Power amplifier

Abstract

A power amplifier circuit includes a current generator and a current mirror driver. The current generator has a first input connected to a first voltage source and an output configured to generate a first current. The current generator includes a first transistor, a second transistor, a first resistor, and a second resistor. The first transistor has an emitter connected to ground. The second transistor has a base connected to a base of the first transistor and an emitter connected to ground. The first resistor is connected between the first voltage source and a collector of the first transistor. The second resistor is connected between the first voltage source and a collector of the second transistor. The current mirror driver has a first input connected to the output of the current generator to receive the first current and an output configured to generate a second current.

Description

Technical Field

[0001] This disclosure relates to a power amplifier, and more specifically, to a bias circuit for a power amplifier. Background Technology

[0002] A power amplifier is a circuit used in a wireless transceiver to amplify the signal to be transmitted. As the complexity of circuitry in wireless transceivers increases, power amplifiers should have more functions and better performance. However, because the bias voltage or current of a power amplifier can vary with operating temperature or voltage source changes, this can adversely affect the performance of the power amplifier. Summary of the Invention

[0003] According to one aspect of this disclosure, a power amplifier circuit includes a current generator and a current mirror driver. The current generator has a first input connected to a first voltage source and an output configured to generate a first current. The current generator includes a first transistor, a second transistor, a first resistor, and a second resistor. The first transistor has an emitter connected to ground. The second transistor has a base connected to the base of the first transistor and an emitter connected to ground. The first resistor is connected between the first voltage source and the collector of the first transistor. The second resistor is connected between the first voltage source and the collector of the second transistor. The current mirror driver has a first input connected to the output of the current generator to receive the first current and an output configured to generate a second current.

[0004] According to another aspect of this disclosure, a power amplifier circuit includes a current generator and a bandgap circuit. The current generator has a first input connected to a first voltage source and an output configured to generate a first current. The bandgap circuit has a first input connected to the output of the current generator to receive the first current and an output configured to generate a reference voltage. Attached Figure Description

[0005] Figure 1A This is a schematic diagram illustrating a power amplifier according to some embodiments of the present disclosure.

[0006] Figure 1B , Figure 1C , Figure 1D , Figure 1E , Figure 1F , Figure 1G and Figure 1H Description of some embodiments according to this disclosure Figure 1A The simulation results of the power amplifier are shown in the figure.

[0007] Figure 2 This is a schematic diagram illustrating a power amplifier according to some embodiments of the present disclosure.

[0008] Figure 3 This is a schematic diagram illustrating a power amplifier according to some embodiments of the present disclosure.

[0009] Figure 4 This is a schematic diagram illustrating a power amplifier according to some embodiments of the present disclosure.

[0010] Figure 5A This is a schematic diagram illustrating a bandgap reference circuit according to some embodiments of the present disclosure.

[0011] Figure 5B , Figure 5C and Figure 5D Description of some embodiments according to this disclosure Figure 5A The simulation results of the bandgap reference circuit are shown in the figure.

[0012] Figure 6 This is a schematic diagram illustrating a bandgap reference circuit according to some embodiments of the present disclosure.

[0013] Figure 7 This is a schematic diagram illustrating a bandgap reference circuit according to some embodiments of the present disclosure.

[0014] Figure 8 This is a schematic diagram illustrating a bandgap reference circuit according to some embodiments of the present disclosure.

[0015] Common reference numerals are used throughout the drawings and detailed description to indicate the same or similar components. The invention can be readily understood from the following detailed description taken in conjunction with the accompanying drawings. Detailed Implementation

[0016] Although specifically described with reference to portable transceivers, the circuitry and methods for biasing gallium arsenide (GaAs) power amplifiers (also referred to as GaAs bias circuitry) can be implemented in any GaAs device requiring bias current and voltage. Furthermore, the circuitry described below can be fabricated using an integrated bipolar field-effect transistor (BIFET) process that utilizes the low turn-on voltage of field-effect transistors. Additionally, in certain embodiments, the transistors described below comprise bipolar junction transistors (BJTs) fabricated using processes referred to as BIFET or BiHEMT processes, which include heterojunction bipolar junction transistors (HBTs) and field-effect transistors (FETs) or pseudo-high electron mobility transistors (pHEMTs). In some embodiments, the transistors described below can be fabricated using processes referred to as GaAs, indium phosphide (InP), silicon-germanium (SiGe), gallium nitride (GaN), complementary metal-oxide-semiconductor (CMOS), silicon-on-insulator (SOI), or any other suitable process.

[0017] As used herein, references to the base, emitter, collector, or other components or other circuit components of a transistor being connected to the base, emitter, collector, or other components or other circuit components of another transistor may refer to a direct connection or a connection in which another circuit component (e.g., a transistor) is disposed.

[0018] Figure 1A This is a schematic diagram illustrating a power amplifier 100 according to some embodiments of the present disclosure. The power amplifier 100 includes a current generator 110, a zero-gain transistor switch 120, a current mirror driver 130, and a transistor M141. In some embodiments, all transistors in the power amplifier 100 are HBTs. Alternatively, the power amplifier 100 may include any other type of transistor.

[0019] Current generator 110 includes transistors M111, M112, M113, and M114, and resistors R111 and R112. The emitters of transistors M111 and M112 are connected to ground. The base of transistor M111 is connected to the base of transistor M112. The collector of transistor M111 is connected to the collector of transistor M113 and the emitter of transistor M114. The collector of transistor M112 is connected to resistor R112. The emitter of transistor M113 is connected to the bases of transistors M111 and M112. The base of transistor M113 is connected to receive a control voltage (or enable voltage) V110. The collector of transistor M113 is connected to the emitter of transistor M114 and the collector of transistor M111. The base and collector of transistor M114 are connected to resistor R111. Resistor R111 is connected between voltage source VDD1 and transistor M114. Resistor R112 is connected between voltage source VDD1 and transistor M112.

[0020] The current generator 110 is configured to receive a control voltage V110 and generate a current I110 when the control voltage V110 exceeds a threshold (e.g., 3.2V). In some embodiments, the current I110 may be expressed by the following equation:

[0021]

[0022] When the value of resistor R111 is equal to the value of resistor R112, the current I110 can be expressed by the following equation, where the current I110 is independent of the voltage source VDD1:

[0023]

[0024] When the value of resistor R111 is twice the value of resistor R112, the current I110 can be expressed by the following equation, where the current I110 is independent of the operating temperature of power amplifier 100:

[0025]

[0026] Figure 1B , Figure 1C , Figure 1D , Figure 1E , Figure 1F , Figure 1G and Figure 1H Simulation results for a power amplifier 100 according to some embodiments of this disclosure are presented. For example... Figure 1B As shown in the diagram, the x-axis represents the control voltage V110 (V), and the y-axis represents the current I110 (mA). Figure 1C As shown in the diagram, the x-axis represents the control voltage V110 (V), and the y-axis represents the current I110 (mA). Figure 1DAs shown in the diagram, the x-axis represents the operating temperature (°C) of the power amplifier 100, and the y-axis represents the current I110 (mA). Figure 1E As shown in the diagram, the x-axis represents the voltage source (V), and the y-axis represents the current I110 (mA). Figure 1F As shown, the x-axis represents the operating temperature (°C) of the power amplifier 100, and the y-axis represents the currents I131 and I141 (mA). Figure 1G As shown in the diagram, the x-axis represents the voltage source VDD2 (V), and the y-axis represents the current I131 (mA). Figure 1H As shown in the figure, the x-axis represents the voltage source VDD2 (V), and the y-axis represents the current I141 (mA).

[0027] In some embodiments, the current generator 110 is configured to generate a substantially constant current I110 (e.g., about 179 mA) once the control voltage V110 exceeds a threshold. In some embodiments, the threshold and the value of the current I110 may vary depending on different specifications.

[0028] like Figure 1B As shown, when the control voltage V110 is less than 2.3V, the current I110 of the current generator 110 is approximately 0mA. In other words, no output current is generated when the current generator 110 is turned off. This reduces the power consumption of the power amplifier 100. According to an embodiment, when the current generator 110 is turned on (e.g., when the control voltage V110 exceeds 3.2V), the current I110 is insensitive to deviations from the control voltage V110. For example, the simulation results illustrating the power amplifier 100 are shown below. Figure 1C As shown, as the control voltage V110 changes from about 3.5V to about 5.5V, the current I110 changes by less than 0.2%.

[0029] The current generator 110 is also insensitive to the operating temperature of the power amplifier or deviations in the voltage source VDD1. For example, as Figure 1D As shown, as the operating temperature of power amplifier 100 changes from approximately -55°C to approximately 125°C, the current I110 exhibits a change of less than 1.5%. For example, as... Figure 1E As shown, as the voltage source VDD1 changes from approximately 4V to approximately 6V, the current I110 exhibits a change of less than 0.2%. According to... Figure 1A-1E In the embodiment shown, current generator 110 can provide a stable current bias (e.g., current I110) that is insensitive to operating temperature and deviations from the voltage source VDD1, which improves the performance of power amplifier 100.

[0030] Zero-gain transistor switch 120 includes transistor M121 and resistors R121 and R122. The emitter of transistor M121 is connected to the output of current generator 110 (e.g., connected to the collector of transistor M112 and resistor R112). Resistor R122 is connected between the base and collector of transistor M121. Resistor R121 is connected between control voltage V110 and the base of transistor M121. In some embodiments, when control voltage V110 is less than a threshold, transistor M121 may act as a diode. When control voltage exceeds the threshold, transistor M121 and resistors R121 and R122 act as a zero-gain amplifier, which maintains the voltage at the base of transistor M132 of current mirror driver 130 at a substantially constant voltage, which in turn maintains a substantially constant current (e.g., the current I141 flowing through transistor M141) at the output stage of power amplifier 100.

[0031] In some embodiments, the zero-gain transistor switch 120 may be omitted or replaced with a diode. However, the current I141 will vary with the control voltage V110. For example, as the control voltage V110 increases from about 3V to about 5.5V, the current I141 may deviate by about 120mA. Such a deviation in the current I141 will adversely affect the performance of the power amplifier 100. By using, as Figure 1A The zero-gain transistor switch 120 shown can maintain a substantially constant current I141. For example, as the control voltage V110 increases from about 3V to about 5.5V, the current I141 can have a deviation of less than about 1mA.

[0032] The current mirror driver 130 includes transistors M131 and M132 and resistors R131 and R132. The emitter of transistor M131 is connected to ground. The base of transistor M131 is connected to resistor R131. The collector of transistor M131 is connected to the output of a current generator (e.g., connected to the collector of transistor M112 and resistor R112) and a zero-gain amplifier switch 120 (e.g., connected to the emitter of transistor M121). The emitter of transistor M132 is connected to resistors R131 and R132. The base of transistor M132 is connected to the zero-gain amplifier switch 120 (e.g., connected to the collector of transistor M121). The collector of transistor M132 is connected to a voltage source VDD2. Resistor R131 is connected between the emitter of transistor M132 and the base of transistor M131. Resistor R132 is connected between the emitter of transistor M132 and the base of transistor M141. In some embodiments, transistors R131 and R132 are configured to adjust or regulate the temperature profile of power amplifier 100.

[0033] The current mirror driver 130 is configured to generate a current I130 flowing to the base of transistor M141 based on the current I131 flowing through transistor M131. In other words, an output current (e.g., current I141) is generated based on the current I131. For example, transistor M131 may act as a current mirror of transistor M141. In some embodiments, transistor M131 has a higher current density than transistor M141, and therefore the voltage (Vbe) between the base and emitter of transistor M131 is higher than that of transistor M141. The difference between Vbe of transistor M131 and Vbe of transistor M141 can be adjusted by changing the values ​​of resistors R131 and R132 to make current I141 independent of changes in the operating temperature of power amplifier 100.

[0034] like Figure 1F As shown, as the operating temperature of power amplifier 100 changes from about -55°C to about 125°C, current I131 exhibits a deviation of less than about 9%, and as the operating temperature of power amplifier 100 changes from about -55°C to about 125°C, current I141 exhibits a deviation of less than about 2%. Figure 1G and Figure 1H As shown, as the voltage source VDD2 changes from approximately 3.2V to approximately 6V, the current I131 exhibits a deviation of less than approximately 5%, and as the voltage source VDD2 changes from approximately 3.2V to approximately 6V, the current I141 exhibits a deviation of less than approximately 5%. A stable DC current bias provided to transistor M141 will improve the performance of power amplifier 100.

[0035] Figure 2 This is a schematic diagram illustrating a power amplifier 200 according to some embodiments of the present disclosure. The power amplifier 200 is similar to... Figure 1A The power amplifier 100 shown differs in that the current mirror driver 230 of the power amplifier 200 additionally includes a resistor R231 connected between the base of transistor M131 and transistor M141. In some embodiments, resistor R231 may act as a dynamic bias resistor, which may increase the 1dB compression point (P1dB) of the power amplifier 200 and improve the performance of the power amplifier 200.

[0036] Figure 3 This is a schematic diagram illustrating a power amplifier 300 according to some embodiments of the present disclosure. The power amplifier 300 is similar to... Figure 2The power amplifier 200 shown differs in that its current generator 310 additionally includes resistors R311 and R312. Resistor R311 is connected between the emitter of transistor M111 and ground. Resistor R312 is connected between the emitter of transistor M112 and ground. Resistors R311 and R312 reduce the sensitivity of the current generator 310 during the manufacturing process and increase the accuracy of the relationship between the currents flowing through transistors M111 and M112.

[0037] Figure 4 This is a schematic diagram illustrating a power amplifier 400 according to some embodiments of the present disclosure. The power amplifier 400 is similar to... Figure 1A The power amplifier 100 shown differs from the power amplifier 400 in that the current mirror driver 430 of the power amplifier 400 additionally includes a resistor R431 connected between the emitter of transistor M131 and ground. Resistor R431 can reduce the aspect ratio of transistor M131 to reduce the size of power amplifier 400.

[0038] Figure 5A This is a schematic diagram illustrating a bandgap reference circuit 500 according to some embodiments of the present disclosure. The bandgap reference circuit 500 includes a current generator 110, a zero-gain amplifier switch 120, and a bandgap core 510. In some embodiments, the current generator 110 and the zero-gain amplifier switch 120 of the bandgap reference circuit 500 are coupled with, for example, Figure 1A The current generator 110 of the power amplifier 100 shown is the same as the zero-gain amplifier switch 120, and its description herein also applies. In other embodiments, the current generator 110 of the bandgap reference circuit 500 may be replaced with, as shown below. Figure 3 The power amplifier 300 shown has a current generator 310.

[0039] The bandgap core 510 includes transistors M511, M512, M513, and M514, and resistors R511, R512, and R513. The emitter of transistor M511 is connected to ground. The base of transistor M511 is connected to the collector of transistor M512. The collector of transistor M511 is connected to current generator 110 (e.g., connected to the collector of transistor M112) and zero-gain amplifier switch 120 (e.g., connected to the emitter of transistor M121). The emitter of transistor M512 is connected to ground via resistor R513. The base of transistor M512 is connected to both the collector and base of transistor M513. The emitter of transistor M513 is connected to ground. The emitter of transistor M514 is connected to resistors R511 and R512. The base of transistor M514 is connected to zero-gain amplifier switch 120 (e.g., connected to the collector of transistor M121). The collector of transistor M514 is connected to voltage source VDD1.

[0040] Figure 5B , Figure 5C and Figure 5D Simulation results of a bandgap reference circuit 500 according to some embodiments of this disclosure are presented. For example... Figure 5B As shown, the x-axis represents the operating temperature (°C) of the bandgap reference circuit 500, and the y-axis represents the voltage V500 (mV) at the output of the bandgap reference circuit 500. Figure 5C As shown, the x-axis represents the voltage source VDD1 (V), and the y-axis represents the voltage V500 (mV) at the output of the bandgap reference circuit 500. Figure 5D As shown, the x-axis represents the control voltage V110 (V), and the y-axis represents the voltage V500 (mV) at the output of the bandgap reference circuit 500.

[0041] like Figure 5B As shown, as the operating temperature of the bandgap reference circuit 500 changes from approximately -55°C to approximately 125°C, the voltage V500 exhibits a change of less than 0.008%. Figure 5C As shown, as the voltage source VDD1 changes from approximately 4.5V to approximately 5.5V, the voltage V500 exhibits a change of less than 0.002%. Figure 5D As shown, as the current generator 110 changes from approximately 3.5V to approximately 5.5V, the voltage V500 exhibits a change of less than 0.002%. The bandgap reference circuit 500 provides a stable reference voltage that is insensitive to operating temperature, voltage source VDD1, and control voltage V110. This increases the power supply rejection ratio (PSRR) of the bandgap reference circuit 500 and improves its performance.

[0042] Figure 6 This is a schematic diagram illustrating a bandgap reference circuit 600 according to some embodiments of the present disclosure. The bandgap reference circuit 600 is similar to... Figure 5A The bandgap reference circuit 500 shown differs from the bandgap reference circuit 600 in that its bandgap core 610 additionally includes resistors R611 and R612. Resistor R611 is connected between the base of transistor M513 and resistor R512. Resistor R612 is connected between the collector of transistor M513 and resistor R512.

[0043] Figure 7 This is a schematic diagram illustrating a bandgap reference circuit 700 according to some embodiments of the present disclosure. The bandgap reference circuit 700 is similar to... Figure 6The bandgap reference circuit 600 shown differs in that the current generator 710 of the bandgap reference circuit 700 additionally includes a transistor M711, and the bandgap core 720 of the bandgap reference circuit 700 additionally includes a resistor R721. Transistor M711 is connected between resistor R111 and the collector of transistor M114. Resistor R721 is connected between the base of transistor M511 and ground.

[0044] Figure 8 This is a schematic diagram illustrating a bandgap reference circuit 800 according to some embodiments of the present disclosure. The bandgap reference circuit 800 is similar to... Figure 7 The bandgap reference circuit 700 shown differs from the bandgap reference circuit 800 in that the bandgap reference circuit 810 additionally includes a resistor R811. Resistor R811 is connected between resistor R512 and ground.

[0045] As used herein, unless the context clearly indicates otherwise, the singular terms “a / an” and “the” may include multiple indicators.

[0046] Additionally, quantities, ratios, and other values ​​are sometimes presented in range format in this document. It should be understood that such range format is for convenience and brevity and should be interpreted flexibly, including not only values ​​explicitly specified as range limits, but also all individual values ​​or subranges covered within the range, as if each value and subrange were explicitly specified.

[0047] As used herein and unless otherwise defined, the terms “approximately,” “substantially,” “about,” and “approximately” are used to indicate and explain small variations. When used in conjunction with an event or situation, the terms may cover situations where the event or situation has clearly occurred and situations where the event or situation is very close to occurring. For example, when used in conjunction with numerical values, the terms may cover a range of variations less than or equal to ±10% of the numerical value, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%. For example, if the difference between two values ​​is less than or equal to ±10% of the average of the values, such as less than or equal to ±5%, less than or equal to ±4%, less than or equal to ±3%, less than or equal to ±2%, less than or equal to ±1%, less than or equal to ±0.5%, less than or equal to ±0.1%, or less than or equal to ±0.05%, then the two values ​​can be considered "substantially" the same or equal.

[0048] Although this disclosure has been described and illustrated with reference to specific embodiments thereof, such descriptions and illustrations are not limiting of this disclosure. It will be readily understood by those skilled in the art that various changes can be made and equivalent elements can be substituted within embodiments without departing from the true spirit and scope of this disclosure as defined by the appended claims. Illustrations may not be drawn to scale. Differences may exist between the technical representation in this disclosure and actual equipment due to variables in the manufacturing process, etc. Other embodiments of this disclosure may exist that are not specifically described. The description and drawings should be considered illustrative rather than restrictive. Modifications may be made to adapt particular circumstances, materials, composition, methods, or processes to the objectives, spirit, and scope of this disclosure. All such modifications are intended to be within the scope of the appended claims. Although the methods disclosed herein have been described with reference to specific operations performed in a particular order, it should be understood that these operations may be combined, subdivided, or reordered to form equivalent methods without departing from the teachings of this disclosure. Therefore, the order and grouping of operations are not limited by this disclosure unless specifically indicated herein.

Claims

1. A power amplifier circuit, comprising: A current generator having a first input connected to a first voltage source and an output configured to generate a first current, the current generator comprising: The first transistor has an emitter connected to ground; The second transistor has a base connected to the base of the first transistor and an emitter connected to ground; A first resistor is connected between the first voltage source and the collector of the first transistor; The second resistor is connected between the first voltage source and the collector of the second transistor; A third transistor has a base connected to a second voltage source, an emitter connected to the base of the first transistor, and a collector connected to the collector of the first transistor; and A fourth transistor having an emitter connected to the collector of the first transistor, wherein the base and collector of the fourth transistor are connected to the first resistor; and A current mirror driver having a first input connected to the output of the current generator to receive the first current and an output configured to generate a second current.

2. The power amplifier circuit according to claim 1, wherein as the first voltage source has a voltage change of about 2 V, the first current has a current change of less than 0.2%.

3. The power amplifier circuit according to claim 1, wherein the resistance of the first resistor is substantially the same as the resistance of the second resistor.

4. The power amplifier circuit according to claim 1, wherein the ratio of the resistance of the first resistor to the resistance of the second resistor is approximately 2:

1.

5. The power amplifier circuit of claim 1, wherein the current generator further comprises: A third resistor is connected between the emitter of the first transistor and ground; and A fourth resistor is connected between the emitter of the second transistor and ground.

6. The power amplifier circuit according to claim 1, further comprising: The fifth transistor has an emitter connected to the output of the current generator and a collector connected to the second input of the current mirror driver; A fifth resistor is connected between the collector and base of the fifth transistor; and A sixth resistor is connected between the second voltage source and the base of the fifth transistor.

7. The power amplifier circuit according to claim 1, wherein the current mirror driver comprises: The seventh transistor has an emitter connected to ground and a collector connected to the output of the current generator; The eighth transistor has a base connected to the second input of the current mirror driver, an emitter connected to the base of the seventh transistor, and a collector connected to the second voltage source; A seventh resistor is connected between the base of the seventh transistor and the emitter of the eighth transistor; and An eighth resistor is connected between the emitter of the eighth transistor and the output of the current mirror driver.

8. The power amplifier circuit of claim 7, wherein the current mirror driver further includes a ninth resistor connected between the base of the seventh transistor of the current mirror driver and the eighth resistor of the current mirror driver.

9. The power amplifier circuit of claim 1, further comprising a ninth transistor having an emitter connected to ground, a base connected to the output of the current mirror driver and configured to receive the second current, and a collector connected to the output matching element OMN.

10. The power amplifier circuit of claim 1, wherein the output of the current mirror driver is connected to the input matching element IMN.

11. The power amplifier circuit of claim 1, wherein the first current has a current change of less than 1.5% as the operating temperature of the power amplifier changes from about -55°C to about 125°C.

12. The power amplifier circuit of claim 1, wherein the current generator and the current mirror driver comprise only one type of transistor, and wherein the transistor is a heterojunction bipolar transistor (HBT).

13. A power amplifier circuit, comprising: A current generator having a first input connected to a first voltage source and an output configured to generate a first current; and A bandgap circuit having a first input connected to the output of the current generator to receive the first current and an output configured to generate a reference voltage. The current generator mentioned above includes: The first transistor has an emitter connected to ground; The second transistor has a base connected to the base of the first transistor and an emitter connected to ground; A first resistor is connected between the first voltage source and the collector of the first transistor; The second resistor is connected between the first voltage source and the collector of the second transistor; The third transistor has a base connected to a second voltage source, an emitter connected to the base of the first transistor, and a collector connected to the collector of the first transistor. A fourth transistor having an emitter connected to the collector of the first transistor, wherein the base and collector of the fourth transistor are connected to the first resistor. A third resistor is connected between the emitter of the first transistor and ground; and A fourth resistor is connected between the emitter of the second transistor and ground.

14. The power amplifier circuit of claim 13, wherein as the first voltage source has a voltage change of about 2 V, the first current has a current change of less than 0.2%.

15. The power amplifier circuit of claim 13, wherein the resistance of the first resistor is substantially the same as the resistance of the second resistor.

16. The power amplifier circuit according to claim 13, wherein the ratio of the resistance of the first resistor to the resistance of the second resistor is approximately 2:

1.

17. The power amplifier circuit according to claim 13, further comprising: The fifth transistor has an emitter connected to the output of the current generator and a collector connected to the second input of the bandgap circuit; A fifth resistor is connected between the collector and base of the fifth transistor; and A sixth resistor is connected between the second voltage source and the base of the fifth transistor.

18. The power amplifier circuit of claim 13, wherein the bandgap circuit comprises: The sixth transistor has an emitter connected to ground and a collector connected to the output of the current generator; A seventh transistor having an emitter connected to ground via a seventh resistor and a collector connected to the base of the sixth transistor; The eighth transistor has an emitter connected to ground, a base connected to the base of the seventh transistor, and a collector connected to the base of the seventh transistor; A ninth transistor having an emitter connected to the base of the sixth transistor via an eighth resistor, a collector connected to the second input of the bandgap circuit, and a collector connected to a second voltage source; A ninth resistor is connected between the emitter of the ninth transistor and the base of the seventh transistor; A tenth resistor is connected between the ninth resistor and the base of the seventh transistor; and The eleventh resistor is connected between the ninth resistor and the base of the eighth transistor.

19. The power amplifier circuit of claim 13, wherein the first current has a current change of less than 1.5% as the operating temperature of the power amplifier changes from about -55°C to about 125°C.

Images