| 摘要 |
<p>PURPOSE:To improve the accuracy of delay time, and to improve the noise eliminating capacity, by connecting a shunting circuit to a time constant circuit which decides the delay time, and increasing the time constant of the time constant circuit after a time point when an output pulse is obtained. CONSTITUTION:A shunting circuit 20 is connected to a time constant circuit 10. Now, it is assumed that the switching means SW of the circuit 20 is turned on when the control signal VE' is set at H. The signal VE' is inverted to H at and after the time point when the output pulse P0 of a window comparator 5 is obtained. Thus the SW is turned on simultaneously with the fall of the pulse P0. A constant current circuit 21 is connected in parallel to a capacitor C, and a part of the charging current of the capacitor C flows into the circuit 21. As a result, the rise characteristics of the charging current VB3 is slackened, and the time during which the VB3 rises up to the base potential VB4 of a transistor TRQ4 is increased. Thus it is possible to set the time constant of the circuit 10 at a small value, therefore, a prescribed delay time can be obtained accurately. Furthermore, the noise eliminating capability is improved since the reversing period of the TRQ3 can be increased.</p> |
