Amplification circuit of current-mode amplifier, PCB (Printed Circuit Board) and low-frequency amplifier

Abstract

The invention discloses an amplifying circuit of a current type amplifier, a PCB (Printed Circuit Board) and a low-frequency amplifier. The amplifying circuit comprises a first primary amplifying part, a second primary amplifying part, a first secondary amplifying part, a second secondary amplifying part and a third-stage amplifying part, the transmitting end of the first primary amplification part and the transmitting end of the second primary amplification part are respectively connected with the input end of the first secondary amplification part and the input end of the second secondary amplification part; the current collection end of the first primary amplification part and the current collection end of the second primary amplification part are respectively connected with the transmitting end of the second secondary amplification part and the transmitting end of the first secondary amplification part; the transmitting end of the first secondary amplification part and the transmitting end of the second secondary amplification part are respectively connected with the input end of the third-stage amplification part; according to the amplifying circuit disclosed by the invention, a multi-stage amplifying structure is adopted, so that not only is remarkable current gain realized, but also the definition and accuracy of signals in a transmission process are ensured; and a feedback circuit is established, so that the stability of the whole circuit and the resistance to external interference can be improved.

Description

Technical Field

[0001] The present invention relates to the technical field of amplifiers, and in particular to an amplifier circuit, a PCB board and a low-frequency amplifier of a current-type amplifier. Background Art

[0002] The current push-pull current amplifier uses two complementary transistors to input a weak current signal through the base, and after amplification, output a large current signal through the emitter; as a technology, linear amplifiers are widely used in fields such as audio and video signal processing and measurement; looking back at the evolution of amplifier design over the past hundred years, with the continuous advancement of technology, the distortion of linear amplifiers during operation has been significantly reduced.

[0003] However, the distortion problem faced by the amplifier during operation still needs to be further optimized. The limiting factor mainly comes from the circuit design of the current amplification part of the amplifier's back end. In traditional current amplifiers, the distortion mainly comes from the Cob change caused by the voltage difference between the collector and base of the internal transistor. The greater the voltage fluctuation, the more serious the distortion. In the process of increasing the amplifier power, as the load current increases, the current distortion also increases. Therefore, the greater the power demand and the higher the load current, the greater the distortion.

[0004] Traditionally, there are two main methods for reducing distortion:

[0005] 1. Use transistors with higher linearity and better performance to build the circuit to reduce distortion; this method increases the sensitivity of the transistor itself to the collector-emitter voltage difference, which is one of the basic parameters of the transistor, thereby reducing distortion during the selection process of the transistor itself.

[0006] 2. Share the load current of a single transistor by increasing the number of transistors, that is, reduce the load current of each transistor to reduce current distortion; this method reduces distortion from the perspective of circuit design.

[0007] Although the above two methods can reduce distortion to a certain extent, they will increase the production cost of the circuit, and the effect of reducing distortion is relatively limited.

[0008] It can be seen that the existing technology still needs to be improved and enhanced. Summary of the invention

[0009] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide an amplifying circuit of a current-type amplifier, which adopts a multi-stage amplification structure to achieve significant current gain and ensure the clarity and accuracy of the signal during transmission; a feedback circuit is built to improve the stability of the entire circuit and its resistance to external interference.

[0010] In order to achieve the above object, the present invention adopts the following technical solutions:

[0011] An amplifier circuit of a current-type amplifier comprises a first first-stage amplifier, a second first-stage amplifier, a first second-stage amplifier, a second second-stage amplifier and a third-stage amplifier; the input end of the first first-stage amplifier and the input end of the second first-stage amplifier are respectively used to receive input signals, the transmitting end of the first first-stage amplifier is connected to the input end of the first second-stage amplifier, the transmitting end of the second first-stage amplifier is connected to the input end of the second second-stage amplifier, the collector end of the first first-stage amplifier is connected to the transmitting end of the second second-stage amplifier, and the collector end of the second first-stage amplifier is connected to the transmitting end of the first second-stage amplifier; the transmitting end of the first second-stage amplifier and the transmitting end of the second second-stage amplifier are connected to each other, and both are respectively connected to the input end of the third-stage amplifier, and the output end of the third-stage amplifier is used to output an amplified signal.

[0012] In the amplification circuit of the current-type amplifier, the three-stage amplification part includes a first three-stage amplification group and a second three-stage amplification group, the emission end of the first two-stage amplification part is connected to the input end of the first three-stage amplification group, the emission end of the second two-stage amplification part is connected to the input end of the second three-stage amplification group, and the output end of the first three-stage amplification group and the output end of the second three-stage amplification group are respectively used to output amplified signals.

[0013] In the amplification circuit of the current-type amplifier, the first-stage amplifying part includes a first transistor Q1, a first resistor R1 and a first diode D1, the base of the first transistor Q1 is used to receive an input signal, the emitter of the first transistor Q1 is connected to the cathode of the first diode D1 through the first resistor R1, the anode of the first diode D1 is connected to the input end of the first-stage amplifying part, and the collector of the first transistor Q1 is connected to the emitter of the second-stage amplifying part.

[0014] In the amplification circuit of the current-type amplifier, the second first-stage amplifying part includes a second triode Q2, a second resistor R2 and a second diode D2, the base of the second triode Q2 is used to receive an input signal, the emitter of the second triode Q2 is connected to the positive electrode of the second diode D2 through the second resistor R2, the cathode of the second diode D2 is connected to the input end of the second second-stage amplifying part, and the collector of the second triode Q2 is connected to the emitter end of the first second-stage amplifying part.

[0015] In the amplification circuit of the current-type amplifier, the first two-stage amplification part includes a first current source and a third transistor Q3, the negative end of the first current source is connected to the base of the third transistor Q3, the emitter of the third transistor Q3 is respectively connected to the collector of the second transistor Q2, the emitter end of the second two-stage amplification part and the input end of the first three-stage amplification group, and the collector of the third transistor Q3 and the positive end of the first current source are used to connect to an external power supply device.

[0016] In the amplification circuit of the current-type amplifier, the second secondary amplification part includes a second current source and a fourth transistor Q4, the positive end of the second current source is connected to the base of the fourth transistor Q4; the emitter of the fourth transistor Q4 is connected to the emitter of the third transistor Q3 through the third resistor R3, and is respectively connected to the collector of the first transistor Q1 and the input end of the second three-stage amplification group; the collector of the fourth transistor Q4 and the negative end of the second current source are used to connect to an external power supply device.

[0017] In the amplification circuit of the current-type amplifier, the first three-stage amplification group includes a fourth resistor R4, a fifth transistor Q5 and a sixth resistor R6, one end of the fourth resistor R4 is connected to the emitter of the third transistor Q3, the other end of the fourth resistor R4 is connected to the base of the fifth transistor Q5, the emitter of the fifth transistor Q5 is connected to one end of the sixth resistor R6, the collector of the fifth transistor Q5 is used to connect to an external power supply device, and the other end of the sixth resistor R6 is used to output an amplified signal; thermal coupling is achieved between the first transistor Q1, the first diode D1, the third transistor Q3 and the fifth transistor Q5.

[0018] In the amplification circuit of the current-type amplifier, the second three-stage amplification group includes a fifth resistor R5, a sixth triode Q6 and a seventh resistor R7, one end of the fifth resistor R5 is connected to the emitter of the third triode Q3, the other end of the fifth resistor R5 is connected to the base of the sixth triode Q6, the emitter of the sixth triode Q6 is connected to one end of the seventh resistor R7, the collector of the sixth triode Q6 is used to connect to an external power supply device, and the other end of the seventh resistor R7 is used to output the amplified signal; thermal coupling is achieved between the second triode Q2, the second diode D2, the fourth triode Q4 and the sixth triode Q6.

[0019] The present invention also provides a PCB board accordingly, on which an amplifying circuit of any of the above-mentioned current-type amplifiers is printed.

[0020] The present invention also provides a low-frequency amplifier accordingly, wherein the low-frequency amplifier uses an amplifying circuit of any of the above-mentioned current-type amplifiers to realize operation control.

[0021] Beneficial effects:

[0022] The present invention provides an amplifying circuit of a current-type amplifier, which adopts a multi-stage amplifying structure, and can not only achieve significant current gain, but also ensure the clarity and accuracy of the signal during transmission through step-by-step amplification; in particular, the transmitting end of the first primary amplifying part is connected to the input end of the first secondary amplifying part, and the transmitting end of the second primary amplifying part is connected to the input end of the second secondary amplifying part. This design not only ensures continuous amplification of the signal, but also enhances the feedback mechanism inside the circuit through this cross-connection method, thereby improving the stability of the entire circuit and the resistance to external interference; in addition, the transmitting ends of the first secondary amplifying part and the second secondary amplifying part are connected to each other, and these two ports are respectively connected to the input end of the third-stage amplifying part. This connection method helps to balance the amplification effects of the two channels, ensures that the signal still maintains high quality after multi-stage amplification, and reduces possible signal distortion. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A circuit block diagram of the amplifier circuit provided by the present invention;

[0024] Figure 2 This is a circuit schematic diagram of the amplifier circuit provided by the present invention.

[0025] Explanation of the main component symbols: 1-first primary amplifier, 2-second primary amplifier, 3-first secondary amplifier, 4-second secondary amplifier, 5-third stage amplifier, 51-first third stage amplifier group, 52-second third stage amplifier group. DETAILED DESCRIPTION

[0026] The present invention provides an amplifier circuit, a PCB board and a low-frequency amplifier of a current-mode amplifier. In order to make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail below with reference to the accompanying drawings and examples.

[0027] In the description of the present invention, it should be understood that the terms "installation", "connection" and the like should be understood in a broad sense, and a person skilled in the art can understand the specific meanings of the above terms in the present invention according to specific circumstances.

[0028] The amplifier circuit disclosed in this application is suitable for low-frequency amplifiers. It should be noted that low-frequency amplifiers and high-frequency amplifiers have significant differences in design and application. These differences are not only reflected in their respective operating frequency ranges, but also involve bandwidth, linearity, power level and output impedance.

[0029] First, low-frequency amplifiers mainly serve the audio field. The signal frequency range they process is usually between 20Hz and 200kHz, which covers the limit of human hearing. Such amplifiers are widely used in home audio systems, professional recording equipment, and various audio processing equipment; high-frequency amplifiers are active in the field of radio frequency communications. The signal frequency range they process ranges from tens of kHz to several GHz. The signal changes very quickly within this range, so high-frequency amplifiers must have the ability to respond quickly to ensure signal integrity and transmission efficiency. They play a vital role in wireless communications, satellite communications, radar systems, and various microwave communication equipment;

[0030] Secondly, the bandwidth of low-frequency amplifiers is relatively wide, because low-frequency signals change slowly, and the amplifier can maintain good amplification performance over a wide frequency range. This wide-band characteristic enables low-frequency amplifiers to process various complex audio signals, such as music or speech, without distortion. In contrast, the bandwidth of high-frequency amplifiers is relatively narrow, because high-frequency signals change very quickly, requiring more precise frequency control to ensure the quality of signal transmission. In high-frequency applications, bandwidth limitations often mean that the amplifier can only provide optimal performance within a specific frequency band, which requires designers to carefully select and adjust the parameters of the amplifier;

[0031] Furthermore, in low-frequency amplifiers, since the signal changes slowly, it is relatively easy to maintain high linearity, so the distortion is small and a purer audio output can be provided; in high-frequency amplifiers, since the signal changes quickly, nonlinear distortion is more likely to occur, so designers must take various measures, such as using high-linearity transistors, optimizing circuit design, etc., to reduce distortion and ensure accurate signal transmission;

[0032] Finally, since high-frequency signals have less energy, high-frequency amplifiers often need to go through multiple stages of amplification to achieve sufficient power output. Therefore, high-frequency amplifiers usually have more power levels than low-frequency amplifiers; low-frequency amplifiers can reach the required power level through one or two stages of amplification. In addition, the output impedance of low-frequency amplifiers is usually low, which allows them to directly drive loads such as speakers, while high-frequency amplifiers have a higher output impedance, which requires a matching network to ensure that the signal can be efficiently transmitted to a variety of different loads.

[0033] In summary, there are obvious differences between low-frequency amplifiers and high-frequency amplifiers in terms of operating frequency range, bandwidth, linearity, power level and output impedance. These differences make them suitable for different application scenarios and needs, meeting various needs from daily audio playback to complex high-frequency communications.

[0034] See also Figure 1 and Figure 2 The present invention provides an amplifier circuit of a current-type amplifier, comprising a first first-stage amplifier 1, a second first-stage amplifier 2, a first second-stage amplifier 3, a second second-stage amplifier 4 and a third-stage amplifier 5; the input end of the first first-stage amplifier 1 and the input end of the second first-stage amplifier 2 are respectively used to receive input signals, the transmitting end of the first first-stage amplifier 1 is connected to the input end of the first second-stage amplifier 3, the transmitting end of the second first-stage amplifier 2 is connected to the input end of the second second-stage amplifier 4, the collector end of the first first-stage amplifier 1 is connected to the transmitting end of the second second-stage amplifier 4, and the collector end of the second first-stage amplifier 2 is connected to the transmitting end of the first second-stage amplifier 3; the transmitting end of the first second-stage amplifier 3 and the transmitting end of the second second-stage amplifier 4 are connected to each other, and both are respectively connected to the input end of the third-stage amplifier 5, and the output end of the third-stage amplifier 5 is used to output an amplified signal.

[0035] The present invention provides an amplification circuit of a current-type amplifier, which adopts a multi-stage amplification structure, which can not only achieve significant current gain, but also ensure the clarity and accuracy of the signal during transmission through step-by-step amplification; in particular, the transmitter end of the first-stage amplifier is connected to the input end of the second-stage amplifier, and the transmitter end of the second-stage amplifier is connected to the input end of the third-stage amplifier. This cascade design not only ensures continuous amplification of the signal, but also enhances the feedback mechanism inside the circuit through cross-connection, thereby improving the stability of the entire circuit and the resistance to external interference. In addition, the design can also realize a clamping function, effectively reducing the output capacitance (Cob) change of the transistor caused by the collector-emitter voltage (Vce) change, thereby reducing the occurrence of distortion; in addition, the transmitter ends of the first and second-stage amplifiers 3 and the second and second-stage amplifiers 4 are interconnected, and these two ports are respectively connected to the input end of the third-stage amplifier 5. This connection method helps to balance the amplification effects of the two channels, ensures that the signal still maintains high quality after multi-stage amplification, and reduces possible signal distortion.

[0036] For further information, see Figure 1 and Figure 2 The three-stage amplifier 5 includes a first three-stage amplifier group 51 and a second three-stage amplifier group 52. The transmitting end of the first two-stage amplifier 3 is connected to the input end of the first three-stage amplifier group 51, and the transmitting end of the second two-stage amplifier 4 is connected to the input end of the second three-stage amplifier group 52. The output end of the first three-stage amplifier group 51 and the output end of the second three-stage amplifier group 52 are respectively used to output amplified signals.

[0037] For further information, see Figure 2The first-stage amplifier 1 includes a first transistor Q1, a first resistor R1 and a first diode D1. The base of the first transistor Q1 is used to receive an input signal. The emitter of the first transistor Q1 is connected to the cathode of the first diode D1 through the first resistor R1. The anode of the first diode D1 is connected to the input end of the first-stage amplifier 3. The collector of the first transistor Q1 is connected to the emitter of the second-stage amplifier 4.

[0038] In this embodiment, a compact amplifier circuit structure is formed by the combination of the first transistor Q1, the first resistor R1 and the first diode D1, which reduces the number of components in the circuit and helps to reduce the complexity and cost of the circuit; the first transistor Q1 is used as an amplifier element, and its base receives the input signal and outputs the amplified signal through the emitter, thereby achieving effective amplification of the input current signal. At the same time, the coordinated use of the first resistor R1 and the first diode D1 can further adjust the amplification factor and the stability of the circuit.

[0039] For further information, see Figure 2 The second first-stage amplifier 2 includes a second transistor Q2, a second resistor R2 and a second diode D2, the base of the second transistor Q2 is used to receive an input signal, the emitter of the second transistor Q2 is connected to the positive electrode of the second diode D2 through the second resistor R2, the cathode of the second diode D2 is connected to the input end of the second second-stage amplifier 4, and the collector of the second transistor Q2 is connected to the emitter end of the first second-stage amplifier 3.

[0040] In this embodiment, a compact amplifier circuit structure is formed by the combination of the second transistor Q2, the second resistor R2 and the second diode D2, which reduces the number of components in the circuit and helps to reduce the complexity and cost of the circuit; the second transistor Q2 is used as an amplifier element, and its base receives the input signal and outputs the amplified signal through the emitter, thereby achieving effective amplification of the input current signal. At the same time, the coordinated use of the second resistor R2 and the second diode D2 can further adjust the amplification factor and the stability of the circuit.

[0041] For further information, see Figure 2 The first secondary amplifier part 3 includes a first current source and a third transistor Q3, the negative end of the first current source is connected to the base of the third transistor Q3, the emitter of the third transistor Q3 is respectively connected to the collector of the second transistor Q2, the emitter end of the second secondary amplifier part 4 and the input end of the first three-stage amplifier group 51, and the collector of the third transistor Q3 and the positive end of the first current source are used to connect to an external power supply device.

[0042] In this embodiment, the external power supply device is a VCC power supply voltage; the initial amplification of the signal is achieved through the first and second stage amplification parts 3, and the amplified signal is transmitted to the subsequent first and third stage amplification groups 51 by the third transistor Q3, thereby reducing the number of components and reducing costs; the first current source provides a stable current for the third transistor Q3, ensuring the stability of the transistor during the amplification process, thereby improving the stability of the entire circuit.

[0043] For further information, see Figure 2 The second secondary amplifier 4 includes a second current source and a fourth transistor Q4, the positive end of the second current source is connected to the base of the fourth transistor Q4; the emitter of the fourth transistor Q4 is connected to the emitter of the third transistor Q3 through a third resistor R3, and is respectively connected to the collector of the first transistor Q1 and the input end of the second three-stage amplifier group 52; the collector of the fourth transistor Q4 and the negative end of the second current source are used to connect to an external power supply device.

[0044] In this embodiment, the external power supply device is a VSS ground voltage; the preliminary amplification of the signal is achieved through the second and second-stage amplifier unit 4, and the amplified signal is transmitted to the subsequent second and third-stage amplifier group 52 by the fourth transistor Q4, thereby reducing the number of components and reducing costs; the second current source provides a stable current for the fourth transistor Q4, ensuring the stability of the transistor during the amplification process, thereby improving the stability of the entire circuit.

[0045] For further information, see Figure 2 The first three-stage amplification group 51 includes a fourth resistor R4, a fifth transistor Q5 and a sixth resistor R6, one end of the fourth resistor R4 is connected to the emitter of the third transistor Q3, the other end of the fourth resistor R4 is connected to the base of the fifth transistor Q5, the emitter of the fifth transistor Q5 is connected to one end of the sixth resistor R6, the collector of the fifth transistor Q5 is used to connect to an external power supply device, and the other end of the sixth resistor R6 is used to output an amplified signal; thermal coupling is achieved among the first transistor Q1, the first diode D1, the third transistor Q3 and the fifth transistor Q5.

[0046] For further information, see Figure 2The second three-stage amplification group 52 includes a fifth resistor R5, a sixth transistor Q6 and a seventh resistor R7, one end of the fifth resistor R5 is connected to the emitter of the third transistor Q3, the other end of the fifth resistor R5 is connected to the base of the sixth transistor Q6, the emitter of the sixth transistor Q6 is connected to one end of the seventh resistor R7, the collector of the sixth transistor Q6 is used to connect to an external power supply device, and the other end of the seventh resistor R7 is used to output an amplified signal; thermal coupling is achieved among the second transistor Q2, the second diode D2, the fourth transistor Q4 and the sixth transistor Q6.

[0047] In this embodiment, thermal coupling is achieved between the first triode Q1, the first diode D1, the third triode Q3 and the fifth triode Q5, and thermal coupling is achieved between the second triode Q2, the second diode D2, the fourth triode Q4 and the sixth triode Q6; so-called thermal coupling means that these electronic components have a mutual influence on the temperature change. When the temperature of one of the components increases or decreases due to a change in the working state, this temperature change will be transmitted to other electronic components through heat conduction or other heat exchange methods, so that the temperature of these electronic components will also change accordingly; through thermal coupling, the temperature distribution between the various electronic components is made more uniform, and the error and drift caused by the temperature gradient are reduced, thereby improving the stability of the amplifier group during operation and the accuracy of the output signal.

[0048] In this embodiment, by introducing the first three-stage amplification group 51 and the second three-stage amplification group 52, the circuit realizes dual signal amplification, which not only ensures the quality of the signal during transmission, but also significantly improves the strength and stability of the signal, and enhances the reliability of the entire system; specifically, the first three-stage amplification group 51 and the second three-stage amplification group 52 realize dual signal amplification through independent resistors and transistor combinations, thereby enhancing the strength and stability of the signal; the third resistor R3 is respectively connected to the emitter of the third transistor Q3 and the emitter of the fourth transistor Q4. This design connects the two three-stage amplification groups together to share the same signal source. This connection method not only simplifies the circuit layout, but also reduces the number of components, thereby reducing the cost and improving the integration of the circuit; the sixth resistor R6 and the seventh resistor R7 are respectively used as the output resistors of the two amplification groups. Their function is to transmit the amplified signal to the subsequent circuit. The setting of these two resistors not only ensures the smooth output of the signal, but also plays a certain filtering role to ensure the purity of the output signal.

[0049] The working principle of the amplifier circuit disclosed in the present application is as follows: in the first half cycle of the input signal, the signal is input through the base of the first triode Q1 and output at the emitter of the first triode Q1. The signal then passes through the first resistor R1 and the first diode D1, and is finally sent to the base of the third triode Q3 for second-stage current amplification. The signal amplified by the third triode Q3 is output from the emitter of the third triode Q3, passes through the fourth resistor R4, and then enters the fifth triode Q5 for third-stage current amplification, and is finally output through the sixth resistor R6.

[0050] In the second half cycle of the input signal, the signal is input through the base of the second triode Q2 and output at the emitter of the second triode Q2. The signal then passes through the second resistor R2 and the second diode D2, and is finally sent to the base of the fourth triode Q4 for second-stage current amplification. The signal amplified by the fourth triode Q4 is output from the emitter of the fourth triode Q4, passes through the fifth resistor R5, and then enters the sixth triode Q6 for third-stage current amplification, and is finally output through the seventh resistor R7.

[0051] Since the voltage (Vce) between the collector and the emitter in the transistor amplifier circuit will cause the change of the transistor junction capacitance (Cob), this change may cause distortion. Therefore, the collector of the first transistor Q1 is connected to the emitter of the fourth transistor Q4, and the collector of the second transistor Q2 is connected to the emitter of the third transistor Q3. Through this clamping method, the key voltage parameters can be stabilized to reduce the Cob change caused by the Vce change, thereby reducing the occurrence of distortion. Specifically, when the input current signal enters the base of the first transistor Q1, the collector of the first transistor Q1 is connected to the emitter of the fourth transistor Q4. The potential of the first transistor Q1 is increased, and the emitter of the first transistor Q1 outputs the same voltage signal, which flows to the base of the third transistor Q3 through the first resistor R1 and the first diode D1, and then is output through the emitter of the third transistor Q3. The signal output by the emitter of the third transistor Q3 flows to the collector of the first transistor Q1 through the third resistor R3, so as to clamp the Vce voltage of the first transistor Q1 at a relatively stable level to prevent it from continuing to rise and generating an excessive surge voltage, thereby reducing the change of Cob caused by the change of Vce, and further reducing the distortion caused by voltage fluctuation.

[0052] Under the condition of maintaining the same load current as the traditional amplifier circuit, the amplification circuit of the current amplifier of the present application can achieve a wider linear working area, thereby obtaining a lower distortion; the distortion of the current amplifier mainly comes from the Cob change caused by the voltage difference between the collector and the emitter of the transistor. The greater the Cob change, the more serious the distortion; the amplification circuit of the current amplifier controls the voltage difference between the collector and the emitter within a very small range by constructing a feedback loop, greatly expanding the linear working area of ​​the transistor, and achieving:

[0053] 1. The circuit design optimizes the working state of the relatively weak triode to achieve excellent distortion performance while reducing the cost of options;

[0054] 2. Its distortion performance is enough to surpass the distortion level of traditional current amplifiers achieved by connecting multiple transistors in parallel, thereby reducing the procurement and production costs of raw materials;

[0055] 3. The Class B amplifier structure achieves low distortion performance comparable to or even better than that of the Class A amplifier, while maintaining the high energy efficiency of the Class B amplifier, further reducing the cost of use.

[0056] The present invention also provides a PCB board accordingly, on which an amplifying circuit of any of the above-mentioned current-type amplifiers is printed.

[0057] The present invention also provides a low-frequency amplifier accordingly, wherein the low-frequency amplifier uses an amplifying circuit of any of the above-mentioned current-type amplifiers to realize operation control.

[0058] It is understandable that those skilled in the art can make equivalent substitutions or changes based on the technical solution and inventive concept of the present invention, and all these changes or substitutions should fall within the protection scope of the present invention.

Claims

1. An amplifier circuit of a current-mode amplifier, characterized in that: It includes a first first-stage amplifier, a second first-stage amplifier, a first second-stage amplifier, a second second-stage amplifier and a third-stage amplifier; the input end of the first first-stage amplifier and the input end of the second first-stage amplifier are respectively used to receive input signals, the transmitting end of the first first-stage amplifier is connected to the input end of the first second-stage amplifier, the transmitting end of the second first-stage amplifier is connected to the input end of the second second-stage amplifier, the collector end of the first first-stage amplifier is connected to the transmitting end of the second second-stage amplifier, and the collector end of the second first-stage amplifier is connected to the transmitting end of the first second-stage amplifier; The transmitting end of the first two-stage amplifier part and the transmitting end of the second two-stage amplifier part are connected to each other, and are respectively connected to the input end of the three-stage amplifier part. The output end of the three-stage amplifier part is used to output an amplified signal.

2. The amplifying circuit of a current-mode amplifier according to claim 1, characterized in that: The three-stage amplification unit includes a first three-stage amplification group and a second three-stage amplification group. The transmitting end of the first two-stage amplification unit is connected to the input end of the first three-stage amplification group, the transmitting end of the second two-stage amplification unit is connected to the input end of the second three-stage amplification group, and the output end of the first three-stage amplification group and the output end of the second three-stage amplification group are respectively used to output amplified signals.

3. The amplifying circuit of a current-mode amplifier according to claim 2, characterized in that: The first-stage amplifier includes a first transistor Q1, a first resistor R1 and a first diode D1. The base of the first transistor Q1 is used to receive an input signal. The emitter of the first transistor Q1 is connected to the cathode of the first diode D1 through the first resistor R1. The anode of the first diode D1 is connected to the input end of the first-stage amplifier. The collector of the first transistor Q1 is connected to the emitter of the second-stage amplifier.

4. The amplifying circuit of a current-mode amplifier according to claim 3, characterized in that: The second first-stage amplifier includes a second transistor Q2, a second resistor R2 and a second diode D2, the base of the second transistor Q2 is used to receive an input signal, the emitter of the second transistor Q2 is connected to the positive electrode of the second diode D2 through the second resistor R2, the cathode of the second diode D2 is connected to the input end of the second second-stage amplifier, and the collector of the second transistor Q2 is connected to the emitter end of the first second-stage amplifier.

5. The amplifying circuit of a current-mode amplifier according to claim 4, characterized in that: The first-stage two-stage amplifier unit includes a first current source and a third transistor Q3, the negative end of the first current source is connected to the base of the third transistor Q3, the emitter of the third transistor Q3 is respectively connected to the collector of the second transistor Q2, the emitter end of the second-stage amplifier unit and the input end of the first three-stage amplifier group, and the collector of the third transistor Q3 and the positive end of the first current source are used to connect to an external power supply device.

6. The amplifying circuit of a current-mode amplifier according to claim 5, characterized in that: The second two-stage amplification part includes a second current source and a fourth transistor Q4, the positive end of the second current source is connected to the base of the fourth transistor Q4; the emitter of the fourth transistor Q4 is connected to the emitter of the third transistor Q3 through a third resistor R3, and is respectively connected to the collector of the first transistor Q1 and the input end of the second three-stage amplification group; the collector of the fourth transistor Q4 and the negative end of the second current source are used to connect to an external power supply device.

7. The amplifying circuit of a current-mode amplifier according to claim 6, characterized in that: The first three-stage amplification group includes a fourth resistor R4, a fifth triode Q5 and a sixth resistor R6, one end of the fourth resistor R4 is connected to the emitter of the third triode Q3, the other end of the fourth resistor R4 is connected to the base of the fifth triode Q5, the emitter of the fifth triode Q5 is connected to one end of the sixth resistor R6, the collector of the fifth triode Q5 is used to connect to an external power supply device, and the other end of the sixth resistor R6 is used to output an amplified signal; thermal coupling is achieved among the first triode Q1, the first diode D1, the third triode Q3 and the fifth triode Q5.

8. The amplifying circuit of a current-mode amplifier according to claim 7, characterized in that: The second three-stage amplification group includes a fifth resistor R5, a sixth triode Q6 and a seventh resistor R7, one end of the fifth resistor R5 is connected to the emitter of the third triode Q3, the other end of the fifth resistor R5 is connected to the base of the sixth triode Q6, the emitter of the sixth triode Q6 is connected to one end of the seventh resistor R7, the collector of the sixth triode Q6 is used to connect to an external power supply device, and the other end of the seventh resistor R7 is used to output an amplified signal; thermal coupling is achieved among the second triode Q2, the second diode D2, the fourth triode Q4 and the sixth triode Q6.

9. A PCB board, characterized in that: The PCB board is printed with an amplifier circuit of the current-type amplifier as described in any one of claims 1-8.

10. A low frequency amplifier, characterized in that: The low-frequency amplifier uses the amplification circuit of the current-type amplifier as described in any one of claims 1-8 to achieve operation control.

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