| 摘要 |
<p>PURPOSE:To enable to use one external terminal for C connection of IC, by comparing the terminal voltage of C in the time constant circuit consisting of a resistor and a capacitor with the reference voltage, and controlling the charge and discharge of C through the reset of FF circuit with the output. CONSTITUTION:At normal state, transistors TrQ1,Q2,Q3,Q4 are OFF, and the capacitor C is charged to the voltage VC via the resistor R4 from the power supply terminal 13. The voltage VC is set greater than the base voltage (reference voltage VB) of TrQ6 and TrQ5 is also OFF. When the trigger signal (a) is fed to the terminal 11, TrQ1,Q2 are held ON,TrQ4 is ON, the voltage Vc across C is discharged and the base voltage of TrQ5 falls down. When the base voltages of Q5 and Q6 are equal, Q5 is ON and Q3 is ON, Q1, Q2, Q4 are OFF, the voltage decrease in C stops and charging is started in the time constant of CR4. The time when the base voltage of TrQ5 is under the power supply voltage VCC is the sum of T1 determined with the reference voltage VB and T2 determined with the time constant of CR4. Since one end of C is connected to ground, the number of terminals of IC is less.</p> |
