Bias circuit

Abstract

The present invention is provided with: a first transistor that supplies bias from an emitter or a source to a first amplifier; a first terminal electrically connected to a circuit for controlling the bias of a predetermined amplifier; and a first inverting amplifier, a first input terminal of which is electrically connected to the emitter or source of the first transistor, and a first output terminal of which is electrically connected to the base or gate of the first transistor and the first terminal, the first inverting amplifier inverting and amplifying a voltage supplied to the first input terminal.

Description

Technical Field

[0001] The present disclosure relates to bias circuits. Background Art

[0002] In general, a Doherty amplifier circuit is connected in parallel with a carrier amplifier and a peak amplifier, wherein the carrier amplifier operates independently of the power level of the input signal, and the peak amplifier is turned off when the power level of the input signal is low, and is turned on when the power level of the input signal is high. In the Doherty amplifier circuit, when the power level of the input signal is high, the carrier amplifier operates while maintaining saturation at a saturated output power level. That is, in the Doherty amplifier circuit, the peak amplifier is operated at a timing when the carrier amplifier is close to saturation. As a result, the Doherty amplifier circuit can improve efficiency compared to a conventional power amplifier circuit. Therefore, in a power amplifier circuit such as a Doherty amplifier circuit, in order to improve efficiency, a circuit for detecting the saturation of the power amplifier is sometimes provided.

[0003] Prior Art Literature

[0004] Patent Literature

[0005] Patent Document 1: U.S. Patent Application Publication No. 2021 / 36661 Summary of the invention

[0006] Problem that the invention aims to solve

[0007] Patent document 1 discloses a power amplifier circuit including a saturation detection circuit for detecting the saturation of a power amplifier. The saturation detection circuit described in Patent document 1 electrically connects the input terminal of the saturation detector for detecting the saturation of the power amplifier to the base of the power amplifier. The saturation detection circuit described in Patent document 1 senses the saturation of the power amplifier by utilizing the voltage drop at the base terminal caused by the increase in the base current when the power amplifier is saturated. That is, in the saturation detection circuit, in order to detect the saturation of the power amplifier, it is necessary to generate a voltage drop at the base terminal of the power amplifier. Therefore, the saturation detection circuit changes the bias point of the power amplifier due to the voltage drop. Therefore, in the power amplifier circuit described in Patent document 1, there arises a problem that a stable bias cannot be supplied to the power amplifier.

[0008] Therefore, an object of the present disclosure is to provide a bias circuit that supplies a stable bias to a power amplifier.

[0009] Technical solutions to solve problems

[0010] A bias circuit according to one aspect of the present invention comprises: a first transistor for supplying a bias to a first amplifier from an emitter or a source; a first terminal electrically connected to a circuit for controlling a bias of a given amplifier; and a first inverting amplifier having a first input terminal electrically connected to the emitter or the source of the first transistor, a first output terminal electrically connected to a base or a gate of the first transistor and the first terminal, and inverting and amplifying a voltage supplied to the first input terminal.

[0011] In addition, a bias circuit according to one aspect of the present invention includes: a control terminal to which a reference signal for controlling a bias of a first amplifier is input; a first transistor whose base or gate is electrically connected to the control terminal and supplies a bias to the first amplifier from an emitter or a source; a second transistor whose collector or drain is electrically connected to a base or a gate, and whose collector or drain is electrically connected to an emitter or a source of the first transistor; a third transistor whose base or a gate is electrically connected to the control terminal and to a base or a gate of the first transistor; and an inverting amplifier whose collector or a drain is electrically connected to an emitter or a source of the third transistor, and whose base or a gate is electrically connected to a base or a gate of the second transistor, and which inverts and amplifies a voltage supplied to a base or a gate.

[0012] Effects of the Invention

[0013] According to the present disclosure, it is possible to provide a bias circuit that supplies a stable bias to a power amplifier. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a diagram showing an example of the structure of the power amplifier module according to the first embodiment.

[0015] Figure 2 : is a diagram showing an example of the structure of a carrier bias circuit.

[0016] Figure 3 This is a diagram showing an example of a power amplifier module according to a first modification.

[0017] Figure 4 This is a diagram showing an example of a power amplifier module according to a second modification.

[0018] Figure 5 This is a diagram showing an example of a power amplifier module according to a third modification.

[0019] Figure 6 This is a diagram showing an example of a power amplifier module according to a fourth modification.

[0020] Figure 7 This is a diagram showing an example of a power amplifier module according to a fifth modification.

[0021] Figure 8 The figures show the structure of the peak bias circuit of the power amplifier module according to the fifth modification. (a) is a figure showing an example of the structure of the peak bias circuit according to the first example, and (b) is a figure showing an example of the structure of the peak bias circuit according to the second example.

[0022] Fig. 9 This is a diagram showing an example of the configuration of a carrier bias circuit of a power amplifier module according to the second embodiment.

[0023] Fig.10 It is a diagram showing an example of the configuration of a carrier bias circuit of a power amplifier module according to the third embodiment.

[0024] Fig.11 It is a diagram showing an example of the configuration of a carrier bias circuit of a power amplifier module according to a fourth embodiment.

[0025] Fig.12 This is a diagram showing an example of the configuration of a carrier bias circuit of a power amplifier module according to the fifth embodiment.

[0026] Fig.13 FIG. 1 is a diagram showing an example of the configuration of a peak bias circuit of a power amplifier module according to a modification.

[0027] Fig.14 This is a diagram showing an example of the configuration of a carrier bias circuit of a power amplifier module according to the sixth embodiment.

[0028] Fig.15 This is a diagram showing an example of the configuration of a carrier bias circuit of a power amplifier module according to the seventh embodiment.

[0029] Fig.16 This is a diagram showing an example of the configuration of a carrier bias circuit of a power amplifier module according to the eighth embodiment.

[0030] Fig.17 This is a diagram showing an example of the configuration of a carrier bias circuit of a power amplifier module according to the ninth embodiment.

[0031] Fig.18 FIG. 1 is a diagram showing an example of the configuration of a peak bias circuit in a power amplifier module according to a modification.

[0032] Fig.19 It is a plan view showing the layout on a semiconductor substrate of a carrier bias circuit in a power amplifier module according to a modification of the fifth embodiment. DETAILED DESCRIPTION

[0033] Hereinafter, each embodiment of the present disclosure will be described with reference to each drawing. Here, circuit elements with the same reference numerals represent the same circuit elements, and repeated descriptions are omitted.

[0034] ===Structure of the power amplifier module 100 according to the first embodiment===

[0035] Reference Figure 1 The structure of the power amplifier module according to the first embodiment will be described. Figure 1 1 is a diagram showing an example of the structure of the power amplifier module 100 of the first embodiment. The power amplifier module 100 is mounted on a mobile phone, for example, and is used to amplify the power of a signal sent to a base station. The power amplifier module 100 can amplify the power of signals of communication standards such as 2G (2nd generation mobile communication system), 3G (3rd generation mobile communication system), 4G (4th generation mobile communication system), 5G (5th generation mobile communication system), LTE (Long Term Evolution) -FDD (Frequency Division Duplex), LTE-TDD (Time Division Duplex), LTE-Advanced, LTE-Advanced Pro, etc. In addition, the communication standards of the signals amplified by the power amplifier module 100 are not limited to these.

[0036] like Figure 1 As shown, the power amplifier module 100 includes, for example, a carrier amplifier 110, a carrier bias circuit 120, a peak amplifier 130, a peak bias circuit 140, and a detection circuit 150. The power amplifier module 100 includes, for example, a Doherty amplifier circuit composed of the carrier amplifier 110 and the peak amplifier 130.

[0037] The carrier amplifier 110 is an amplifier that amplifies the signal RF1 output from the distributor 160 and outputs a signal RF11. The carrier amplifier 110 is biased to, for example, class A, class AB, or class B. That is, the carrier amplifier 110 amplifies the input signal regardless of the power level of the input signal such as a small instantaneous input power and outputs the amplified signal.

[0038] The carrier bias circuit 120 is a circuit that supplies a bias to the carrier amplifier 110. The carrier bias circuit 120 has a structure that suppresses a voltage drop caused by the bias supplied to the carrier amplifier 110. The structure that suppresses the voltage drop in the carrier bias circuit 120 will be described later.

[0039] In addition, the carrier bias circuit 120 generates a signal indicating that the carrier amplifier 110 is saturated (hereinafter referred to as a “detection signal D sat”.) is output to the detection circuit 150. Regarding the carrier bias circuit 120 for outputting the detection signal D sat The structure will be described later.

[0040] The peak amplifier 130 is, for example, an amplifier that amplifies the signal RF2 output from the distributor 160 and outputs a signal RF21. The peak amplifier 130 is biased to class A, class AB, class B, or class C, for example.

[0041] The peak bias circuit 140 is a circuit for supplying a bias to the peak amplifier 130. The peak bias circuit 140 is based on, for example, a detection signal D output from a detection circuit 150 described later. sat The bias supplied to the peak amplifier 130 is controlled.

[0042] The detection circuit 150 detects the detection signal D output from the carrier bias circuit 120. sat The detection circuit 150 detects the detection signal D sat In the case of cont The peak bias circuit 140 outputs the peak bias circuit 140. The peak bias circuit 140 controls the peak bias circuit 140 based on the control signal D cont The bias is controlled so that the peak amplifier 130 is activated. Thus, the power amplification module 100 can activate the peak amplifier 130 at an appropriate timing when the carrier amplifier 110 is saturated or starts to be saturated.

[0043] The distributor 160 distributes the signal RFin into, for example, a signal RF1 input to the carrier amplifier 110 and a signal RF2 input to the peak amplifier 130. Here, the phase of the signal RF2 is, for example, delayed by approximately 90 degrees relative to the phase of the signal RF1. The distributor 160 may be, for example, a distributed constant circuit such as a coupled line 3dB coupler or a Wilkinson type distributor. In addition, the phrase "approximately 90 degrees" includes, for example, a range of 45 degrees to 135 degrees.

[0044] The synthesizing unit 170 synthesizes, for example, the signal RF11 output from the carrier amplifier 110 and passed through a phase shifter (not shown) and the signal RF21 output from the peak amplifier 130 , and outputs the amplified signal Pout.

[0045] <<Configuration of Carrier Bias Circuit 120>>

[0046] Reference Figure 2 An example of the configuration of the carrier bias circuit 120 that outputs the detection signal will be described. Figure 2 1 is a diagram showing an example of the structure of the carrier bias circuit 120. Figure 2As shown, the carrier bias circuit 120 includes, for example, a transistor 121 , an inverting amplifier 122 , a bias terminal 123 , a control terminal 124 , and a detection terminal 125 .

[0047] Here, the bias terminal 123 is, for example, a terminal for supplying a bias from the carrier bias circuit 120 to the carrier amplifier 110, and is a terminal electrically connected to the base of the transistor 111. In addition, the control terminal 124 is, for example, a terminal to which a signal for adjusting the reference voltage 126 is input. In addition, the detection terminal 125 is, for example, a terminal for outputting the detection signal D sat The detection terminal 125 is a terminal electrically connected to a circuit that controls the bias of a given amplifier. In the present embodiment, the detection terminal 125 is electrically connected to a detection circuit 150 that adjusts the bias of the peak amplifier 130, for example.

[0048] In addition, Figure 2 In the figure, the carrier amplifier 110 is described as a carrier amplifier including a transistor 111, a resistor 112 and a capacitor 113, wherein one end of the resistor 112 is electrically connected to the bias terminal 123, and the other end is electrically connected to the base of the transistor 111, and the capacitor 113 blocks the DC component of the signal RF1 input through the terminal 115.

[0049] The transistor 121 is composed of, for example, a bipolar transistor or a field effect transistor. In the following, as an example, the transistor 121 is described as a bipolar transistor. In addition, when the transistor 121 is a field effect transistor, the base is read as a gate, the collector is read as a drain, and the emitter is read as a source.

[0050] In transistor 121, the base is electrically connected to the output terminal of inverting amplifier 122, the emitter is electrically connected to bias terminal 123 and the inverting input terminal of inverting amplifier 122, and the collector is electrically connected to power supply V cc The base of the transistor 111 of the carrier amplifier 110 is electrically connected to the bias terminal 123 . That is, the transistor 121 supplies a bias to the carrier amplifier 110 through the bias terminal 123 .

[0051] The inverting amplifier 122 is constituted by, for example, an operational amplifier as a differential amplifier. The inverting amplifier 122 has an inverting input terminal and a non-inverting input terminal, and operates so that the potential difference between the inverting input terminal and the non-inverting input terminal becomes 0. The output terminal of the inverting amplifier 122 is electrically connected to the detection terminal 125 and the base of the transistor 121. In addition, the non-inverting input terminal of the inverting amplifier 122 is electrically connected to the control terminal 124, and a reference voltage 126 is supplied through the control terminal 124. The inverting input terminal of the inverting amplifier 122 is electrically connected to the emitter of the transistor 121. That is, the inverting amplifier 122 and the transistor 121 form a feedback circuit. As a result, the carrier bias circuit 120 can output a stable bias relative to changes in the output of the transistor 121. In addition, the inverting amplifier 122 outputs a detection signal D corresponding to the bias supplied from the emitter of the transistor 121 through the detection terminal 125. sat Output to the detection circuit 150.

[0052] <<Operation of Carrier Bias Circuit 120>>

[0053] Next, refer to Figure 1 , Figure 2 The operation of the carrier bias circuit 120 will be described. First, the operation of the carrier bias circuit 120 to suppress a voltage drop when supplying a bias will be described.

[0054] along with Figure 1 As the input signal RFin shown in FIG. 1 increases, the signal RF1 input from the distributor 160 to the carrier amplifier 110 increases. If the signal RF1 increases, Figure 2 The emitter current of the transistor 121 of the carrier bias circuit 120 shown in FIG. 1 increases. In the transistor 121, as the emitter current increases, the base-emitter voltage V be That is, as the input signal RFin becomes larger, the voltage drop of the carrier bias circuit 120 increases.

[0055] Here, the emitter of the transistor 121 is electrically connected to the inverting input terminal of the inverting amplifier 122. In addition, a fixed voltage V is supplied to the non-inverting input terminal of the inverting amplifier 122. ref That is, in the carrier bias circuit 120, when the voltage of the non-inverting input terminal is fixed, the emitter current of the transistor 121 increases, thereby increasing the voltage of the inverting input terminal (which is equal to the voltage V be At this time, the difference between the voltage at the non-inverting input terminal and the voltage at the inverting input terminal of the inverting amplifier 122 becomes larger, so the output of the inverting amplifier 122 becomes larger. As a result, in the carrier bias circuit 120, the base voltage of the transistor 121 becomes higher, which can increase the voltage V beIn this way, the carrier bias circuit 120 applies feedback when the voltage drop increases as the input signal RFin increases, so that the voltage V be With voltage V ref Thus, the carrier bias circuit 120 can supply a stable bias.

[0056] More specifically, for example, when the gain of the inverting amplifier 122 is set to A, the output voltage V0 of the carrier bias circuit 120 can be expressed by equation (1). Here, it is ideal that the gain A of the operational amplifier becomes infinite.

[0057] [Mathematical formula 1]

[0058] … (1)

[0059] As shown in equation (1), when the gain A is sufficiently large, the output voltage V0 of the carrier bias circuit 120 becomes equal to the voltage V ref That is, in the carrier bias circuit 120, the voltage V of the transistor 121 is be This does not affect the output voltage V0 of the carrier bias circuit 120. That is, in the carrier bias circuit 120, even when the emitter current of the transistor 121 increases, the voltage fluctuation can be suppressed.

[0060] Next, the detection signal D is output to the carrier bias circuit 120 for causing the peak amplifier 130 to operate at an appropriate timing. sat The action when

[0061] The inverting amplifier 122 outputs the voltage of the inverting input terminal and the voltage V ref That is, the inverting amplifier 122 can output a signal that amplifies the small voltage drop caused by the emitter current of the transistor 121. Therefore, although in the circuit shown in Patent Document 1, a voltage drop is intentionally generated by the resistor 27 to detect the saturation of the amplifier, the carrier bias circuit 120 can output the detection signal D indicating the saturation state of the carrier amplifier 110 from the detection terminal 125 while suppressing the voltage drop through the above-mentioned action of the inverting amplifier 122. sat .

[0062] Specifically, the detection signal D sat The voltage V dl It can be shown by equation (2). Here, in the operational amplifier, ideally, the gain A is infinite.

[0063] [Mathematical formula 2]

[0064] … (2)

[0065] As shown in equation (2), when the gain A is sufficiently large, the voltage V dl becomes and the voltage V ref With voltage V be That is, in the carrier bias circuit 120, the detection signal D can be increased. sat voltage level.

[0066] According to the above, in the carrier bias circuit 120, the voltage drop accompanying the increase of the emitter current of the transistor 121 can be suppressed, and the detection signal D can be increased. sat voltage level.

[0067] <<First Modification>>

[0068] Reference Figure 3 A first modified example of the power amplifier module 100 will be described. Figure 3 FIG. 1 is a diagram showing an example of a power amplifier module 100a according to a first modification. Figure 3 As shown, the power amplifier module 100a involved in the first variant is compared with the power amplifier module 100, and the detection circuit 150 controls the peak amplifier 130a of the driving stage. Specifically, the power amplifier module 100a includes, for example, a plurality of carrier amplifiers 110, 110a electrically connected in series and a plurality of peak amplifiers 130, 130a electrically connected in series. Specifically, it includes: the carrier amplifier 110a of the driving stage, which amplifies the signal RF1 output from the distributor 160 and outputs the amplified signal RF1; and the carrier amplifier 110 of the output stage, which further amplifies and outputs the amplified signal RF1 output from the carrier amplifier 110a of the driving stage. In addition, it includes: the peak amplifier 130a of the driving stage, which amplifies the signal RF2 output from the distributor 160 and outputs the amplified signal RF2; and the peak amplifier 130 of the output stage, which further amplifies and outputs the amplified signal RF2 output from the peak amplifier 130a of the driving stage. The carrier bias circuit 120 is electrically connected to the carrier amplifier 110 of the output stage among the plurality of carrier amplifiers 110 and 110a, and converts the detection signal D sat The detection circuit 150 outputs the control signal D to the peak bias circuit 140a of the peak amplifier 130a of the driving stage among the plurality of peak amplifiers 130 and 130a. cont The peak bias circuit 140a is based on the control signal D contThe bias is controlled so that the peak amplifier 130a of the driving stage is activated. Thus, the power amplifier module 100a can activate the peak amplifier 130a of the driving stage at an appropriate timing when the carrier amplifier 110 is saturated. In addition, in the power amplifier module 100a, the detection circuit 150 can also output the control signal D to the peak bias circuit 140 and the peak bias circuit 140a. cont Thus, when the carrier amplifier 110 is saturated, the peak amplifier 130 a of the driver stage and the peak amplifier 130 of the output stage can be operated at appropriate timing.

[0069] <<Second Modification>>

[0070] Reference Figure 4 A second modification of the power amplifier module 100 will be described. Figure 4 FIG. 1 is a diagram showing an example of a power amplifier module 100b according to a second modification. Figure 4 As shown, the power amplifier module 100b involved in the second variant is compared with the power amplifier module 100, and the detection circuit 150 controls the carrier amplifier 110a of the driving stage. Specifically, the power amplifier module 100b includes, for example, a plurality of carrier amplifiers 110, 110a and a plurality of peak amplifiers 130, 130a. The carrier bias circuit 120 is electrically connected to the carrier amplifier 110 of the output stage, and outputs a detection signal D to the detection circuit 150. sat The detection circuit 150 outputs a control signal D to, for example, the carrier bias circuit 120a of the carrier amplifier 110a of the driver stage. cont The carrier bias circuit 120a is based on the control signal D cont The bias supplied from the carrier bias circuit 120a of the driver stage to the carrier amplifier 110a is controlled. Thus, the power amplifier module 100b can adjust the output of the carrier amplifier 110a of the driver stage at an appropriate timing when the carrier amplifier 110 is saturated, thereby suppressing the distortion of the output of the carrier amplifier 110 of the output stage.

[0071] <<Third Modification>>

[0072] Reference Figure 5 A third modified example of the power amplifier module 100 will be described. Figure 5 FIG. 1 is a diagram showing an example of a power amplifier module 100c according to a third modification. Figure 5 As shown, the power amplifier module 100c according to the third variation is compared with the power amplifier module 100, and the detection circuit 150 obtains the detection signal D from the peak bias circuit 140 of the output stage. sat , and the control signal D contThe peak bias circuit 140 outputs the detection signal D to the driver stage. Specifically, the power amplifier module 100c includes, for example, a plurality of carrier amplifiers 110, 110a and a plurality of peak amplifiers 130, 130a. The peak bias circuit 140 is electrically connected to the peak amplifier 130 of the output stage and outputs the detection signal D to the detection circuit 150. sat The detection circuit 150 outputs a control signal D to, for example, the peak bias circuit 140a of the peak amplifier 130a of the driver stage. cont The peak bias circuit 140a is based on the control signal D cont The bias supplied from the peak bias circuit 140a of the driver stage to the peak amplifier 130a is controlled. Thus, the power amplifier module 100c can adjust the output of the peak amplifier 130a of the driver stage according to the output level of the peak amplifier 130, thereby suppressing the distortion of the output of the peak amplifier 130 of the output stage.

[0073] <<Fourth Modification>>

[0074] Reference Figure 6 A fourth modified example of the power amplifier module 100 will be described. Figure 6 FIG. 1 is a diagram showing an example of a power amplifier module 100d according to a fourth modification. Figure 6 As shown, the power amplifier module 100d according to the fourth modification does not form a Doherty circuit compared to the power amplifier module 100, and a plurality of amplifiers are electrically connected in series. In the power amplifier module 100d, the detection circuit 150 controls the amplifier 110d of the driving stage.

[0075] Here, the output stage bias circuit 120b is configured to have the same structure as the carrier bias circuit 120. The power amplifier module 100d includes, for example, a driver stage amplifier 110c and an output stage amplifier 110d. The output stage bias circuit 120d is electrically connected to the output stage amplifier 110c and outputs a detection signal D to the detection circuit 150. sat The detection circuit 150 outputs a control signal D to the driver stage bias circuit 120c of the driver stage amplifier 110d, for example. cont The driver stage bias circuit 120c is based on the control signal D cont The bias supplied from the driver stage bias circuit 120c to the amplifier 110d is controlled. Thus, the power amplifier module 100d can adjust the output of the driver stage amplifier 110d according to the output level of the output stage amplifier 110c, thereby suppressing distortion of the output of the output stage amplifier 110c.

[0076] ≪Fifth Modification≫

[0077] Reference Figure 7 , Figure 8A fifth modification of the power amplifier module 100 will be described. Figure 7 FIG. 1 is a diagram showing an example of a power amplifier module 100e according to the fifth modification. Figure 7 As shown, the power amplifier module 100e according to the fifth modification is different from the power amplifier module 100 in that the detection signal D is directly input from the carrier bias circuit 120 to the peak bias circuit 140. sat , and adjusts the output of the peak amplifier 130. In the power amplifier module 100e, the peak bias circuit 140 is based on the detection signal D sat The bias supplied to the peak amplifier 130 is controlled.

[0078] Reference Figure 8 (a) and (b) are used to explain the detection signal D output from the carrier bias circuit 120. sat Details of the configuration of the peak bias circuit 140 that controls the bias of the peak amplifier 130 .

[0079] Figure 8 (a) is a diagram showing a first example of the configuration of a peak bias circuit 140 x according to the first example. The peak bias circuit 140 x includes a transistor 141 .

[0080] The transistor 141 is composed of, for example, a bipolar transistor or a field effect transistor. In the following, as an example, the transistor 141 is described as a bipolar transistor. In addition, when the transistor 141 is a field effect transistor, the base is read as a gate, the collector is read as a drain, and the emitter is read as a source.

[0081] In transistor 141, the base is electrically connected to the detection terminal 125 included in the carrier bias circuit 120 or the output terminal of the inverting amplifier 122, the emitter is electrically connected to the bias terminal 143, and the collector is electrically connected to the power supply V cc 2 is electrically connected. The bias terminal 143 is electrically connected to the base of the transistor 131 of the peak amplifier 130 .

[0082] That is, the transistor 141 supplies a bias to the peak amplifier 130 via the bias terminal 143 .

[0083] In the power amplifier module 100e, the detection signal D is directly input from the detection terminal 125 included in the carrier bias circuit 120 to the base of the transistor 141 included in the peak bias circuit 140. sat Here, the transistor 141 operates as an emitter follower, so the detection signal D satThe impedance of is supplied to the peak bias circuit 140 in a state lower than when it is output from the carrier bias circuit 120. Thus, when the carrier amplifier 110 is saturated, the peak amplifier 130 can be automatically operated (without using the detection circuit 150) at an appropriate timing.

[0084] Figure 8 (b) is a diagram showing a configuration of a peak bias circuit 140 y according to the second example. The peak bias circuit 140 y includes a transistor 141 and a transistor 142 .

[0085] The transistor 142 is composed of, for example, a bipolar transistor or a field effect transistor. In the following, as an example, the transistor 141 is described as a bipolar transistor. In addition, when the transistor 141 is a field effect transistor, the base is read as a gate, the collector is read as a drain, and the emitter is read as a source.

[0086] In the transistor 142, the base is electrically connected to the emitter of the transistor 121 included in the carrier bias circuit 120, the emitter is electrically connected to the ground, and the collector is electrically connected to the base of the transistor 141. The transistor 142 functions as an emitter-grounded inverting amplifier, inverts and amplifies the voltage of the emitter of the carrier bias circuit 120 (or the voltage of the inverting input terminal of the inverting amplifier 122), and outputs it to the base of the transistor 141. Thus, even when a voltage drop that cannot be completely suppressed by the carrier bias circuit 120 occurs at the emitter of the transistor 121, a bias can be appropriately supplied to the peak amplifier 130.

[0087] In addition, although the control signal D is output from the detection circuit 150 in the above description, cont For example, the detection signal D may be directly input from the carrier bias circuit 120 to the peak amplifier 130. sat , and adjust the output of the peak amplifier 130.

[0088] ===Power amplifier module 200 according to the second embodiment===

[0089] Reference Fig. 9 The configuration of the carrier bias circuit 220 of the power amplifier module 200 according to the second embodiment will be described. Figure 7 1 is a diagram showing an example of the configuration of a carrier bias circuit 220 of a power amplifier module 200 according to the second embodiment.

[0090] like Fig. 9As shown, the power amplifier module 200 is provided with a carrier bias circuit 220 in which an inverting amplifier 122 of the carrier bias circuit 120 is constituted by a transistor (hereinafter referred to as transistor 222) that inverts and amplifies a voltage, compared with the power amplifier module 100. The following describes the structure different from the power amplifier module 100.

[0091] Specifically, Fig. 9 As shown, the carrier bias circuit 220 includes a transistor 221 and a transistor 222. The base or gate of the transistor 221 is connected to the input reference signal S base The control terminal 225 is electrically connected to the reference signal S base This is a signal for controlling the bias point of the carrier amplifier 210 .

[0092] The transistor 222 is composed of, for example, a bipolar transistor or a field effect transistor. In the following, as an example, the transistor 222 is described as a bipolar transistor. In addition, when the transistor 222 is a field effect transistor, the base is read as a gate, the collector is read as a drain, and the emitter is read as a source.

[0093] First, the structure of the carrier bias circuit 220 is described. The collector of the transistor 222 is electrically connected to the control terminal 225 and the detection terminal 226. That is, in the carrier bias circuit 220, the control terminal 225 and the detection terminal 226 may also be connected to the same node. The base of the transistor 222 is electrically connected to the emitter of the transistor 221 and the bias terminal 224 through the resistor 223. The emitter of the transistor 222 is electrically connected to the ground. In addition, the base of the transistor 222 does not need to be connected to the emitter of the transistor 221 through the resistor 223, and may be directly electrically connected to the emitter of the transistor 221. Thus, the carrier bias circuit 220 can be miniaturized.

[0094] Next, the operation of the carrier bias circuit 220 will be described. In the carrier bias circuit 220, most of the current input to the control terminal 225 flows to the collector of the transistor 222. In addition, a current corresponding to the current flowing to the collector of the transistor 222 flows to the base of the transistor 221. Due to the current flowing to the base of the transistor 221, a voltage V between the base and the emitter of the transistor 221 is generated. be Therefore, it is decided Figure 7 The voltage V of transistor 222 is shown ref. Here, if the bias current supplied to the carrier amplifier 210 of the carrier bias circuit 220 increases, the output voltage of the carrier bias circuit 220 decreases due to the voltage drop. At this time, the current flowing to the base of the transistor 222 decreases. In this way, the voltage is inverted and amplified by the transistor 222, so that the collector potential of the transistor 222 increases and the base potential of the transistor 221 increases. Based on the above, in the carrier bias circuit 220, the feedback mechanism functions to suppress the decrease in the output voltage. In addition, as described above, the collector potential of the transistor 222 increases, so that a large detection signal D can be obtained through the detection terminal 226. sat .

[0095] That is, compared with the carrier bias circuit 120, the carrier bias circuit 220 uses one transistor (transistor 222) to realize the inverting amplifier 122 and the reference voltage 126 (voltage V ref ) is supplied, so the circuit can be miniaturized.

[0096] In addition, in the transistor 222, the base and the collector may be electrically connected via the capacitor 227. This can suppress oscillation that may occur due to positive feedback of a part of the emitter current of the transistor 221 as the base current of the transistor 222. Therefore, in the carrier bias circuit 220 having the capacitor electrically connected between the base and the collector, the circuit characteristics are stable.

[0097] In addition, it is assumed that the carrier bias circuit 220 can replace Figure 6 The present invention is applied to the output stage bias circuit 120d in the power amplifier module 100d according to the fourth modification shown in FIG.

[0098] ===Power amplifier module 300 according to the third embodiment===

[0099] Reference Fig.10 The configuration of the carrier bias circuit 320 of the power amplifier module 300 according to the third embodiment will be described. Fig.10 FIG. 1 is a diagram showing an example of the configuration of a carrier bias circuit 320 of a power amplifier module 300 according to the third embodiment.

[0100] like Fig.10 As shown, the power amplifier module 300 is further provided with a diode-connected transistor 323 via a resistor 323a in the carrier bias circuit 320, compared with the power amplifier module 200. The components different from the power amplifier module 200 will be described below.

[0101] The carrier bias circuit 320 includes a transistor 321 , a transistor 322 , and a transistor 323 .

[0102] The transistor 323 is composed of, for example, a bipolar transistor or a field effect transistor. In the following, as an example, the transistor 323 is described as a bipolar transistor. In addition, when the transistor 323 is a field effect transistor, the base is read as a gate, the collector is read as a drain, and the emitter is read as a source.

[0103] The collector of transistor 323 is electrically connected to the emitter of transistor 321. The base of transistor 323 is electrically connected to the base of transistor 322. The emitter of transistor 323 is electrically connected to ground. That is, in carrier bias circuit 320, transistor 323 is electrically connected to the emitter of transistor 321 in a diode-connected manner.

[0104] Here, the base of the transistor 322 is electrically connected to the base of the transistor 323 .

[0105] One end of the resistor 323a is connected to the base of the transistor 323, and the other end is connected to the collector of the transistor 323. That is, the transistor 323 is diode-connected via the resistor 323a.

[0106] The operation of the carrier bias circuit 320 is the same as that of the carrier bias circuit 220, so the description thereof is omitted. In addition, in the carrier bias circuit 320, by connecting the diode-connected transistor 323 to the emitter of the transistor 321, the base current of the transistor 322 can be reduced. Specifically, by connecting the diode-connected transistor 323 to the emitter of the transistor 321, a current of about several tens of times or more of the base current of the transistor 322 can be consumed at the emitter of the transistor 321. That is, in the second embodiment, it is possible to suppress oscillation that may be generated by positively feeding back a part of the emitter current of the transistor 221 as the base current of the transistor 222. Therefore, in the carrier bias circuit 320 having the transistor 323, the characteristics of the circuit are stable. In addition, in the carrier bias circuit 320, by providing the transistor 323 that suppresses oscillation, the capacitor 227 in the carrier bias circuit 220 can be omitted, so that the circuit can be miniaturized.

[0107] Furthermore, for example, when the base of the transistor 323 is directly connected to the bias terminal 324 electrically connected to the base of the transistor 311 constituting the carrier amplifier 310, the RF signal input to the base of the transistor 311 through the terminal 315 is also simultaneously input to the base of the transistor 322. At this time, the RF signal flowing into the base of the transistor 322 is consumed in the transistor 322, so the power of the RF signal input to the base of the transistor 311 is reduced, which may cause a decrease in the gain of the carrier amplifier 310. Furthermore, the transistor 322 amplifies the RF signal flowing into the base and outputs it from the detection terminal 326, which may cause a malfunction of the carrier bias circuit 320.

[0108] In contrast, in the power amplifier module 300, a transistor 323 connected in diode connection via a resistor 323a is provided in the carrier bias circuit 320. This can reduce the inflow of the RF signal input to the carrier amplifier 310 into the base of the transistor 322, and can reduce malfunction of the carrier bias circuit 320.

[0109] In addition, it is assumed that the carrier bias circuit 320 can replace Figure 6 The present invention is applied to the output stage bias circuit 120d in the power amplifier module 100d according to the fourth modification shown in FIG.

[0110] ===Power amplifier module 400 according to the fourth embodiment===

[0111] Reference Fig.11 The configuration of the carrier bias circuit 420 of the power amplifier module 400 according to the fourth embodiment will be described. Fig.11 1 is a diagram showing an example of the configuration of a carrier bias circuit 420 of a power amplifier module 400 according to the fourth embodiment.

[0112] like Fig.11 As shown, the power amplifier module 400 is further provided with a transistor 424 in the carrier bias circuit 420 compared with the power amplifier module 300. The components different from the power amplifier module 300 will be described below.

[0113] The carrier bias circuit 420 includes a transistor 421 , a transistor 422 , a transistor 423 , a resistor 423 a , and a transistor 424 .

[0114] The transistor 424 is composed of, for example, a bipolar transistor or a field effect transistor. In the following, as an example, the transistor 424 is described as a bipolar transistor. In addition, when the transistor 424 is a field effect transistor, the base is read as a gate, the collector is read as a drain, and the emitter is read as a source.

[0115] The collector of transistor 424 is connected to the power supply V cc The base of the transistor 424 is electrically connected to the control terminal 426 and the base of the transistor 421. The emitter of the transistor 424 is electrically connected to the collector of the transistor 422.

[0116] In addition, the collector of the transistor 422 is electrically connected to the detection terminal 427 .

[0117] The operation of the carrier bias circuit 420 is the same as that of the carrier bias circuit 320, and thus its description is omitted. In addition, in the carrier bias circuit 420, in addition to the effect of the carrier bias circuit 320, since the detection signal D is output from the emitter of the transistor 424, sat Therefore, the detection signal D output from the detection terminal 427 can be obtained with higher accuracy. sat .

[0118] ===Power amplifier module 500 according to the fifth embodiment===

[0119] Reference Fig.12 The configuration of the carrier bias circuit 520 of the power amplifier module 500 according to the fifth embodiment will be described. Fig.12 1 is a diagram showing an example of the configuration of a carrier bias circuit 520 of a power amplifier module 500 according to the fifth embodiment.

[0120] like Fig.12 As shown, the power amplifier module 500 is further provided with a transistor 525 in the carrier bias circuit 520 compared with the power amplifier module 400. The components different from the power amplifier module 400 will be described below.

[0121] The carrier bias circuit 520 includes a transistor 521 , a transistor 522 , a transistor 523 , a resistor 523 a , a transistor 524 , and a transistor 525 .

[0122] The transistor 525 is composed of, for example, a bipolar transistor or a field effect transistor. In the following, as an example, the transistor 525 is described as a bipolar transistor. In addition, when the transistor 525 is a field effect transistor, the base is read as a gate, the collector is read as a drain, and the emitter is read as a source.

[0123] The transistor 525 is a diode-connected transistor. The collector and base of the transistor 525 are electrically connected to the base of the transistor 524. The emitter of the transistor 525 is electrically connected to the collector of the transistor 522. In addition, the collector of the transistor 522 is electrically connected to the detection terminal 528. That is, the voltage V between the base and the emitter of the transistor 524 is proportional to the voltage V between the base and the emitter of the transistor 524. beThis forms a current mirror relationship. Thus, a current proportional to the current input from the control terminal 527 can flow to the collector of the transistor 524 .

[0124] The operation of the carrier bias circuit 520 is the same as that of the carrier bias circuit 420, and thus the description thereof is omitted. In addition, in the carrier bias circuit 520, as described above, a current proportional to the current input from the control terminal 527 can flow to the collector of the transistor 524, so that in addition to the effect of the carrier bias circuit 420 according to the fourth embodiment, an effect is achieved in that the carrier bias circuit 420 can be configured with an input current having a lower accuracy than the accuracy of the current input from the control terminal 426.

[0125] Specifically, in the carrier bias circuit 420 according to the fourth embodiment, the reference voltage V is determined by the base currents of the transistors 421 and 424, which have significantly small current values. ref Therefore, high accuracy is required for the current input from the control terminal 426. On the other hand, in the carrier bias circuit 520 involved in this embodiment, the current input from the control terminal 527 is also supplied to the collector of the transistor 525, so the current used to determine the reference voltage V ref Thus, the operation of the carrier bias circuit 420 is stabilized.

[0126] <<Modifications>>

[0127] Reference Fig.13 A modification example of the power amplifier module 500 will be described. Fig.13 1 is a diagram showing an example of the configuration of a peak bias circuit 540 in a power amplifier module 500a according to a modified example. In the power amplifier module 500a according to the modified example, similarly to the power amplifier module 100e, the detection signal D is directly input from the carrier bias circuit 520 to the peak bias circuit 540. sat , and adjusts the output of the peak amplifier 530. In the power amplifier module 500a, the peak bias circuit 540 is based on the detection signal D sat The bias supplied to the peak amplifier 530 is controlled.

[0128] The peak bias circuit 540 includes a transistor 541, a transistor 542, a transistor 543, a resistor 543a, a transistor 544, and a detection terminal 548. The peak bias circuit 540 has a structure similar to that of the carrier bias circuit 420 of the power amplifier module 400 according to the fourth embodiment, and therefore the components different from the carrier bias circuit 420 will be described below. In addition, the peak bias circuit 540 may also have the same structure as that of the carrier bias circuit of each power amplifier module according to the first embodiment, the second embodiment, the third embodiment, and the fifth embodiment.

[0129] The difference between the peak bias circuit 540 and the carrier bias circuit 420 is that the base of the transistor 541 and the base of the transistor 544 are not connected to the control terminal. Instead, in the peak bias circuit 540, the base of the transistor 541 and the base of the transistor 544 are electrically connected to the base of the transistor 524 and the base of the transistor 525 included in the carrier bias circuit 520. That is, in the power amplifier module 500a, the detection signal D directly input from the carrier bias circuit 520 to the peak bias circuit 540 is sat It is not a signal output from the detection terminal, but a signal output from the base of the transistor 524 and the base of the transistor 525 .

[0130] The detection signal D input to the peak bias circuit 540 is output from the base of the transistor 524 and the base of the transistor 525 included in the carrier bias circuit 520. sat , so that the detection signal D sat The voltage shift of the peak bias circuit 540 is input to the peak bias circuit 540. For example, in this modification, the detection signal D is smaller than that output from the detection terminal 528 of the carrier bias circuit 520. sat The voltage shift of the transistor 525 is equal to the voltage (Vbe) between the base and the emitter of the transistor 525. As a result, a detection signal D with a more appropriate voltage can be input to the peak amplifier 530. sat .

[0131] In this case, the signals output from the detection terminal 528 of the carrier bias circuit 520 and the detection terminal 548 of the peak bias circuit 540 can be used for controls other than the control of the peak bias circuit (eg, control of input power to the power amplifier module 500a itself).

[0132] ===Power amplifier module 600 according to the sixth embodiment===

[0133] Reference Fig.14 The configuration of the carrier bias circuit 620 of the power amplifier module 600 according to the sixth embodiment will be described. Fig.141 is a diagram showing an example of the configuration of a carrier bias circuit 620 in a power amplifier module 600 according to the sixth embodiment.

[0134] like Fig.14 As shown in FIG. 1 , the power amplifier module 600 is further provided with a transistor 629 in the carrier bias circuit 620 compared with the power amplifier module 500. In addition, the power amplifier module 600 is changed from the collector of the transistor 622 to the collector of the transistor 629 to connect the detection terminal 628 compared with the power amplifier module 500. The components different from the power amplifier module 500 are described below.

[0135] The carrier bias circuit 620 includes a transistor 621 , a transistor 622 , a transistor 623 , a resistor 623 a , a transistor 624 , a transistor 625 , and a transistor 629 .

[0136] The transistor 629 is composed of, for example, a bipolar transistor or a field effect transistor. In the following, as an example, the transistor 629 is described as a bipolar transistor. In addition, when the transistor 629 is a field effect transistor, the base is read as a gate, the collector is read as a drain, and the emitter is read as a source.

[0137] The base of transistor 629 is electrically connected to the base of transistor 622 and the base of transistor 623. The emitter of transistor 629 is electrically connected to ground. In addition, the collector of transistor 629 is electrically connected to detection terminal 628. That is, transistor 629 is an inverting amplifier whose input terminal is electrically connected to the input terminal of inverting amplifier 122 of power amplifier module 100 according to the first embodiment, inverts and amplifies the voltage supplied to the input terminal, and outputs it from the output terminal. Thus, a current proportional to the current flowing to the collector of transistor 622 can flow to the collector of transistor 629. Furthermore, if transistor 622 and transistor 629 are arranged on the same semiconductor substrate at a close distance, a current that copies the current flowing to the collector of transistor 622 can also flow to the collector of transistor 629.

[0138] That is, the ratio of the collector current of transistor 629 to the collector current of transistor 622 can be freely selected according to the size ratio of transistors 622 and 629. Specifically, when transistors 622 and 629 are bipolar transistors, the ratio of the collector current of transistor 629 can be selected according to the emitter area ratio of transistors 622 and 629. In addition, when transistors 622 and 629 are field effect transistors, the ratio of the drain current of transistor 629 can be selected according to the gate width ratio of transistors 622 and 629. Thus, even when a circuit requiring a relatively large current is connected to the detection terminal 628, the power amplifier module 600 can be operated stably.

[0139] In addition, for example, in the saturation detection circuit described in Patent Document 1 as a prior art document, the operation is stabilized by electrically connecting the input terminal of the saturation detector to the base of the power amplifier and thermally coupling them. However, generally speaking, the temperature of the power amplifier varies greatly depending on the location where it is arranged, so it is actually difficult to arrange the saturation detector near the center of the power amplifier where the temperature is most likely to rise and thermally couple it.

[0140] In contrast, according to the structure of the carrier bias circuit 620 of the power amplifier module 600, a stable operation can be achieved without thermally coupling the transistor 629 connected to the detection terminal 628 and the transistor 611 constituting the carrier amplifier 610. Therefore, in the carrier bias circuit 620, a relatively free arrangement of transistors can be performed compared to the saturation detection circuit described in the prior art document.

[0141] In addition, in the carrier bias circuit 620, if the thermal environment of the transistor 629 is made close to the thermal environment of the transistor 629, the operation can be made more stable. Here, the transistor 622 and the transistor 629 are sufficiently smaller than the transistor 611 constituting the carrier amplifier 610, so the distance between the transistor 622 and the transistor 629 can be reduced and arranged. Therefore, if the distance between the transistor 622 and the transistor 629 is shortened compared to the distance between the transistor 629 and the portion with the highest temperature in the transistor 611 (for example, the center portion of the transistor 611), the thermal environment of the transistor 629 can be made close to the thermal environment of the transistor 629.

[0142] The transistor 629 may be electrically connected to an inverting amplifier in any of the power amplifier modules 100 according to the first embodiment to the power amplifier modules 500 according to the fifth embodiment. In this case as well, the effect of enabling stable operation of each power amplifier module can be achieved.

[0143] ===Power amplifier module 700 according to the seventh embodiment===

[0144] Reference Fig.15 The configuration of the carrier bias circuit 720 of the power amplifier module 700 according to the seventh embodiment will be described. Fig.15 1 is a diagram showing an example of the configuration of a carrier bias circuit 720 of a power amplifier module 700 according to the seventh embodiment.

[0145] like Fig.15 As shown, the power amplifier module 700 has the following structure compared with the power amplifier module 400, that is, there is no detection terminal 427 in the carrier bias circuit 420. That is, the carrier bias circuit 720 does not have an output detection signal D sat Furthermore, the power amplifier module 700 does not have Figure 1 , Figure 3 to Figure 6 The detection circuit 150 shown in FIG. 7 is a structure in which the detection terminal 427 is deleted from the carrier bias circuit 420, and the description of each component of the carrier bias circuit 720 will be omitted.

[0146] The operation of the carrier bias circuit 720 is the same as that of the carrier bias circuit 320 and the carrier bias circuit 420, and the base current of the transistor 722 can be reduced. That is, in the carrier bias circuit 720, it is possible to suppress oscillation that may be generated by positively feeding back a part of the emitter current of the transistor 721 as the base current of the transistor 722. Therefore, in the carrier bias circuit 720 including the transistor 623, the circuit characteristics are stable.

[0147] ===Power amplifier module 800 according to the eighth embodiment===

[0148] Reference Fig.16 The structure of the carrier bias circuit 820 of the power amplifier module 800 according to the eighth embodiment will be described. Fig.16 This is a diagram showing an example of the configuration of a carrier bias circuit 820 of a power amplifier module 800 according to the eighth embodiment.

[0149] like Fig.16 As shown, the power amplifier module 800 is a structure that is different from the power amplifier module 500, that is, it does not have the detection terminal 528 in the carrier bias circuit 520. That is, the carrier bias circuit 820 does not have an output detection signal D sat Furthermore, the power amplifier module 800 does not have Figure 1 , Figure 3 to Figure 6The detection circuit 150 shown in FIG. 8 is a structure of the carrier bias circuit 820 in which the detection terminal 528 is deleted from the structure of the carrier bias circuit 520, and the description of each component of the carrier bias circuit 820 will be omitted.

[0150] The operation of the carrier bias circuit 820 is the same as that of the carrier bias circuit 520, and it is possible to cause a current proportional to the current input from the control terminal 827 to flow to the collector of the transistor 824. Therefore, in addition to the effect of the carrier bias circuit 720, the following effect is achieved, that is, compared with the accuracy of the current input from the control terminal 726 in the carrier bias circuit 720, it can be configured with lower accuracy.

[0151] ===Power amplifier module 900 according to the ninth embodiment===

[0152] Reference Fig.17 The configuration of the carrier bias circuit 920 of the power amplifier module 900 according to the ninth embodiment will be described. Fig.17 1 is a diagram showing an example of the configuration of a carrier bias circuit 920 of a power amplifier module 900 according to the ninth embodiment.

[0153] like Fig.17 As shown, compared with the power amplifier module 600 , the power amplifier module 900 further includes transistors 930 and 931 in the carrier bias circuit 920 .

[0154] The transistor 930 and the transistor 931 are constituted by, for example, a bipolar transistor or a field effect transistor. In the following, as an example, the transistor 930 and the transistor 931 are each a bipolar transistor for description. In addition, when the transistor 930 and the transistor 931 are field effect transistors, the base below is read as a gate, the collector is read as a drain, and the emitter is read as a source.

[0155] The base of the transistor 930 is electrically connected to the base of the transistor 924 and the base of the transistor 925. The collector of the transistor 930 is electrically connected to the power supply Vcc. In addition, the emitter of the transistor 930 is electrically connected to the base of the transistor 931 via the resistor 932.

[0156] Here, the emitter of transistor 924 and the emitter of transistor 925 are connected to the collector of transistor 922. As with transistor 222 of power amplifier module 200, the collector potential of transistor 922 increases as the bias current supplied to carrier amplifier 910 by carrier bias circuit 920 increases. In addition, a signal whose voltage is shifted from the collector of transistor 922 by an amount corresponding to the voltage (Vbe) between the base and emitter of transistor 925 is supplied to the base of transistor 924 and the base of transistor 925. In other words, the potential of the base of transistor 924 and the base of transistor 925 increases as the bias current supplied to carrier amplifier 910 by carrier bias circuit 920 increases.

[0157] In the power amplifier module 900, the base of the transistor 924 and the base of the transistor 925 are connected to the base of the transistor 930 that operates as a collector grounded amplifier. As a result, the voltage of the signal output from the emitter of the transistor 930 also increases as the bias current supplied to the carrier amplifier 910 by the carrier bias circuit 920 increases. In addition, the signal output from the emitter of the transistor 930 is a signal branched from the middle of the feedback circuit composed of the transistor 922 and the transistor 921 that are inverting amplifiers, and is a signal that has been subjected to collector grounding amplification. Therefore, in the power amplifier module 900, a detection signal Dsat with good accuracy output from the emitter of the transistor 930 can be obtained.

[0158] The base of the transistor 931 is electrically connected to the collector of the transistor 929. The collector of the transistor 931 is electrically connected to the detection terminal 928. In addition, the emitter of the transistor 931 is electrically connected to the ground.

[0159] Here, the base of transistor 929 is connected to the base of transistor 922 as an inverting amplifier in a feedback circuit including transistors 921 and 922. That is, the signal input to the base of transistor 929 is input without being inverted and amplified by transistor 922, so if the bias current supplied to carrier amplifier 910 by carrier bias circuit 920 increases, it decreases. Therefore, the collector current of transistor 929 decreases, and the voltage drop amount in resistor 932 decreases. On the other hand, as described above, if the bias current supplied to carrier amplifier 910 by carrier bias circuit 920 increases, the emitter output of transistor 930 increases. That is, due to the increase in the emitter output of transistor 930 and the decrease in the voltage drop amount of resistor 932 accompanied by the decrease in the collector current of transistor 929, the base potential of transistor 391 increases significantly. As a result, regarding the collector current of the transistor 391, when the bias current supplied to the carrier amplifier 910 by the carrier bias circuit 920 increases, it is possible to output a detection signal D which is significantly increased compared to the power amplifier module 600. sat .

[0160] <<Modifications>>

[0161] Reference Fig.18 A modification example of the power amplifier module 900 will be described. Fig.18 1 is a diagram showing an example of the configuration of a peak bias circuit 940 in a power amplifier module 900a according to a modified example. Similar to the power amplifier module 500a, the power amplifier module 900a according to the modified example directly inputs a detection signal D from a carrier bias circuit 920 to the peak bias circuit 940. sat , and adjusts the output of the peak amplifier 960. In the power amplifier module 900a, the peak bias circuit 940 is based on the detection signal D sat The bias supplied to the peak amplifier 960 is controlled.

[0162] The peak bias circuit 940 includes a transistor 941, a transistor 942, a transistor 943, a resistor 943a, a transistor 944, a transistor 945, a transistor 950, a transistor 951, a resistor 952, a resistor 953, a control terminal 947, and an active control terminal 948. The structure of the peak bias circuit 940 is similar to that of the carrier bias circuit 920, so the components different from the carrier bias circuit 920 are described below. In addition, the peak bias circuit 940 can also be set to the same structure as the carrier bias circuit of each power amplifier module involved in the first embodiment, the second embodiment, the third embodiment, or the fifth embodiment.

[0163] The transistor 950 and the transistor 951 are constituted by, for example, a bipolar transistor or a field effect transistor. In the following, as an example, the transistor 950 and the transistor 951 are each a bipolar transistor for description. In addition, when the transistor 950 and the transistor 951 are field effect transistors, the base below is read as a gate, the collector is read as a drain, and the emitter is read as a source.

[0164] The base of the transistor 950 is electrically connected to the collector of the transistor 951 and is connected to the input reference signal S base The control terminal 947 is electrically connected, wherein the reference signal S base is a signal for controlling the bias point of the peak amplifier 960. In addition, the base of the transistor 950 is electrically connected to the base of the transistor 941, the base of the transistor 944, and the base of the transistor 945. The collector of the transistor 950 is electrically connected to the power supply Vcc. The emitter of the transistor 950 is electrically connected to the base of the transistor 951 via the resistor 952, and is electrically connected to the active control terminal 948.

[0165] The base of the transistor 951 is electrically connected to the emitter of the transistor 950 via the resistor 952 and the resistor 953, and is electrically connected to the active control terminal 948 via the resistor 953. The emitter of the transistor 951 is electrically connected to the ground.

[0166] When the bias current supplied to the carrier amplifier 910 of the carrier bias circuit 920 is small, no current is output from the detection terminal 928. That is, the same amount of current flows through the emitter of the transistor 950, the resistor 952, the resistor 953, and the base of the transistor 951. In this case, the transistor 951 is turned on, and a large current flows through the collector of the transistor 951, so the current flowing out from the control terminal 947 is consumed by the collector of the transistor 951. Therefore, when the bias current supplied to the carrier amplifier 910 of the carrier bias circuit 920 is small, the circuit portion composed of the transistor 941, the transistor 942, the transistor 943, the transistor 944, the transistor 945, and the resistor 943a is turned off, and the bias current supplied from the peak bias circuit 940 to the peak amplifier 960 decreases.

[0167] On the other hand, when the bias current supplied to the carrier amplifier 910 by the carrier bias circuit 920 is large, a large detection signal D is supplied from the carrier bias circuit 920 to the active control terminal 948. satAs a result, the current flowing to the resistor 952 increases, and the voltage drop across the resistor 952 also increases. As a result, the base voltage of the transistor 951 decreases, and the transistor 951 becomes off. Therefore, the current does not flow to the collector of the transistor 951, and the control signal S input from the control terminal 947 is turned off. base Most of is supplied to the circuit portion composed of transistor 941, transistor 942, transistor 943, transistor 944, transistor 945 and resistor 943a. That is, the bias current supplied to the peak amplifier 960 of the peak bias circuit 940 increases.

[0168] Reference Fig.19 A modification of the power amplifier module 500 according to the fifth embodiment will be described. Fig.19 1 is a plan view showing the layout on the semiconductor substrate 1000 of the carrier bias circuit 520 of the power amplifier module 500 a according to the modification example according to the fifth embodiment.

[0169] The transistor 511 included in the carrier amplifier 510 is composed of, for example, a plurality of transistors Qrf1, Qrf2, Qrf3, ... connected in parallel to each other. Fig.19 In the embodiment, the plurality of transistors Qrf1 , Qrf2 , Qrf3 . . . respectively have a base electrode, a collector electrode, and an emitter electrode, and are provided on the semiconductor substrate 1000 so as to be arranged in the x direction.

[0170] On the semiconductor substrate 1000, the shortest distance d1 connecting the transistor 522 of the carrier bias circuit 520 and the transistor 511 included in the carrier amplifier 510 and the shortest distance d2 connecting the transistor 523 of the carrier bias circuit 520 and the transistor 511 included in the carrier amplifier 510 are shorter than the shortest distance connecting the other transistors (here, the transistor 521, the transistor 524, and the transistor 525) included in the carrier bias circuit 520 and the transistor 511 included in the carrier amplifier 510. Here, the so-called distance d1 is the distance between the transistor closest to the transistor 522 (in the case of the plurality of transistors Qrf1, Qrf2, Qrf3, ...) Fig.19 The distance d2 is the shortest distance between the emitter electrode of the transistor Qrf1) and the emitter electrode of the transistor 522. The distance d2 is the distance between the transistor closest to the transistor 523 (in Fig.19 is the shortest distance between the emitter electrode of transistor Qrf1) and the emitter electrode of transistor 523. Fig.19In the embodiment, both the distance d1 and the distance d2 are smaller than the distance connecting each emitter electrode of other transistors (for example, transistor 521, transistor 524 and transistor 525) included in the carrier bias circuit 520 and the emitter electrode of the transistor closest to the other transistors among the multiple transistors Qrf1, Qrf2, Qrf3...

[0171] By setting such a layout, the transistor 522 and the transistor 523 among the multiple transistors included in the carrier bias circuit 520 are located closest to the transistor 511 of the carrier amplifier 510. At this time, the temperature of the transistor 522 and the transistor 523 becomes the same as the temperature of the transistor 511. Here, the bases of the transistors 522 and 523 are connected in common with the base of the transistor 511. Therefore, a current proportional to the current flowing to the collector of the transistor 511 flows to the collectors of the transistors 522 and 523. Here, the collector of the transistor 522 is determined by the sum of the current source and the current proportional to the current supplied from the current source. That is, when the current supplied from the current source is a current that does not depend on temperature, the base current of the transistor 511 having a base connected in common with the base of the transistor 522 becomes fixed. As described above, even when a temperature difference occurs in the carrier bias circuit 520 , that is, even when the temperatures of the transistors 521 , 524 , and 525 vary, the base current of the transistor 511 of the carrier amplifier 510 can be stabilized.

[0172] ===Summary===

[0173] The carrier bias circuit 120 of the power amplifier module 100 according to the exemplary embodiment of the present disclosure includes: a transistor 121 (first transistor) that supplies a bias to the carrier amplifier 110 (first amplifier) ​​from an emitter or source; a detection terminal 125 (first terminal) that is electrically connected to a circuit (for example, a detection circuit 150) that controls the bias of a given amplifier (for example, a peak amplifier 130); and an inverting amplifier 122 (first inverting amplifier) ​​whose input terminal is electrically connected to the emitter or source of the transistor 121 (first transistor) and whose output terminal is electrically connected to the base or gate of the transistor 121 (first transistor) and the detection terminal 125 (first terminal), and inverts and amplifies the voltage supplied to the input terminal. That is, the inverting amplifier 122 outputs a signal corresponding to the bias supplied from the transistor 121 (first transistor) to the carrier amplifier 110 (first amplifier) ​​from the output terminal. As a result, the carrier bias circuit 120 can supply a stable bias.

[0174] In addition, the inverting amplifier 122 (first inverting amplifier) ​​of the carrier bias circuit 120 of the power amplifier module 100 is an operational amplifier having an inverting input terminal electrically connected to the emitter or source of the transistor 121 (first transistor) and a non-inverting input terminal to which a reference signal (for example, a reference voltage 126) for controlling the bias supplied to the carrier amplifier 110 (first amplifier) ​​is input. Thus, a stable bias can be supplied with a simple structure.

[0175] In the carrier bias circuit 220 of the power amplifier module 200, the transistor 222 (first inverting amplifier) ​​is a transistor (for example, a bipolar transistor or a field effect transistor), the output terminal is a collector or a drain, and the input terminal is a base or a gate. Thus, compared with the carrier bias circuit 120, it can be miniaturized.

[0176] In the carrier bias circuit 220 of the power amplifier module 200 , the transistor 222 (first inverting amplifier) ​​has its base or gate and collector or drain electrically connected via a capacitor, thereby suppressing oscillation of the carrier bias circuit 220 caused by noise.

[0177] In addition, the carrier bias circuit 320 of the power amplifier module 300 further includes a transistor 323 (a second transistor) whose collector or drain is electrically connected to the base or gate. In the transistor 323 (a second transistor), the collector or drain is electrically connected to the emitter or source of the transistor 321 (a first transistor), the base or gate is electrically connected to the base or gate of the transistor 322 (a first inverting amplifier), and the emitter or source is electrically connected to the ground. Thus, the oscillation of the carrier bias circuit 320 caused by noise can be suppressed.

[0178] In addition, the carrier bias circuit 420 of the power amplifier module 400 further includes a control terminal 124 (second terminal) to which a reference signal S for controlling the bias of the carrier amplifier 110 (first amplifier) ​​is input. base and transistor 424 (third transistor), the base or gate of which is electrically connected to control terminal 426 (second terminal) and the base or gate of transistor 421 (first transistor), and the emitter or source of which is electrically connected to the collector or drain of transistor 422 (first inverting amplifier). Thus, the output impedance of carrier bias circuit 420 can be reduced.

[0179] In addition, the carrier bias circuit 520 of the power amplifier module 500 further includes a transistor 525 (fourth transistor) whose collector or drain and base or gate are electrically connected. In the transistor 525 (fourth transistor), the collector or drain and base or gate are electrically connected to the base or gate of the transistor 524 (third transistor), and the emitter or source is electrically connected to the collector or drain of the transistor 522 (first inverting amplifier). Thus, the reference voltage V ref The accuracy of the current can thus stabilize the operation of the carrier bias circuit 420.

[0180] In addition, the carrier bias circuit 620 of the power amplifier module 600 further includes a transistor 629 (a second inverting amplifier) ​​whose input terminal is electrically connected to the input terminal (here, the base or the gate) of the transistor 622, and inverts and amplifies the voltage supplied to the input terminal, and outputs it from the output terminal. Thus, a current proportional to the current flowing to the collector of the transistor 622 can flow to the collector of the transistor 629, so that even if a circuit requiring a relatively large current is connected to the detection terminal 628, the power amplifier module 600 can operate stably.

[0181] In addition, the transistor 629 (second inverting amplifier) ​​of the power amplifier module 600 is a transistor whose emitter or source is electrically connected to the ground, whose output terminal is the collector or drain, and whose input terminal is the base or gate, and the transistor 622 (first inverting amplifier) ​​and the transistor 629 (second inverting amplifier) ​​are provided on the same semiconductor substrate. Thus, a current that copies the current flowing to the collector of the transistor 622 can flow to the collector of the transistor 629, so that even when a circuit that requires a relatively large current is connected to the detection terminal 628, the power amplifier module 600 can operate stably.

[0182] Furthermore, in the power amplifier module 600 , the distance between the transistor 622 (first inverting amplifier) ​​and the transistor 629 (second inverting amplifier) ​​is smaller than the distance between the transistor 622 (first inverting amplifier) ​​and the carrier amplifier 610 (first amplifier).

[0183] By making the thermal environment of the transistor 629 close to the thermal environment of the transistor 629 , the operation can be made more stable.

[0184] In addition, in the carrier bias circuit 120 of the power amplifier module 100, the carrier amplifier 110 (first amplifier) ​​is a carrier amplifier constituting a Doherty amplifier circuit, and the output terminal of the inverting amplifier 122 (first inverting amplifier) ​​is electrically connected to the detection terminal 125 (first terminal), and the detection terminal 125 (first terminal) is electrically connected to the peak bias circuit 140 (first bias circuit) that supplies a bias to the peak amplifier 130 (second amplifier) ​​constituting the Doherty amplifier circuit or the control circuit (first bias control circuit) that controls the bias supplied from the peak bias circuit 140 (first bias circuit). Thus, the carrier bias circuit 120 can properly operate the peak amplifier 130 at the timing when the carrier amplifier 110 is saturated.

[0185] Furthermore, in the carrier bias circuit 120 of the power amplifier module 100, the detection terminal 125 (first terminal) is connected to the peak bias circuit 140 (first bias circuit), and the peak bias circuit 140 supplies a bias to the peak amplifier 130 (second amplifier) ​​based on the detection signal output from the detection terminal 125. Thus, even without providing a detection circuit, the peak bias circuit 140 can be automatically operated at an appropriate timing.

[0186] Furthermore, in the power amplifier module 100, the peak bias circuit 140 (first bias circuit) includes a transistor 141 (fifth transistor) that supplies a bias to the peak amplifier 130 (second amplifier) ​​from an emitter or a source, and a detection signal is input to a base or a gate of the transistor 141. Thus, even without providing a detection circuit, the peak bias circuit 140 can be automatically operated at an appropriate timing.

[0187] In the power amplifier module 100, the peak bias circuit 140 (first bias circuit) further includes a transistor 142 (sixth transistor) whose base or gate is connected to the emitter or source of the transistor 121 (first transistor), and the collector or drain of the transistor 142 is connected to the base or gate of the transistor 141 (fifth transistor), and the emitter or source is electrically connected to the ground. Thus, even when a voltage drop that cannot be completely suppressed by the carrier bias circuit 120 occurs, a bias can be appropriately supplied to the peak amplifier 140.

[0188] In the power amplifier module 500, the amplifier 510 is a carrier amplifier constituting the Doherty amplifier circuit, and the base or gate of the transistor 524 (third transistor) and the collector or drain and the base or gate of the transistor 525 (fourth transistor) are electrically connected to a peak bias circuit 540 (first bias circuit) for supplying a bias to a peak amplifier 530 (second amplifier) ​​constituting the Doherty amplifier circuit. Thus, a detection signal with a more appropriate voltage can be input to the peak bias circuit 540.

[0189] In addition, in the power amplifier module 500, the peak bias circuit 540 (first bias circuit) includes: a transistor 541 (seventh transistor) that supplies a bias from an emitter or source to a peak amplifier 530 (second amplifier); a detection terminal 548 (second terminal) that is electrically connected to a circuit that controls a bias of a given amplifier; and a transistor 542 (first inverting amplifier) ​​that has an input terminal electrically connected to an emitter or source of the transistor 541, an output terminal electrically connected to a base or gate of the transistor 541 and the detection terminal 548, and inverts and amplifies a voltage supplied to the input terminal. Thus, a stable bias can be supplied even in the peak bias circuit.

[0190] In the carrier bias circuit 120 of the power amplifier module 100a, the peak amplifier (second amplifier) ​​includes a peak amplifier 130 (first peak amplifier) ​​and a peak amplifier 130a (second peak amplifier) ​​electrically connected in series at the preceding stage of the peak amplifier 130 (first peak amplifier), and the detection terminal 125 (first terminal) is electrically connected to a peak bias circuit 140a (second bias circuit) that supplies a bias to the peak amplifier 130a (second peak amplifier) ​​or a control circuit (second bias control circuit) that controls the bias supplied from the peak bias circuit 140a (second bias circuit). Thus, the carrier bias circuit 120 can properly operate the peak amplifier 130 at the timing when the carrier amplifier 110 is saturated.

[0191] In the carrier bias circuit 120 of the power amplifier module 100d, the detection terminal 125 (first terminal) is electrically connected to the driver stage bias circuit 120c (bias circuit) or the control circuit (bias control circuit), wherein the driver stage bias circuit 120c (bias circuit) supplies a bias to the driver stage amplifier 110d (second amplifier) ​​electrically connected in series with the output stage amplifier 110c (first amplifier), and the control circuit (bias control circuit) controls the bias supplied from the driver stage bias circuit 120c (bias circuit). Thus, the output of the driver stage amplifier 110d can be adjusted according to the output level of the output stage amplifier 110c, so that the distortion of the output of the output stage amplifier 110c can be suppressed.

[0192] Furthermore, the carrier bias circuit 720 of the power amplifier module 700 includes a control terminal 726 to which a reference signal S for controlling the bias of the carrier amplifier 710 (first amplifier) ​​is input. base; transistor 721 (first transistor), base or gate electrically connected to control terminal 726, emitter or source supplying bias to carrier amplifier 710 (first amplifier); transistor 723 (second transistor), collector or drain electrically connected to base or gate, collector or drain electrically connected to emitter or source of transistor 721 (first transistor); transistor 724 (third transistor), base or gate electrically connected to control terminal 726 and base or gate of transistor 721 (first transistor); and transistor 722 (inverting amplifier), collector or drain electrically connected to emitter or source of transistor 724 (third transistor), base or gate electrically connected to base or gate of transistor 723 (second transistor), inverting and amplifying the voltage supplied to the base or gate. Thus, carrier bias circuit 720 can supply a stable bias. In addition, oscillation that may be generated by positively feeding back a part of emitter current of transistor 721 as base current of transistor 722 can be suppressed.

[0193] In addition, in the carrier bias circuit 820 of the power amplifier module 800, a transistor 825 (a fourth transistor) is further provided, wherein the collector or drain and the base or gate are electrically connected. In the transistor 825 (a fourth transistor), the collector or drain and the base or gate are electrically connected to the base or gate of the transistor 824 (a third transistor), and the emitter or source is electrically connected to the collector or drain of the transistor 822 (an inverting amplifier). Thus, the reference voltage V ref The accuracy of the current can thus stabilize the operation of the carrier bias circuit 820.

[0194] The above-described embodiments are intended to make the present disclosure easy to understand and are not intended to limit the present disclosure. The present disclosure can be changed or improved without departing from its main purpose, and the present disclosure also includes its equivalents. That is, as long as the features of the present disclosure are possessed, embodiments in which those skilled in the art appropriately apply design changes to the embodiments are also included in the scope of the present disclosure. The elements and their configurations, etc., possessed by the embodiments are not limited to the exemplified contents and can be appropriately changed.

[0195] Description of Reference Numerals

[0196] 100, 200, 300, 400, 500, 600, 700, 800, 900: power amplifier module;

[0197] 120, 220, 320, 420, 520, 620, 720, 820, 920: carrier bias circuit;

[0198] 121, 221, 321, 421, 521, 621, 721, 821, 921: transistors;

[0199] 122: Inverting amplifier;

[0200] 222, 322, 422, 522, 622, 722, 822, 922: transistors.

Claims

1. A bias circuit comprising: a first transistor for supplying a bias to the first amplifier from an emitter or a source; The first terminal is electrically connected to a circuit for controlling a bias of a given amplifier; and The first inverting amplifier has a first input terminal electrically connected to the emitter or source of the first transistor, and a first output terminal electrically connected to the base or gate of the first transistor and the first terminal, and inverts and amplifies the voltage supplied to the first input terminal.

2. The bias circuit according to claim 1, in, The first inverting amplifier is an operational amplifier. The operational amplifier has: an inverting input terminal electrically connected to the emitter or source of the first transistor; and A reference signal for controlling a bias supplied to the first amplifier is input to the non-inverting input terminal.

3. The bias circuit according to claim 1, in, The first inverting amplifier is a transistor, the first output terminal is a collector or a drain, and the first input terminal is a base or a gate.

4. The bias circuit according to claim 3, in, The first inverting amplifier has a base or a gate and a collector or a drain electrically connected via a capacitor.

5. The bias circuit according to claim 3 or claim 4, in, The device further comprises: a second transistor, wherein the collector or the drain is electrically connected to the base or the gate, In the second transistor, the collector or drain is electrically connected to the emitter or source of the first transistor, the base or gate is electrically connected to the base or gate of the first inverting amplifier, and the emitter or source is electrically connected to the ground.

6. The bias circuit according to claim 5, in, Also available: a second terminal to which a reference signal for controlling a bias of the first amplifier is input; and The third transistor has a base or a gate electrically connected to the second terminal and the base or the gate of the first transistor, and an emitter or a source electrically connected to the collector or the drain of the first inverting amplifier.

7. The bias circuit according to claim 6, in, It also includes: a fourth transistor, the collector or the drain and the base or the gate are electrically connected, In the fourth transistor, the collector or drain and the base or gate are electrically connected to the base or gate of the third transistor, and the emitter or source is electrically connected to the collector or drain of the first inverting amplifier.

8. The bias circuit according to any one of claims 1 to 4, in, The invention further comprises a second inverting amplifier having a second input terminal connected to the first input terminal of the first inverting amplifier, inverting and amplifying a voltage supplied to the second input terminal, and outputting the amplified voltage from a second output terminal.

9. The bias circuit according to claim 8, in, The second inverting amplifier is a transistor whose emitter or source is electrically connected to the ground, the second output terminal is a collector or a drain, and the second input terminal is a base or a gate. The first inverting amplifier and the second inverting amplifier are provided on the same semiconductor substrate.

10. The bias circuit according to claim 9, in, A distance between the first inverting amplifier and the second inverting amplifier is smaller than a distance between the first inverting amplifier and the first amplifier.

11. The bias circuit according to any one of claims 1 to 4, in, The first amplifier is a carrier amplifier constituting a Doherty amplifier circuit. The output terminal of the first inverting amplifier is electrically connected to the first terminal, and the first terminal is electrically connected to a first bias circuit that supplies a bias to a second amplifier that is a peak amplifier constituting the Doherty amplifier circuit or a first bias control circuit that controls the bias supplied from the first bias circuit.

12. The bias circuit according to claim 11, in, The first terminal is connected to the first bias circuit. The first bias circuit supplies a bias to the second amplifier based on the detection signal output from the first terminal.

13. The bias circuit according to claim 12, in, The first bias circuit includes a fifth transistor for supplying a bias to the second amplifier from an emitter or a source. The detection signal is input to the base or the gate of the fifth transistor.

14. The bias circuit according to claim 13, in, The first bias circuit further comprises: a sixth transistor, a base or a gate of which is connected to an emitter or a source of the first transistor, In the sixth transistor, a collector or a drain is connected to the base or the gate of the fifth transistor, and an emitter or a source is electrically connected to the ground.

15. The bias circuit according to claim 7, in, The first amplifier is a carrier amplifier constituting a Doherty amplifier circuit. The base or gate of the third transistor and the collector or drain and the base or gate of the fourth transistor are electrically connected to a first bias circuit, and the first bias circuit supplies a bias to a second amplifier as a peak amplifier constituting the Doherty amplifier circuit.

16. The bias circuit according to claim 15, in, The first bias circuit comprises: a seventh transistor for supplying a bias to the second amplifier from an emitter or a source; The second terminal is electrically connected to a circuit for controlling a bias of a given amplifier; and An inverting amplifier, wherein an input terminal is electrically connected to the emitter or source of the seventh transistor, and an output terminal is electrically connected to the base or gate of the seventh transistor and the second terminal, and inverts and amplifies a voltage supplied to the input terminal.

17. The bias circuit according to claim 11, in, The second amplifier includes a first peak amplifier and a second peak amplifier electrically connected in series at a preceding stage of the first peak amplifier. The first terminal is electrically connected to a second bias circuit that supplies a bias to the second peak amplifier or a second bias control circuit that controls the bias supplied from the second bias circuit.

18. The bias circuit according to any one of claims 1 to 4, in, The first terminal is electrically connected to a bias circuit that supplies a bias to a second amplifier or a bias control circuit that controls the bias supplied from the bias circuit, and the second amplifier is electrically connected in series with the first amplifier.

19. A bias circuit comprising: a control terminal to which a reference signal for controlling a bias of the first amplifier is input; a first transistor, the base or the gate of which is electrically connected to the control terminal, and the emitter or the source of which supplies a bias to the first amplifier; A second transistor, wherein the collector or drain is electrically connected to the base or gate, and the collector or drain is electrically connected to the emitter or source of the first transistor; a third transistor, a base or a gate of which is electrically connected to the control terminal and the base or the gate of the first transistor; and The inverting amplifier has a collector or a drain electrically connected to the emitter or the source of the third transistor, and a base or a gate electrically connected to the base or the gate of the second transistor, and inverts and amplifies the voltage supplied to the base or the gate.

20. The bias circuit according to claim 19, in, It also includes: a fourth transistor, the collector or the drain and the base or the gate are electrically connected, In the fourth transistor, the collector or drain and the base or gate are electrically connected to the base or gate of the third transistor, and the emitter or source is electrically connected to the collector or drain of the inverting amplifier.

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