| 摘要 |
PROBLEM TO BE SOLVED: To provide a drive circuit and the like which makes amplitude of an excitation current of an oscillator constant, regardless of manufacturing variation and a change in a frequency in addition to a temperature change.SOLUTION: A drive circuit 10 for outputting a drive signal 208 for exciting an oscillator 60 includes: a current voltage conversion circuit 20 for converting an input excitation current 200 into a voltage; a full wave rectification circuit 30 for full wave rectifying an output voltage 202 from the current voltage conversion circuit; a drive signal generation circuit 50 for generating a drive signal based on the output voltage from the current voltage conversion circuit; and a comparison adjustment circuit 40 for comparing the output voltage from the full wave rectification circuit with a comparison voltage, and adjusting the amplitude of the drive signal. The comparison adjustment circuit includes a comparison voltage supply circuit 42 for supplying the comparison voltage. The comparison voltage supply circuit generates the comparison voltage by a constant current source and a second resistance made of the same material as a first resistance included in the current voltage conversion circuit. |
