Patent ID: 6933797

Claim:
An oscillation circuit having an oscillation source and a main circuit portion connected by a signal path to the oscillation source and driven by the oscillation source, the main circuit portion comprising: an inverter connected to the oscillation source by the signal path; a feedback resistor connected between the output side and the input side of the inverter; an element that galvanically separates the signal path between an input terminal of the signal path and the input side of the inverter; and a potential stabilization circuit that connects the input terminal side of the signal path to a circuit portion with a stabilized potential through an element that functions as a resistor, wherein an electrostatic protection circuit is provided on the input terminal side of the signal path, and wherein the electrostatic protection circuit comprises at least one of: a first protection circuit connected between the signal path and a predetermined constant voltage side, for causing any electrostatic voltage of a first polarity that intrudes into the signal path to be bypassed selectively to the constant voltage side; and a second protection circuit connected between the signal path and a reference potential side, for causing any electrostatic voltage of a second polarity that intrudes into the signal path to be bypassed selectively to the reference potential side.