SU1327275A1 - Push-pull amplifier - Google Patents

Abstract

The invention relates to electronics and extends the output voltage range. U-l contains field-effect transistors (PT) 1 and 2 of the input stage, PT 3 and 4 of the first intermediate stage, additional PT 5 and 6, PT 7 and 8 of the second intermediate stage, resistor 9, PT 10 and 11 of the output stage, additional PT 12 and 13. 1 Il.

Description

The invention relates to electronics and can be used in analog circuits.

The purpose of the invention is the expansion of the output voltage range.

The drawing shows a circuit diagram of a push-pull yci titel.

The push-pull amplifier contains field-effect transistors 1 and 2 of the input stage, field-effect transistors 3 and 4 of the first intermediate stage, the first 5 and second 6 additional field-effect transistors, field-effect transistors 7 and 8 of the second intermediate stage, resistor 9, field-effect transistors 10 and 11 of the output one cascade, third 12 and fourth 13 additional field-effect transistors.

Push-pull amplifier works as follows.

In static relsim, the output voltage of the circuit is close to zero or half the source voltage — with unipolar power supply. Field effect transistors 1-4, 7, 8 are open, 10-3 are closed. A circuit containing a resistor 9 and field-effect transistors 7, 8 carries direct current, the value of which does not depend on the level of the input signal. When the voltage on the gates of field-effect transistors 7 and 8 is set to the level (E - Od), where E "is the supply voltage, V is the threshold voltage, the field-effect transistor 7 closes, 12 opens, and the current remains constant. Similarly, the current is switched from the field-effect transistor 8 to the transistor 13 when the voltage is reduced to the level - (Е j - Vj). Thus, the pairs of transistors 7, 12 and 8, 13 act as current switches controlled by the voltage on the drain of the transistors 5 and

6, which is close to the weekend. At the same time, groups of transistors 10, 7, 12, and P, 8, 13 form two circuits of complex current reflectors that control output transistors.

10 and P. These current reflectors are turned on only at a certain level of the output signal, i.e. perform the functions of amplitude discriminator. Discrimination threshold V is determined by the voltage of the power supply, the specific steepness of the field-effect transistors

7.8 and the value of the resistor 9 - in accordance with the approximate - ratio

V,

 t (Е „- V, - V (E, - 2Vo) / R) 7

Q

five

0

five

0

0

five

If the output voltage range does not reach the threshold values, then the field-effect transistors 7 and 8 remain in the open state, and the field-effect transistors 10-13 in the closed state. Needless to say, the current in the load provides an output cascade of low level signals at field-effect transistors 3 and 4, connected according to a circuit with an outgoing drain. This achieves a reduction in the output impedance of the amplifier. When the output voltage of one of the threshold levels is exceeded, the corresponding field effect transistor 7 or 8 is closed, depending on the polarity of the signal. As a result of the operation of the key element, the current flowing through the resistor 9 switches to one of the transistors, forming current reflectors 12 or 13. This causes one of the field-effect transistors to turn 10 or 1 and the output signal increases accordingly. connects the high-level output stage at the field-effect transistors 10, P, connected according to the common source circuit. At the same time, the output signal swing can reach the levels of power supply voltage, which is unattainable for the cascade on the source followers.

Claims (1)

Claim 0 A two-stage amplifier containing a series-connected input cascade, implemented on field-effect transistors having a different structure, 5 connected in a circuit with a common source, and the first intermediate stage performed on field-effect transistors I having a different structure, included according to the scheme with a common drain, between the valves. which are connected in series by DC. The first and second additional field-effect transistors, having different structures, the gates of which are combined and connected to the drains of these transistors, while the field-effect transistor of each arm of the input stage has the same structure as the structure of the additional transistor and the opposite structure of the transistor of this arm of the first intermediate stage, characterized in that, in order to expand the output voltage range, a second intermediate stage introduced in series into the field-effect transistor is introduced orah having a different structure, connected according to a common source circuit, the gates of which are combined and connected to the gate point of additional field-effect transistors, and a resistor is inserted between the drains and an output stage executed on field-effect transistors having different structure connected source, drains Editor M.Tovtin Order 3407/54 Compiled by N. Dubrovska Tehred ..In. KadarKorrektor V.But ha Circulation 901 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, st. Project, 4 which are combined and connected to the source connection point of the transistors of the first intermediate stage and are the output of a push-pull amplifier, and parallel to each transistor of the second intermediate stage are the third and fourth additional field-effect transistors, respectively, the gates of which are connected to the corresponding drains of these transistors and the gates of the output stage transistors, This structure of the field-effect transistor of each shoulder of the first intermediate stage, the additional transistor and the field of the transistor of the output stage corresponds to the structure of the FET input stage of the shoulder.