Variable gain amplifier, vector modulation phase shifter and communication device

Abstract

The present invention is applicable to the technical field of integrated circuit design, and provides a variable gain amplifier, a vector modulation phase shifter and a communication device. The variable gain amplifier comprises: a first load module, a second load module, a third load module and at least two amplification modules; the resistance value of the first load module is the same as the resistance value of the second load module; the amplification module comprises: a first transconductance amplification unit, a second transconductance amplification unit, a first switch unit, a second switch unit, a third switch unit and a fourth switch unit. By controlling the opening and closing of the first switch unit, the second switch unit, the third switch unit and the fourth switch unit, the total operating current flowing through the input port of the variable gain amplifier remains unchanged when each amplification module is opened or closed, thereby, the impedance of the input port of the variable gain amplifier remains unchanged in various gain states, and the input port standing wave ratio remains unchanged.

Description

Technical Field

[0001] The present invention belongs to the technical field of wireless communication, and in particular relates to a variable gain amplifier, a vector modulation phase shifter and a communication device. Background Art

[0002] Vector modulated phase shifters can be used in a variety of communications, data transmission, civil or military radars. Figure 1 The vector modulation phase shifter is composed of a single-ended to differential circuit, a differential quadrature generation circuit, an I-channel differential digitally controlled VGA (Variable Gain Amplifier) ​​and a Q-channel differential digitally controlled VGA, an analog adder, a differential to single-ended circuit, and a digital control circuit. The differential quadrature generation circuit generates I-channel signals and Q-channel signals. The differential digitally controlled VGA is used to change the amplitude of the I-channel signal and the Q-channel signal. The adder realizes vector synthesis. The two-channel signals with different amplitudes are synthesized into signals with different angles to realize the phase shifting function.

[0003] Due to the different working current and working state of VGA in different gain states, the input impedance and input port standing wave ratio are different. Therefore, the vector modulation phase shifter exhibits different input port standing waves in different phase shift states. When the vector modulation phase shifter is cascaded with the previous stage circuit, it will affect the phase of the previous stage circuit, thereby reducing the phase shift accuracy of the vector modulation phase shifter. Summary of the invention

[0004] In view of this, an embodiment of the present invention provides a variable gain amplifier, a vector modulation phase shifter and a communication device to solve the problem in the prior art that the operating current of the variable gain amplifier is different and the input port standing wave ratio is different in different gain states, thereby affecting the phase shifting accuracy of the vector modulation phase shifter.

[0005] A first aspect of an embodiment of the present invention provides a variable gain amplifier, comprising: a first load module, a second load module, a third load module and at least two amplification modules; the resistance value of the first load module is the same as the resistance value of the second load module;

[0006] The amplification module includes: a first transconductance amplification unit, a second transconductance amplification unit, a first switch unit, a second switch unit, a third switch unit and a fourth switch unit;

[0007] A first transconductance amplifier unit, the input end of which is used to receive an external RF forward input signal, and the output end is respectively connected to the first end of the first switch unit and the first end of the second switch unit; the first switch unit, the second end of which is respectively connected to the first load module and the first output end of the variable gain amplifier, and the control end is used to receive a first control signal; the second switch unit, the second end of which is connected to the third load module, and the control end is used to receive a second control signal; the first control signal is complementary to the second control signal;

[0008] A second transconductance amplifier unit, the input end of which is used to receive an external RF negative input signal, and the output end is respectively connected to the first end of the third switch unit and the first end of the fourth switch unit; the third switch unit, the second end of which is respectively connected to the second load module and the second output end of the variable gain amplifier, and the control end is used to receive the first control signal; the fourth switch unit, the second end of which is connected to the third load module, and the control end is used to receive the second control signal;

[0009] The transconductance of the first transconductance amplifying unit is the same as the transconductance of the second transconductance amplifying unit.

[0010] Optionally, the first transconductance amplification unit includes a first triode, and the second transconductance amplification unit includes a second triode;

[0011] The first triode has a base connected to the input end of the first transconductance amplifying unit, a collector connected to the output end of the first transconductance amplifying unit, and an emitter connected to ground; the second triode has a base connected to the input end of the second transconductance amplifying unit, a collector connected to the output end of the second transconductance amplifying unit, and an emitter connected to ground.

[0012] Optionally, both the first transistor and the second transistor are NPN transistors.

[0013] Optionally, the first switch unit includes: a first switch tube;

[0014] The first switch tube has a control end connected to the control end of the first switch unit, a first end connected to the first end of the first switch unit, and a second end connected to the second end of the first switch unit.

[0015] Optionally, the first switch tube includes a third triode;

[0016] The third triode has a base connected to the control end of the first switch unit, an emitter connected to the first end of the first switch unit, and a collector connected to the second end of the first switch unit.

[0017] Optionally, the circuit structures of the second switch unit, the third switch unit and the fourth switch unit are the same as the circuit structure of the first switch unit.

[0018] Optionally, the transconductances of the first transconductance amplification units corresponding to the respective amplification modules are distributed in a geometric progression.

[0019] Optionally, the first control signals received by different amplification modules are the same or different, and the second control signals received by different amplification modules are the same or different.

[0020] A second aspect of the embodiments of the present invention provides a vector modulation phase shifter, comprising a variable gain amplifier as provided in the first aspect of the embodiments of the present invention.

[0021] A third aspect of the embodiments of the present invention provides a communication device, comprising the vector modulation phase shifter provided by the second aspect of the embodiments of the present invention.

[0022] The embodiment of the present invention provides a variable gain amplifier, including a first load module, a second load module, a third load module and at least two amplification modules; the resistance value of the first load module is the same as the resistance value of the second load module; the current flowing into the first load module and the third load module is adjusted by the selection and disconnection of at least two amplification modules, so as to achieve adjustable gain. The amplification module includes: a first transconductance amplification unit, a second transconductance amplification unit, a first switch unit, a second switch unit, a third switch unit and a fourth switch unit; when the first switch unit and the third switch unit are turned on, the second switch unit and the fourth switch unit are turned off at the same time, and at this time, the variable gain amplifier outputs the amplified differential RF signal. When the first switch unit and the third switch unit are turned off, the second switch unit and the fourth switch unit are turned on at the same time. Since the transconductance of the first transconductance amplification unit and the second transconductance amplification unit are the same, the current flowing through the second load module is equal in magnitude and the phase difference is 180°, which cancels each other out, and the variable gain amplifier is cut off and has no output. The variable gain amplifier is turned on and off by selecting different branches, but the current flowing through the input end of the variable gain amplifier remains unchanged when turned on and off, the impedance of the input port of the variable gain amplifier remains unchanged in various gain states, and the input port standing wave ratio remains unchanged, thereby effectively improving the phase shifting accuracy of the vector modulation phase shifter using the above variable gain amplifier. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0024] Figure 1 is a structural schematic diagram of a vector modulation phase shifter provided by an embodiment of the present invention;

[0025] Figure 2 is a structural schematic diagram of a variable gain amplifier provided by an embodiment of the present invention;

[0026] Figure 3 is a structural schematic diagram of an amplification module provided by an embodiment of the present invention;

[0027] Figure 4 is a circuit schematic diagram of an amplification module provided by an embodiment of the present invention;

[0028] Figure 5 It is a standing wave simulation curve of the input port of a variable gain amplifier with five amplification modules in full gain state provided by an embodiment of the present invention;

[0029] Figure 6 It is a vector synthesis principle diagram of a vector modulation phase shifter provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0030] In the following description, specific details such as specific system structures, technologies, etc. are provided for the purpose of illustration rather than limitation, so as to provide a thorough understanding of the embodiments of the present invention. However, it should be clear to those skilled in the art that the present invention may be implemented in other embodiments without these specific details. In other cases, detailed descriptions of well-known systems, devices, circuits, and methods are omitted to prevent unnecessary details from obstructing the description of the present invention.

[0031] In order to illustrate the technical solution of the present invention, specific embodiments are provided below for illustration.

[0032] refer to Figure 2 and Figure 3 An embodiment of the present invention provides a variable gain amplifier, comprising: a first load module 11, a second load module 12, a third load module 13 and at least two amplification modules 14; the resistance value of the first load module 11 is the same as the resistance value of the second load module 12.

[0033] The amplifying module 14 includes a first transconductance amplifying unit 141 , a second transconductance amplifying unit 142 , a first switch unit 143 , a second switch unit 144 , a third switch unit 145 and a fourth switch unit 146 .

[0034] The first transconductance amplifier unit 141 has an input end for receiving an external RF forward input signal Vin+, and an output end connected to the first end of the first switch unit 143 and the first end of the second switch unit 144 respectively; the first switch unit 143 has a second end connected to the first load module 11 and the first output end of the variable gain amplifier respectively, and a control end for receiving a first control signal Ctr1; the second switch unit 144 has a second end connected to the third load module 13, and a control end for receiving a second control signal Ctr2; the first control signal Ctr1 is complementary to the second control signal Ctr2.

[0035] The second transconductance amplifier unit 142 has an input end for receiving an external RF negative input signal Vin-, and an output end connected to the first end of the third switch unit 145 and the first end of the fourth switch unit 146 respectively; the third switch unit 145 has a second end connected to the second load module 12 and the second output end of the variable gain amplifier respectively, and a control end for receiving a first control signal Ctr1; the fourth switch unit 146 has a second end connected to the third load module 13, and a control end for receiving a second control signal Ctr2; the transconductance of the first transconductance amplifier unit 141 and the transconductance of the second transconductance amplifier unit 142 are the same.

[0036] refer to Figure 2 , Figure 2 A connection diagram of at least two amplification modules 14 and a first load module 11, a second load module 12 and a third load module 13 is provided. For each amplification module 14, the first output end is connected to the first load module 11 and the first output end of the variable gain amplifier, the second output end is connected to the second load module 12 and the second output end of the variable gain amplifier, the third output end is connected to the third load module 13, the first input end is connected to the first input end of the variable gain amplifier, the second input end is connected to the second input end of the variable gain amplifier, the first control end is used to receive different first control signals Ctr1, and the second control end is used to receive different second control signals Ctr2; the external RF input signal is a differential signal, the first input end of the variable gain amplifier is used to receive an external RF positive input signal Vin+, the second input end of the variable gain amplifier is used to receive an external RF negative input signal Vin-, and the first output end of the variable gain amplifier and the second output end of the variable gain amplifier are used to output the amplified differential RF signal.

[0037] For example, the number of amplification modules 14 is 5, the current at the first input end of the variable gain amplifier is the sum of the input currents of each amplification module 14, and each first control signal Ctr1 and each second control signal Ctr2 are respectively used to control the opening and closing of each amplification module 14, thereby controlling the current at the first input end of the variable gain amplifier, and further controlling the amplification factor of the amplified differential RF signal output by the variable gain amplifier to the external RF input signal, thereby achieving adjustable gain.

[0038] The first control signal Ctr1 is complementary to the second control signal Ctr2. Figure 3 , Figure 3The figure shows the connection relationship between an amplifier module 14 and the first load module 11, the second load module 12 and the third load module 13. When the first control signal Ctr1 is an on signal, the second control signal Ctr2 is an off signal, the first switch unit 143 and the third switch unit 145 are closed, the second switch unit 144 and the fourth switch unit 146 are disconnected, the first transconductance amplifier unit 141, the first switch unit 143 and the first load module 11 form a first path, the second transconductance amplifier unit 142, the third switch unit 145 and the second load module 12 form a second path, and current flows through, and the amplifier module 14 is turned on. Assume that the current flowing through the first path is I 1 =Vin+ / g m1 , the current flowing through the second path is I 2 =Vin- / g m2 , where g m1 is the transconductance of the first transconductance amplifying unit 141, g m2 is the transconductance of the second transconductance amplifying unit 142, and the amplifying module 14 is turned on.

[0039] When the first switch unit 143 and the third switch unit 145 are disconnected, and the second switch unit 144 and the fourth switch unit 146 are closed, the first transconductance amplifier unit 141, the second switch unit 144 and the third load module 13 form a third path, and the second transconductance amplifier unit 142, the fourth switch unit 146 and the third load module 13 form a fourth path. Since the current of the transconductance amplifier unit is only related to the input voltage and the transconductance value, the current flowing through the third path remains unchanged and is I 1 , the current flowing through the fourth path remains unchanged and is I 2 , due to the transconductance g of the first transconductance amplification unit 141 m1 The transconductance g of the second transconductance amplification unit 142 m2 The same, then I 1 with I 2 The magnitudes are the same, and the phase difference is 180°, so the total current flowing into the third load module 13 is offset to 0, and the amplification module 14 is turned off.

[0040] As can be seen from the above, no matter when the amplifying module 14 is turned on or off, the current flowing through the first input terminal of the amplifying module 14 and the current flowing through the second input terminal of the amplifying module 14 remain unchanged. Since the current at the first input terminal of the variable gain amplifier is the sum of the currents at the first input terminals of each amplifier module 14, the current flowing through the first input terminal of the variable gain amplifier remains unchanged no matter when each amplifying module 14 in the variable gain amplifier is turned on or off, that is, the operating current of the variable gain amplifier remains unchanged in each gain state, the input port impedance remains unchanged, and the input port standing wave ratio remains unchanged.

[0041] Since the resistance value of the first load module 11 is the same as that of the second load module 12, and the transconductance of the first transconductance amplifier module 14 is the same as that of the second transconductance amplifier module 14, the signal Out1 output from the first output terminal of the variable gain amplifier and the signal Out2 output from the second output terminal of the variable gain amplifier are equal-proportion amplifications of the external RF positive input signal Vin+ and the external RF negative input signal Vin-, and the first output terminal and the second output terminal of the variable gain amplifier output distortion-free amplified external RF signals.

[0042] In some embodiments, reference Figure 4 The first transconductance amplification unit 141 may include a first transistor Neg_Q F1 The second transconductance amplification unit 142 includes a second transistor Neg_Q F2 .

[0043] The first transistor Neg_Q F1 , the base is connected to the input end of the first transconductance amplifying unit 141, the collector is connected to the output end of the first transconductance amplifying unit 141, and the emitter is grounded; the second transistor Neg_Q F2 The base is connected to the input end of the second transconductance amplifying unit 142, the collector is connected to the output end of the second transconductance amplifying unit 142, and the emitter is grounded.

[0044] In some embodiments, the first transistor Neg_Q F1 And the second transistor Neg_Q F2 Both can be NPN transistors.

[0045] In some embodiments, the first switch unit 143 may include: a first switch tube.

[0046] The first switch tube has a control end connected to the control end of the first switch unit 143 , a first end connected to the first end of the first switch unit 143 , and a second end connected to the second end of the first switch unit 143 .

[0047] In some embodiments, the first switch tube may include a third transistor having a base connected to the control end of the first switch unit 143 , an emitter connected to the first end of the first switch unit 143 , and a collector connected to the second end of the first switch unit 143 .

[0048] In some embodiments, the third transistor may be an NPN transistor.

[0049] refer to Figure 4 , the first switch tube Pos_Q A1 The base is connected to the control end of the first switch unit 143 , the emitter is connected to the first end of the first switch unit 143 , and the collector is connected to the second end of the first switch unit 143 .

[0050] In some embodiments, the circuit structures of the second switch unit 144, the third switch unit 145 and the fourth switch unit 146 may be the same as the circuit structure of the first switch unit 143. For example, the second switch unit 144, the third switch unit 145 and the fourth switch unit 146 may each include an NPN transistor.

[0051] refer to Figure 4 , the second switch tube Pos_Q c1 The base is connected to the control end of the second switch unit 144, the emitter is connected to the first end of the second switch unit 144, and the collector is connected to the second end of the second switch unit 144. The third switch tube Neg_QC1 has a base connected to the control end of the third switch unit 145, an emitter connected to the first end of the third switch unit 145, and a collector connected to the second end of the third switch unit 145. The fourth switch tube Neg_QA1 has a base connected to the control end of the fourth switch unit 146, an emitter connected to the first end of the fourth switch unit 146, and a collector connected to the second end of the fourth switch unit 146.

[0052] In some embodiments, the transconductances of the first transconductance amplifying units 141 corresponding to the respective amplifying modules 14 may be distributed in a geometric progression. For example, the transconductances of the first transconductance amplifying units 141 may be gm, 2gm, 4gm, ..., 2 N-1 gm, the transconductance of each second transconductance amplifying unit 142 is the same as that of the corresponding first transconductance amplifying unit 141, which are gm, 2gm, 4gm, ..., 2 N-1 The transconductance of each amplifier module 14 is distributed in a geometric progression so that the gain of the variable gain amplifier can be uniformly and continuously adjustable.

[0053] In some embodiments, the first control signals Ctr1 received by different amplifying modules 14 are the same or different, and the second control signals Ctr2 received by different amplifying modules 14 are the same or different. For example, the variable gain amplifier includes 5 amplifying modules 14, and the first control signals Ctr1 of each amplifying module 14 can be: 1, 0, 0, 0, 1, that is, the first control signal Ctr1 of the first amplifying module 14 is high, the first control signals Ctr1 of the second amplifying module 14, the third amplifying module 14 and the fourth amplifying module 14 are all low, and the first control signal Ctr1 of the fifth amplifying module 14 is high; or, the first control signals Ctr1 of each amplifying module 14 can be: 1, 1, 1, 1, and the control signals of each amplifying module 14 are all high. According to the state of the first control signal Ctr1 received by different amplifying modules 14, the variable gain amplifier can have 2 5 working status.

[0054] Figure 5 The input port standing wave simulation curves of the variable gain amplifier with 5 amplification modules 14 in 32 gain states are shown, and the 32 curves completely overlap. It can be seen that the variable gain amplifier using the structure in the above embodiment can maintain the same standing wave in different gain states.

[0055] An embodiment of the present invention further provides a vector modulation phase shifter, comprising the variable gain amplifier provided by the above embodiment of the present invention.

[0056] For example, refer to Figure 1 , the vector modulation phase shifter may include: a single-ended to differential circuit, a differential quadrature generation circuit, an I-channel variable gain amplifier and a Q-channel variable gain amplifier, an analog adder, a differential to single-ended circuit and a digital control circuit. The differential quadrature circuit generates I and Q signals, the variable gain amplifier circuit changes the amplitude of the I and Q signals, the digital control circuit is used to generate each first control signal Ctr1 and each second control signal Ctr2 to control the I-channel variable gain amplifier and the Q-channel variable gain amplifier, each analog adder realizes vector synthesis of the I and Q signals, and the I and Q signals of different amplitudes are synthesized into signals of different angles, thereby realizing the phase shifting function, reference Figure 6 In the embodiment of the present invention, the variable gain amplifier provided in the above embodiment is used to amplify the I and Q signals. The standing wave ratio of the input port of the variable gain amplifier remains unchanged, and the phase shifting precision of the vector modulation phase shifter is accurate.

[0057] An embodiment of the present invention provides a communication device, including the vector modulation phase shifter provided by the above embodiment of the present invention.

[0058] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. Such modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention, and should be included in the protection scope of the present invention.

Claims

1. A variable gain amplifier, characterized in that: include: A first load module, a second load module, a third load module and at least two amplification modules; The resistance value of the first load module is the same as the resistance value of the second load module; The amplification module includes: a first transconductance amplification unit, a second transconductance amplification unit, a first switch unit, a second switch unit, a third switch unit and a fourth switch unit; The first transconductance amplifier unit has an input end for receiving an external RF forward input signal, and an output end connected to the first end of the first switch unit and the first end of the second switch unit respectively; the first switch unit has a second end connected to the first load module and the first output end of the variable gain amplifier respectively, and a control end for receiving a first control signal; the second switch unit has a second end connected to the third load module, and a control end for receiving a second control signal; the first control signal is complementary to the second control signal; wherein, when the first control signal is an on signal, the second control signal is an off signal; when the first control signal is an off signal, the second control signal is an on signal; the on signal is used to control the corresponding switch unit to be turned on, and the off signal is used to control the corresponding switch unit to be turned off; The second transconductance amplifier unit has an input end for receiving an external RF negative input signal, and an output end connected to the first end of the third switch unit and the first end of the fourth switch unit respectively; the third switch unit has a second end connected to the second load module and the second output end of the variable gain amplifier respectively, and a control end for receiving the first control signal; the fourth switch unit has a second end connected to the third load module, and a control end for receiving the second control signal; The transconductance of the first transconductance amplifying unit and the transconductance of the second transconductance amplifying unit are the same; The first control signals received by different amplification modules are the same or different, and the second control signals received by different amplification modules are the same or different.

2. The variable gain amplifier according to claim 1, wherein: The first transconductance amplification unit includes a first triode, and the second transconductance amplification unit includes a second triode; The first transistor has a base connected to the input end of the first transconductance amplifying unit, a collector connected to the output end of the first transconductance amplifying unit, and an emitter connected to ground; the second transistor has a base connected to the input end of the second transconductance amplifying unit, a collector connected to the output end of the second transconductance amplifying unit, and an emitter connected to ground.

3. The variable gain amplifier according to claim 2, wherein: The first transistor and the second transistor are both NPN transistors.

4. The variable gain amplifier according to claim 1, wherein: The first switch unit includes: a first switch tube; The first switch tube has a control end connected to the control end of the first switch unit, a first end connected to the first end of the first switch unit, and a second end connected to the second end of the first switch unit.

5. The variable gain amplifier according to claim 4, wherein: The first switch tube includes a third triode; The third transistor has a base connected to the control end of the first switch unit, an emitter connected to the first end of the first switch unit, and a collector connected to the second end of the first switch unit.

6. The variable gain amplifier according to claim 1, wherein: The circuit structures of the second switch unit, the third switch unit and the fourth switch unit are the same as the circuit structure of the first switch unit.

7. The variable gain amplifier according to claim 1, wherein: The transconductances of the first transconductance amplifying units corresponding to the respective amplifying modules are distributed in a geometric progression.

8. A vector modulation phase shifter, characterized in that: Comprising a variable gain amplifier as claimed in any one of claims 1 to 7.

9. A communication device, characterized in that: Comprising the vector modulation phase shifter as claimed in claim 8.

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