CN210168014U - Bias circuit for radio frequency power amplifier and radio frequency power amplifier - Google Patents
Bias circuit for radio frequency power amplifier and radio frequency power amplifier Download PDFInfo
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- CN210168014U CN210168014U CN201920947441.0U CN201920947441U CN210168014U CN 210168014 U CN210168014 U CN 210168014U CN 201920947441 U CN201920947441 U CN 201920947441U CN 210168014 U CN210168014 U CN 210168014U
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Abstract
Compared with the prior art, the bias circuit provided by the application is added with the feedback loop with the gain, and the feedback loop is insensitive to temperature, so that the bias circuit added with the feedback loop can amplify a temperature feedback signal generated by an HBT (heterojunction bipolar transistor) in the bias circuit, and the sensitivity of the bias circuit in feedback compensation of the temperature is improved, the influence of the temperature on the bias circuit can be relatively reduced, and the feedback loop is insensitive to the temperature, so that the bias circuit is not provided with variables caused by the temperature change of the feedback loop. Therefore, the influence degree of the bias circuit in the radio frequency power amplifier on temperature change is relatively reduced, so that the change amplitude of the output current of the radio frequency power amplifier can be obviously reduced.
Description
Technical Field
The utility model relates to a power electronic technology field, in particular to a bias circuit and radio frequency power amplifier for radio frequency power amplifier.
Background
With the rapid development of wireless communication technology, people put higher and higher requirements on performance indexes of communication systems. As an important component of a wireless communication system, the linearity of a radio frequency power amplifier is particularly important, and a radio frequency power amplifier in the radio frequency power amplifier mainly adopts an HBT (Heterojunction Bipolar Transistor), but the power characteristics of the HBT in the actual operation process are often limited by high temperature response due to poor heat conductivity of the HBT, so in the actual application, temperature compensation needs to be performed on a bias circuit in the radio frequency power amplifier. Referring to fig. 1, fig. 1 is a circuit diagram illustrating a bias circuit in a radio frequency power amplifier for temperature compensation in the prior art, in the bias circuit, since the overall feedback gain of the bias circuit is very low, the temperature compensation effect of the bias circuit is poor, and thus the variation amplitude of the output current of the radio frequency power amplifier is large. For the technical problem, no effective solution exists at present.
Therefore, it is an urgent technical problem to be solved by those skilled in the art how to further reduce the variation amplitude of the output current of the rf power amplifier.
SUMMERY OF THE UTILITY MODEL
In view of the above, the present invention provides a bias circuit for an rf power amplifier to reduce the amplitude of the variation of the output current of the rf power amplifier. The specific scheme is as follows:
a bias circuit for a radio frequency power amplifier, comprising: the first resistor, the second resistor, the third resistor, the fourth resistor, the first capacitor, the second capacitor, the third capacitor, the first HBT, the second HBT, the third HBT and the inductor; wherein, the first end of the first resistor is connected with VCC, the second end of the first resistor is connected with the collector of the first HBT, the emitter of the first HBT is respectively connected with the first end of the second resistor and the first end of the third resistor, the base of the first HBT is respectively connected with the anode of the first capacitor and the first end of the fourth resistor, the cathode of the first capacitor is grounded, the second end of the fourth resistor is connected with Vref, the first end of the fourth resistor is also connected with the collector of the second HBT, the emitter of the second HBT is grounded, the base of the second HBT is connected with the second end of the third resistor, the second end of the second resistor is respectively connected with the first end of the second capacitor and the base of the third HBT, the second end of the second capacitor is the input end of the radio frequency circuit, the emitter of the third HBT is grounded, the collector of the third HBT is respectively connected with the first end of the third capacitor and the inductor, the second end of the third capacitor is the output end of the radio frequency circuit; further comprising: a feedback loop with a gain, and the feedback loop is insensitive to temperature; and the feedback loop is connected in series on a branch where the fourth resistor and the first capacitor are located.
Preferably, the feedback loop specifically includes:
a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a fourth HBT, and a fifth HBT;
a first end of the fifth resistor and a first end of the sixth resistor are respectively connected with Vref, a second end of the fifth resistor is connected with a collector of the fourth HBT, an emitter of the fourth HBT is connected with a first end of a seventh resistor, a second end of the sixth resistor is connected with a collector of the fifth HBT, an emitter of the fifth HBT is connected with a first end of the eighth resistor, a second end of the eighth resistor is respectively connected with a second end of the seventh resistor and a first end of the ninth resistor, a second end of the ninth resistor is grounded, a base of the fourth HBT is respectively connected with a first end of the tenth resistor and a first end of the eleventh resistor, a second end of the tenth resistor is connected with Vref, and a second end of the eleventh resistor is grounded; the base electrode of the fourth HBT and the base electrode of the fifth HBT are a first signal input terminal and a second signal input terminal, respectively, and the second terminal of the fifth resistor is a signal output terminal.
Preferably, the fifth resistor and the sixth resistor have the same resistance, the seventh resistor and the eighth resistor have the same resistance, and the fourth HBT and the fifth HBT have the same specification parameters.
Correspondingly, the utility model also discloses a radio frequency power amplifier, includes the bias circuit for radio frequency power amplifier as aforementioned discloses.
It is thus clear that in the utility model discloses in, through the feedback loop who adds the gain in radio frequency power amplifier's bias circuit, can amplify the temperature feedback signal that is produced by first HBT and second HBT in the bias circuit to improve the sensitivity when the bias circuit carries out feedback compensation to the temperature from this, thereby can reduce the influence of temperature to the bias circuit, and, because this feedback loop is insensitive to the temperature, just so can not bring the variable that arouses because feedback loop temperature variation for the bias circuit. Therefore, through the utility model provides a biasing circuit for radio frequency power amplifier, owing to reduced the influence degree that biasing circuit among the radio frequency power amplifier received temperature variation relatively, just so can show the change amplitude that reduces radio frequency power amplifier output current. Correspondingly, the utility model discloses a radio frequency power amplifier has above-mentioned beneficial effect equally.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
Fig. 1 is a circuit diagram illustrating a prior art temperature compensation for a bias circuit in a radio frequency power amplifier;
fig. 2 is a block diagram of a bias circuit for a radio frequency power amplifier according to an embodiment of the present invention;
fig. 3 is a structural diagram of a bias circuit according to an embodiment of the present invention;
fig. 4 is a block diagram of another bias circuit for an rf power amplifier according to an embodiment of the present invention;
FIG. 5 is a diagram illustrating a variation of an output current of an RF power amplifier according to the prior art;
fig. 6 is a schematic diagram illustrating a variation of an output current of a radio frequency power amplifier according to an embodiment of the present invention.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
Referring to fig. 2, fig. 2 is a bias circuit for a radio frequency power amplifier according to an embodiment of the present invention, the bias circuit includes: the method comprises the following steps: a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a first capacitor C1, a second capacitor C2, a third capacitor C3, a first HBT1, a second HBT and a third HBT; wherein a first terminal of the first resistor R1 is connected to VCC, a second terminal of the first resistor R1 is connected to a collector of the first HBT1, an emitter of the first HBT1 is connected to a first terminal of the second resistor R2 and a first terminal of the third resistor R3, respectively, a base of the first HBT1 is connected to a positive terminal of the first capacitor C1 and a first terminal of the fourth resistor R4, a negative terminal of the first capacitor C1 is grounded, a second terminal of the fourth resistor R4 is connected to Vref, a first terminal of the fourth resistor R4 is further connected to a collector of the second HBT, an emitter of the second HBT is grounded, a base of the second HBT is connected to a second terminal of the third resistor R3, a second terminal of the second resistor R2 is connected to a first terminal of the second capacitor C2 and a base of the third HBT, a second terminal of the second capacitor C2 is an input terminal of the radio frequency circuit, a base of the third HBT is connected to a ground, a collector of the third HBT is connected to a collector of the third HBT 3, the second end of the third capacitor C3 is the output end of the radio frequency circuit; further comprising: a feedback loop with gain, and the feedback loop is insensitive to temperature; the feedback loop is connected in series on a branch where the fourth resistor R4 and the first capacitor C1 are located.
Referring to fig. 1, in the rf power amplifier, since the area of the transistor in the rf circuit is much larger than that of the transistor in the bias circuit, the temperature of the rf circuit rises faster than that of the bias circuit in the operating environment, specifically, referring to fig. 1, the voltage difference between the base and the emitter of the third HBT is larger than that of the first HBT, that is, Δ Vbe3＞ΔVbe1(ii) a At this time, the potential at the point X is decreased, and if the rf power amplifier is to return to the normal operation state, the potential at the point X must be increased.
Specifically, in fig. 1, Δ V is caused because the temperature of the rf circuit rises faster than the temperature of the bias circuitbe3＞ΔVbe1The potential at point X decreases, and at this time, the potential at point Y is: vY＝Vref-Ic2R4Wherein V isYIs the potential of Y point, VrefIs a reference voltage, Ic2Is the current of the collector of the second HBT, R4Is the resistance value of the fourth resistor; obviously, in this case, the potential at the Y point is in a rising state, and at this time, V is in a rising stateb2＝Vref-(Ic1+Ib2)R1Wherein V isb2Is the voltage of the base of the second HBT, VrefIs a reference voltage, Ic1Is the current of the collector of the first HBT, Ib2Is the current of the base of the second HBT, R1As the resistance value of the first resistor, it is conceivable that the potential at the X point is raised when the potential at the Y point is raised.
Referring to fig. 2, since a feedback loop with gain is added to the bias circuit of the rf power amplifier, and since the feedback loop is not sensitive to temperature, in the present embodiment, the current I of the collector of the second HBTc2Current I compared to collector of second HBT in prior art radio frequency power amplifierc2Will be reduced, and the potential expression V from Y point will be reducedY＝Vref-Ic2R4It is understood that, at this time, the potential at the Y point is increased as compared with the potential at the Y point in the conventional art. In this case, the potential at the point X is increased compared with the potential at the point X in the prior art, thereby relatively increasing the compensation effect of the bias circuit on the temperature compensation. As a result, the magnitude of the change in the output current in the rf power amplifier is relatively small.
It is thus clear that in the utility model discloses in, through the feedback loop who adds the gain in radio frequency power amplifier's bias circuit, can amplify the temperature feedback signal that is produced by first HBT and second HBT in the bias circuit to improve the sensitivity when the bias circuit carries out feedback compensation to the temperature from this, thereby can reduce the influence of temperature to the bias circuit, and, because this feedback loop is insensitive to the temperature, just so can not bring the variable that arouses because feedback loop temperature variation for the bias circuit. Therefore, through the utility model provides a biasing circuit for radio frequency power amplifier, owing to reduced the influence degree that biasing circuit among the radio frequency power amplifier received temperature variation relatively, just so can show the change amplitude that reduces radio frequency power amplifier output current.
Based on the above embodiments, the present embodiment further describes and optimizes the technical solution, please refer to fig. 3, and fig. 3 is a structural diagram of a feedback loop provided by an embodiment of the present invention. Specifically, the feedback loop specifically includes:
a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a fourth HBT and a fifth HBT;
a first terminal of a fifth resistor R5 and a first terminal of a sixth resistor R6 are respectively connected to Vref, a second terminal of a fifth resistor R5 is connected to a collector of the fourth HBT, an emitter of the fourth HBT is connected to a first terminal of a seventh resistor R7, a second terminal of the sixth resistor R6 is connected to a collector of the fifth HBT, an emitter of the fifth HBT is connected to a first terminal of an eighth resistor R8, a second terminal of an eighth resistor R8 is respectively connected to a second terminal of the seventh resistor R7 and a first terminal of the ninth resistor R9, a second terminal of the ninth resistor R9 is grounded, a base of the fourth HBT is respectively connected to a first terminal of the tenth resistor R10 and a first terminal of the eleventh resistor R11, a second terminal of the tenth resistor R10 is connected to Vref, and a second terminal of the eleventh resistor R11 is grounded; the base of the fourth HBT and the base of the fifth HBT are a first signal input terminal and a second signal input terminal, respectively, and the second terminal of the fifth resistor R5 is a signal output terminal.
In this embodiment, a specific structure diagram of a feedback loop with gain is provided, please refer to fig. 4, the overall structure of the feedback loop is a symmetric differential amplifier, it can be understood that the differential amplifier is an electronic amplifier capable of amplifying the voltage difference between two input terminals with a fixed gain, and it has the following two characteristics:
1) the differential amplifier amplifies the differential mode signal, specifically, when the input signal of the differential amplifier is the differential mode signal vId, that is, two voltage signals with equal magnitude and opposite polarity are input at the two input ends V1 and V2 of the differential amplifier, which results in the voltage increment at the two output ends of the differential amplifier, that is, the two output ends of the differential amplifier output two voltages vod with equal magnitude and opposite polarity1And vod2The output voltage of the differential amplifier is V0＝vod1-vod2＝2vod1Vod. It follows that the differential amplifier is capable of efficiently amplifying differential mode signals.
2) Difference (D)Specifically, when the input signal of the differential amplifier is the common mode signal vIc, that is, two voltage signals with the same magnitude and the same polarity are input to the two input ends V1 and V2 of the differential amplifier, this will result in a voltage increment of the two output ends of the differential amplifier to ground, that is, the two output ends of the differential amplifier will output two voltages voc with the same magnitude and the same polarity1And voc2At this time, the output voltage of the differential amplifier is V0＝voc1-voc 20. It follows that the differential amplifier is also capable of effectively rejecting common mode signals.
Referring to fig. 4, fig. 4 is a schematic diagram of another bias circuit for an rf power amplifier according to an embodiment of the present invention. Since the voltage V1 at the two input terminals of the differential amplifier is V2 at normal temperature, the differential amplifier is in a common mode at normal temperature.
It will be appreciated that when the circuit diagram of figure 4 is in operation, the temperature of the rf circuit rises more rapidly than the temperature of the bias circuit, resulting in avbe3＞ΔVbe1At this time, the potential at the point X is lowered, and since the potential at the point Y is: vY＝Vref-Ic2R4Therefore, in this case, the potential at the Y point rises; and because of Vb2＝Vref-(Ic1+Ib2)R1Therefore, at this time, the potential at the point Z also rises, and since the feedback loop in this embodiment is a feedback loop with a gain, the potential at the point X also rises further due to the gain of the feedback loop. Obviously, compared with the prior art, because the feedback loop performs voltage boosting on the bias circuit twice, the voltage at the point X can be further boosted by the method provided in this embodiment, that is, by the method in this embodiment, the degree of influence of temperature change on the bias circuit in the radio frequency power amplifier can be relatively reduced, so that the change amplitude of the output current of the radio frequency power amplifier can be greatly reduced.
Specifically, referring to fig. 5 and fig. 6, fig. 5 is a schematic diagram illustrating a variation of an output current of a radio frequency power amplifier in the prior art; fig. 6 is a schematic diagram illustrating a variation of an output current of a radio frequency power amplifier according to an embodiment of the present invention; as shown in fig. 5, when the rf power amplifier operates at-20 ℃ to 80 ℃, the amplitude of the change in the output current of the rf power amplifier is 13mA, and as shown in fig. 6, when the rf power amplifier operates at-20 ℃ to 80 ℃, the amplitude of the change in the output current of the rf power amplifier is 6.68 mA.
Therefore, the technical scheme provided by the embodiment can obviously reduce the change amplitude of the output current of the radio frequency power amplifier.
In a preferred embodiment, the fifth resistor and the sixth resistor have the same resistance, the seventh resistor and the eighth resistor have the same resistance, and the fourth HBT and the fifth HBT have the same specification parameters.
Specifically, in the present embodiment, under the condition that the differential amplifier is symmetrical in circuit, the fifth resistor R5 and the sixth resistor R6 are set to be resistors with equal resistance values, the seventh resistor R7 and the eighth resistor R8 are set to be resistors with equal resistance values, and the fourth HBT and the fifth HBT are set to be HBTs with the same specification parameters, so that the differential amplifier in the feedback loop becomes a differential amplifier with symmetrical structure, and thus the differential amplifier has stronger zero point suppression capability, interference resistance capability and noise suppression capability, and thus the operation state of the bias circuit is more stable and reliable.
Therefore, the technical scheme provided by the embodiment can further ensure the safety and stability of the radio frequency power amplifier in the operation process.
Correspondingly, the utility model also discloses a radio frequency power amplifier, including aforementioned a biasing circuit who discloses for radio frequency power amplifier.
The utility model discloses a radio frequency power amplifier has aforementioned a biasing circuit's for radio frequency power amplifier beneficial effect who discloses.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (4)
1. A bias circuit for a radio frequency power amplifier, comprising: the first resistor, the second resistor, the third resistor, the fourth resistor, the first capacitor, the second capacitor, the third capacitor, the first HBT, the second HBT, the third HBT and the inductor; wherein, the first end of the first resistor is connected with VCC, the second end of the first resistor is connected with the collector of the first HBT, the emitter of the first HBT is respectively connected with the first end of the second resistor and the first end of the third resistor, the base of the first HBT is respectively connected with the anode of the first capacitor and the first end of the fourth resistor, the cathode of the first capacitor is grounded, the second end of the fourth resistor is connected with Vref, the first end of the fourth resistor is also connected with the collector of the second HBT, the emitter of the second HBT is grounded, the base of the second HBT is connected with the second end of the third resistor, the second end of the second resistor is respectively connected with the first end of the second capacitor and the base of the third HBT, the second end of the second capacitor is the input end of the radio frequency circuit, the emitter of the third HBT is grounded, the collector of the third HBT is respectively connected with the first end of the third capacitor and the inductor, the second end of the third capacitor is the output end of the radio frequency circuit; it is characterized by also comprising: a feedback loop with a gain, and the feedback loop is insensitive to temperature; and the feedback loop is connected in series on a branch where the fourth resistor and the first capacitor are located.
2. The bias circuit for a radio frequency power amplifier according to claim 1, wherein the feedback loop specifically comprises:
a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a fourth HBT, and a fifth HBT;
a first end of the fifth resistor and a first end of the sixth resistor are respectively connected with Vref, a second end of the fifth resistor is connected with a collector of the fourth HBT, an emitter of the fourth HBT is connected with a first end of a seventh resistor, a second end of the sixth resistor is connected with a collector of the fifth HBT, an emitter of the fifth HBT is connected with a first end of the eighth resistor, a second end of the eighth resistor is respectively connected with a second end of the seventh resistor and a first end of the ninth resistor, a second end of the ninth resistor is grounded, a base of the fourth HBT is respectively connected with a first end of the tenth resistor and a first end of the eleventh resistor, a second end of the tenth resistor is connected with Vref, and a second end of the eleventh resistor is grounded; the base electrode of the fourth HBT and the base electrode of the fifth HBT are a first signal input terminal and a second signal input terminal, respectively, and the second terminal of the fifth resistor is a signal output terminal.
3. The bias circuit of claim 2, wherein said fifth resistor and said sixth resistor have equal resistance values, said seventh resistor and said eighth resistor have equal resistance values, and said fourth HBT and said fifth HBT have equal specification parameters.
4. A radio frequency power amplifier comprising a bias circuit for a radio frequency power amplifier according to any one of claims 1 to 3.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201920947441.0U CN210168014U (en) | 2019-06-20 | 2019-06-20 | Bias circuit for radio frequency power amplifier and radio frequency power amplifier |
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| CN201920947441.0U CN210168014U (en) | 2019-06-20 | 2019-06-20 | Bias circuit for radio frequency power amplifier and radio frequency power amplifier |
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| CN210168014U true CN210168014U (en) | 2020-03-20 |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110113014A (en) * | 2019-06-20 | 2019-08-09 | 广东工业大学 | A kind of biasing circuit and radio-frequency power amplifier for radio-frequency power amplifier |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110113014A (en) * | 2019-06-20 | 2019-08-09 | 广东工业大学 | A kind of biasing circuit and radio-frequency power amplifier for radio-frequency power amplifier |
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Effective date of registration: 20220224 Address after: 510700 Room 305, No. 11, caipin Road, Huangpu District, Guangzhou, Guangdong Patentee after: Zhenzhi microchip (Guangzhou) Technology Co.,Ltd. Address before: No.729, Dongfeng East Road, Yuexiu District, Guangzhou City, Guangdong Province 510060 Patentee before: GUANGDONG University OF TECHNOLOGY |