| 摘要 |
PURPOSE:To obtain a pulse having width only corresponding to a time constant by providing a charging and discharging part for charging and discharging the output of a comparator detecting whether input voltage drops to send out the output to a voltage drop detector so as to delay the same by the time constant thereof. CONSTITUTION:A charging and discharging part 3 charged from the output of a comparator 1 with a predetermined time constant and instantaneously performing discharge is provided between the comparator 1 and a voltage drop detection circuit 2. By this constitution, even when voltage is simultaneously applied to the comparator 1 and the detector 2, the output voltage of the charging the discharging part 3 applied to the detector 2 is applied so as to be delayed from the above-mentioned applied voltage by the time constant of the charging and discharging part 3. By this method, a pulse having width only corresponding to the time constant is obtained and, since the width of the output pulse of the voltage drop detection circuit does not becomes extremely narrow, for example, the voltage drop detection circuit used on the side of the moving station of automobile telephone system is improved. |
