| 摘要 |
PURPOSE:To obtain a function generator by a MOS-IC by actuating a switch for connecting a resistor to an amplifier so that the gain of the amplifier is changed when an output voltage exceeds a prescribed value. CONSTITUTION:Resistors R3, R5 are connected through switches SW1, SW2 between the inverted input terminal and output terminal of an amplifier APM1 in addition to a feedback resistor Rs and the output voltage Vout of the amplifier AMP1 is supervised by comparators COMP1, COMP2. When an input voltage VIN is close to the voltage Vc, the output is low, both the outputs of the comparators COM1, COM2 are high and both the switches SW1, SW2 are turned off. At that time, the gain is -R2/R1. If the input voltage is increased or dropped and exceeds a certain point, any one of the outputs of the comparators COM1, COM2 is turned to low, so that any one of the switches SW1, SW2 is turned on, the feedback resistance value is reduced and the gain is reduced. |
