Oscillation circuit with reduced power consumption

摘要

The oscillation circuit includes a piezoelectric crystal which produces a first signal in response to an energising signal being applied as an input signal and amplifies the first signal by varying degrees to form a second signal. A first device responsive to the second signal controls the degree of amplification of the first signal by the piezoelectric crystal. The first device includes a wave-shaping circuit. The piezoelectric crystal includes a number of amplifiers which are arranged in parallel, with one of the amplifiers being controlled by the first device. The first device controls the degree of amplification by enabling/disabling one of the amplifiers controlled by the first device. One of the amplifiers controlled by the first device is a tri-state amplifier which is controlled by a power limiting amplifier having a predetermined threshold value of input required before an output is generated which is sufficient to disable the controlled amplifier.