Gilbert amplifier control circuit and communication device
By introducing driving modules, adjustment modules and voltage stabilization modules into the Gilbert amplifier circuit, the problem of temperature-affected gain of the Gilbert amplifier circuit is solved, and the stable control of gain and signal stability is achieved.
Patent Information
- Application Number
- CN202411871150.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-18
- Publication Date
- 2025-04-25
AI Technical Summary
The output gain of existing Gilbert amplifier circuits is greatly affected by temperature, resulting in signal instability and inconsistency.
A Gilbert amplifier control circuit is designed, including a driving module, a regulation module and a voltage stabilization module. By transmitting a driving signal that is not affected by temperature changes, the control voltage of the Gilbert amplifier module is adjusted, and the operating conditions of the control voltage are maintained through the voltage stabilization module.
The gain of the Gilbert amplifier module is realized by the driving signal, but does not change with temperature, improving the stability and consistency of the output signal.
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Figure CN119891963A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of power electronics technology, and in particular to a Gilbert amplifier control circuit and a communication device. Background Art
[0002] The Gilbert amplifier circuit is a current source circuit with high precision and stability. In circuit design, the Gilbert unit is often used as a Gilbert amplifier, which achieves gain changes by changing the equivalent transconductance. This method has little effect on the time constant of the signal path node and has the advantage of bandwidth stability. The Gilbert amplifier circuit has a small change in the current output value within a wide voltage range. This is because the reference voltage source of the circuit has a high stability and can achieve the stability level of the current source circuit. However, it is still affected by factors such as temperature, voltage, and process, resulting in instability and inconsistency of the output signal, that is, the gain is greatly affected by temperature changes. Summary of the invention
[0003] The main purpose of the present application is to provide a Gilbert amplifier control circuit and a communication device, aiming to solve the technical problem that the output gain of the existing Gilbert amplifier circuit is greatly affected by temperature.
[0004] To achieve the above-mentioned purpose, the present application proposes a Gilbert amplifier control circuit, which includes: a driving module, an adjusting module, a voltage regulating module and a Gilbert amplifier module; the driving module is connected to the Gilbert amplifier module through the adjusting module; the voltage regulating module is also connected to the adjusting module and the Gilbert amplifier module respectively; the driving module is used to transmit a driving signal to the adjusting module; the adjusting module is used to adjust the control voltage of the Gilbert amplifier module according to the driving signal; the voltage regulating module is used to maintain the control voltage working conditions of the adjusting module and the Gilbert amplifier module to be consistent; the adjusting module is also used to feed back a feedback voltage corresponding to the driving signal to the Gilbert amplifier module based on the control voltage; the Gilbert amplifier module is also used to adjust the output gain based on the feedback voltage and the control voltage.
[0005] In one embodiment, the Gilbert amplifier module includes: a first resistor, a second resistor, a first triode, a second triode, a third triode, a fourth triode, a fifth triode, a sixth triode, a first current source, a second current source and an RC network; the first end of the first resistor and the first end of the second resistor are both connected to a working power supply; the second end of the first resistor and the second end of the second resistor are respectively connected to the collector of the first triode and the collector of the fourth triode; the collector of the second triode and the collector of the third triode are respectively connected to the collector of the fourth triode and the collector of the first triode; The base is connected to the base of the third triode; the base of the first triode is connected to the base of the fourth triode; the emitter of the first triode is connected to the emitter of the second triode and the collector of the fifth triode; the emitter of the third triode is connected to the emitter of the fourth triode and the collector of the sixth triode; the emitter of the fifth triode is connected to the emitter of the sixth triode through the RC network; the emitter of the fifth triode is also grounded through the first current source; the emitter of the sixth triode is also grounded through the second current source; the RC network is used to compensate for the gain of the Gilbert amplifier module.
[0006] In one embodiment, the driving module includes: a reference current source and a first reference resistor; the first end and the second end of the first reference resistor are respectively connected to a working power supply and the first end of the reference current source; the second end of the first reference resistor is also connected to the first input end of the adjustment module; the second end of the reference current source is grounded.
[0007] In one embodiment, the adjustment module includes: a second reference resistor, a seventh transistor and a first operational amplifier; the first end and the second end of the second reference resistor are respectively connected to a working power supply and the collector of the seventh transistor; the collector of the seventh transistor is also connected to the second input end of the first operational amplifier; the emitter of the seventh transistor is connected to the voltage stabilizing module; the base of the seventh transistor is connected to the base of the second transistor; the first input end of the first operational amplifier is connected to the second end of the first reference resistor; and the output end of the first operational amplifier is connected to the base of the second transistor.
[0008] In one embodiment, the voltage stabilizing module includes: a second operational amplifier, a first filter resistor and a second filter resistor; the first input end of the second operational amplifier is connected to the first end of the first filter resistor and the first end of the second filter resistor; the second input end of the second operational amplifier is connected to the output end of the second operational amplifier and the emitter of the seventh transistor; the second end of the first filter resistor is connected to the emitter of the second transistor; the second end of the second filter resistor is connected to the emitter of the third transistor.
[0009] In one embodiment, the first resistor and the second resistor have the same parameters, the first filter resistor and the second filter resistor have the same parameters, the first transistor and the fourth transistor have the same parameters, the second transistor and the third transistor have the same parameters, the fifth transistor and the sixth transistor have the same parameters, and the first current source and the second current source have the same parameters.
[0010] In one embodiment, the RC network includes: a third resistor and a first capacitor; the first end of the third resistor is connected to the emitter of the fifth transistor and the first end of the first capacitor; the second end of the third resistor is connected to the emitter of the sixth transistor and the second end of the first capacitor.
[0011] In addition, to achieve the above-mentioned purpose, the present application also proposes a communication device, which uses the Gilbert amplifier control circuit as described above.
[0012] One or more technical solutions proposed in this application have at least the following technical effects:
[0013] The driving module transmits a driving signal that is not affected by temperature changes to the regulating module; the regulating module adjusts the control voltage of the Gilbert amplifier module according to the driving signal; the voltage stabilizing module maintains the same working conditions of the control voltages of the regulating module and the Gilbert amplifier module; the Gilbert amplifier module adjusts the output gain based on the feedback voltage and the control voltage. This achieves that the gain of the Gilbert amplifier module is controlled by the driving signal and does not change with temperature. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.
[0015] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.
[0016] Figure 1 A circuit diagram of an existing Gilbert amplifier;
[0017] Figure 2 A structural block diagram provided for an embodiment of the Gilbert amplifier control circuit of the present application;
[0018] Figure 3 A circuit diagram of an implementation method provided for the Gilbert amplifier control circuit embodiment of the present application;
[0019] Figure 4 Another circuit diagram of an implementation method provided for the Gilbert amplifier control circuit embodiment of the present application.
[0020] Description of Figure Numbers:
[0021] Label illustrate Label illustrate 10 Driver module R1 / R2 The first and second resistors 20 Adjustment module T1 to T7 The first to seventh transistors 30 Voltage regulator module Isource1 The first current source 40 Gilbert Amplifier Module Isource2 The second current source R3 / R4 The first and second reference resistors RC circuit RC Network AMP1 / AMP2 First and second operational amplifiers R5 / R6 The first and second filter resistors
[0022] The purpose, features and advantages of this application will be further described in conjunction with the embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION
[0023] It should be understood that the specific embodiments described herein are only used to explain the technical solutions of the present application and are not used to limit the present application.
[0024] In order to better understand the technical solution of the present application, a detailed description will be given below in conjunction with the accompanying drawings and specific implementation methods.
[0025] The Gilbert amplifier circuit is a current source circuit with high precision and stability. In circuit design, the Gilbert cell is often used as a Gilbert amplifier, which achieves gain changes by changing the equivalent transconductance. This method has little effect on the time constant of the signal path node and has the advantage of bandwidth stability. The Gilbert amplifier circuit has a small change in the current output value within a wide voltage range. This is because the reference voltage source of the circuit has a high stability and can achieve the stability level of the current source circuit. However, it is still affected by factors such as temperature, voltage, and process, resulting in instability and inconsistency of the output signal, that is, the gain is greatly affected by temperature changes.
[0026] Please refer to Figure 1 , Figure 1 The circuit structure diagram of an existing Gilbert amplifier is shown in FIG.
[0027] It should be noted that Figure 1 The working principle of the Gilbert amplifier circuit shown is that by adjusting the voltage difference between VBias1 and VBias2, the DC current flowing through the first transistor T1, the second transistor T2, the third transistor T3 and the fourth transistor T4 can be controlled. This current distribution relationship further determines the distribution of the AC gain current. It can be understood that since the distribution of the AC gain current is consistent with the DC current, the gain of the Gilbert amplifier can be adjusted by changing the DC current.
[0028] It should be noted that when the temperature changes, even if the voltage difference between the control voltages VBias1 and VBias2 remains unchanged, the DC current distribution relationship between T1 and T2, T4 and T3 will change. This is due to the characteristic that the base-emitter voltage (VBE) of the transistor changes with temperature.
[0029] Similarly, due to the change in the DC current distribution relationship, the AC gain current distribution relationship between the first transistor T1 and the second transistor T2, the fourth transistor T4 and the third transistor T3 will also change, resulting in a change in the gain of the Gilbert amplifier.
[0030] Specifically, the formula IC = IS*exp(VBE*q / kT) describes the relationship between the transistor collector current IC and the temperature T and the base-emitter voltage VBE. Among them, IS is the saturation current, which is related to the specific process and size of the transistor, q is the electron charge, and k is the Boltzmann constant. Because IC T1 +IC T2 =Isource1,IC T1 / IC T2 =(IS*exp(VBE T1 *q / kT)) / (IS*exp(VBE T2 *q / kT))=exp((VBE T1 -VBE T2 )*q / kT).
[0031] It can be seen from this formula that as the temperature T changes, even if the voltage difference between VBias1 and VBias2 remains unchanged, the current distribution relationship between gains T1 and T2 will change due to temperature changes; similarly, T4 and T3 also change.
[0032] In order to reduce the impact of temperature changes on the gain of the Gilbert amplifier, a circuit that can automatically compensate for temperature changes is usually designed to keep the Gilbert amplifier gain stable. This usually involves using a thermal element (such as a thermistor or thermocouple) to monitor temperature changes and adjust the voltage difference between the control voltages VBias1 and VBias2 accordingly. However, the temperature compensation circuit has the problem of under-compensation or over-compensation and increases power consumption and cost. At the same time, the instability of the thermal element is also a considerable problem.
[0033] Based on this, the embodiment of the present application provides a Gilbert amplifier control circuit, which optimizes the circuit structure by adding a driving module, a regulating module and a voltage stabilizing module to achieve gain that does not change with temperature. Figure 2 , Figure 2 A structural block diagram of a Gilbert amplifier control circuit embodiment of the present application.
[0034] In this embodiment, the Gilbert amplifier control circuit includes: a driving module 10, an adjusting module 20, a voltage regulating module 30 and a Gilbert amplifier module 40. The driving module 10 is connected to the Gilbert amplifier module 40 through the adjusting module 20; the voltage regulating module 30 is also connected to the adjusting module 20 and the Gilbert amplifier module 40 respectively.
[0035] It should be noted that the driving module 10 is used to transmit a driving signal to the regulating module 20 .
[0036] It will be appreciated that the drive signal may be a voltage or current signal from a control source that is not affected by temperature variations and is used to indicate a desired gain level.
[0037] It should be noted that the regulating module 20 is used to regulate the control voltage of the Gilbert amplifier module 40 according to the driving signal.
[0038] It can be understood that in the design of the Gilbert amplifier control circuit, the synergy between the adjustment module 20 and the Gilbert amplifier module 40 is crucial. The main task of the adjustment module 20 is to accurately adjust the bias voltage required by the transistor in the Gilbert amplifier module 40, that is, the control voltage, according to the driving signal from the driving module 10.
[0039] It is understandable that since the core of the Gilbert amplifier module 40 is a triode, it has significant amplification characteristics. The triode can amplify a small input signal into a larger output signal through the current relationship between its base, emitter and collector. In order to ensure that the triode can work normally and exert its amplification characteristics, it is necessary to provide it with an appropriate bias voltage. This bias voltage determines the working point of the triode, which in turn affects its amplification factor and linearity.
[0040] It should be noted that the voltage stabilizing module 30 is used to maintain the control voltage working conditions of the regulating module 20 and the Gilbert amplifier module 40 to be consistent.
[0041] It is understandable that in order to correctly establish the connection between the adjustment module 20 and the Gilbert amplifier module 40, it is necessary to ensure that the working conditions of the devices in the adjustment module and the transistors in the Gilbert amplifier module 40 are consistent, that is, to maintain the same bias voltage, and the voltage regulator module 30 is required for sampling.
[0042] It is understood that the main function of the voltage regulator module 30 is to ensure that the control voltage of the regulator module 20 and the Gilbert amplifier module 40 remains stable throughout the entire operating range. This includes maintaining the consistent operating conditions of the two modules under external interference such as power supply voltage fluctuations, load changes, and temperature changes.
[0043] In specific implementation, the voltage stabilizing module 30 can be implemented in a variety of ways, including but not limited to a voltage stabilizer, an operational amplifier, and a power management module. Each of these implementations has its own advantages and disadvantages, and the specific choice depends on factors such as application requirements, cost budget, and design complexity.
[0044] It is understood that in order to ensure that the control voltages between the adjustment module 20 and the Gilbert amplifier module 40 are consistent, the voltage regulator module 30 needs to perform accurate sampling. The sampling process usually involves real-time monitoring of the control voltages of the two modules and comparing the monitoring results with a preset reference voltage. Based on the comparison results, the voltage regulator module 30 adjusts its output voltage to ensure that the control voltages of the two modules remain consistent.
[0045] The regulating module 20 is further used for feeding back a feedback voltage corresponding to the driving signal to the Gilbert amplifier module 40 based on a control voltage; the Gilbert amplifier module 40 is further used for adjusting an output gain based on the feedback voltage and the control voltage.
[0046] It is understood that the Gilbert amplifier module 40 is a core component, and its gain can be changed by adjusting the control voltage. This design enables the circuit to adapt to different gain requirements while maintaining high stability and linearity.
[0047] It should be noted that since the driving signal is not affected by temperature, the output control voltage and feedback voltage are not affected by temperature. At this time, the transistor amplification characteristics in the Gilbert amplifier module 40 are constant, so the gain is not affected by temperature and only depends on the feedback voltage.
[0048] In this embodiment, the driving module transmits a driving signal that is not affected by temperature changes to the regulating module; the regulating module adjusts the control voltage of the Gilbert amplifier module according to the driving signal; the voltage stabilizing module maintains the same working conditions of the control voltages of the regulating module and the Gilbert amplifier module; the Gilbert amplifier module adjusts the output gain based on the feedback voltage and the control voltage. This achieves that the gain of the Gilbert amplifier module is controlled by the driving signal and does not change with temperature.
[0049] Specifically, this application provides a feasible implementation method, please refer to Figure 3 , Figure 3 A circuit diagram of an implementation scheme provided for the Gilbert amplifier control circuit embodiment of the present application.
[0050] In this embodiment, the Gilbert amplifier module 40 includes: a first resistor R1, a second resistor R2, a first transistor T1, a second transistor T2, a third transistor T3, a fourth transistor T4, a fifth transistor T5, a sixth transistor T6, a first current source Isource1, a second current source Isource2 and an RC network.
[0051] It should be noted that the first end of the first resistor R1 and the first end of the second resistor R2 are both connected to the working power supply; the second end of the first resistor R1 and the second end of the second resistor R2 are respectively connected to the collector of the first transistor T1 and the collector of the fourth transistor T4.
[0052] It can be understood that the first ends of the two resistors are connected to the working power supply to provide the necessary DC bias for the Gilbert amplifier module, and their second ends are respectively connected to the collectors of the first transistor T1 and the fourth transistor T4 to set the static working point of the transistors.
[0053] It should be noted that the collector of the second transistor T2 and the collector of the third transistor T3 are connected to the collector of the fourth transistor T4 and the collector of the first transistor T1 respectively; the base of the second transistor T2 is connected to the base of the third transistor T3; the base of the first transistor is connected to the base of the fourth transistor; the emitter of the first transistor T1 is connected to the emitter of the second transistor T2 and the collector of the fifth transistor T5; the emitter of the third transistor T3 is connected to the emitter of the fourth transistor T4 and the collector of the sixth transistor T6.
[0054] It can be understood that the six transistors constitute the core of the Gilbert amplifier. They are connected in the above manner to achieve differential input and differential output. Specifically, the fifth transistor T5 and the sixth transistor T6 constitute an input differential pair, which converts and amplifies the input signal and loads it on the output load first resistor R1 and second resistor R2 to generate a differential output. Further, the first transistor T1 and the second transistor T2, the fourth transistor T4 and the third transistor T3 adjust the effective gain by adjusting the effective current flowing through the output load first resistor R1 and second resistor R2. This connection method enables the Gilbert amplifier to amplify the input signal and maintain good differential performance.
[0055] It should be noted that the emitter of the fifth transistor T5 is connected to the emitter of the sixth transistor T6 through the RC network.
[0056] It can be understood that the RC network is connected between the emitters of the fifth transistor T5 and the sixth transistor T6 to compensate for the gain of the Gilbert amplifier module. By adjusting the parameters of the RC network, the gain frequency response of the amplifier can be optimized and its stability and linearity can be improved.
[0057] Specifically, the RC network may include a third resistor and a first capacitor; the first end of the third resistor is connected to the emitter of the fifth transistor and the first end of the first capacitor; the second end of the third resistor is connected to the emitter of the sixth transistor and the second end of the first capacitor.
[0058] It should be noted that the third resistor and the first capacitor can be adjusted by normal switches, or adjustable devices can be selected. The performance of the circuit can be optimized by adjusting the resistance of the third resistor and the capacitance of the first capacitor. For example, by changing the resistance of the third resistor, the degree of gain conversion can be adjusted, thereby changing the gain and stability of the amplifier. Similarly, by changing the capacitance of the first capacitor, the size and position of the frequency compensation can be adjusted to meet different application requirements.
[0059] It should be noted that the emitter of the fifth transistor T5 is also grounded through the first current source Isource1; the emitter of the sixth transistor T6 is also grounded through the second current source Isource2; and the RC network is used to compensate for the gain of the Gilbert amplifier module.
[0060] It can be understood that the two current sources are respectively connected to the emitters of the fifth transistor T5 and the sixth transistor T6 and are grounded, which provide stable DC currents for the transistors, help maintain the working state of the transistors stable, and reduce the impact of temperature changes on the performance of the amplifier.
[0061] Furthermore, the driving module 10 includes: a reference current source IREF and a first reference resistor R3; the first end and the second end of the first reference resistor R3 are respectively connected to a working power supply and the first end of the reference current source IREF; the second end of the first reference resistor R3 is also connected to the first input end of the adjustment module 20; the second end of the reference current source IREF is grounded.
[0062] It can be understood that the first reference resistor R3 is used to convert the current provided by the reference current source IREF into a voltage. The first end of the first reference resistor R3 is connected to the working power supply, and the second end of R3 is connected to the first end of the reference current source IREF and the first input end of the adjustment module 20. In this way, a voltage drop proportional to the IREF current will be generated on R3, and this voltage drop is used as an input signal of the adjustment module 20.
[0063] It is understandable that, in addition to adjusting the reference current source IREF, the value of the first reference resistor R3 may also be adjusted, and the voltage output to the first input terminal of the adjustment module 20 may also be adjusted.
[0064] Furthermore, the regulating module 20 includes: a second reference resistor R4, a seventh transistor T7 and a first operational amplifier AMP1.
[0065] Among them, the first end and the second end of the second reference resistor R4 are respectively connected to the working power supply and the collector of the seventh transistor T7; the collector of the seventh transistor T7 is also connected to the second input end of the first operational amplifier AMP1; the emitter of the seventh transistor T7 is connected to the voltage stabilizing module 30; the base of the seventh transistor T7 is connected to the base of the second transistor T2; the first input end of the first operational amplifier AMP1 is connected to the second end of the first reference resistor R3; the output end of the first operational amplifier AMP1 is connected to the base of the second transistor T2.
[0066] It is understandable that the first end of the second reference resistor R4 is connected to the working power supply to provide the necessary DC bias for the seventh transistor T7, and the second end is connected to the collector of the seventh transistor T7 to convert the collector current of the seventh transistor T7 into a voltage to be supplied to the second input end of the first operational amplifier AMP1.
[0067] It can be understood that the collector of the seventh transistor T7 is connected to the second end of the second reference resistor R4 and the second input end of the first operational amplifier AMP1 (in this structure, it is a non-inverting input). In this way, the collector voltage of T7 is used as an input signal of AMP1. The base is connected to the base of the second transistor T2, which means that T7 and T2 are interrelated and their working states are basically consistent.
[0068] It can be understood that the first input terminal (inverting input in this structure) of the first operational amplifier AMP1 is connected to the second terminal of the first reference resistor R3 to receive the driving signal from the driving module 10. The second input terminal (inverting input in this structure) is connected to the collector of the seventh transistor T7. The output terminal is connected to the base of the second transistor T2 to provide a control signal for T2, which is based on the difference between the input signal of AMP1 (i.e., the voltage drop on R3 and the collector voltage of T7).
[0069] Furthermore, the voltage stabilizing module 30 includes: the second operational amplifier AMP2; the first input terminal of the second operational amplifier AMP2 is connected to the emitter of the second transistor T2 and the emitter of the third transistor T3; the second input terminal of the second operational amplifier AMP2 is connected to the output terminal of the second operational amplifier AMP2 and the emitter of the seventh transistor T7.
[0070] It can be understood that the first input terminal (usually the non-inverting input terminal) of the second operational amplifier AMP2 is connected to the first terminal of the first filter resistor and the first terminal of the second filter resistor; the second input terminal (usually the inverting input terminal) of the second operational amplifier is connected to the output terminal of the second operational amplifier and the emitter of the seventh transistor. This connection method forms a voltage follower structure, ensuring that the output voltage of the second operational amplifier AMP2 follows the voltage of the first input terminal of the second operational amplifier AMP2.
[0071] It should be noted that, under the above connection relationship, due to the follower effect of the second operational amplifier AMP2, the emitter voltage of T7 will be stabilized at a specific value, which depends on the input voltage of the first input terminal of the second operational amplifier AMP2 (i.e., the voltage between the emitters of T2 and T3) and the gain of the second operational amplifier AMP2. Ideally, if the gain of the second operational amplifier AMP2 is high enough, the emitter voltage of T7 will be very close to the average value of the emitter voltages of T2 and T3, achieving voltage consistency. Therefore, the emitter voltage of T7 can be regarded as a sampling of the average value of the emitter voltages of T2 and T3.
[0072] Furthermore, the voltage stabilizing module 30 further includes: a first filter resistor R5 and a second filter resistor R6. The first input terminal of the second operational amplifier is connected to the first terminal of the first filter resistor and the first terminal of the second filter resistor; the second input terminal of the second operational amplifier is connected to the output terminal of the second operational amplifier and the emitter of the seventh transistor; the second terminal of the first filter resistor is connected to the emitter of the second transistor; the second terminal of the second filter resistor is connected to the emitter of the third transistor.
[0073] It can be understood that the first filter resistor R5 and the second filter resistor R6 together form a voltage divider, which divides the voltage between the emitters of T2 and T3 and sends the divided voltage to the non-inverting input terminal of AMP2. When the resistance values of the first filter resistor R5 and the second filter resistor R6 are large enough, this voltage division process helps to reduce the influence of the high-frequency signal of the emitters of T2 and T3 on the first input terminal of the second operational amplifier AMP2, because the attenuation effect of the resistor on the high-frequency signal is stronger than that on the low-frequency signal.
[0074] Specifically, the first resistor R1 and the second resistor R2 have the same parameters, the first filter resistor R5 and the second filter resistor R6 have the same parameters and are much larger than the first resistor R1; the first transistor T1 and the fourth transistor T4 have the same parameters, the second transistor T2 and the third transistor T3 have the same parameters, the fifth transistor T5 and the sixth transistor T6 have the same parameters, and the first current source Isource1 and the second current source Isource2 have the same parameters.
[0075] Specifically, the selection of the second reference resistor R4 and the seventh transistor T7 needs to satisfy that the parameter ratio of the second transistor T2 and the seventh transistor T7 is k times the parameter ratio of the second reference resistor R4 and the second resistor R2. The parameter k can be measured through experiments and is usually 1 / 4.
[0076] It is understandable that, in this structure, the bias voltage VBias2 can be a constant value or a variable value, and the voltage value of the control voltage VBias1 is obtained by the output of the first operational amplifier AMP1. In addition, this structure can also be adjusted, such as Figure 4 As shown, VBias2 is selected as the control voltage outputted by the amplifier, and the base voltage VBias1 of the second transistor T2 and the third transistor T3 can be a constant value or a variable value. In normal operation, we set the reference current source IREF, then the drive signal VREF = VDD-IREF*R3.
[0077] It can be understood that the amplifier will automatically adjust the value of the control voltage VBias1 so that the feedback voltage VFB=VDD-IR4*R4=VREF (IR4 is the current flowing through the resistor R4).
[0078] It can be understood that the amplifier AMP1 has two input terminals, the first input terminal receives the drive signal VREF, and the second input terminal receives the feedback voltage VFB. There is a comparator inside the amplifier for comparing the voltage values of VREF and VFB. When the reference signal VREF and VFB are not equal, the comparator will output an error signal. This error signal will be used to adjust the value of VBias1, thereby changing the working state of the circuit so that the feedback voltage VFB gradually approaches the drive signal VREF. Through a closed-loop feedback system, the amplifier can continuously monitor the voltages of the drive signal VREF and the feedback voltage VFB, and adjust VBias1 as needed.
[0079] Furthermore, IR4=IREF*B (here it is assumed that the first reference resistor is B times the second reference resistor); because the working conditions of T2 are the same as those of T3 and T7, the role of the operational amplifier shown in the figure is to ensure that the working conditions of the seventh transistor T7 are the same as those of the second transistor T2, and the current flowing through the second transistor T2 and the third transistor T3 are equal, which is equal to the current flowing through the seventh transistor T7 multiplied by the coefficient A (here it is assumed that the parameters of the second transistor T2 are A times the parameters of the seventh transistor T7). Therefore, IT2=IT3=IT7*A=IR4*A=IREF*A*B. By adjusting different IREF values, the current value of IT2 can be adjusted.
[0080] It can be understood that based on the above content, when the gain ΔI is generated in the variable gain amplifier module loop, the gain ΔI is determined by the device parameters and does not change with temperature. Since the output of the first current source Isource1 is constant, the current of the left structure is Isource1+ΔI, and the current IT1 flowing through the first transistor all =Isource1*(IT1 / Isource1)+ΔI*(IT1 / Isource1), the current IT3 flowing through the third transistor all It is Isource2*(IT3 / Isource2)-ΔI*(IT3 / Isource2). Since IT1 / Isource1 and IT3 / Isource2 do not change with temperature, a new distribution relationship that does not change with temperature is established, that is, the circuit gain (R1*ΔI*(IT1 / Isource1-IT3 / Isource2)) does not change with temperature.
[0081] The communication device provided by the present application adopts the Gilbert amplifier control circuit in the above embodiment, which can solve the technical problem that the output gain of the existing Gilbert amplifier circuit is greatly affected by temperature. Compared with the prior art, the beneficial effects of the communication device provided by the present application are the same as the beneficial effects of the Gilbert amplifier control circuit provided by the above embodiment, and other technical features in the communication device are the same as the features disclosed in the above embodiment method, which will not be repeated here.
[0082] The above descriptions are only some embodiments of the present application, and are not intended to limit the patent scope of the present application. All equivalent structural changes made using the contents of the present application specification and drawings under the technical concept of the present application, or direct / indirect applications in other related technical fields are included in the patent protection scope of the present application.
Claims
1. A Gilbert amplifier control circuit, characterized in that: The Gilbert amplifier control circuit comprises: a driving module, a regulating module, a voltage stabilizing module and a Gilbert amplifier module; The driving module is connected to the Gilbert amplifier module through the regulating module; The voltage stabilizing module is also connected to the regulating module and the Gilbert amplifier module respectively; The driving module is used to transmit a driving signal to the regulating module; The regulating module is used to regulate the control voltage of the Gilbert amplifier module according to the driving signal; The voltage stabilizing module is used to maintain the control voltage working conditions of the regulating module and the Gilbert amplifier module consistent; The regulating module is further configured to feed back a feedback voltage corresponding to the driving signal to the Gilbert amplifier module based on a control voltage; The Gilbert amplifier module is further configured to adjust the output gain based on the feedback voltage and the control voltage.
2. The Gilbert amplifier control circuit according to claim 1, characterized in that The Gilbert amplifier module includes: a first resistor, a second resistor, a first triode, a second triode, a third triode, a fourth triode, a fifth triode, a sixth triode, a first current source, a second current source and an RC network; The first end of the first resistor and the first end of the second resistor are both connected to a working power supply; The second end of the first resistor and the second end of the second resistor are connected to the collector of the first transistor and the collector of the fourth transistor respectively; The collector of the second triode and the collector of the third triode are connected to the collector of the fourth triode and the collector of the first triode respectively; The base of the second triode is connected to the base of the third triode; The base of the first transistor is connected to the base of the fourth transistor; The emitter of the first triode is connected to the emitter of the second triode and the collector of the fifth triode; The emitter of the third triode is connected to the emitter of the fourth triode and the collector of the sixth triode; The emitter of the fifth transistor is connected to the emitter of the sixth transistor through the RC network; The emitter of the fifth triode is also grounded through the first current source; The emitter of the sixth triode is also grounded through the second current source; The RC network is used to compensate the gain of the Gilbert amplifier module.
3. The Gilbert amplifier control circuit according to claim 2, characterized in that: The driving module comprises: a reference current source and a first reference resistor; The first end and the second end of the first reference resistor are connected to a working power supply and a first end of the reference current source respectively; The second end of the first reference resistor is also connected to the first input end of the adjustment module; A second terminal of the reference current source is grounded.
4. The Gilbert amplifier control circuit according to claim 3, characterized in that: The regulating module comprises: a second reference resistor, a seventh transistor and a first operational amplifier; The first end and the second end of the second reference resistor are connected to the working power supply and the collector of the seventh transistor respectively; The collector of the seventh triode is also connected to the second input terminal of the first operational amplifier; The emitter of the seventh triode is connected to the voltage stabilizing module; The base of the seventh transistor is connected to the base of the second transistor; The first input terminal of the first operational amplifier is connected to the second terminal of the first reference resistor; The output terminal of the first operational amplifier is connected to the base of the second transistor.
5. The Gilbert amplifier control circuit according to claim 4, characterized in that The voltage stabilizing module comprises: a second operational amplifier, a first filter resistor and a second filter resistor; The first input terminal of the second operational amplifier is connected to the first terminal of the first filter resistor and the first terminal of the second filter resistor; The second input terminal of the second operational amplifier is connected to the output terminal of the second operational amplifier and the emitter of the seventh triode; The second end of the first filter resistor is connected to the emitter of the second transistor; The second end of the second filtering resistor is connected to the emitter of the third transistor.
6. The Gilbert amplifier control circuit according to claim 5, characterized in that The first resistor and the second resistor have the same parameters, the first filter resistor and the second filter resistor have the same parameters, the first transistor and the fourth transistor have the same parameters, the second transistor and the third transistor have the same parameters, the fifth transistor and the sixth transistor have the same parameters, and the first current source and the second current source have the same parameters.
7. The Gilbert amplifier control circuit according to claim 6, characterized in that The RC network includes: a third resistor and a first capacitor; A first end of the third resistor is connected to the emitter of the fifth transistor and the first end of the first capacitor; The second end of the third resistor is connected to the emitter of the sixth transistor and the second end of the first capacitor.
8. A communication device, characterized in that: The communication device applies the Gilbert amplifier control circuit according to any one of claims 1 to 7.