Temperature compensated bias circuit and power amplifier

Abstract

The present invention provides a temperature compensation bias circuit (100) including a third resistor (R3), a fourth resistor (R4), a fifth resistor (R5), a sixth resistor (R6), a seventh resistor (R7), a second capacitor (C2), a third capacitor (C3), a fifth capacitor (C5), a fifth transistor (T5), a sixth transistor (T6), and a seventh transistor (T7). The present invention also provides a power amplifier using the temperature compensation bias circuit (100). Compared with the related art, the adoption of the temperature compensation bias circuit (100) and the power amplifier of the present invention has little impact on the bias point under radio frequency operating conditions, and the power amplifier has good temperature compensation effect and high linearity.

Description

[Technical field]

[0001] The present invention relates to the field of amplifier circuits, and more particularly to temperature compensated bias circuits and power amplifiers. [Background technology]

[0002] At present, in the wireless transceiver system in the communication field, the radio frequency power amplifier (PA) is one of the key units in the wireless communication link, whose function is to amplify the electric signal with modulated modulation information to a certain power level, and excite the back-end antenna to generate the corresponding electromagnetic wave signal, so as to realize wireless signal transmission.

[0003] Here, the current power amplifier adopts GaAsHBT process, which has very poor thermal conductivity, and as the temperature increases, the thermal conductivity continues to decrease, so that when it operates under large signal conditions, it will cause considerable power loss and accumulate more heat, which is the self-heating effect. The base-emitter junction of the transistor can be regarded as a PN junction, so as the temperature increases, the electrons in the emitter region will be thermally excited, and the total number of transitioning electrons will gradually increase with the increase of temperature. Temperature affects the parameters of the transistor, and the static operating point of the transistor will change with the change of temperature due to the change of the parameters of the transistor. Therefore, solving the temperature drift of the transistor has always been an important task in transistor circuit design.

[0004] The temperature compensation bias circuit of the related art includes a voltage detection circuit, an overvoltage protection module, and a controlled bias circuit module. As shown in FIG. 1, FIG. 1 is an application circuit principle diagram of the temperature compensation bias circuit of the related art. The temperature compensation bias circuit shown is a temperature compensation bias circuit commonly used in the related art. Here, the temperature compensation bias circuit includes a first resistor R1, a second resistor R2, a first transistor T1, a second transistor T2, a third transistor T3, and a first capacitor C1. The temperature compensation bias circuit shown, the DC blocking resistor CIN, the choke inductor L1, and the power amplification transistor T4 together constitute a radio frequency power amplifier circuit. Here, the bias current of the power amplification transistor T4 is provided by a current mirror consisting of the first transistor T1 and the third transistor T3, and by adjusting the current limiting resistor R1, that is, adjusting the static current of the power amplification transistor T4, the first transistor T1 and the second transistor T2, which are used as diodes by connecting the base and collector, can cooperate with the ballast resistor R2 to play the role of temperature compensation.

[0005] However, when the temperature compensation bias circuit of the related art is actually applied, the temperature compensation bias circuit needs to concentrate the first transistor T1, the second transistor T2, the third transistor T3, and the power amplifier transistor T4 on the layout. The first transistor T1, the second transistor T2, the third transistor T3, and the power amplifier transistor T4 are in roughly the same temperature environment, and when the temperature rises, the current I of the power amplifier transistor T4 and the third transistor T3 be At the same time, under the influence of temperature rise, under the current mirror structure, the conduction current of the first transistor T1 and the second transistor T2 also increases, and according to the analysis of Ohm's law, the voltage drop across the first resistor R1 also increases, the base voltage of the third transistor T3 decreases, and the I beis reduced, which has the effect of suppressing temperature drift. However, such a solution has the following problems. To achieve optimal temperature compensation, the first transistor T1, the second transistor T2, the third transistor T3, and the power amplifier transistor T4 all need to operate in the same state and have the same temperature environment, and the parameters of the four transistor devices need to be perfectly consistent, which cannot be achieved in practical applications. We can only maximize the suppression of temperature drift by ensuring a centralized layout so that the temperature of each device, especially the first transistor T1, the second transistor T2, and the power amplifier transistor T4, is as constant as possible. Adjusting the second resistor R2, which is a ballast resistor, can also play a role in adjusting temperature compensation to a certain extent, but the second resistor R2 also affects the bias point under radio frequency operating conditions. Specifically, when a high-power radio frequency signal is input, the change in the gain curve and the change in linearity performance of the power amplifier are affected, and as shown in Figure 2, the resistance value of RA>the resistance value of RB>the resistance value of RC>the resistance value of RD. Therefore, the larger the resistance value of the second resistor R2, the smaller the gain. Therefore, how to design a bias circuit that reduces the influence of the ballast resistor on the bias point under radio frequency operating conditions and optimizes the temperature compensation effect and linearity of the power amplifier of the radio frequency amplifier circuit is a technical problem that needs to be urgently solved by those skilled in the art.

[0006] Therefore, to solve the above problems, it is necessary to provide a new temperature compensated bias circuit and power amplifier. Summary of the Invention [Problem to be solved by the invention]

[0007] In view of the above shortcomings in the prior art, the present invention provides a temperature compensation bias circuit and a power amplifier, which has little effect on the bias point under radio frequency operating conditions, and the power amplifier has good temperature compensation effect and high linearity. [Means for solving the problem]

[0008] In order to solve the above technical problem, an embodiment of the present invention provides, in a first aspect, a temperature compensated bias circuit for providing a bias current to a power amplifier, the temperature compensated bias circuit comprising: a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, a second capacitor, a third capacitor, a fifth capacitor, a fifth transistor, a sixth transistor, and a seventh transistor; a first end of the third resistor is connected to a first end of the fourth resistor and a reference voltage; a second end of the third resistor is connected to a first end of the fifth capacitor and a base of the fifth transistor, a second end of the fifth capacitor connected to ground; a second end of the fourth resistor is connected to the collector of the fifth transistor, the first end of the third capacitor, the base of the seventh transistor, the first end of the second capacitor, and the collector of the sixth transistor, respectively; a second end of the third capacitor connected to ground; a second end of the second capacitor is connected to a first end of the fifth resistor; a second end of the fifth resistor is connected to a base of the sixth transistor and a first end of the sixth resistor; The emitter of the sixth transistor is connected to ground; an emitter of the fifth transistor is connected to an emitter of the seventh transistor, a second end of the sixth resistor, and a first end of the seventh resistor, respectively; The collector of the seventh transistor is connected to a battery voltage; The present invention provides a temperature compensation bias circuit, wherein a second terminal of the seventh resistor functions as an output terminal of the temperature compensation bias circuit.

[0009] Preferably, the seventh resistor is a resistor whose parameters are adjustable.

[0010] Preferably, the second capacitor is a capacitor whose parameters are adjustable, and the fifth resistor is a resistor whose parameters are adjustable.

[0011] Preferably, the sixth resistor is a resistor whose parameters are adjustable.

[0012] In a second aspect, an embodiment of the present invention provides a power amplifier comprising the above temperature compensation bias circuit provided by an embodiment of the invention.

[0013] Preferably, the power amplifier further comprises a fourth capacitor, a second inductor, and a radio frequency amplifying transistor; a first end of the fourth capacitor serves as an input end of the power amplifier; a second end of the fourth capacitor is connected to the output end of the bias circuit module and the base of the radio frequency amplifying transistor respectively; The emitter of the radio frequency amplifier transistor is connected to ground; A collector of the radio frequency amplifier transistor serves as an output terminal of the power amplifier, and a collector of the radio frequency amplifier transistor is connected to a second terminal of the second inductor; A first end of the second inductor is connected to a power supply voltage.

[0014] Preferably, the second inductor is a choke coil or a chip inductor. Effect of the Invention

[0015] Compared with the related art, the temperature compensation bias circuit of the present invention, by arranging the fifth transistor, the seventh transistor, and the fourth resistor, when the temperature rises, the I E5 The current also increases with increasing temperature, I E5 =I C5 +I B5 , I B5 I C5 is much smaller than I E5 ≒I C5 , I C5 increases with increasing temperature. The collector voltage of the fifth transistor T5 is V C5 =VCC-I C5 *R4 and I C5As increases, V C5 decreases, the base voltage of the seventh transistor T7 decreases, and I E7 By decreasing, I B8 The current of I B8 The increase of the bias voltage is suppressed, and the temperature compensation role is played. More preferably, the temperature compensation bias circuit of the present invention can further adjust the temperature compensation effect of the bias by configuring a seventh resistor R7 and adjusting the value of the seventh resistor R7. Therefore, the influence on the bias point of the temperature compensation bias circuit and the power amplifier in the radio frequency operating state is small, the temperature compensation effect of the power amplifier is good, and the linearity is high. [Brief description of the drawings]

[0016] The present invention will now be described in detail with reference to the drawings. The above and other aspects of the present invention will become more clear and easier to understand from the detailed description taken in conjunction with the following drawings. [Figure 1] FIG. 1 is a diagram showing the application circuit principle of a temperature compensation bias circuit according to a related art. [Diagram 2] FIG. 2 is a graph showing the relationship between gain and input power of the circuit of FIG. 1. [Diagram 3] FIG. 2 is a diagram showing the application circuit principle of a temperature compensation bias circuit according to the present invention; [Figure 4] 1 is a schematic diagram comparing curves of the relationship between static current and temperature in an application circuit of a temperature compensation bias circuit of the related art and a temperature compensation bias circuit of the present invention; [Diagram 5] 4 is a schematic diagram of the relationship curve between the VBE8 voltage and the input power of the temperature compensation bias circuit of the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

[0018] The specific embodiments / examples described herein are specific specific embodiments of the present invention, and are intended to explain the concept of the present invention, and are all interpretive and exemplary, and should not be construed as limiting the embodiments and the scope of the present invention. In addition to the examples described herein, a person skilled in the art may also adopt other obvious technical solutions based on the claims and the contents disclosed in the specification of this application. These technical solutions include any obvious substitutions and modifications of the examples described herein, all of which are within the protection scope of the present invention.

[0019] The present invention provides a temperature compensated bias circuit 100 .

[0020] 3 to 5, Fig. 3 is a diagram showing the application circuit principle of the temperature compensation bias circuit of the present invention. The present invention further provides a power amplifier using the temperature compensation bias circuit 100. Specifically, the power amplifier includes the temperature compensation bias circuit 100, a fourth capacitor C4, a second inductor L2, and a radio frequency amplification transistor T8.

[0021] The circuit connections of the power amplifier are as follows:

[0022] A first terminal of the fourth capacitor C4 serves as an input terminal RFIN of the power amplifier.

[0023] The second end of the fourth capacitor C4 is respectively connected to the output end of the bias circuit module and the base of the radio frequency amplifying transistor T8.

[0024] The emitter of the radio frequency amplifier transistor T8 is connected to ground GND.

[0025] The collector of the radio frequency amplifier transistor T8 is connected to the second end of the second inductor L2. The collector of the radio frequency amplifier transistor T8 serves as the output end RFOUT of the power amplifier.

[0026] A first end of the second inductor L2 is connected to a power supply voltage VCC.

[0027] Here, the fourth capacitor C4 is used as a DC blocking capacitor, which only passes radio frequency signals and prevents DC voltage from entering the radio frequency amplifying transistor T8.

[0028] The second inductor L2 is a choke coil or a chip inductor. The second inductor L2 is used to block radio frequency signals from entering the power supply and allows only direct current to pass. In this embodiment, the second inductor L2 is a choke coil.

[0029] The temperature compensation bias circuit 100 includes a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a seventh resistor R7, a second capacitor C2, a third capacitor C3, a fifth capacitor C5, a fifth transistor T5, a sixth transistor T6, and a seventh transistor T7.

[0030] The circuit connections of the temperature compensation bias circuit 100 are as follows.

[0031] A first end of the third resistor R3 is connected to a first end of the fourth resistor R4 and a reference voltage VRef.

[0032] A second end of the third resistor R3 is connected to a first end of the fifth capacitor C5 and a base of the fifth transistor T5, respectively.

[0033] A second end of the fifth capacitor C5 is connected to the ground GND.

[0034] The second end of the fourth resistor R4 is connected to the collector of the fifth transistor T5, the first end of the third capacitor C3, the base of the seventh transistor T7, the first end of the second capacitor C2, and the collector of the sixth transistor T6 respectively.

[0035] The second end of the third capacitor C3 is connected to the ground GND.

[0036] A second end of the second capacitor C2 is connected to a first end of the fifth resistor R5.

[0037] A second end of the fifth resistor R5 is connected to the base of the sixth transistor T6 and a first end of the sixth resistor R6, respectively.

[0038] The emitter of the sixth transistor T6 is connected to the ground GND.

[0039] The emitter of the fifth transistor T5 is connected to the emitter of the seventh transistor T7, the second end of the sixth resistor R6, and the first end of the seventh resistor R7, respectively.

[0040] The collector of the seventh transistor T7 is connected to the battery voltage VBat.

[0041] The second terminal of the seventh resistor R 7 functions as the output terminal of the temperature compensation bias circuit 100 .

[0042] The operating principle of the temperature compensation bias circuit 100 is as follows.

[0043] The temperature compensation bias circuit 100 is used to provide a bias current for the power amplifier. Specifically, the combination of the fifth transistor T5 and the seventh transistor T7 provides a base bias current for the radio frequency amplifier transistor T8, and I B8 =I E5 +I E7 +I B6 The seventh resistor R7 is used as a ballast resistor. The third resistor R3 is a base current limiting resistor of the fifth transistor T5, and can adjust the static operating point of the fifth transistor T5. The fourth resistor R4 is a collector resistor of the fifth transistor T5, and the fourth resistor R4 and the sixth transistor T6 together determine the static operating point of the seventh transistor T7.

[0044] When the temperature of a transistor operating at the static operating point increases, the base current of the radio frequency amplifier transistor T8 increases, and the I E5 The current also increases with increasing temperature. I E5 =I C5 +I B5 , I B5 I C5 is much smaller than I E5 ≒I C5 , I C5 increases with increasing temperature. The collector voltage of the fifth transistor T5 is V C5 =VCC-I C5 *R4 and I C5 As increases, V C5 decreases, the base voltage of the seventh transistor T7 decreases, and I E7 By decreasing I B8 The current of I B8 This suppresses the increase in temperature and serves as a temperature compensation.

[0045] In this embodiment, the seventh resistor R7 is a resistor whose parameters are adjustable. By adjusting the value of the seventh resistor R7, the bias temperature compensation effect of the temperature compensation bias circuit 100 can be further adjusted. The bias temperature compensation effect of the conventional bias scheme and the scheme of the present invention is compared. As shown in FIG. 4, FIG. 4 is a schematic diagram comparing the static current vs. temperature relationship curves in the application circuit of the temperature compensation bias circuit of the related art and the temperature compensation bias circuit 100 of the present invention. From FIG. 4, it can be concluded that W1 is the static current vs. temperature relationship curve of the temperature compensation bias circuit of the related art. W2 is the static current vs. temperature relationship curve of the temperature compensation bias circuit 100 of the present invention. W2 shows that when the temperature is from 35° C. to 85° C., the static current output by the temperature compensation bias circuit 100 increases from 0.088 amperes to 0.099 amperes, and the current is basically stable with little change. The temperature drift of the radio frequency amplification transistor T8 under the same normal temperature static operating current is obviously smaller than that of the temperature compensation bias circuit of the related art. Therefore, the temperature compensation bias circuit 100 of the present invention achieves temperature compensation of the bias circuit, and the ballast resistor is used to adjust the gain curve of the power amplifier in addition to the function of temperature compensation, so that the purpose of optimizing the temperature compensation effect and linearity of the power amplifier by adjusting the bias can be achieved. The seventh resistor R7, which is a ballast resistor, can adjust the base current of the power amplifier T8 when large power is input, and plays the role of adjusting the gain curve of the power amplifier. The seventh resistor R7 can play the role of adjusting the gain of the radio frequency amplification transistor T8 without participating in the above temperature compensation, and has little impact on the temperature compensation performance of this solution. When the power of the input signal is too high, the swing amplitude exceeds the static bias point, the conduction angle decreases, and under a large signal input, the gain of the power amplifier decreases, and gain compression occurs.

[0046] The temperature compensation bias circuit 100 is connected to the ground GND through the fifth capacitor C5 and the third capacitor C3. The addition of the fifth capacitor C5, which is a linear capacitor, and the third capacitor C3, which is a linear capacitor, increases the radio frequency components leaking into the bias, so that the emitter currents of the fifth transistor T5 and the seventh transistor T7 in a stable radio frequency state increase, and I B8 =I E7 +I E5 +I B6 This increases the static bias point of the radio frequency amplifier transistor T8 when a large signal is input, and delays gain compression. The fifth capacitor C5 and the third capacitor C function as filter capacitors, and whether or not a grounded filter capacitor is provided in the temperature compensation bias circuit 100 depends on the V BE8 As shown in FIG. 5, the V BE8 1 is a schematic diagram of a voltage vs. input power relationship curve, where W3 is the V BE8 W4 is a voltage vs. input power curve of the circuit after removing the fifth capacitor C5 and the third capacitor C from the temperature compensation bias circuit 100 of the present invention. BE8 5 is a relationship curve between voltage and input power. As can be seen from FIG. 5, the grounded filter capacitor arranged in the temperature compensation bias circuit 100 directly affects the radio frequency amplifier transistor T8, thereby increasing the static bias point of the radio frequency amplifier transistor T8 when a large signal is input, and delaying the gain compression. By adjusting the size ratio of the fifth capacitor C5 and the third capacitor C3, the flatness of the entire gain curve with the increase of the input power can be further adjusted, and the linearity level of the power amplifier can be optimized.

[0047] This is to further reduce the baseband impedance of the temperature compensation bias circuit 100, thereby improving the problem of linearity degradation of the output signal of the power amplifier. The temperature compensation bias circuit 100 includes the sixth transistor T6 and the sixth resistor R6 for isolation. When no radio frequency signal is input to the power amplifier, the power supply voltage VCC is converted into a bias voltage for the seventh transistor T7 by the voltage difference between the fourth resistor R4 and the sixth transistor T6, and a bias current I B8 and outputted to the input terminal of the radio frequency amplifying transistor T8 through the seventh resistor R7. Also, when a radio frequency signal is inputted to the power amplifier, the seventh resistor R7 blocks most of the radio frequency signal, but a small amount still leaks out and is sent from the temperature compensation bias circuit 100, specifically, the radio frequency signal attenuated by the seventh resistor R7 is isolated from the base low resistance point of the sixth transistor T6 by the sixth resistor R6, so that the radio frequency signal attenuated by the seventh resistor R7 is transmitted to the seventh transistor T7, and then the seventh resistor R7 passes the radio frequency signal attenuated by the seventh transistor T7. Here, when the radio frequency signal is a large signal (i.e., a signal with large power), the emitter of the seventh transistor T7 has a certain radio frequency swing, and the bias voltage of the base-emitter junction (BE junction) of the seventh transistor T7 becomes small due to the detection effect of the radio frequency swing passing through the base-emitter junction (BE junction) of the seventh transistor T7, and the I E7 The output is increased, compensating for the decrease in the base voltage of the radio frequency amplifier transistor T8 as the power of the input signal increases, and suppressing the AM-AM distortion of the power amplifier when the signal is large.

[0048] In this embodiment, the second capacitor C2 is a capacitor with adjustable parameters, and the fifth resistor R5 is a resistor with adjustable parameters.

[0049] The second capacitor C2 and the fifth resistor R5 form a phase margin network. When a radio frequency signal is coupled to the base of the sixth transistor T6 through the second capacitor C2 and the fifth resistor R5, the base potential of the sixth transistor T6 decreases with the increase in the power of the radio frequency signal due to the detection effect of the radio frequency signal coupled to the sixth transistor T6 passing through the base-emitter junction of the sixth transistor T6, and the emitter potential of the seventh transistor T7 also decreases, causing obvious AM-AM distortion in the power amplifier at large signals and further degrading the linearity of the power amplifier. Thus, it can be seen that the introduction of the second capacitor C2 and the fifth resistor R5, whose parameters are adjustable, improves the stability of the bias circuit.

[0050] In this embodiment, the sixth resistor R6 is a resistor whose parameters can be adjusted. The sixth resistor R6 and the second capacitor C2 for isolation can be switched. That is, the sixth resistor R6 can be a variable resistor, and the second capacitor C2 can be a variable capacitor. By changing the values ​​of the sixth resistor R6 and the second capacitor C2, different baseband impedance bandwidths and noise suppression degrees of the temperature compensation bias circuit 100 can be selected according to different modulation bandwidth signals, thereby achieving the purpose of increasing the applicability and flexibility of the circuit of the temperature compensation bias circuit 100.

[0051] In addition, the relevant circuits, resistors and transistors adopted in the present invention are all circuits and components commonly used in this field, and the corresponding specific indicators and parameters are adjusted according to actual applications, so detailed description is omitted here.

[0052] Compared with the related art, the temperature compensation bias circuit of the present invention, by arranging the fifth transistor, the seventh transistor, and the fourth resistor, when the temperature rises, the I E5 The current also increases with increasing temperature, I E5 =I C5 +I B5 , I B5 IC5 is much smaller than I E5 ≒I C5 , I C5 increases with increasing temperature. The collector voltage of the fifth transistor T5 is V C5 =VCC-I C5 *R4 and I C5 As increases, V C5 decreases, the base voltage of the seventh transistor T7 decreases, and I E7 By decreasing I B8 The current of I B8 The increase of the bias voltage is suppressed, and the temperature compensation role is played. More preferably, the temperature compensation bias circuit of the present invention can further adjust the temperature compensation effect of the bias by configuring a seventh resistor R7 and adjusting the value of the seventh resistor R7. Therefore, the influence on the bias point of the temperature compensation bias circuit and the power amplifier in the radio frequency operating state is small, the temperature compensation effect of the power amplifier is good, and the linearity is high.

[0053] It should be noted that the various embodiments described with reference to the accompanying drawings are only used to explain the present invention, and do not limit the scope of the present invention. Those skilled in the art should understand that any modifications or equivalent replacements made to the present invention without departing from the spirit and scope of the present invention should be included within the scope of the present invention. In addition, unless otherwise required by the context, words appearing in the singular form include the plural form, and vice versa. Furthermore, unless otherwise specified, the whole or part of any embodiment can be used in combination with the whole or part of any other embodiment.

Claims

1. 1. A temperature compensated bias circuit for providing a bias current to a power amplifier, comprising: a third resistor, a fourth resistor, a fifth resistor, a sixth resistor, a seventh resistor, a second capacitor, a third capacitor, a fifth capacitor, a fifth transistor, a sixth transistor, and a seventh transistor; a first end of the third resistor is connected to a first end of the fourth resistor and a reference voltage; a second end of the third resistor is connected to a first end of the fifth capacitor and a base of the fifth transistor, The second end of the fifth capacitor is connected to ground; a second end of the fourth resistor is connected to the collector of the fifth transistor, the first end of the third capacitor, the base of the seventh transistor, the first end of the second capacitor, and the collector of the sixth transistor, respectively; The second end of the third capacitor is connected to ground; a second end of the second capacitor is connected to a first end of the fifth resistor; a second end of the fifth resistor is connected to a base of the sixth transistor and a first end of the sixth resistor, The emitter of the sixth transistor is connected to ground, an emitter of the fifth transistor is connected to an emitter of the seventh transistor, a second end of the sixth resistor, and a first end of the seventh resistor, respectively; The collector of the seventh transistor is connected to a battery voltage; A temperature compensation bias circuit, wherein a second terminal of the seventh resistor functions as an output terminal of the temperature compensation bias circuit.

2. 2. The temperature compensated bias circuit of claim 1, wherein the seventh resistor is a resistor whose parameters are adjustable.

3. 2. The temperature compensated bias circuit of claim 1, wherein the second capacitor is a parameter-adjustable capacitor and the fifth resistor is a parameter-adjustable resistor.

4. 2. The temperature compensated bias circuit of claim 1, wherein the sixth resistor is a resistor whose parameters are adjustable.

5. A power amplifier comprising the temperature compensation bias circuit according to any one of claims 1 to 5.

6. a fourth capacitor, a second inductor, and a radio frequency amplifier transistor; a first end of the fourth capacitor serving as an input end of the power amplifier; The second end of the fourth capacitor is connected to the output end of the bias circuit module and the base of the radio frequency amplifying transistor respectively; The emitter of the radio frequency amplifier transistor is connected to ground; A collector of the radio frequency amplifier transistor serves as an output terminal of the power amplifier, and a collector of the radio frequency amplifier transistor is connected to a second terminal of the second inductor; 6. The power amplifier of claim 5, wherein a first end of the second inductor is connected to a power supply voltage.

7. 7. The power amplifier according to claim 6, wherein the second inductor is a choke coil or a chip inductor.

Images