Variable gain amplifier circuit, Internet of Things chip and electronic equipment

Abstract

The present application provides a variable gain amplifier circuit, an Internet of Things chip and an electronic device, wherein the variable gain amplifier circuit comprises: an exponential control circuit, a first switch group, a second switch group, an input circuit, an output circuit and a power supply voltage. The technical solution provided by the present application has the advantage of dynamically adjusting the gain.

Description

Technical Field

[0001] The present invention relates to the fields of communications and the Internet of Things, and in particular to a variable gain amplifier circuit, an Internet of Things chip and electronic equipment. Background Art

[0002] In recent years, with the rapid development of RF integrated circuit technology, many wireless communication products are used in daily life. Low cost and portability requirements have put forward higher standards for the design of these wireless communication products. With the development of the Internet of Things, more and more IoT devices need to be connected to the Internet, so the demand for IoT chips is increasing.

[0003] The IoT chip needs to adjust the gain of the RF signal, so a gain amplifier needs to be set. The existing gain amplifier cannot dynamically adjust the gain of the gain amplifier. Summary of the invention

[0004] The embodiments of the present invention provide a variable gain amplifier circuit, an Internet of Things chip, and an electronic device, which can realize dynamic gain adjustment of gain amplification.

[0005] In a first aspect, an embodiment of the present invention provides a variable gain amplifier circuit, the variable gain amplifier circuit comprising: an exponential control circuit, a first switch group, a second switch group, an input circuit, an output circuit and a power supply voltage; wherein,

[0006] The input end of the index control circuit is connected to the control voltage, the output end of the index control circuit is connected to the control port of the first switch group, the control port of the second switch group is connected to the reference voltage VeRf, the output ports of the first switch group and the second switch group are connected to the input end of the output circuit, the two input ports of the first switch group are respectively connected to the first output end and the second output end of the input circuit, and the two input ports of the second switch group are respectively connected to the first output end and the second output end of the input circuit;

[0007] The input circuit further comprises two input ports, and the two input ports are respectively connected to two input signals of the radio frequency signal;

[0008] The output circuit comprises two output ports and an input port, the two output ports respectively output the amplified radio frequency signals, and the input port is connected to the power supply voltage VDD;

[0009] The exponential control circuit is used to dynamically change the output terminal voltage according to the voltage change of the control voltage, and the output terminal voltage is used to control the closing or closing of the first switch group and the second switch group to dynamically adjust the gain of the variable gain amplifier circuit.

[0010] In a second aspect, an Internet of Things chip is provided, wherein the Internet of Things chip includes the variable gain amplifier circuit provided in the first aspect.

[0011] According to a third aspect, an electronic device is provided, wherein the electronic device comprises the Internet of Things chip provided according to the second aspect.

[0012] The implementation of the embodiments of the present invention has the following beneficial effects:

[0013] The technical solution provided by the present application comprises a variable gain amplifier circuit in which the input end of the exponential control circuit is connected to the control voltage Vcont, the output end of the exponential control circuit is connected to the control port of the first switch group 102, the control port of the second switch group is connected to the reference voltage VeRf, the sources of the first switch group and the second switch group are connected to the input end of the output circuit, the drain of the first switch group is connected to the first output end of the input circuit, and the drain of the second switch group is connected to the second output end of the input circuit; the input circuit comprises two input ports, the two input ports are respectively connected to two input signals of the radio frequency signal; the output circuit comprises two output ports, the two output ports respectively output the amplified radio frequency signal; the exponential control circuit is used to dynamically change the output voltage Vc according to the voltage change of the control voltage Vcont, and the output voltage Vc is used to control the closing or closing of the first switch group and the second switch group to dynamically adjust the gain of the variable gain amplifier circuit. This solution can achieve the closing or shutting down of the switch group by simply adjusting the voltage of Vcont. For example, when the Vc voltage is much smaller than the reference voltage Vref, only the second switch group works and the first switch group is disconnected. At this time, the gain of the variable gain amplifier circuit reaches the maximum value; when the Vc voltage is much larger than the reference voltage Vref, only the first switch group works and the second switch group is turned off. At this time, the gain of the variable gain amplifier circuit will be minimum. In addition, since the source electrodes of the first switch group and the second switch group are connected, the output impedance is increased and the Miller effect is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description are some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying any creative work.

[0015] Figure 1 It is a structural block diagram of a variable gain amplifier circuit provided by the present application;

[0016] Figure 2 A schematic diagram of the structure of an output circuit provided in this application;

[0017] Figure 3A schematic diagram of the structure of the first switch group provided in this application;

[0018] Figure 4 A schematic diagram of the structure of the second switch group provided in this application;

[0019] Figure 5 A schematic diagram of the structure of the output circuit provided by this application;

[0020] Figure 6 A schematic diagram of the structure of the index control circuit provided in this application;

[0021] Figure 7 A schematic diagram of the structure of a variable gain amplifier circuit provided in Example 1 of the present application. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] The terms "first", "second", "third" and "fourth" etc. in the specification and claims of the present invention and the drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but may optionally include steps or units that are not listed, or may optionally include other steps or units that are inherent to these processes, methods, products or devices.

[0024] Reference to "embodiments" herein means that a particular feature, result, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0025] The concepts involved in this application are introduced below.

[0026] VGA (Variable Gain Amplifier) ​​has the property of adjustable gain, which can change the gain level of the amplifier as needed. This flexibility makes variable gain amplifiers very useful in many applications. Here are some common uses of variable gain amplifiers: Communication Systems: Variable gain amplifiers are widely used in wireless communication systems. At the receiving end, it can automatically adjust the gain according to the strength of the received signal to adapt to different signal strengths and distances. At the transmitting end, it can adjust the gain of the amplifier to match different transmission distances and signal requirements.

[0027] The polyphase filter (PPF) at the subsequent stage suppresses the image frequency interference, and at the same time, the I and Q orthogonal signals are combined at the output end of the polyphase filter network to generate a differential signal.

[0028] The automatic gain control loop (AGC) adjusts the gain of the differential IF signal, and then the analog RF signal is quantized into a digital IF through the analog-to-digital converter (ADC).

[0029] In the transmitting part of the IoT equipment chip, the modulated digital intermediate frequency signal processed by the baseband circuit is converted into an analog intermediate frequency through the DAC. After filtering out-of-band harmonics, the up-converter moves the intermediate frequency signal to the radio frequency. The radio frequency signal is then amplified and gain adjusted through the variable gain amplifier (VGA) and power amplifier (PPA) and output to the antenna port.

[0030] Miller effect is a phenomenon in electronics where the distributed capacitance or parasitic capacitance between the input and output of an inverting amplifier circuit is magnified by the amplifier, and its equivalent capacitance value to the input end is expanded by 1+K times, where K is the voltage magnification factor of the amplifier circuit. Although the Miller effect generally refers to the amplification of capacitance, the impedance between any input and other high-amplification nodes can also change the input impedance of the amplifier through the Miller effect.

[0031] See also Figure 1 , Figure 1 is a structural block diagram of a variable gain amplifier circuit, wherein the variable gain amplifier circuit may specifically include: an index control circuit 101, a first switch group 102, a second switch group 103, an input circuit 104, an output circuit 105 and a power supply voltage VDD, wherein:

[0032] The input end of the index control circuit 101 is connected to the control voltage Vcont, the output end of the index control circuit 101 is connected to the control port of the first switch group 102, the control port of the second switch group 103 is connected to the reference voltage VeRf, the output ports of the first switch group 102 and the second switch group 103 are connected to the input end of the output circuit 105, the two input ports of the first switch group 102 are respectively connected to the first output end and the second output end of the input circuit 104, and the two input ports of the second switch group 103 are respectively connected to the first output end and the second output end of the input circuit 104;

[0033] The input circuit 104 further includes two input ports, and the two input ports are respectively connected to two input signals of the radio frequency signal;

[0034] The output circuit 105 includes two output ports and one input port, the two output ports respectively output the amplified RF signals, and the input port is connected to the power supply voltage VDD;

[0035] The exponential control circuit 101 is used to dynamically change the output voltage Vc according to the voltage change of the control voltage Vcont, and the output voltage Vc is used to control the closing or closing of the first switch group 102 and the second switch group 103 to dynamically adjust the gain of the variable gain amplifier circuit.

[0036] The technical solution provided by the present application comprises a variable gain amplifier circuit in which the input end of the exponential control circuit is connected to the control voltage Vcont, the output end of the exponential control circuit is connected to the control port of the first switch group 102, the control port of the second switch group is connected to the reference voltage VeRf, the sources of the first switch group and the second switch group are connected to the input end of the output circuit, the drain of the first switch group is connected to the first output end of the input circuit, and the drain of the second switch group is connected to the second output end of the input circuit; the input circuit comprises two input ports, the two input ports are respectively connected to two input signals of the radio frequency signal; the output circuit comprises two output ports, the two output ports respectively output the amplified radio frequency signal; the exponential control circuit is used to dynamically change the output voltage Vc according to the voltage change of the control voltage Vcont, and the output voltage Vc is used to control the closing or closing of the first switch group and the second switch group to dynamically adjust the gain of the variable gain amplifier circuit. This solution can achieve the closing or shutting down of the switch group by simply adjusting the voltage of Vcont. For example, when the Vc voltage is much smaller than the reference voltage Vref, only the second switch group works and the first switch group is disconnected. At this time, the gain of the variable gain amplifier circuit reaches the maximum value; when the Vc voltage is much larger than the reference voltage Vref, only the first switch group works and the second switch group is turned off. At this time, the gain of the variable gain amplifier circuit will be minimum. In addition, since the source electrodes of the first switch group and the second switch group are connected, the output impedance is increased and the Miller effect is reduced.

[0037] For example, see Figure 2 , Figure 2 A schematic diagram of the structure of an output circuit provided in this application, such as Figure 2 As shown, the output circuit includes: a first MOS transistor M1 and a fourth MOS transistor M4; wherein,

[0038] The gate of the first MOS tube M1 is an input port RF of the input circuit. in+ The source of the first MOS tube M1 is the first output terminal RF of the input circuit. in- , the drain of the first MOS tube M1 is grounded;

[0039] The gate of the fourth MOS transistor M4 is another input port of the input circuit, the source of the fourth MOS transistor M4 is the second output end of the input circuit, and the drain of the fourth MOS transistor M4 is grounded.

[0040] For example, see Figure 3 , Figure 3 This is a schematic diagram of the structure of the first switch group 102 provided in the present application, such as Figure 3 As shown, the first switch group 102 may include: a second MOS transistor M2 and a sixth MOS transistor M6; wherein,

[0041] The gate of the second MOS transistor M2 and the gate of the sixth MOS transistor M6 are both control ports of the first switch group 102, and the source of the second MOS transistor M2 and the source of the sixth MOS transistor M6 are both output ports of the first switch group 102;

[0042] The drain of the second MOS transistor M2 is an input port of the first switch group, and the drain of the sixth MOS transistor M6 is another input port of the first switch group.

[0043] For example, see Figure 4 , Figure 4 This is a schematic diagram of the structure of the second switch group 103 provided in the present application, as shown in Figure 4 As shown, the second switch group 103 may include: a third MOS transistor M3 and a fifth MOS transistor M5; wherein,

[0044] The gate of the third MOS transistor M3 and the gate of the fifth MOS transistor M5 are both control ports of the second switch group 103, and the source of the third MOS transistor M3 and the source of the fifth MOS transistor M5 are both output ports of the second switch group 103;

[0045] The drain of the third MOS transistor M3 is an input port of the second switch group, and the drain of the sixth MOS transistor M6 is another input port of the second switch group.

[0046] For example, see Figure 5 , Figure 5 This is a schematic diagram of the structure of the output circuit 105 provided in the present application, wherein the output circuit may specifically include: two output resistors; wherein,

[0047] One end of the first output resistor Rout1 is the input port of the output circuit 105 , and the other end is an output port of the output circuit. One end of the second output resistor Rout2 is the input port of the output circuit 105 , and the other end is another output port of the output circuit.

[0048] Optionally, the output circuit 105 may further include: two output capacitors, wherein:

[0049] One end of the first output capacitor C1 is connected to the other end of the first output resistor Rout1 , and the other end of the first output capacitor C1 is an output port RF of the output circuit 105 out+ One end of the second output capacitor C2 is connected to the other end of the second output resistor Rout2, and the other end of the second output capacitor C2 is another output port RF of the output circuit 105. out- That is, the two output capacitors are connected between the two output resistors and the two output ports of the output circuit. Adding two output capacitors can improve the stability of the output signal.

[0050] For example, see Figure 6 , Figure 6 This is a schematic diagram of the structure of the index control circuit 101 provided in the present application, wherein the index control circuit may include: a resistor and a seventh MOS tube M7, wherein:

[0051] One end of the first resistor R1 is the input end Vcont of the index control circuit 101, the other end of the first resistor R1 is connected to the gate of the seventh MOS transistor M7, one end of the second resistor R2 is connected to the gate of the seventh MOS transistor M7, and the other end of the second resistor R2 is grounded;

[0052] The drain of the seventh MOS transistor M7 is connected to the power supply voltage VDD, the source of the seventh MOS transistor M7 is the output terminal Vc of the index control circuit 101, the source of the seventh MOS transistor M7 is also connected to one end of the third resistor R3, and the other end of the third resistor R3 is grounded.

[0053] Embodiment 1

[0054] See also Figure 7 , Figure 7 A schematic diagram of a variable gain amplifier circuit provided in the first embodiment of the present application is shown in FIG. Figure 7 As shown, the variable gain amplifier circuit may specifically include: a MOS tube and a resistor, wherein:

[0055] One end of the first resistor R1 is connected to the control voltage Vcont, and the other end of the first resistor R1 is connected to the gate of the seventh MOS tube M7; one end of the second resistor R2 is connected to the gate of the seventh MOS tube M7, and the other end is grounded; the drain of the seventh MOS tube M7 is connected to the power supply voltage VDD, the source of the seventh MOS tube M7 is connected to the gate of the second MOS tube M2 and the gate of the sixth MOS tube M6, one end of the third resistor R3 is connected to the source of the seventh MOS tube M7, and the other end of the third resistor R3 is grounded.

[0056] The source of the second MOS tube M2 is connected to the source of the sixth MOS tube M6, the drain of the second MOS tube M2 is connected to the source of the first MOS tube M1, the drain of the first MOS tube M1 is grounded, and the gate of the first MOS tube M1 is connected to the first RF input signal RF in+ The drain of the sixth MOS tube M6 is connected to the source of the fourth MOS tube M4, the drain of the fourth MOS tube M4 is grounded, and the gate of the fourth MOS tube M4 is connected to the second RF input signal RF in- ;

[0057] The source of the first MOS tube M1 is also connected to the drain of the third MOS tube M3, the gate of the third MOS tube M3 is connected to the reference voltage Vref, and the source of the third MOS tube M3 is connected to the first output port RF out+ ;

[0058] The source of the fourth MOS tube M4 is also connected to the drain of the fifth MOS tube M5, the gate of the fifth MOS tube M5 is connected to the reference voltage Vref, and the source of the fifth MOS tube M5 is connected to the second output port RF out- ;

[0059] One end of the first output resistor Rout1 is connected to the source of the second MOS transistor M2 and the source of the sixth MOS transistor M6, and the other end of the first output resistor Rout1 is connected to the first output port RF out+ ;

[0060] One end of the second output resistor Rout2 is connected to the source of the second MOS transistor M2 and the source of the sixth MOS transistor M6, and the other end of the second output resistor Rout2 is connected to the second output port RF out- .

[0061] In the variable gain amplifier of the embodiment of the present application, M2, M3, M5 and M6 form a signal addition structure. By changing the value of the control voltage Vcont, the voltage Vc will also change accordingly, thereby adjusting the difference between the reference voltage Vref and Vc. The change in voltage Vc causes the current flowing through M2, M3, M5 and M6 to change, thereby adjusting the gain.

[0062] The specific working principle is as follows: when the Vc voltage is much smaller than the reference voltage Vref, only M3 and M5 work, and the gain reaches the maximum value at this time; when the Vc voltage is much larger than the reference voltage Vref, only M2 and M6 work, and the gain will be minimum at this time; in addition, the common source and common gate structure formed by M1 and M3 as well as M4 and M5 increases the output impedance and reduces the Miller effect.

[0063] The present application also provides an Internet of Things chip, the Internet of Things chip includes: Figure 1 or Figure 7 The variable gain amplifier circuit shown.

[0064] For example, the variable gain amplifier circuit can be arranged in the transmitting part of the Internet of Things chip.

[0065] An embodiment of the present application also provides an electronic device, which includes the above-mentioned Internet of Things chip.

[0066] It should be noted that, for the above-mentioned method embodiments, for the sake of simplicity, they are all described as a series of action combinations, but those skilled in the art should know that the present invention is not limited by the described order of actions, because according to the present invention, certain steps can be received in other orders or performed simultaneously. Secondly, those skilled in the art should also know that the embodiments described in the specification are all optional embodiments, and the actions and modules involved are not necessarily required by the present invention.

[0067] In the above embodiments, the description of each embodiment has its own emphasis. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0068] In the several embodiments provided in the present application, it should be understood that the disclosed device can be implemented in other ways. For example, the device embodiments described above are only schematic, such as the division of the units, which is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, and the indirect coupling or communication connection of the device or unit can be electrical or other forms.

[0069] A person skilled in the art can understand that all or part of the steps in the various methods of the above embodiments can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable memory, and the memory can include: a flash drive, a read-only memory (English: Read-Only Memory, abbreviated as: ROM), a random access memory (English: Random Access Memory, abbreviated as: RAM), a magnetic disk or an optical disk, etc.

[0070] The embodiments of the present invention are described in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A variable gain amplifier circuit, characterized in that: The variable gain amplifier circuit comprises: an exponential control circuit, a first switch group, a second switch group, an input circuit, an output circuit and a power supply voltage; wherein, The input end of the index control circuit is connected to the control voltage, the output end of the index control circuit is connected to the control port of the first switch group, the control port of the second switch group is connected to the reference voltage VeRf, the output ports of the first switch group and the second switch group are connected to the input end of the output circuit, the two input ports of the first switch group are respectively connected to the first output end and the second output end of the input circuit, and the two input ports of the second switch group are respectively connected to the first output end and the second output end of the input circuit; The input circuit further comprises two input ports, and the two input ports are respectively connected to two input signals of the radio frequency signal; The output circuit comprises two output ports and an input port, the two output ports respectively output the amplified radio frequency signals, and the input port is connected to the power supply voltage; The exponential control circuit is used to dynamically change the output terminal voltage according to the voltage change of the control voltage, and the output terminal voltage is used to control the closing or closing of the first switch group and the second switch group to dynamically adjust the gain of the variable gain amplifier circuit; The first switch group includes: a second MOS transistor and a sixth MOS transistor; wherein, The gate of the second MOS tube and the gate of the sixth MOS tube are both control ports of the first switch group, and the source of the second MOS tube and the source of the sixth MOS tube are both output ports of the first switch group; The drain of the second MOS transistor is an input port of the first switch group, and the drain of the sixth MOS transistor is another input port of the first switch group; The second switch group includes: a third MOS tube and a fifth MOS tube; wherein, The gate of the third MOS tube and the gate of the fifth MOS tube are both control ports of the second switch group, and the source of the third MOS tube and the source of the fifth MOS tube are both output ports of the second switch group; The drain of the third MOS transistor is an input port of the second switch group, and the drain of the fifth MOS transistor is another input port of the second switch group; The index control circuit includes: a resistor and a seventh MOS tube, wherein: One end of the first resistor is the input end of the index control circuit, the other end of the first resistor is connected to the gate of the seventh MOS transistor, one end of the second resistor is connected to the gate of the seventh MOS transistor, and the other end of the second resistor is grounded; The drain of the seventh MOS tube is connected to the power supply voltage, the source of the seventh MOS tube is the output end of the index control circuit, the source of the seventh MOS tube is also connected to one end of the third resistor, and the other end of the third resistor is grounded.

2. The variable gain amplifier circuit according to claim 1, characterized in that: The input circuit includes: a first MOS tube and a fourth MOS tube; wherein, The gate of the first MOS transistor is an input port of the input circuit, the source of the first MOS transistor is a first output terminal of the input circuit, and the drain of the first MOS transistor is grounded; The gate of the fourth MOS transistor is another input port of the input circuit, the source of the fourth MOS transistor is the second output end of the input circuit, and the drain of the fourth MOS transistor is grounded.

3. The variable gain amplifier circuit according to claim 1, characterized in that: The output circuit includes: two output resistors; wherein, One end of the first output resistor is an input end of the output circuit, and the other end is an output port of the output circuit; One end of the second output resistor is the input end of the output circuit, and the other end is another output port of the output circuit.

4. The variable gain amplifier circuit according to claim 3, characterized in that: The output circuit also includes: two output capacitors, wherein: One end of a first output capacitor is connected to the other end of the first output resistor, and the other end of the first output capacitor is an output port of the output circuit; One end of the second output capacitor is connected to the other end of the second output resistor, and the other end of the second output capacitor is another output port of the output circuit.

5. An Internet of Things chip, characterized in that: The Internet of Things chip includes the variable gain amplifier circuit as described in any one of claims 1 to 4.

6. The Internet of Things chip according to claim 5, characterized in that: The variable gain amplifier circuit is arranged in the transmitting part of the Internet of Things chip.

7. An electronic device, characterized in that: The electronic device comprises the Internet of Things chip as described in claim 5 or 6.

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