| 摘要 |
PURPOSE:To prevent the titled circuit from being affected with the voltage rising characteristic caused by a time constant circuit by adopting the circuit constitution where a capacitor is charged up by a constant current source so as to realize entire circuits on a semiconductor chip with a comparatively small area. CONSTITUTION:When a voltage VA is applied to a power supply voltage terminal 1 through the application of power, a current flows to an electric path comprising resistors 2, 3 and a transistor (TR)Q1 of diode connection, when the voltage exceeds a diode forward voltage VD. When a terminal voltage of the resistor 3 exceeds a base-emitter voltage VBE2 of a TRQ2, a constant current Is flows to the TRQ2 through a TRQ3. The constant current Is of the TRQ3 is applied to the resistor 4 through a TRQ4 coupled therewith by means of current mirror. When a terminal voltage V3 of the resistor 4 exceeds a base-emitter voltage VBE5 of a TRQ5, the collector potential of the TRQ5 goes nearly to ground potential so as to turn off TRs Q6, Q7 coupled to the input of it. On the other hand, when the TRQ6 is turned off, a capacitor 6 connected to a collector terminal is charged by the constant current Is through a TRQ9. |
