| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an oscillator which is capable of obtaining an oscillation output of high precision having less variance in oscillation period in spite of the variance in threshold voltage among MOS transistors during manufacturing. <P>SOLUTION: Each circuit comprises MOS transistors and includes a current source circuit 1, a capacitor 2, a first charging/discharging circuit 3, a second charging/discharging circuit 4, a first charge determination amplifier 5, a second charge determination amplifier 6, a delay inverter stage 7, a delay inverter stage 8, and a latch circuit 9. A current mirror relation is given between the current source circuit 1 and the charge determination amplifiers 5 and 6, and optimum values of both of them are obtained by using a preliminarily defined expression wherein m is the mirror ratio and K is conductivity factors of input MOS transistors constituting the charge determination amplifiers 5 and 6. When the oscillator is designed under these optimum values, the variance in threshold voltage among MOS transistors is compensated to reduce the fluctuation of the oscillation period during use though the variance in threshold voltage among the MOS transistors occurs during manufacturing. <P>COPYRIGHT: (C)2008,JPO&INPIT</p> |
