Power detection circuit and method and power detector

Abstract

The invention provides a power detection circuit and method and a power detector. A switching tube module is used for generating an output signal according to a preset input signal; the capacitance shunting module is used for shunting an alternating current signal in the output signal, so that the shunted first signal flows into the capacitance shunting module; and the direct current generation module is used for filtering residual signals in the alternating current signals and outputting a voltage result according to direct current signals in the output signals. The capacitance shunting module is additionally arranged at the output end of the switching tube module, when the frequency of the preset input signal is higher, the first signal flowing into the capacitance shunting module in the alternating current signal is more, and correspondingly, the residual signal flowing into the direct current generation module is less, so that the alternating current voltage swing generated by the parasitic inductor can be effectively controlled, and the stability of the device is improved. When the power supply voltage is low voltage, it can be ensured that the switch tube in the switch tube module works in a normal bias state, and then the accuracy of the corresponding relation between the finally output voltage result and the input signal is improved.

Description

Technical Field

[0001] The present invention relates to the field of circuit technologies, and in particular, to a power detection circuit, method, and power detector. Background Art

[0002] In the microwave power detector of the prior art, the main principle generally is that after the input signal passes through a switching tube, the DC current generated by the switching tube will increase, and at the same time, harmonic components such as the fundamental wave, second harmonic, and third harmonic of the input signal are also generated, and finally a voltage drop is generated on the resistor of the subsequent circuit. The common problem in the current technical solutions is that when the input signal is large, the AC current signal generated in the switching tube is also relatively large. When this AC current signal flows through the metal wire connected to the subsequent circuit, at high frequencies, the metal wire will exhibit inductive characteristics. At this time, it is equivalent to a large current flowing through an inductor, which will generate a relatively large voltage swing. Moreover, if the power supply voltage is low, the excessive voltage swing will cause the switching tube to enter the linear region, which directly affects the accuracy of the corresponding relationship between the final output voltage and the input signal. Summary of the Invention

[0003] The purpose of the present invention is to provide a power detection circuit, method, and power detector to improve the accuracy of the corresponding relationship between the final output voltage and the input signal.

[0004] A power detection circuit provided by the present invention includes: a switching tube module, a capacitor shunt module, and a DC generation module; the output end of the switching tube module is respectively connected to the input end of the DC generation module and the capacitor shunt module; there is a parasitic inductance between the switching tube module and the DC generation module; the switching tube module is used to generate an output signal according to a received preset input signal; wherein, the output signal includes: a DC signal and an AC signal; the capacitor shunt module is used to shunt the AC signal so that the shunted first signal flows into the capacitor shunt module; wherein, the higher the frequency of the preset input signal, the smaller the impedance of the capacitor shunt module, and the more the first signal flowing into the capacitor shunt module; the DC generation module is used to filter the remaining signal in the AC signal except the first signal and output a voltage result according to the DC signal.

[0005] Further, the preset input signal includes: a preset DC voltage and a sine wave voltage signal; the switching tube module includes: a first resistor, the first end of the first resistor is connected to the DC voltage; a first capacitor, the first end of the first capacitor is connected to the sine wave voltage signal; a first switching tube, having a first end, a second end, and a third end, the first end of the first switching tube is respectively connected to the second end of the first resistor and the second end of the first capacitor; the second end of the first switching tube is respectively connected to the input end of the DC generation module and the capacitor shunt module; the third end of the first switching tube is grounded.

[0006] Further, the capacitance shunt module includes: a shunt capacitor, the first end of the shunt capacitor is connected to the second end of the first switching transistor; the second end of the shunt capacitor is grounded.

[0007] Further, the AC signal includes: a fundamental frequency component and a harmonic component.

[0008] Further, the DC generation module includes: a second switching transistor having a first end, a second end and a third end, the first end of the second switching transistor is connected to a power supply; the second end of the second switching transistor is connected to the second end of the first switching transistor; a second resistor, the first end of the second resistor is connected to the third end of the second switching transistor; a second capacitor, the first end of the second capacitor is connected to the power supply, the second end of the second capacitor is connected to the second end of the second resistor; a third switching transistor having a first end, a second end and a third end, the first end of the third switching transistor is connected to the power supply, the third end of the third switching transistor is connected to the second end of the second capacitor; a third resistor, the first end of the third resistor is connected to the second end of the third switching transistor; the second end of the third resistor is grounded, and a voltage result is output through the first end of the third resistor.

[0009] Further, the voltage result is the product of the DC signal and the third resistor.

[0010] Further, the first switching transistor is: a MOS transistor or a BJT transistor.

[0011] Further, the switching transistor module and the DC generation module are connected by a metal wire. The longer the length of the metal wire, the greater the parasitic inductance, and the smaller the diameter of the metal wire, the greater the parasitic inductance.

[0012] A power detection method provided by the present invention, the method includes: the switching transistor module generates an output signal according to a received preset input signal; wherein, the output signal includes: a DC signal and an AC signal; the capacitance shunt module shunts the AC signal so that the shunted first signal flows into the capacitance shunt module; wherein, the higher the frequency of the preset input signal, the smaller the impedance of the capacitance shunt module, and the more the first signal flowing into the capacitance shunt module; the DC generation module filters the remaining signal in the AC signal except the first signal and outputs a voltage result according to the DC signal.

[0013] A power detector provided by the present invention includes the power detection circuit of any one of the above.

[0014] The power detection circuit, method and power detector provided by the present invention add a capacitor shunt module at the output end of the switching transistor module. When the frequency of the preset input signal is higher, more of the first signal in the AC signal flows into the capacitor shunt module, and correspondingly, less of the remaining signal flows into the DC generation module. In this way, the AC voltage swing generated by the parasitic inductance can be effectively controlled. When the power supply voltage is low, it can ensure that the switching transistors in the switching transistor module operate in a normal bias state, thereby improving the accuracy of the correspondence between the finally output voltage result and the input signal. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0016] Figure 1 Schematic diagram of a power detection circuit provided by an embodiment of the present invention;

[0017] Figure 2 Schematic diagram of a power detection circuit provided by an embodiment of the present invention;

[0018] Figure 3 Flowchart of a power detection method provided by an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the protection scope of the present invention.

[0020] In the existing microwave power detector, when the input signal is large, the AC current signal generated in the switching transistor is also relatively large. When this AC current signal flows through the metal wire connected to the subsequent circuit, at high frequencies, the metal wire will exhibit inductive characteristics. At this time, it is equivalent to a large current flowing through an inductor, which will generate a relatively large voltage swing. Moreover, if the power supply voltage is low, the excessive voltage swing will cause the switching transistor to enter the linear region, which directly affects the accuracy of the correspondence between the finally output voltage and the input power. Based on this, the embodiments of the present invention provide a power detection circuit, method and power detector, and this technology can be applied to applications that need to eliminate the non-ideal characteristics in power detection.

[0021] To facilitate the understanding of this embodiment, first, a power detection circuit disclosed in the embodiments of the present invention will be introduced. As Figure 1 shown, the circuit includes: a switch tube module 10, a capacitor shunt module 11, and a DC generation module 12; the output end of the switch tube module 10 is respectively connected to the input end of the DC generation module 12 and the capacitor shunt module 11; there is a parasitic inductance between the switch tube module 10 and the DC generation module 12; this parasitic inductance generally refers to the inductance generated by the connection line between the switch tube module 10 and the DC generation module 12.

[0022] The switch tube module 10 is used to generate an output signal according to the received preset input signal; wherein, the output signal includes: a DC signal and an AC signal; the capacitor shunt module 11 is used to shunt the AC signal so that the shunted first signal flows into the capacitor shunt module 11; wherein, the higher the frequency of the preset input signal, the smaller the impedance of the capacitor shunt module 11, and the more the first signal flowing into the capacitor shunt module 11; the DC generation module 12 is used to filter the remaining signal in the AC signal except the first signal and output a voltage result according to the DC signal.

[0023] The above-mentioned DC signal generally refers to a DC current, and the AC signal refers to an AC current; in actual implementation, after the preset input signal passes through the switch tube module 10, a DC current and an AC current can be generated. Since the output end of the switch tube module 10 is respectively connected to the input end of the DC generation module 12 and the capacitor shunt module 11, therefore, the capacitor shunt module 11 will shunt a part of the AC signal, and moreover, when the frequency of the preset input signal is higher, the high-frequency component in the AC signal will also increase. However, since the higher the frequency of the preset input signal, the smaller the impedance of the capacitor shunt module 11, therefore, in the AC signal, the more the high-frequency first signal shunted to the capacitor shunt module 11, correspondingly, in the AC signal, the less the high-frequency remaining signal flowing into the DC generation module 12. The DC generation module 12 filters out the remaining signal in the AC signal through filtering, leaving only the DC signal related to the amplitude of the input signal. Based on this DC signal, a voltage result can be output.

[0024] In the above power detection circuit, by adding a capacitor shunt module at the output end of the switch tube module, when the frequency of the preset input signal is higher, the more the first signal in the AC signal flowing into the capacitor shunt module, and correspondingly, the less the remaining signal flowing into the DC generation module. In this way, the AC voltage swing generated by the parasitic inductance can be effectively controlled. When the power supply voltage is low, it can ensure that the switch tube in the switch tube module works in a normal bias state, thereby improving the accuracy of the corresponding relationship between the finally output voltage result and the input signal.

[0025] Further, as Figure 2Schematic diagram of a power detection circuit. The preset input signal includes: a preset DC voltage Vb and a sine wave voltage signal Vin. The switching transistor module includes: a first resistor R1, a first capacitor C1, and a first switching transistor T1. The resistance value of the first resistor R1 and the capacitance value of the first capacitor C1 can both be set according to actual requirements. The first switching transistor T1 can be a suitable switching transistor selected according to actual requirements, which is not limited here.

[0026] The first end of the first resistor R1 is connected to the DC voltage Vb. The voltage value of the DC voltage Vb can be set as needed to establish an appropriate operating condition for the first switching transistor T1.

[0027] The first end of the first capacitor C1 is connected to the sine wave voltage signal Vin. The frequency of the sine wave voltage signal Vin can also be set according to actual requirements, which is not limited here.

[0028] The first switching transistor T1 has a first end, a second end, and a third end. The first end of the first switching transistor T1 is respectively connected to the second end of the first resistor R1 and the second end of the first capacitor C1. The second end of the first switching transistor T1 is respectively connected to the input end of the DC generation module and the capacitor shunt module. The third end of the first switching transistor T1 is grounded. For example, as Figure 2 shown, taking the first switching transistor T1 as an NPN-type BJT transistor as an example, the first end can be the base of the NPN-type BJT transistor, the second end can be the collector of the NPN-type BJT transistor, and the third end can be the emitter of the NPN-type BJT transistor. The base of the NPN-type BJT transistor is respectively connected to the second end of the first resistor R1 and the second end of the first capacitor C1, the emitter is grounded, and the collector is respectively connected to the input end of the external DC generation module and the capacitor shunt module.

[0029] Furthermore, as Figure 2 shown, the capacitor shunt module includes: a shunt capacitor Cfilter. The first end of the shunt capacitor Cfilter is connected to the second end of the first switching transistor T1. The second end of the shunt capacitor Cfilter is grounded. In actual implementation, the capacitor shunt module can be realized only by a shunt capacitor Cfilter. The capacitance value of the shunt capacitor Cfilter can be set according to actual requirements. Generally, the larger the capacitance value of the shunt capacitor Cfilter, the smaller the capacitive impedance of the shunt capacitor Cfilter. When the capacitance value of the shunt capacitor Cfilter is set large enough, the capacitive impedance of the shunt capacitor Cfilter will be very small, and the hindrance to the alternating current will be smaller, and correspondingly, more alternating current will be shunted to the shunt capacitor Cfilter.

[0030] Furthermore, the AC signal includes a fundamental frequency component and harmonic components; in actual implementation, the AC signal generated by the switching transistor module usually includes a fundamental frequency component and harmonic components such as the second harmonic and the third harmonic.

[0031] Furthermore, as Figure 2 shown, the DC generation module includes: a second switching transistor MP1, a second resistor R2, a second capacitor C2, a third switching transistor MP2, and a third resistor Ro; the second switching transistor MP1 and the third switching transistor MP2 can both be appropriate switching transistors selected according to actual requirements. For example, MOS transistors can be selected, etc., which are not limited here; the resistance values of the second resistor R2 and the third resistor Ro, as well as the capacitance value of the second capacitor C2, can all be selected as needed.

[0032] The second switching transistor MP1 has a first terminal, a second terminal, and a third terminal. The first terminal of the second switching transistor MP1 is connected to the power supply VDD; the second terminal of the second switching transistor MP1 is connected to the second terminal of the first switching transistor T1; the first terminal of the second resistor R2 is connected to the third terminal of the second switching transistor MP1; the first terminal of the second capacitor C2 is connected to the power supply VDD, and the second terminal of the second capacitor C2 is connected to the second terminal of the second resistor R2;

[0033] The third switching transistor MP2 has a first terminal, a second terminal, and a third terminal. The first terminal of the third switching transistor MP2 is connected to the power supply VDD, and the third terminal of the third switching transistor MP2 is connected to the second terminal of the second capacitor C2; the first terminal of the third resistor Ro is connected to the second terminal of the third switching transistor MP2; the second terminal of the third resistor Ro is grounded, and the voltage result Vo is output through the first terminal of the third resistor Ro.

[0034] Furthermore, the voltage result Vo is the product of the DC signal and the third resistor. That is, the voltage result Vo is the voltage related to the input signal generated on the third resistor Ro after the DC signal passes through it.

[0035] Furthermore, the first switching transistor is a MOS transistor or a BJT transistor, which can be specifically selected according to actual requirements.

[0036] Furthermore, the switching transistor module and the DC generation module are connected by a metal wire. The longer the length of the metal wire, the greater the parasitic inductance, and the smaller the diameter of the metal wire, the greater the parasitic inductance. For example, Figure 2For example, there is a parasitic inductance Lparasitic between the second terminal of the first switching transistor and the second terminal of the second switching transistor. This parasitic inductance Lparasitic is not an actually artificially added device, but an additional inductance generated by the metal wire during current transmission due to factors such as the length and shape of the metal wire. Generally, the longer the metal wire, the larger the parasitic inductance, and the smaller the diameter of the metal wire, the larger the parasitic inductance. Therefore, it is necessary to design a reasonable metal wire length, diameter, etc. according to actual needs to minimize the parasitic inductance as much as possible.

[0037] As Figure 2 shown, under the excitation of the sine wave voltage signal Vin, the first switching transistor T1 will generate a radio frequency current i_rf (corresponding to the above-mentioned AC signal) and a direct current i_dc (corresponding to the above-mentioned DC signal). The radio frequency current i_rf is filtered out by the filtering action of the second resistor R2 and the second capacitor C2, while the direct current i_dc generates a voltage result Vo = i_dc × Ro related to the input signal on the third resistor Ro. However, in actual circuit layout, a certain parasitic inductance Lparasitic will be generated between the first switching transistor T1 and the second switching transistor MP1. In the prior art, if the frequency of the input sine wave voltage signal Vin is very high, a large voltage swing will be generated when the radio frequency current i_rf flows through the parasitic inductance Lparasitic. Especially in the case of a low power supply voltage and a large input signal power, in this way, the first switching transistor T1 will have the risk of entering the linear region, and then the circuit state will change. Therefore, in this solution, a shunt capacitor Cfilter will be added in parallel at the output of the first switching transistor T1. Thus, the radio frequency current i_rf will be shunted between the parasitic inductance Lparasitic and the shunt capacitor Cfilter. As Figure 2 shown in the figure, the current flowing through the parasitic inductance Lparasitic is i_rf_L, and the current flowing through the shunt capacitor Cfilter is i_rf_C. At high frequencies, when the shunt capacitor Cfilter is large enough, the capacitance impedance will be very small, while the inductance impedance of the parasitic inductance Lparasiticd will become large. At this time, most of the alternating current will flow through the shunt capacitor Cfilter and will not enter the branch of the parasitic inductance Lparasitic. In this way, the AC voltage swing generated by the parasitic inductance Lparasitic will be greatly reduced, ensuring the normal operation of the first switching transistor T1.

[0038] The above power detection circuit can eliminate the problem of large RF voltage swings caused by the inductance of the subsequent stage trace in the case of high-frequency large-signal input of the power detector, ensuring that the first switching transistor operates in a normal bias state, thereby effectively eliminating the influence caused by the non-ideal characteristics in the microwave power detector.

[0039] An embodiment of the present invention discloses a power detection method, asFigure 3 As shown in the figure, the method includes the following steps:

[0040] Step S302, the switching tube module generates an output signal according to the received preset input signal; wherein, the output signal includes: a DC signal and an AC signal;

[0041] Step S304, the capacitor shunt module shunts the AC signal so that the shunted first signal flows into the capacitor shunt module; wherein, the higher the frequency of the preset input signal, the smaller the impedance of the capacitor shunt module, and the more the first signal flowing into the capacitor shunt module;

[0042] Step S306, the DC generation module filters the remaining signal in the AC signal except the first signal and outputs a voltage result according to the DC signal.

[0043] In the above power detection method, when the frequency of the preset input signal is higher, the more the first signal flowing into the capacitor shunt module in the AC signal, and correspondingly, the less the remaining signal flowing into the DC generation module. In this way, the AC voltage swing generated by the parasitic inductance can be effectively controlled. When the power supply voltage is low, it can ensure that the switching tube in the switching tube module works in a normal bias state, thereby improving the accuracy of the corresponding relationship between the finally output voltage result and the input signal.

[0044] An embodiment of the present invention discloses a power detector, including the power detection circuit in the above embodiment.

[0045] The main principle of the microwave power detector is that after the sine wave voltage signal passes through the first switching tube, the DC current generated by the first switching tube will increase, and at the same time, harmonic components such as the fundamental wave, second harmonic, and third harmonic of the input signal will also be generated. The high-frequency components are filtered in the subsequent DC generation module, leaving only the DC current component related to the amplitude of the input signal, and a voltage drop is generated on the third resistor in the subsequent DC generation module as the finally output voltage result.

[0046] In the above power detector, in the case of a large microwave high-frequency signal input, the problem of large RF voltage swing caused by the inductance of the subsequent trace can be eliminated, ensuring that the first switching tube works in a normal bias state, thereby effectively eliminating the influence caused by the non-ideal characteristics of the microwave power detector.

[0047] Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A power detection circuit, characterized in that, The circuit includes: a switching transistor module, a capacitor shunting module, and a DC generation module; the output end of the switching transistor module is respectively connected to the input end of the DC generation module and the capacitor shunting module; there is a parasitic inductance between the switching transistor module and the DC generation module; The switching transistor module is used to generate an output signal according to a received preset input signal; wherein, the output signal includes: a DC signal and an AC signal; The capacitor shunting module is used to shunt the AC signal so that the shunted first signal flows into the capacitor shunting module; wherein, the higher the frequency of the preset input signal, the smaller the impedance of the capacitor shunting module, and the more the first signal flowing into the capacitor shunting module; The DC generation module is used to filter the remaining signal in the AC signal except the first signal and output a voltage result according to the DC signal.

2. The circuit according to claim 1, wherein The preset input signal includes: a preset DC voltage and a sine wave voltage signal; the switching transistor module includes: A first resistor, the first end of the first resistor is connected to the DC voltage; A first capacitor, the first end of the first capacitor is connected to the sine wave voltage signal; A first switching transistor, having a first end, a second end, and a third end, the first end of the first switching transistor is respectively connected to the second end of the first resistor and the second end of the first capacitor; the second end of the first switching transistor is respectively connected to the input end of the DC generation module and the capacitor shunting module; the third end of the first switching transistor is grounded.

3. The circuit according to claim 2, wherein The capacitor shunting module includes: A shunting capacitor, the first end of the shunting capacitor is connected to the second end of the first switching transistor; the second end of the shunting capacitor is grounded.

4. The circuit according to claim 1, wherein The AC signal includes: a fundamental frequency component and a harmonic component.

5. The circuit according to claim 2, wherein, The DC generation module includes: A second switching transistor, having a first end, a second end, and a third end, the first end of the second switching transistor is connected to a power supply; the second end of the second switching transistor is connected to the second end of the first switching transistor; A second resistor, the first end of the second resistor is connected to the third end of the second switching transistor; A second capacitor, the first end of the second capacitor is connected to the power supply, and the second end of the second capacitor is connected to the second end of the second resistor; A third switching transistor, having a first end, a second end, and a third end, the first end of the third switching transistor is connected to the power supply, and the third end of the third switching transistor is connected to the second end of the second capacitor; A third resistor, the first end of the third resistor is connected to the second end of the third switching transistor; the second end of the third resistor is grounded, and the voltage result is output through the first end of the third resistor.

6. The circuit according to claim 5, wherein The voltage result is the product of the DC signal and the third resistor.

7. The circuit according to claim 2, wherein The first switching transistor is: a MOS transistor or a BJT transistor.

8. The circuit according to claim 1, wherein The switching transistor module and the DC generation module are connected by a metal wire. The longer the length of the metal wire, the greater the parasitic inductance, and the smaller the diameter of the metal wire, the greater the parasitic inductance.

9. A power detection method, characterized in that, The method includes: The switching transistor module generates an output signal according to a received preset input signal; wherein, the output signal includes: a DC signal and an AC signal; The capacitive shunt module shunts the AC signal so that the shunted first signal flows into the capacitive shunt module; wherein, the higher the frequency of the preset input signal, the smaller the impedance of the capacitive shunt module, and the more the first signal flowing into the capacitive shunt module; The DC generation module filters the remaining signal in the AC signal except the first signal and outputs a voltage result according to the DC signal.

10. A power detector, characterized in that, It includes the power detection circuit according to any one of claims 1-8.

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