Amplifier gate-source voltage stabilizing circuit based on diode parallel connection

Abstract

The invention discloses an amplifier gate-source voltage stabilizing circuit based on diode parallel connection. The amplifier gate-source voltage stabilizing circuit comprises a multi-stage radio frequency amplifier, a bias resistance circuit connected with the multi-stage radio frequency amplifier in parallel, a diode series branch and a negative feedback circuit connected with a transistor source electrode of the multi-stage radio frequency amplifier. The gate-source voltage stabilization is realized by using the non-linear relationship between the diode resistance and the voltage in the diode series branch and the voltage division characteristic of the negative feedback circuit. By utilizing the characteristic that the diode resistor changes along with the voltage and combining the negative feedback resistor of the source electrode, the bias partial voltage of the grid electrode of the transistor and the voltage change of the power supply are in a non-linear relationship, so that the grid-source voltage is stable, and the gain stability of the radio-frequency amplifier circuit is improved.

Description

Technical Field

[0001] The invention relates to a radio frequency active amplifier, in particular to an amplifier gate-source voltage stabilization circuit based on parallel diodes. Background Art

[0002] As an important component of the signal transceiver system, the RF active amplifier can realize the energy amplification of the transmitted or received signal and is widely used in the radar and communication fields. In radar and communication systems, the signal transceiver gain design is very important. For example, the gain design of the low-noise amplifier often needs to be kept within a certain range. First, sufficient gain is required to improve the sensitivity of the receiver. Secondly, it cannot be too large. Insufficient linearity of the post-stage circuit module may cause signal saturation distortion. Generally speaking, after the circuit design of the amplifier is completed, the gain is basically determined. However, in actual use, the gain of the amplifier is very susceptible to the DC power supply voltage. Once a voltage deviation occurs, the gate-drain voltage of the amplifier transistor will deviate, further causing the gain to change and the overall system to be affected. Therefore, how to ensure that the gate-source voltage of the transistor is stable when the power supply voltage deviates is of great research significance.

[0003] At present, in the design of gate-drain voltage regulation, source negative feedback resistors are usually used for voltage division, and voltage regulation is achieved through voltage negative feedback. Although the source negative feedback resistor design has a certain voltage regulation effect, when the voltage deviation reaches a certain level, there will still be a relatively obvious gate-drain voltage change, resulting in gain changes. Summary of the invention

[0004] Purpose of the invention: The purpose of the present invention is to provide an amplifier gate-source voltage stabilization circuit based on parallel diodes. By utilizing the characteristics of the diode resistance changing with voltage and combining the source negative feedback resistor, the transistor gate bias voltage divider and the power supply voltage change are nonlinearly related, thereby achieving gate-source voltage stability and improving the gain stability of the RF amplifier circuit.

[0005] Technical solution: An amplifier gate-source voltage stabilization circuit based on diode parallel connection of the present invention comprises a multi-stage radio frequency amplifier, a bias resistor circuit arranged in parallel with the multi-stage radio frequency amplifier, a diode series branch, and a negative feedback circuit connected to the transistor source of the multi-stage radio frequency amplifier;

[0006] The gate-source voltage is stabilized by utilizing the nonlinear relationship between the diode resistance and the voltage in the diode series branch and the voltage division characteristic of the negative feedback circuit.

[0007] Furthermore, the multi-stage radio frequency amplifier includes N transistors arranged in series, and the bias resistor circuit includes N+1 bias resistors arranged in series.

[0008] Furthermore, the number of the diode series branches is N, one end of the Nth diode series branch is connected to the gate of the Nth transistor and the bias resistor circuit, and the other end is grounded;

[0009] The Nth diode series branch includes N diodes arranged in series.

[0010] Further, the first resistor R1 in the bias resistor circuit is connected in parallel with the first-stage transistor gate G1 and the first diode branch to the ground;

[0011] The second resistor R2 in the bias resistor circuit is connected in parallel between the first-stage transistor gate G1 and the second-stage transistor gate G2, and the second diode branch is connected in parallel with the second-stage transistor gate G2 and grounded;

[0012] The third resistor R3 in the bias resistor circuit is connected in parallel between the second-stage transistor gate G2 and the next-stage transistor gate, and recursively, the Nth diode branch and the Nth-stage transistor gate G N Parallel grounding;

[0013] The N+1th resistor R in the bias resistor circuit N+1 Connect the gate G of the Nth transistor N and DC power supply Vcc.

[0014] Furthermore, the number of the negative feedback circuits is N, and the Nth negative feedback circuit is connected to the source of the Nth stage transistor.

[0015] Furthermore, the negative feedback circuit includes an inductor L, a negative feedback resistor R f and capacitor C;

[0016] One end of the inductor L is connected to the transistor source S, and the other end is connected to the capacitor C. The negative feedback resistor R f Connect capacitor C in parallel to ground.

[0017] Furthermore, each stage of the multi-stage radio frequency amplifier selects whether to connect a diode branch in parallel according to actual circuit design requirements.

[0018] Furthermore, each stage of the multi-stage radio frequency amplifier is selected to be connected to a negative feedback circuit according to actual circuit design requirements.

[0019] Furthermore, the bias resistor is an equivalent resistor.

[0020] Furthermore, the diode series branches are all forward biased and connected in series to ground, which is equivalent to a resistor that changes nonlinearly with voltage.

[0021] Beneficial effects: Compared with the prior art, the significant technical effects of the present invention are as follows:

[0022] The gate-source voltage stabilization circuit of the present invention achieves a better voltage stabilization effect than the traditional method of using source negative feedback alone by adding a diode branch in the bias circuit. It is actually measured that the gain variation is reduced by 90% under the same voltage deviation.

[0023] The gate-source voltage stabilization circuit of the present invention is applicable to various non-zero bias transistor amplifier circuits and has universal applicability.

[0024] Compared with other complex active bias circuits or voltage stabilizer structures, the gate-source voltage stabilization circuit of the present invention has the characteristics of simple structure and small occupied area while ensuring the voltage stabilization effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a structural schematic diagram of an amplifier gate-source voltage stabilization circuit based on parallel diodes according to the present invention;

[0026] Figure 2 It is a schematic diagram of an amplifier circuit without adding a gate-source voltage stabilization circuit in the prior art;

[0027] Figure 3 It is a simulation gain curve diagram of the amplifier of the present invention without adding the gate-source voltage stabilization circuit at different voltages;

[0028] Figure 4 A simulation gain curve diagram of an amplifier with a gate-source voltage stabilization circuit added at different voltages according to the present invention;

[0029] Figure 5 It is a graph of the measured gain of the amplifier at different voltages without adding the gate-source voltage stabilization circuit of the present invention;

[0030] Figure 6 The actual measured gain curve diagram of the amplifier with the gate-source voltage stabilization circuit added at different voltages of the present invention. DETAILED DESCRIPTION

[0031] The technical solution of the present invention is described in detail below in conjunction with specific implementation methods and the accompanying drawings of the specification.

[0032] like Figure 1 As shown, the amplifier gate-source voltage stabilization circuit based on diode parallel connection of the present invention utilizes the characteristics of diode resistance changing with voltage, combined with the source negative feedback resistor, so that the transistor gate bias voltage division and the power supply voltage change are nonlinearly related, thereby achieving gate-source voltage stabilization and improving the gain stability of the radio frequency amplifier circuit. The amplifier gate-source voltage stabilization circuit includes a multi-stage radio frequency amplifier, a bias resistor circuit, a diode series branch, and a negative feedback circuit. Among them, the bias resistor circuit, the diode series branch and the multi-stage radio frequency amplifier are arranged in parallel, and the negative feedback circuit is connected to the transistor source of the multi-stage radio frequency amplifier.

[0033] The multi-stage radio frequency amplifier is an N-stage amplifier circuit, including N amplifying transistors from stage 1 to stage N, the N transistors are arranged in series, and N is a positive integer.

[0034] The bias resistor circuit is composed of N+1 bias resistors connected in series.

[0035] The number of diode series branches is N, one end of the Nth diode series branch is connected to the gate of the Nth transistor and the bias resistor circuit, and the other end is grounded. The Nth diode series branch includes N diodes arranged in series.

[0036] The number of negative feedback circuits is N, and the Nth negative feedback circuit is connected to the source of the Nth transistor. The negative feedback circuit includes an inductor L, a negative feedback resistor R f and capacitor C; one end of the inductor L is connected to the transistor source S, and the other end is connected to the capacitor C, the negative feedback resistor R f Connect capacitor C in parallel to ground.

[0037] The amplifier gate-source voltage stabilization circuit of the present invention realizes gate-source voltage stabilization by utilizing the nonlinear relationship between diode resistance and voltage and the voltage-dividing characteristic of negative feedback resistance.

[0038] The connection method of the multi-stage RF amplifier, the bias resistor circuit, and the diode series branch is as follows:

[0039] The first resistor R1 in the bias resistor circuit is connected in parallel with the first-stage transistor gate G1 and the first diode branch to the ground; the second resistor R2 in the bias resistor circuit is connected in parallel between the first-stage transistor gate G1 and the second-stage transistor gate G2, and the second diode branch is connected in parallel with the second-stage transistor gate G2 to the ground;

[0040] The third resistor R3 in the bias resistor circuit is connected in parallel between the second-stage transistor gate G2 and the next-stage transistor gate. Recursively, the Nth diode branch and the Nth-stage transistor gate G N Parallel grounding;

[0041] The N+1th resistor R in the bias resistor circuit N+1 Connect the gate G of the Nth transistor N and DC power supply Vcc.

[0042] According to actual circuit design requirements, each stage of the multi-stage RF amplifier can be selected to connect a diode branch in parallel or not. The diode branch is composed of one or more diodes connected in series.

[0043] According to actual circuit design requirements, each stage of the multi-stage RF amplifier can choose whether to connect to a corresponding negative feedback circuit.

[0044] The bias resistor uses an equivalent resistor, which can be implemented with either a passive resistor or an active resistor in the actual circuit.

[0045] The diode series branches are all forward biased and connected in series to ground, and can be equivalent to a resistor that changes nonlinearly with voltage.

[0046] The gate-source voltage stabilization circuit achieves gate-source voltage stabilization by utilizing the nonlinear relationship between diode resistance and voltage and the voltage-dividing characteristics of the negative feedback resistor, as follows:

[0047] When the power supply voltage becomes smaller, the transistor gate voltage becomes smaller, and the gate-source voltage becomes smaller; at this time, the diode resistance becomes smaller, and the source current becomes smaller. Because the diode is connected in parallel with the bias resistor, the total gate bias resistance becomes smaller, the gate voltage rises, and the gate-source voltage rises. Because the source negative feedback resistance divider voltage decreases with the current, the gate-source voltage further rises, thus achieving a gate-source voltage stabilization effect when the voltage decreases to a certain extent.

[0048] When the power supply voltage increases, the transistor gate voltage increases, and the gate-source voltage increases; at this time, the diode resistance increases, and the source current increases. Because the diode is connected in parallel with the bias resistor, the total gate bias resistance increases, the gate voltage drops, and the gate-source voltage drops. Because the source negative feedback resistor divider increases with the current, the gate-source voltage drops further, thus achieving a stable gate-source voltage effect when the voltage increases to a certain extent.

[0049] like Figure 1 As shown, the gate-source voltage stabilization circuit of the present invention realizes gate-source voltage stabilization by connecting a diode branch in parallel to the gate of the transistor and adding a negative feedback circuit to the source.

[0050] like Figure 2 As shown, it is a schematic diagram of the amplifier design without adding a gate-source voltage stabilization circuit, and Figure 1 By comparison, it can be clearly seen that the difference between the two is whether they have a diode branch structure.

[0051] like Figure 3 As shown, the simulation gain curve of the amplifier of the present invention without adding the gate-source voltage stabilization circuit at different voltages is given. The standard power supply voltage is 3.3V; when the voltage deviates from 3.3V to 3V, the gate-source voltage changes from 0.378V to 0.345V, the change is 0.033V, and the maximum gain change is 2.8dB. When the voltage deviates from 3.3V to 3.6V, the gate-source voltage changes from 0.378V to 0.413V, the change is 0.035V, and the maximum gain change is 2dB.

[0052] like Figure 4As shown, a simulation gain curve diagram of the amplifier of the present invention with a gate-source voltage stabilization circuit added at different voltages is given, the standard voltage is 3.3V; when the voltage deviates from 3.3V to 3V, the gate-source voltage changes from 0.373V to 0.373V, a change of 0.001V, and a gain change of 0.17dB; when the voltage deviates from 3.3V to 3.6V, the gate-source voltage changes from 0.373V to 0.374V, a change of 0.001V, and a gain change of 0.21dB; it can be seen that after adding the gate-source voltage stabilization circuit, under the same voltage deviation, the gate-source voltage change is significantly reduced, and the gain change is significantly reduced.

[0053] like Figure 5 As shown, the measured gain curve of the amplifier of the present invention without adding the gate-source voltage stabilization circuit at different voltages is given, the standard voltage is 3.3V; when the voltage deviates from 3.3V to 3V, the measured gain changes by about 2.7dB; when the voltage deviates from 3.3V to 3.6V, the measured gain changes by about 2dB; the measured results are basically consistent with the simulation.

[0054] like Figure 6 As shown, the measured gain curve diagram of the amplifier with the gate-source voltage stabilization circuit added at different voltages of the present invention is given, the standard voltage is 3.3V; when the voltage deviates from 3.3V to 3V, the measured gain changes by about 0.1dB; when the voltage deviates from 3.3V to 3.6V, the measured gain changes by about 0.05dB; the measured results prove that the gain of the amplifier after adding the gate-source voltage stabilization circuit can still remain basically unchanged when the power supply voltage deviates, and the stability is significantly improved.

[0055] The amplifier gate-source voltage stabilization circuit of the present invention effectively reduces the variation of the gate-source voltage when the power supply voltage deviates, achieves the stabilization effect of the gate-source voltage, and improves the stability of the amplifier gain.

Claims

1. An amplifier gate-source voltage stabilization circuit based on parallel diodes, characterized in that: It includes a multi-stage radio frequency amplifier, a bias resistor circuit and a diode series branch arranged in parallel with the multi-stage radio frequency amplifier, and a negative feedback circuit connected to the transistor source of the multi-stage radio frequency amplifier; The gate-source voltage is stabilized by utilizing the nonlinear relationship between the diode resistance and the voltage in the diode series branch and the voltage division characteristic of the negative feedback circuit.

2. The amplifier gate-source voltage stabilization circuit based on parallel diodes according to claim 1, characterized in that: The multi-stage radio frequency amplifier includes N transistors arranged in series, and the bias resistor circuit includes N+1 bias resistors arranged in series.

3. The amplifier gate-source voltage stabilization circuit based on parallel diodes according to claim 2, characterized in that: The number of the diode series branches is N, one end of the Nth diode series branch is connected to the gate of the Nth transistor and the bias resistor circuit, and the other end is grounded; The Nth diode series branch includes N diodes arranged in series.

4. The amplifier gate-source voltage stabilization circuit based on parallel diodes according to claim 3, characterized in that: The first resistor R1 in the bias resistor circuit is connected in parallel with the first-stage transistor gate G1 and the first diode branch to the ground; The second resistor R2 in the bias resistor circuit is connected in parallel between the first-stage transistor gate G1 and the second-stage transistor gate G2, and the second diode branch is connected in parallel with the second-stage transistor gate G2 and grounded; The third resistor R3 in the bias resistor circuit is connected in parallel between the second-stage transistor gate G2 and the next-stage transistor gate, and recursively, the Nth diode branch and the Nth-stage transistor gate G N Parallel grounding; The N+1th resistor R in the bias resistor circuit N+1 Connect the gate G of the Nth transistor N and DC power supply Vcc.

5. The amplifier gate-source voltage stabilization circuit based on parallel diodes according to claim 2, characterized in that: The number of the negative feedback circuits is N, and the Nth negative feedback circuit is connected to the source of the Nth stage transistor.

6. The amplifier gate-source voltage stabilization circuit based on parallel diodes according to claim 5, characterized in that: The negative feedback circuit includes an inductor L, a negative feedback resistor R f and capacitor C; One end of the inductor L is connected to the transistor source S, and the other end is connected to the capacitor C. The negative feedback resistor R f Connect capacitor C in parallel to ground.

7. The amplifier gate-source voltage stabilization circuit based on parallel diodes according to claim 1, characterized in that: Each stage of the multi-stage radio frequency amplifier is configured to select whether to connect a diode branch in parallel according to actual circuit design requirements.

8. The amplifier gate-source voltage stabilization circuit based on parallel diodes according to claim 1, characterized in that: Each stage of the multi-stage radio frequency amplifier is selected to be connected to a negative feedback circuit according to actual circuit design requirements.

9. The amplifier gate-source voltage stabilization circuit based on parallel diodes according to claim 2, characterized in that: The bias resistor is an equivalent resistor.

10. The amplifier gate-source voltage stabilization circuit based on parallel diodes according to claim 3, characterized in that: The diode series branches are all forward biased and connected in series to ground, and are equivalent to resistors that vary nonlinearly with voltage.

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