| 摘要 |
PURPOSE:To prevent the generation of noise caused by the switching of the transistor by a second input signal in a differential multiplier. CONSTITUTION:In a state that a first input signal does not exist, only bias is impressed and a second input signal is impressed, the collector currents of transistors 5 and 6 are equal with each other and the currents are supplied to the emitters of transistors 7, 8, 13 and 14. According to the operating states of the transistors 7, 8, 13 and 14, the collector current of each transistor changes. The base currents of the transistors 7, 8, 13 and 14 are supplied to also current mirror circuits 17 and 18, and the output currents which are made the half of the input current are generated. The output current of the current mirror circuit is supplied to load resistors 9 and 10 via the current mirror circuits 19 and 20 after the output current is added. Thus, the current flowing in the load resistors 9 and 10 can be made constant, regardless of the operations of the transistors 7, 8, 13 and 14. |
