output amplitude of the oscillator according to the application. However, in the circuit structure of the aforementioned Japanese Patent Application No. 2004-255119, it cannot be selected / adjusted arbitrarily. The disadvantage of oscillating the amplitude of the output voltage

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