| 摘要 |
PROBLEM TO BE SOLVED: To optimally adjust drive ability of an oscillation circuit by a simple circuit configuration.SOLUTION: A semiconductor device comprises a chip 10 having an oscillation circuit 20, an amplifier 30 an effective value measuring circuit 40 and a control part 50. The oscillation circuit 20 includes an inverting amplifier 22 and a resistance 24 parallely connected to the inverting amplifier 22. The inverting amplifier 22 of the oscillation circuit 20 is connected to a crystal oscillator 70 outside the chip 10 and the oscillator circuit 20 creates an oscillation signal by driving the crystal oscillator 70. The effective value measuring circuit 40 measures an effective value VE of the oscillation signal obtained by the oscillation circuit 20. The control part 50 controls a gain of the inverting amplifier 22 so as to make the effective value VE be a target voltage VT. |
