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CN-224218369-U - Differential amplifying circuit, power amplifier and electronic equipment

CN224218369UCN 224218369 UCN224218369 UCN 224218369UCN-224218369-U

Abstract

The utility model discloses a differential amplifying circuit, a power amplifier and electronic equipment, relates to the field of electronic circuits, and solves the problem of low linearity of a differential amplifier adopting a current multiplexing structure. According to the utility model, the input power supply voltage is fed into the first-stage amplifying circuit through the input transformer, the current is multiplexed to the second-stage amplifying circuit, the first-stage amplifying circuit is grounded through the bypass capacitor in an alternating current manner, the second-stage amplifying circuit is directly grounded, after the input signal is amplified by the first-stage amplifying circuit, the second-stage amplifying circuit is directly grounded, so that the alternating current signal is more ideal in grounding, the voltage swing on a transistor in the common-source common-gate amplifying circuit is higher, the linearity of the amplifier can be obviously improved, the cascade linearity is ensured, and the problem of linearity deterioration caused by a traditional current multiplexing structure of a differential amplifier is solved.

Inventors

  • LIU LANG
  • LI ZHENNAN

Assignees

  • 成都市时代速信科技有限公司

Dates

Publication Date
20260508
Application Date
20250424

Claims (10)

  1. 1. A differential amplifying circuit, comprising: The high-voltage power supply comprises an input transformer (11), a first-stage amplifying circuit (12), an intermediate transformer (13), a second-stage amplifying circuit (14), an output transformer (15) and a bypass capacitor, wherein the first-stage amplifying circuit (12) is a common-source amplifying circuit, and the second-stage amplifying circuit (14) is a common-source common-gate amplifying circuit; the input end of the input transformer (11) receives an input voltage signal, the output end of the input transformer (11) is connected with the input end of the first-stage amplifying circuit (12), the output end of the first-stage amplifying circuit (12) is connected with the input end of the intermediate transformer (13), the output end of the intermediate transformer (13) is connected with the input end of the second-stage amplifying circuit (14), the output end of the second-stage amplifying circuit (14) is connected with the input end of the output transformer (15), the common end of the first-stage amplifying circuit (12) is connected with the center tap point of the main coil of the output transformer (15), the common end of the first-stage amplifying circuit (12) is grounded through a bypass capacitor, and the common end of the second-stage amplifying circuit (14) is directly grounded.
  2. 2. The differential amplification circuit according to claim 1, wherein the first stage amplification circuit (12) comprises a first transistor, a second transistor, a first neutralization capacitor, a second neutralization capacitor; The first end of the secondary coil of the input transformer (11) is connected with the grid electrode of the first transistor, the second end of the secondary coil of the input transformer (11) is connected with the grid electrode of the second transistor, the source electrode of the first transistor and the source electrode of the second transistor are connected with the first end of the bypass capacitor and the center tap point of the main coil of the output transformer (15), the second end of the bypass capacitor is grounded, the grid electrode of the first transistor is connected with the drain electrode of the second transistor and the second end of the main coil of the intermediate transformer (13) through the second neutralization capacitor, and the grid electrode of the second transistor is connected with the drain electrode of the first transistor and the first end of the main coil of the intermediate transformer (13) through the first neutralization capacitor.
  3. 3. The differential amplifier circuit according to claim 1, wherein the second-stage amplifier circuit (14) includes a third transistor, a fourth transistor, a fifth transistor, a sixth transistor, a first capacitor, a second capacitor; A first end of a secondary coil of the intermediate transformer (13) is connected with a gate of the third transistor, a source electrode of the third transistor is grounded, a drain electrode of the third transistor is connected with a source electrode of the fourth transistor, a gate electrode of the fourth transistor is connected with a first bias power supply, and a gate electrode of the fourth transistor is grounded through the first capacitor; a second end of a secondary coil of the intermediate transformer (13) is connected with a grid electrode of the fifth transistor, a source electrode of the fifth transistor is grounded, a drain electrode of the fifth transistor is connected with a source electrode of the sixth transistor, the grid electrode of the sixth transistor is connected with a first bias power supply, and the grid electrode of the sixth transistor is grounded through the second capacitor; The drain of the fourth transistor is connected with the first end of the main coil of the output transformer (15), and the drain of the sixth transistor is connected with the second end of the main coil of the output transformer (15).
  4. 4. The differential amplifier circuit according to claim 3, wherein the second-stage amplifier circuit (14) further comprises a seventh transistor, an eighth transistor, a first blocking capacitor, a second blocking capacitor; the grid electrode of the seventh transistor is connected with the first end of the secondary coil of the intermediate transformer (13) through the first blocking capacitor, the grid electrode of the seventh transistor is connected with a second bias power supply, the source electrode of the seventh transistor is grounded, and the drain electrode of the seventh transistor is connected with the drain electrode of the third transistor; The grid electrode of the eighth transistor is connected with the second end of the secondary coil of the intermediate transformer (13) through the second blocking capacitor, the grid electrode of the eighth transistor is connected with a second bias power supply, the source electrode of the eighth transistor is grounded, and the drain electrode of the eighth transistor is connected with the drain electrode of the fourth transistor.
  5. 5. A differential amplifying circuit according to claim 3, wherein said second stage amplifying circuit (14) further comprises a first resistor, a second resistor; The grid electrode of the fourth transistor is connected with a first bias power supply through the first resistor, and the grid electrode of the sixth transistor is connected with the first bias power supply through the second resistor.
  6. 6. The differential amplifier circuit according to claim 4, wherein the second-stage amplifier circuit (14) further comprises a third resistor, a fourth resistor; The drain electrode of the seventh transistor is connected with the drain electrode of the third transistor, and the drain electrode of the eighth transistor is connected with the drain electrode of the fourth transistor.
  7. 7. The differential amplifying circuit according to claim 2, wherein the first stage amplifying circuit (12) further comprises a third capacitor; the third capacitor is connected in parallel between the drain electrode of the first transistor and the drain electrode of the second transistor.
  8. 8. The differential amplifying circuit according to any one of claims 1 to 7, further comprising a fourth capacitor; The fourth capacitor is connected in parallel with two ends of the secondary coil of the output transformer (15).
  9. 9. A power amplifier comprising a differential amplifying circuit as claimed in any one of claims 1 to 8.
  10. 10. An electronic device comprising a transmitter in which the power amplifier of claim 9 is employed.

Description

Differential amplifying circuit, power amplifier and electronic equipment Technical Field The present utility model relates to the field of electronic circuits, and in particular, to a differential amplifying circuit, a power amplifier, and an electronic device. Background The amplifier is an important component module of the wireless receiving and transmitting system, and the low-power consumption high-linearity differential amplifier is particularly important in the satellite communication field, and is mainly applied to the aspects of signal quality, system energy efficiency, reliability and the like. Satellite devices are often limited in energy supply, low power designs can significantly reduce overall system performance, extend device life, or reduce battery size to some extent. The circuit with the differential structure has the characteristic of common-mode interference resistance, can effectively inhibit noise in an electromagnetic environment, improves signal integrity, and is of great importance to communication stability in a complex space environment. Meanwhile, the high-linearity design can reduce signal distortion, improve signal integrity, avoid the increase of bit error rate caused by nonlinear effect, and further guarantee the quality of a communication link. Differential amplifiers typically employ a current multiplexing architecture that allows for low power designs by sharing current paths through multiple stages of transistors, which results in the operating points of the transistors at each stage deviating from the optimal linear region. When the multistage amplifying tube dynamically works, the shared current fluctuates along with the input signal, the working points of the various stages of transistors deviate to generate nonlinear superposition, especially third-order intermodulation distortion (IMD 3) superposition, the nonlinearity mainly comes from the change of the transconductance of the transistors along with the amplitude of the input signal (AM-AM distortion), and the nonlinear characteristic is aggravated by the traditional current multiplexing structure. Therefore, the differential amplifier adopting the current multiplexing structure has low linearity and is a technical problem to be solved urgently by the person skilled in the art. Disclosure of utility model The utility model aims to provide a differential amplifying circuit, a power amplifier and electronic equipment, which solve the problem of low linearity of a differential amplifier adopting a current multiplexing structure. In order to solve the above technical problems, the present utility model provides a differential amplifying circuit, comprising: The system comprises an input transformer, a first-stage amplifying circuit, an intermediate transformer, a second-stage amplifying circuit, an output transformer and a bypass capacitor, wherein the first-stage amplifying circuit is a common-source amplifying circuit, and the second-stage amplifying circuit is a common-source common-gate amplifying circuit; The input end of the input transformer receives an input voltage signal, the output end of the input transformer is connected with the input end of the first-stage amplifying circuit, the output end of the first-stage amplifying circuit is connected with the input end of the intermediate transformer, the output end of the intermediate transformer is connected with the input end of the second-stage amplifying circuit, the output end of the second-stage amplifying circuit is connected with the input end of the output transformer, the common end of the first-stage amplifying circuit is connected with the center tap point of the main coil of the output transformer, the common end of the first-stage amplifying circuit is grounded through a bypass capacitor, and the common end of the second-stage amplifying circuit is directly grounded. As an alternative, in the differential amplifying circuit, the first stage amplifying circuit comprises a first transistor, a second transistor, a first neutralization capacitor and a second neutralization capacitor; The first end of the secondary coil of the input transformer is connected with the grid electrode of the first transistor, the second end of the secondary coil of the input transformer is connected with the grid electrode of the second transistor, the source electrode of the first transistor and the source electrode of the second transistor are connected with the first end of the bypass capacitor and the center tap point of the main coil of the output transformer, the second end of the bypass capacitor is grounded, the grid electrode of the first transistor is connected with the drain electrode of the second transistor and the second end of the main coil of the intermediate transformer through the second neutralization capacitor, and the grid electrode of the second transistor is connected with the drain electrode of the first transistor and the first end of the main coil of