Differential power amplifier for baseband linear cancellation

Abstract

The utility model provides a differential power amplifier for baseband linear offset, which comprises a driving stage amplifier, a first transformer, a baseband offset module and a power stage amplifier, and is characterized in that the driving stage amplifier is configured to receive differential signals and provide amplified first differential signals to the first transformer; a first transformer configured between the driver stage amplifier and the power stage amplifier to provide inter-stage impedance matching; the power stage amplifier is configured to receive the first differential signal amplified by the driving stage amplifier and amplify the first differential signal into an output differential signal; the baseband counteracting module is configured between the first transformer and the power stage amplifier so as to counteract a baseband component in the first differential signal; or after the power stage amplifier, a baseband component in the output differential signal is cancelled.

Description

Technical Field

[0001] The utility model relates to the field of wireless communication, and more specifically, to a differential power amplifier for baseband linear cancellation. Background Art

[0002] A power amplifier is a device that supplies energy provided by a power supply to an AC signal and is widely used as an important component in the front end of a communication system in modern communication. With the improvement of data communication modulation protocols and the continuous increase in system bandwidth, the baseband bandwidth can reach up to 100 - 200 MHz, and its impact on performance has become more serious. The design of power amplifiers (PAs) has long been a trade-off among multiple factors. To increase the output bandwidth to meet these new standards, its efficiency and linearity are inevitably affected. In order to reduce energy requirements and improve output power and linearity, new amplifier designs are being studied to further improve system performance and reduce environmental and economic impacts.

[0003] Currently, with the increasing demand for higher spectral utilization, lower latency, enhanced data rate, and extended transmission capacity in wireless communication systems, the demand for devices and circuits with high linearity and high efficiency has become urgent. However, the key power amplifiers (PAs) used in transmitters often face challenges because linearity and efficiency are crucial factors for them, and these two factors often restrict each other.

[0004] Nevertheless, whether using load modulation or power supply envelope modulation, their architectures are quite complex in themselves and require a large amount of chip area. In addition, the addition of digital predistortion (DPD) technology significantly increases the complexity and cost of the system. Currently, there is an increasing emphasis on improving the linearity of power amplifiers (PAs) to the highest possible level without relying on DPD while maintaining relatively good efficiency. Summary of the Utility Model

[0005] To solve the above problems, the utility model provides a differential power amplifier that improves its efficiency and linearity by improving the baseband impedance of the differential amplifier.

[0006] One aspect of the present utility model provides a differential power amplifier for baseband linear cancellation, including a driver stage amplifier, a first transformer, a baseband cancellation module, and a power stage amplifier, characterized in that: the driver stage amplifier is configured to receive a differential signal and provide an amplified first differential signal to the first transformer; the first transformer is configured between the driver stage amplifier and the power stage amplifier to provide inter-stage impedance matching; the power stage amplifier is configured to receive the first differential signal amplified by the driver stage amplifier and amplify the first differential signal into an output differential signal; and the baseband cancellation module is configured between the first transformer and the power stage amplifier to cancel the baseband component in the first differential signal; or it is configured after the power stage amplifier to cancel the baseband component in the output differential signal.

[0007] One aspect of the present utility model provides a differential power amplifier for baseband linear cancellation, characterized in that it further includes a single-ended to differential signal converter, which is configured to receive a single-ended input signal and convert the single-ended input signal into a differential signal.

[0008] One aspect of the present utility model provides a differential power amplifier for baseband linear cancellation, characterized in that it further includes a differential to single-ended signal converter, which is configured to receive the output differential signal and convert the output differential signal into a single-ended output signal.

[0009] One aspect of the present utility model provides a differential power amplifier for baseband linear cancellation, characterized in that the single-ended to differential signal converter or the differential to single-ended signal converter is configured as a transformer.

[0010] One aspect of the present utility model provides a differential power amplifier for baseband linear cancellation, characterized in that it further includes a common mode rejection capacitor, which is configured between two signal lines of the output differential signal.

[0011] One aspect of the present utility model provides a differential power amplifier for baseband linear cancellation, characterized in that the baseband cancellation module includes a first low-pass filter, a second low-pass filter, and a baseband cancellation transformer.

[0012] One aspect of the present utility model provides a differential power amplifier for baseband linear cancellation, characterized in that the first low-pass filter, the second low-pass filter, and the baseband cancellation transformer are configured between two signal lines of the first differential signal. The first low-pass filter is configured to be connected between the first signal line in the first differential signal and the primary coil of the baseband cancellation transformer, and the second low-pass filter is configured to be connected between the second signal line in the first differential signal and the non-homonymous end of the secondary coil of the baseband cancellation transformer.

[0013] One aspect of the present utility model provides a differential power amplifier for baseband linear cancellation, characterized in that the first low-pass filter, the second low-pass filter, and the baseband cancellation transformer are configured between two signal lines of the output differential signal. The first low-pass filter is configured to be connected between the first signal line in the output differential signal and the primary coil of the baseband cancellation transformer, and the second low-pass filter is configured to be connected between the second signal line in the output differential signal and the non-homonymous end of the secondary coil of the baseband cancellation transformer.

[0014] One aspect of the present utility model provides a differential power amplifier for baseband linear cancellation, characterized in that the first low-pass filter and the second low-pass filter are configured as T-type low-pass filters including inductors and capacitors.

[0015] One aspect of the present utility model provides a differential power amplifier for baseband linear cancellation, characterized in that the differential power amplifier includes a differential power amplifier manufactured by CMOS, HBT, or SiGe process. Description of the Drawings

[0016] Figure 1 is a schematic diagram showing a differential power amplifier based on baseband linear cancellation according to an embodiment of the present utility model;

[0017] Figure 2 is a schematic diagram showing the structure of a baseband cancellation module according to an embodiment of the present utility model; and

[0018] Figure 3 is a schematic diagram showing a differential power amplifier based on baseband linear cancellation according to another embodiment of the present utility model. Detailed Description of the Embodiment

[0019] Before proceeding with the following detailed description, it may be advantageous to set forth definitions of certain words and phrases used throughout this document of the present utility model. The terms "coupled", "connected", and their derivatives refer to any direct or indirect communication between two or more elements, whether or not those elements are in physical contact with each other. The terms "transmit", "receive", and "communicate", and their derivatives cover both direct and indirect communication. The terms "comprise" and "include", and their derivatives mean including but not limited to. The term "or" is inclusive, meaning and / or. The phrase "associated with", and its derivatives, mean including, included within, interconnected, containing, contained within, connected or coupled with, communicating with, cooperating with, interlacing, juxtaposed, adjacent to, bound or bound with, having, having an attribute, having a relationship or having a relationship with, etc. The term "controller" refers to any device, system, or part thereof that controls at least one operation. Such a controller can be implemented in hardware, or in a combination of hardware and software and / or firmware. The functions associated with any particular controller can be centralized or distributed, whether local or remote. The phrase "at least one", when used with a list of items, means that different combinations of one or more of the listed items can be used, and it may only be necessary to have one item in the list. For example, "at least one of A, B, C" includes any one of the following combinations: A, B, C, A and B, A and C, B and C, A and B and C.

[0020] Definitions of other specific words and phrases are provided throughout this document of the present utility model. One of ordinary skill in the art should understand that in many cases, if not most cases, such definitions apply to the prior and future use of the words and phrases so defined.

[0021] In this document of the present utility model, the application combination of circuit blocks and the division of sub-circuit blocks are only for illustration, and within the scope not departing from this disclosure, the application combination of circuit blocks and the division of sub-circuit blocks can have different ways.

[0022] The following discussion Figures 1 to 3 and the various embodiments used to describe the principles of this disclosure in this document of the present utility model are for illustration only and should not be construed in any way as limiting the scope of this disclosure. Those skilled in the art will understand that the principles of this disclosure can be implemented in any appropriately arranged system or device.

[0023] In the 5G communication standard, the signal bandwidth is continuously widened, and the memory effect of active transistors becomes more obvious. Due to the physical limitations of actual components, it may be very difficult to reduce the baseband impedance by only improving the bias network using conventional methods. In the present utility model, an alternative structure for reducing the baseband impedance is provided. By connecting a filter network and a transformer before the differential two-way PA, the baseband components of broadband signals can be effectively cancelled, thereby greatly reducing the influence of the bias network on the effective baseband impedance. By cancelling the baseband components of broadband signals, the saturation power, efficiency, and linearity of the differential amplifier are improved.

[0024] Figure 1 FIG. is a schematic diagram of a differential power amplifier based on baseband linear cancellation according to an embodiment of the present utility model.

[0025] As Figure 1 shown, the differential power amplifier according to the present utility model includes: a single-ended to differential signal converter, a driver stage amplifier, a first transformer, a baseband cancellation module, a power stage amplifier, a differential to single-ended signal converter, and an output matching circuit.

[0026] Among them, the single-ended input signal is converted into a differential signal through the single-ended to differential signal converter. According to an embodiment of the present utility model, the single-ended to differential signal converter is configured as a transformer, wherein the input signal as a single-ended signal is input to one end of the primary coil of the transformer, and the transformer converts the single-ended input signal into two differential signals with equal amplitude and opposite phases through the center tap or symmetric winding structure of the secondary coil. By using a transformer to implement the single-ended to differential converter, electrical isolation can be achieved and common-mode rejection can be realized. In addition, by adjusting the turns ratio of the primary / secondary coils of the transformer, the impedance matching between the single-ended signal source impedance and the differential load impedance can also be achieved, reducing signal reflection and improving transmission efficiency.

[0027] The driver stage amplifier receives the differential signal and outputs an amplified first differential signal.

[0028] The first differential signal is provided to the first transformer, and the first transformer is configured to provide inter-stage impedance matching between the driver stage amplifier and the power stage amplifier. The baseband cancellation module is connected between the first transformer and the power stage amplifier. The first differential signal is provided to the power stage amplifier after passing through the baseband cancellation module. Among them, the first part of the first differential signal (the signal with a phase of 180 degrees for the operating signal frequency (F0) and a phase of 0 degrees for the baseband signal) is provided to the first power stage amplification module, and the second part of the first differential signal (the signal with a phase of 0 degrees for the operating signal frequency (F0) and a phase of 0 degrees for the baseband signal) is provided to the second power stage amplification module.

[0029] After the first differential signal is amplified by the power stage amplifier, it is converted into a single-ended output signal through a differential-single-ended converter. The single-ended output signal is output to an external circuit through an output matching circuit.

[0030] Among them, the differential-single-ended converter is configured as an output transformer.

[0031] Among them, a capacitor C is also configured between the two output terminals of the power stage amplifier to further suppress the common-mode signal.

[0032] Although in the embodiment shown in Figure 1 , the first differential signal is amplified by two separate power amplification modules in the power stage amplifier, those skilled in the art should understand that the power stage amplifier can also be configured as a single differential power amplifier.

[0033] Figure 2 is a schematic diagram showing the structure of a baseband cancellation module according to an embodiment of the present invention.

[0034] As Figure 2 shown, the structure of the baseband cancellation module includes a first low-pass filter, a second low-pass filter, and a baseband cancellation transformer.

[0035] Among them, the first low-pass filter, the second low-pass filter, and the baseband cancellation transformer are configured between two signal lines of the first differential signal; the first low-pass filter is connected between the first part of the first differential signal and the baseband cancellation transformer, and the second low-pass filter is connected between the second part of the first differential signal and the baseband cancellation transformer. When the first low-pass filter is connected to the primary coil of the baseband cancellation transformer, the second low-pass filter is connected to the non-homonymous end (non-polar end) of the secondary coil of the baseband cancellation transformer. On the contrary, when the first low-pass filter is connected to the secondary coil of the baseband cancellation transformer, the second low-pass filter is connected to the non-homonymous end (non-polar end) of the primary coil of the baseband cancellation transformer.

[0036] The first low-pass filter is configured as a T-type low-pass filter including an inductor and a capacitor. Among them, the parallel first inductor L1 and the first capacitor C1 and the parallel second inductor L2 and the second capacitor C2 are connected in series between the signal line of the first differential signal and the baseband cancellation transformer; the series-connected third inductor L3 and the third capacitor C3 are connected between the intermediate node N1 of the first capacitor C1 and the second capacitor C2 and the ground node.

[0037] The second low-pass filter is configured as a T-type low-pass filter including an inductor and a capacitor. Among them, the fourth inductor L4 and the fourth capacitor C4 in parallel and the fifth inductor L5 and the fifth capacitor C5 in parallel are connected in series between the signal line of the first differential signal and the baseband cancellation transformer; the series-connected sixth inductor L6 and sixth capacitor C6 are connected between the intermediate node N2 of the fourth capacitor C4 and the fifth capacitor C5 and the ground node.

[0038] By connecting a filter network (low-pass filter) and a baseband cancellation transformer before the two-way PA that amplifies the differential signal. As Figure 2 shown, at node A, the phase of the operating signal frequency (F0) is 180 degrees, and the phase of the baseband signal is 0 degrees, while at node B, the phases of both the operating signal frequency and the baseband signal are 0 degrees. The operating signal frequency is usually set to be greater than 1 GHz, and the baseband signal frequency is usually set to 1 MHz - 200 MHz. Through the low-pass filter network composed of L1, C1, L2, C2, L3, and C3, the operating signal frequency is effectively isolated. At the baseband cancellation transformer, the phase of the baseband signal contained in the signal at node A is converted by 180 degrees through phase transformation, and it cancels out the baseband signal contained in the signal at node B. Therefore, the baseband cancellation module can effectively cancel the baseband component of the broadband signal, thereby greatly reducing the influence of the bias network on the effective baseband impedance. By canceling the baseband component of the broadband signal, the memory effect of the power amplifier can be effectively improved, thereby increasing the saturation power of the differential amplifier. At the same time, the efficiency and linearity are also improved. Here, the baseband component is also called the envelope signal.

[0039] Figure 3 is a schematic diagram showing a differential power amplifier based on baseband linear cancellation according to another embodiment of the present invention.

[0040] As Figure 3 shown, the differential power amplifier according to the present invention includes: a single-ended to differential signal converter, a driver stage amplifier, a first transformer, a baseband cancellation module, a power stage amplifier, a differential to single-ended signal converter, and an output matching circuit.

[0041] Figure 3 The differential power amplifier shown in Figure 1 is different from the differential power amplifier shown in that the baseband cancellation module is configured at the output end of the power amplifier. Among them, after the first differential signal is amplified by the power stage amplifier into an output differential signal, it is provided to the differential to single-ended converter through the baseband cancellation module.

[0042] Among them, the first low-pass filter, the second low-pass filter, and the baseband cancellation transformer are configured between two signal lines of the output differential signal; the first low-pass filter is connected between the first part (the first signal line) of the output differential signal and the baseband cancellation transformer, and the second low-pass filter is connected between the second part (the second signal line) of the output differential signal and the baseband cancellation transformer. When the first low-pass filter is connected to the primary coil of the baseband cancellation transformer, the second low-pass filter is connected to the non-homonymous end (non-polar end) of the secondary coil of the baseband cancellation transformer. On the contrary, when the first low-pass filter is connected to the secondary coil of the baseband cancellation transformer, the second low-pass filter is connected to the non-homonymous end (non-polar end) of the primary coil of the baseband cancellation transformer.

[0043] In addition, a capacitor C can also be configured between two ports of the baseband cancellation module to further suppress the common-mode signal.

[0044] According to the present utility model, since the area occupied by the baseband cancellation module is different for circuits of different frequencies, therefore, designing the baseband cancellation module on the chip may increase the cost. In this embodiment, by configuring the baseband cancellation module at the output end of the power amplifier, while maintaining the effectiveness of the baseband cancellation module, it can be designed outside rather than inside the chip, thereby reducing the chip area occupied and improving the design flexibility.

[0045] The framework of the present utility model is applicable to various differential power amplifiers fabricated using CMOS, HBT, or SiGe processes.

[0046] Although the present disclosure has been described with exemplary embodiments, various changes and modifications can be suggested to those skilled in the art. The present disclosure is intended to cover such changes and modifications that fall within the scope of the appended claims.

[0047] Any description in the present utility model should not be construed as implying that any specific element, step, or function is an essential element that must be included within the scope of the claims. The scope of the subject matter of the utility model is defined only by the claims.

Claims

1. A differential power amplifier for baseband linear cancellation, comprising a driver stage amplifier, a first transformer, a baseband cancellation module, and a power stage amplifier, characterized in that: a driver stage amplifier configured to receive the differential signal and provide an amplified first differential signal to the first transformer; A first transformer is arranged between the driver stage amplifier and the power stage amplifier to provide inter-stage impedance matching; a power stage amplifier configured to receive the first differential signal amplified by the driver stage amplifier and amplify the first differential signal into an output differential signal; as well as A baseband cancellation module, which is configured between the first transformer and the power stage amplifier to cancel the baseband component in the amplified first differential signal; Or it is configured after the power stage amplifier to cancel the baseband component in the output differential signal.

2. The differential power amplifier according to claim 1, characterized in that: Also included is a single-ended-to-differential signal converter configured to receive a single-ended input signal and convert the single-ended input signal to a differential signal.

3. The differential power amplifier according to claim 1, wherein: Also included is a differential-to-single-ended signal converter configured to receive the output differential signal and convert the output differential signal to a single-ended output signal.

4. The differential power amplifier according to claim 2, characterized in that: The single-ended-to-differential signal converter is configured as a transformer.

5. The differential power amplifier according to claim 3, characterized in that: The differential-to-single-ended signal converter is configured as a transformer.

6. The differential power amplifier according to claim 1, characterized in that: Also included is a common mode rejection capacitor that is arranged between two signal lines that output a differential signal.

7. The differential power amplifier according to claim 1, characterized in that: The baseband cancellation module includes a first low-pass filter, a second low-pass filter and a baseband cancellation transformer.

8. The differential power amplifier according to claim 7, characterized in that: The first low-pass filter, the second low-pass filter and the baseband cancellation transformer are arranged between two signal lines of the amplified first differential signal. The first low pass filter is configured to be connected between the first signal line of the amplified first differential signal and the primary coil of the baseband cancellation transformer, The second low pass filter is configured to be connected between the second signal line in the amplified first differential signal and the non-same-name terminal in the secondary coil of the baseband cancellation transformer to cancel the baseband component in the amplified first differential signal.

9. The differential power amplifier according to claim 7, characterized in that: The first low-pass filter, the second low-pass filter and the baseband cancellation transformer are arranged between the two signal lines of the output differential signal. The first low pass filter is configured to be connected between the first signal line in the output differential signal and the primary coil of the baseband cancellation transformer, The second low pass filter is configured to be connected between a second signal line in the output differential signal and a non-double-named end in the secondary winding of the baseband cancellation transformer.

10. The differential power amplifier according to claim 7, characterized in that: The first low pass filter and the second low pass filter are configured as T-type low pass filters including an inductor and a capacitor.

11. The differential power amplifier according to claim 1, characterized in that: The differential power amplifier includes a differential power amplifier manufactured by CMOS, HBT or SiGe process.

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