Patent ID: 7852164
Filing Date: 2010-12-14
Classification: H03B

Abstract:
1. A piezoelectric oscillator, comprising: a piezoelectric resonator; an oscillation circuit including a variable resistance circuit and a first transistor for oscillation; a constant current circuit, the constant current circuit including a first current mirror circuit having an output terminal, and a current control circuit controlling a current flowing in the first current mirror circuit so as to enable an output current of the constant current circuit to be adjusted, the output terminal of the first current mirror circuit being coupled to at least one of a first terminal and a control terminal of the first transistor; and a control circuit coupled to the current control circuit and the variable resistance circuit, the control circuit controlling the current control circuit and a resistance value of the variable resistance circuit, wherein: the control circuit includes a switch circuit, the constant current circuit further includes a constant current source, the current control circuit is configured as a second current mirror circuit including a second transistor receiving an output current of the constant current source, and a plurality of mirror transistors coupling to the second transistor as a current mirror connection, the plurality of mirror transistors are coupled parallel each other and coupled to the first current mirror circuit, and the switch circuit is provided between a reference potential and second terminals of each of the plurality of mirror transistors.