SU500574A1 - Operational amplifier - Google Patents

Description

one

The invention relates to radio engineering and can be used in automation devices.

The operational amplifier is known, which contains a differential amplifier, which is connected in series with an input cascade on transistors of one THTia conductivity, included in a circuit with a common collector, and an output stage in transistors of another conductivity type, connected in a scheme with a common emitter, and integrator .

The purpose of the invention is to improve fast speed.

This is achieved by introducing two additional transistors, the collectors of which are connected and connected to the corresponding power supply bus, the junction of the emitters, through a resistor connected to the common emitter circuit of the output stage transistors of the differential amplifier, and the base to the inputs of the operational amplifier.

The drawing shows the principal schematic of an operational amplifier.

The operational amplifier contains transistors 1 and 2 of the input stage di (1facial amplifier, transistors 3.4 of the output stage of the differential amplifier, additional transistors 5, 6, resistors 7, 8, 9, current generators 1O, 11, load 12 and integrator 13.

The operation operation (1P1O1x amplifier is Ei as follows.

At low levels of the differential signal fed to the inputs 14, 15, the transistors 5, 6 do not have a significant effect on the j) a6oTy of the operational amplifier, the collector current in one of the transistors of the output stage of the differential amplifier increases in proportion to the input voltage of the op amp (op amp), and in the other decreases. This leads to the appearance of a charge current (discharge) of condensate (: 1a 16, connected to the amplifier 17.

For large levels x | 1) | | emi.nogo.nogo ignal entering the inputs 1-1, 15 (I input 5O-1OO MB), one of TpaifijiCTOOB output stage) entsm / g1,; 1 -; 1)

3

Usigatal enters the cut-off mode, and k6n ". The capacitor 16 continues to charge - (once - 1), relatively small in strength, current, numerically equal to the trick-off; Mu current generator 1O. ; Due to the introduction of transistors 5 and 6, the charge current (discharge) of the capacitor. 16 - can many times exceed the stagichv ;. ;: The 3rd current of the 1O generator, which causes an increase in the slew rate of the starting voltage and a decrease in the time for establishing the transient condition.

Suppose that the base of transistor 1 receives a negative voltage increment relative to the base of transistor 2. In this case, transistor 5 enters a cutoff mode and, on the emitters of transistors 3, 4 to 5, 6 will be equal to the voltage on the base of transistor 1 The transI stor 6 enters the actuator and its emitter current will cause an additional increase in the collector current of the load transistor 12 and the discharge current of the capacitor 16. As a result, the capacitor

16 will begin to recharge at a higher rate, which increases the speed of the i-op amp.

I

Claims (1)

Invention Formula An operational amplifier containing a differential amplifier made on series-connected input stage on transistors of one type; capacity included in a circuit with a common collector, and output stage on transistors of a different type of conductivity, connected according to a circuit with a common emitter | and an integrator, characterized in that, in order to improve speed, additional transistors are introduced, the collectors of which are combined and connected to the corresponding power supply bus, the emitter connection point through a resistor is connected to the common emitter circuit of the output amplifier transistors and the base yo inputs of the operational amplifier.