US 7,009,459 B2Granted

Piezoelectric oscillator having a non-inductive load with a collector-emitter capacitor

AssigneeToyo Communication Equipment Co., Ltd.

InventorsTomio Satoh, Jun Matsuoka, Tsuyoshi Ohshima

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Abstract

A piezoelectric oscillation circuit has a series circuit composed of a capacitor Cbe as a part of a load capacitance and a capacitor Ce inserted and connected between a base of an oscillation transistor TR1 and the ground, and has an emitter resistor Re connected to a connection midpoint A of the series circuit and an emitter of the oscillation transistor TR1. Further, a base bias circuit composed of a resistor RB 1 and a resistor RB2 is connected to a base of the oscillation transistor TR1, has a piezoelectric element Xtal and a capacitor C1 inserted and connected in series between the base of the oscillation transistor TR1 and the ground, and further has a resistor Rc connected to a collector of the oscillation transistor TR1 together with the power supply voltage Vcc line, and has a capacitor Cce connected between the collector and the emitter.

Claims5

Dependent claims

A piezoelectric oscillator comprising a piezoelectric vibrator that has a piezoelectric element which is excited in a predetermined frequency, an oscillation amplifier transistor that excites the piezoelectric element by flowing a current to the piezoelectric element, a combined capacitor that is connected between a base of the oscillation amplifier transistor and the ground and that forms a part of a load capacitance, and an emitter resistor that is inserted between an emitter of the oscillation amplifier transistor and the ground, wherein

a non-inductive load is connected to a collector of the oscillation amplifier transistor, and a capacitor is inserted between the collector and the emitter of the oscillation amplifier transistor;
the combined capacitor is composed of a capacitor that is connected between the base and the emitter of the oscillation amplifier transistor and a capacitor that is connected between the emitter and the ground, and the base of the oscillation amplifier transistor is biased at a predetermined potential;
and
the capacitance of the capacitor inserted between the collector and the emitter is at or above the capacitance of the capacitor inserted between the emitter of the oscillation amplifier transistor and the ground.

1 more element

A piezoelectric oscillator comprising a piezoelectric vibrator that has a piezoelectric element which is excited in a predetermined frequency, an oscillation amplifier transistor that continuously excites the piezoelectric element by flowing a current to the piezoelectric element, a combined capacitor that is connected between a base of the oscillation amplifier transistor and the ground and that forms a part of a load capacitance, and an emitter resistor that is inserted between an emitter of the oscillation amplifier transistor and the ground, wherein

a second transistor is connected in cascade to the collector of the oscillation amplifier transistor, a non-inductive load is connected to a collector of the second transistor connected in cascade, and a capacitor is inserted between the collector of the second transistor and the emitter of the oscillation amplifier transistor;
a base of the second transistor is grounded via a capacitor;
the combined capacitor is connected between the base and the emitter of the oscillation amplifier transistor and between the emitter and the around respectively, and the base of the oscillation amplifier transistor and the base of the second transistor are biased at a predetermined potential respectively;
and
the capacitance of the capacitor inserted between the collector and the emitter is at or above the capacitance of the capacitor inserted between the emitter of the oscillation amplifier transistor and the ground.

2 more elements

Dependencies are inferred from the claim text.