An anti-interference power supply circuit based on constant envelope tracking technology

Abstract

The present invention relates to the field of communication technology, and discloses an anti-interference power supply circuit based on constant envelope tracking technology, including: an operational amplifier, a switching switch, a filter circuit, a sampling resistor, a comparator and a push-pull circuit; the output end of the operational amplifier is connected to the first end of the switching switch and the first input end of the comparator; the second end of the switching switch is respectively connected to the input end of the filter circuit or the first end of the sampling resistor; the second input end of the comparator is respectively connected to the output end of the filter circuit, the second end of the sampling resistor and the power input end of the radio frequency power amplifier, and the output end of the comparator is connected to the input end of the push-pull circuit; the output end of the push-pull circuit is connected to the power input end of the radio frequency power amplifier through an inductor. The present invention can effectively track the envelope input signal in a non-interference frequency band, improve work efficiency and reduce power consumption; for the interference frequency band, it can enter the filter path, generate a huge change signal filter for the envelope signal, and reduce interference to the current working frequency band.

Description

Technical Field

[0001] The present invention relates to the field of wireless communications, and in particular to an anti-interference power supply circuit based on constant envelope tracking technology. Background Art

[0002] With the development of communication technology, the 5G era has arrived, and the RF system has become more complicated. At the same time, the power consumption of the RF system has increased sharply with the increase of PA (Power Amplifier). For this reason, a DCDC power supply solution based on ET (Envelope Tracking) has been applied. The ET-based DCDC power supply solution can bring about 20% power consumption optimization to medium-power and high-power RF systems, but it also brings a problem: the DCDC power supply will produce certain signal interference to certain working frequency bands of the RF system, resulting in the existing ET-based DCDC power supply solution introducing signal interference problems while optimizing power consumption. Summary of the invention

[0003] The purpose of the present invention is to provide an anti-interference power supply circuit based on constant envelope tracking technology, which overcomes the defect of the prior art that while optimizing the power consumption problem, a signal interference problem is introduced.

[0004] To achieve this object, the present invention adopts the following technical solutions:

[0005] An anti-interference power supply circuit based on constant envelope tracking technology, comprising: an operational amplifier, a switching switch, a filter circuit, a sampling resistor, a comparator and a push-pull circuit;

[0006] The operational amplifier is used to amplify the envelope input signal, and the output end of the operational amplifier is respectively connected to the first end of the switch and the first input end of the comparator;

[0007] The switching switch is used to connect the operational amplifier with the sampling resistor in a first conduction state, and connect the operational amplifier with the filter circuit in a second conduction state, and the second end of the switching switch is connected to the input end of the filter circuit or the first end of the sampling resistor;

[0008] The second input end of the comparator is connected to the output end of the filter circuit, the second end of the sampling resistor and the power input end of the radio frequency power amplifier respectively, and the output end of the comparator is connected to the input end of the push-pull circuit;

[0009] The output end of the push-pull circuit is connected to the power input end of the radio frequency power amplifier through an inductor.

[0010] Optionally, a control unit is also included for determining whether there is interference in the current operating frequency band of the envelope input signal, and controlling the switching switch to switch to the first conduction state if there is no interference, and controlling the switching switch to switch to the second conduction state if there is interference.

[0011] Optionally, the control unit is specifically used for:

[0012] Acquire an interference frequency band list including at least one interference frequency band information;

[0013] Determine whether the current working frequency band is in the interference frequency band list;

[0014] If so, it is determined that interference exists in the current working frequency band.

[0015] Optionally, the filter circuit is a low-order filter circuit, a high-order filter circuit, a low-pass filter circuit or a high-pass filter circuit.

[0016] Optionally, the filtering circuit is a fixed filter or an adjustable filter.

[0017] Optionally, the filtering circuit includes a filtering resistor and a capacitor;

[0018] The first end of the filter resistor is connected to the output end of the operational amplifier, the second end of the filter resistor and the first end of the capacitor are respectively connected to the power input end of the RF power amplifier, and the second end of the capacitor is grounded.

[0019] Optionally, the capacitor is a tunable capacitor.

[0020] Optionally, the operational amplifier, the switching switch, the filtering circuit, the sampling resistor, the comparator and the push-pull circuit are packaged inside the same chip.

[0021] Optionally, the operational amplifier, the switching switch, the sampling resistor, the comparator and the push-pull circuit are packaged inside the same chip, and the filter circuit is arranged outside the chip.

[0022] Optionally, the push-pull circuit includes two transistors or two field effect transistors.

[0023] Compared with the prior art, the embodiments of the present invention have the following beneficial effects:

[0024] By applying the embodiment of the present invention, for a working frequency band without interference, it can be switched to the first conduction state, effectively track the envelope input signal, improve the working efficiency of the RF power amplifier, and reduce power consumption; for a working frequency band with interference, it can be switched to the second conduction state, enter the filter path, generate a large change signal filter for the envelope signal, reduce the frequent switching of the comparator, and reduce interference to the current working frequency band. The whole solution is simple and efficient, with low complexity, which can not only improve work efficiency, but also achieve anti-interference, and has good promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0026] Figure 1 A schematic diagram of an anti-interference power supply circuit provided by an embodiment of the present invention;

[0027] Figure 2 A simplified schematic diagram of an anti-interference power supply circuit working in a sampling path provided by an embodiment of the present invention;

[0028] Figure 3 A simplified schematic diagram of an anti-interference power supply circuit working in a filtering path provided by an embodiment of the present invention;

[0029] Figure 4 A simplified schematic diagram of another anti-interference power supply circuit working in a filter path provided by an embodiment of the present invention;

[0030] Figure 5 A simplified schematic diagram of another anti-interference power supply circuit working in a filtering path provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0031] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the embodiments described below are only 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.

[0032] In order to solve the power consumption optimization problem and the anti-interference problem at the same time, an embodiment of the present invention provides an anti-interference power supply circuit, such as Figure 1As shown, it specifically includes: an operational amplifier, a switching switch, a filter circuit, a sampling resistor, a comparator and a push-pull circuit;

[0033] An operational amplifier is used to amplify an envelope input signal; the operational amplifier includes a positive input terminal, a negative input terminal and an output terminal, the positive input terminal receives the envelope input signal, the negative input terminal is connected to the power input terminal of the radio frequency power amplifier, and the output terminal is respectively connected to the first terminal of the switching switch and the first input terminal of the comparator.

[0034] The switching switch is used to connect the operational amplifier to the sampling resistor in a first conduction state and to connect the operational amplifier to the filter circuit in a second conduction state; these two conduction states can be switched to achieve different paths. The second end of the switching switch is connected to the input end of the filter circuit or the first end of the sampling resistor.

[0035] The second input end of the comparator is connected to the output end of the filter circuit, the second end of the sampling resistor and the power input end of the radio frequency power amplifier respectively, and the output end of the comparator is connected to the input end of the push-pull circuit;

[0036] The output end of the push-pull circuit is connected to the power input end of the radio frequency power amplifier through an inductor.

[0037] Since the interference of the power supply circuit of the embodiment of the present invention to the radio frequency system generally does not cover all the working frequency bands of the radio frequency system, but only involves part of the working frequency bands, the anti-interference power supply circuit of the embodiment of the present invention can switch the control switch according to actual needs: when there is no need to perform anti-interference processing on the current working frequency band, the switching switch can be controlled to achieve a first conduction state to improve the working efficiency of the radio frequency power amplifier and reduce power consumption; when it is necessary to perform anti-interference processing on the current working frequency band, the switching switch can be controlled to achieve a second conduction state to reduce interference to the current working frequency band through filtering.

[0038] It should be noted that Figure 1 The push-pull circuit shown in the figure is composed of two field effect transistors of N type and P type, and can actually be composed of two transistors, which is not limited in the embodiment of the present invention.

[0039] When the switch is switched to the first conducting state, the simplified anti-interference power supply circuit is as follows: Figure 2 As shown (the figure omits the filter circuit that is not actually working at present), the specific working principle is as follows:

[0040] The envelope input signal is input from the positive electrode of the operational amplifier, the negative electrode of the operational amplifier forms negative feedback to form constant voltage tracking, and the output end of the operational amplifier outputs a constant envelope signal;

[0041] If the voltage amplitude of the constant envelope signal output by the operational amplifier is relatively small, the current flowing through the sampling resistor R will be relatively small, and the voltage difference across the sampling resistor R will also be relatively small, often not exceeding the switching threshold Vth of the comparator, resulting in the push-pull output voltage of the N-type MOS tube and the P-type MOS tube that constitute the push-pull circuit being relatively low, thus achieving the low voltage output requirement under small signal conditions;

[0042] If the voltage amplitude of the constant envelope signal output by the operational amplifier is relatively large, the current flowing through the sampling resistor R will be relatively large, and the voltage difference across the sampling resistor R will increase, causing the voltage difference amplitude to exceed the switching threshold Vth of the comparator. Then, the push-pull output voltage of the N-type MOS tube and the P-type MOS tube that constitute the push-pull circuit will be relatively high, achieving the high voltage output requirement under large signal;

[0043] Obviously, the push-pull output voltage is the power supply provided for the RF power amplifier.

[0044] It can be seen that the above Figure 2 In the example, the current of the sampling resistor R is affected by the amplitude of the envelope input signal. As is known to all, the envelope input signal changes rapidly in the time domain, so the current passing through the sampling resistor R will also change rapidly. This is the interference source with RF radiation when the entire RF system is working. Of course, the operating frequency of the entire DCDC may be several MHz. The interference source will produce multiplier interference according to the medium form and structure of the space, thereby forming interference with certain RF operating frequency bands. Since the current operating frequency band does not belong to the operating frequency band that will be interfered with, the anti-interference power supply circuit of this embodiment can control the switch to switch to the first conduction state at this time to reduce filtering operations and reduce power consumption.

[0045] For example, Figure 2 The filter circuit shown can be specifically a first-order low-pass filter circuit composed of a filter resistor and a capacitor, the first end of the filter resistor is connected to the output end of the operational amplifier, the second end of the filter resistor and the first end of the capacitor are respectively connected to the power input end of the RF power amplifier, and the second end of the capacitor is grounded. It should be noted that in other embodiments, the filter circuit can be fixed or adjustable, and can be any low-order filter circuit, high-order filter circuit, low-pass filter circuit or high-pass filter circuit. The present invention does not limit the specific form of the filter structure, as long as a certain degree of filtering effect can be achieved.

[0046] When the switch is switched to the second conducting state, the simplified anti-interference power supply circuit is as follows: Figure 3 As shown in the figure (the sampling resistor R which is not actually working is omitted in this figure), the specific working principle is as follows:

[0047] When the envelope input signal is amplified by the operational amplifier and output to the filter resistor R of the filter circuit, a voltage drop will occur on the filter resistor R. After the amplitude fluctuation of the constant envelope signal output by the operational amplifier exceeds the preset voltage threshold Vth, the comparator will be reversed, thereby realizing the control and tracking of the current of the RF power amplifier at the output stage of the push-pull circuit, achieving the goal of energy saving; however, because the constant envelope signal changes rapidly in the time domain, then in Figure 3 The topology point of the filter circuit shown will produce large high-frequency harmonic components, which are the source of interference. Therefore, designing the filter circuit here can slow down the fast-changing signal and reduce the high-frequency components, thereby reducing the interference energy of the RF interference source. It is understandable that if the filter circuit is designed at various places in the later stage, the path of the interference signal will be extended, and the filtering effect will be discounted to a certain extent.

[0048] It should be noted that in the embodiment of the present invention, the filter circuit can be packaged in the same chip as all other components of the anti-interference circuit of the embodiment of the present invention, or all other components except the filter circuit can be packaged in a unified chip and the filter circuit can be arranged outside the chip.

[0049] In the first case: If the filter circuit design is packaged in the same chip as other components, the filter circuit can control the resonance point through the tunable capacitor, that is, Figure 4 The tunable capacitor shown is, of course, not limited to RC, and can be other forms of filtering structures. This is just an example and not limiting.

[0050] In the second case: if the filter circuit is set outside the chip packaged by other components, as follows Figure 5 As shown, the filter circuit is designed outside the chip, and the specific design position can be debugged according to the specific interference situation.

[0051] Regardless of which of the above designs is used, the core anti-interference mechanism is the same, it’s just a matter of whether it is implemented inside or outside the chip.

[0052] In addition, in order to achieve automatic switching control, the anti-interference circuit of an embodiment of the present invention also includes a control unit, which is used to determine whether there is interference in the current working frequency band. If there is no interference, the switching switch is controlled to switch to the first conduction state; if there is interference, the switching switch is controlled to switch to the second conduction state.

[0053] When determining whether there is interference in the current working frequency band, the control unit is specifically used to: obtain an interference frequency band list including at least one interference frequency band information, find out whether the current working frequency band is in the interference frequency band list, and if so, determine that there is interference in the current working frequency band.

[0054] By using the pre-acquired interference frequency band list, the RF system can accurately control the switch in real time according to the current working frequency band. It is understandable that the frequency band information in the interference frequency band list can be imported based on the debugging results after all frequency bands are debugged in advance, so that the RF system can identify whether the current working frequency band will cause interference by searching in the interference frequency band list when working. Of course, the interference frequency band list can be adjusted according to the actual application scenario.

[0055] In summary, by applying the embodiments of the present invention, for a working frequency band without interference, it can be switched to the first conduction state, effectively track the envelope input signal, improve the working efficiency of the RF power amplifier, and reduce power consumption; for a working frequency band with interference, it can be switched to the second conduction state, enter the filter path, generate a huge change signal filter for the envelope input signal, reduce the frequent switching of the comparator, and reduce the interference to the current working frequency band. The whole solution is simple and efficient, with low complexity, which can not only improve work efficiency, but also achieve anti-interference, and has good promotion.

[0056] As described above, the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features thereof may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An anti-interference power supply circuit based on constant envelope tracking technology, It is characterized in that include: Operational amplifiers, switches, filter circuits, sampling resistors, comparators, and push-pull circuits; The operational amplifier is used to amplify the envelope input signal, and the output end of the operational amplifier is respectively connected to the first end of the switch and the first input end of the comparator; The switching switch is used to connect the operational amplifier with the sampling resistor in a first conduction state, and connect the operational amplifier with the filter circuit in a second conduction state, and the second end of the switching switch is connected to the input end of the filter circuit or the first end of the sampling resistor; The second input end of the comparator is connected to the output end of the filter circuit, the second end of the sampling resistor and the power input end of the radio frequency power amplifier respectively, and the output end of the comparator is connected to the input end of the push-pull circuit; The output end of the push-pull circuit is connected to the power input end of the radio frequency power amplifier through an inductor.

2. According to claim 1, the anti-interference power supply circuit based on constant envelope tracking technology, It is characterized in that It also includes a control unit for determining whether there is interference in the current working frequency band of the envelope input signal, and controlling the switching switch to switch to the first conducting state if there is no interference, and controlling the switching switch to switch to the second conducting state if there is interference.

3. The anti-interference power supply circuit based on constant envelope tracking technology according to claim 2, It is characterized in that The control unit is specifically used for: Acquire an interference frequency band list including at least one interference frequency band information; Determine whether the current working frequency band is in the interference frequency band list; If so, it is determined that interference exists in the current working frequency band.

4. The anti-interference power supply circuit based on constant envelope tracking technology according to any one of claims 1 to 3, It is characterized in that The filter circuit is a low-order filter circuit, a high-order filter circuit, a low-pass filter circuit or a high-pass filter circuit.

5. The anti-interference power supply circuit based on constant envelope tracking technology according to any one of claims 1 to 3, It is characterized in that The filter circuit is a fixed filter or an adjustable filter.

6. The anti-interference power supply circuit based on constant envelope tracking technology according to claim 1, It is characterized in that The filter circuit includes a filter resistor and a capacitor; The first end of the filter resistor is connected to the output end of the operational amplifier through a switching switch, the second end of the filter resistor and the first end of the capacitor are respectively connected to the power input end of the RF power amplifier, and the second end of the capacitor is grounded.

7. The anti-interference power supply circuit based on constant envelope tracking technology according to claim 6, It is characterized in that The capacitor is a tunable capacitor.

8. The anti-interference power supply circuit based on constant envelope tracking technology according to claim 1, It is characterized in that The operational amplifier, the switching switch, the filtering circuit, the sampling resistor, the comparator and the push-pull circuit are packaged in the same chip.

9. The anti-interference power supply circuit based on constant envelope tracking technology according to claim 1, It is characterized in that The operational amplifier, the switching switch, the sampling resistor, the comparator and the push-pull circuit are packaged inside the same chip, and the filter circuit is arranged outside the chip.

10. The anti-interference power supply circuit based on constant envelope tracking technology according to claim 1, It is characterized in that The push-pull circuit includes two transistors or two field effect transistors.

Images