Patent ID: 7528670

Claim:
A sine wave oscillator having a self-startup circuit, comprising: an operational amplification unit which operationally amplifies and outputs input signals; a first resistor and a first capacitor each having first ends connected in parallel to a plus input terminal of the operational amplification unit and second ends connected to a minus power terminal; a second capacitor having a first end connected to the plus input terminal of the operational amplification unit; a second resistor having a first end connected in series to a second end of the second capacitor and a second end connected to an output terminal of the operational amplification unit; a third resistor having a first end connected to the minus input terminal of the operational amplification unit and a second end connected to the minus power terminal; a fourth resistor connected between the minus input terminal of the operational amplification unit and the output terminal of the operational amplification unit; and a startup circuit having a first end connected to the minus input terminal of the operational amplification unit and a second end connected to the minus power terminal, the startup circuit comprising: a switch, and a delay circuit connected between a supply voltage plus terminal and a minus power terminal and having an output connected to the switch; wherein the switch receives the output of the delay circuit and performs switching on the output of the delay circuit.