| 摘要 |
<p>PURPOSE:To start the oscillation of a clock signal immediately even at a low power supply voltage by decreasing the oscillation start time of a crystal oscillator circuit. CONSTITUTION:At application of power, a clock signal is fed to an external circuit via a switch means 4 from a ring oscillator 1. Moreover, the clock signal is used for a clock signal of a crystal oscillator circuit 40, waveform-shaped by a Schmitt trigger circuit 2 and a resulting signal T is inputted to a counter means 3. The counter means 3 counts the signal T (clock signal) and sends a switching signal S to a switch means 4 when the count is finished to turn off a switch of a switch means 4. Thus, the clock signal is fed stably from the crystal oscillator circuit 40 to an external circuit. The oscillation start time by the crystal oscillator circuit is reduced.</p> |
