Oscillation circuit, constant voltage generation circuit, semiconductor device, electronic equipment and timepiece

摘要

Disclosed are an oscillation circuit (10) and a constant-voltage generation circuit (100). The oscillation circuit comprises: an amplifier group comprising a plurality of signal inversion amplifiers (14-1 - 14-3) formed by transistors (16, 18) having different threshold voltages, one which can be selected for use; and a feedback circuit having a crystal resonator (12). The constant-voltage generation circuit comprises: a constant-current power source (110) one end which is connected to a first potential side; a plurality of control transistors (114-1 - 114-3) each having one end connected to the constant-current power source and another end to an output line; an operational amplifier (112) having one terminal connected to the node between the constant current source and the control transistors whereas a given reference voltage (Vref) is applied to the other input; and an output transistor (116) having one end connected to the constant-voltage output line side, and having its resistance controlled by the output of the operational amplifier (112), whereby the potential of the constant-voltage output line is controlled to be constant. <IMAGE>