Power amplifier circuit

Abstract

The present invention is provided with: a first amplification circuit that is supplied with a first bias from a first bias circuit, amplifies a first signal, and outputs an output signal to a first output terminal; a first trigger circuit including at least one diode whose anode is electrically connected to the first output terminal, the first trigger circuit outputting a first feedback signal corresponding to the voltage of the first output terminal when the voltage of the first output terminal exceeds a predetermined threshold value; a first conversion circuit, a second transistor connected to the first transistor in a current mirror manner; a first resistor connected in series to a collector electrode or a drain electrode of the first transistor; and a second resistor connected in series to a collector electrode or a drain electrode of the second transistor. A third resistor connected in series to the emitter or source of the second transistor, in which the first feedback signal is input to the collector or drain of the first transistor and the collector or drain of the second transistor, and the resistance value of the third resistor is smaller than the resistance value of the second resistor; and a first adjustment circuit including a transistor having a base or a gate to which the signal output from the first conversion circuit is input, and a collector or a drain electrically connected to the first bias circuit so as to adjust the first bias supplied from the first bias circuit.

Description

Technical Field

[0001] The invention relates to a power amplifier circuit. Background Art

[0002] Mobile communication terminals such as mobile phones use power amplifier circuits to amplify RF (Radio Frequency) signals transmitted to base stations. In power amplifier circuits, if the impedance of the mobile phone's antenna mismatches with the amplifier's impedance, for example, the output voltage increases, potentially causing amplifier failure. For example, Patent Document 1 discloses a power amplifier circuit equipped with a protection circuit to address this issue.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: U.S. Patent No. 6,580,321 Summary of the Invention

[0006] Problems to be solved by the invention

[0007] In the power amplifier circuit disclosed in Patent Document 1, when the voltage at the output terminal exceeds a certain voltage, a circuit comprising multiple diodes connected in series operates. In this power amplifier circuit, the current flowing through the circuit comprising multiple diodes is supplied to the base of the transistor, thereby suppressing the bias applied to the amplifier. This allows the power amplifier circuit to suppress voltage increases at the output terminal.

[0008] However, in the power amplifier circuit disclosed in Patent Document 1, as the temperature increases, the diodes operate at a lower voltage. Therefore, as the temperature increases, the circuit having multiple diodes connected in series operates earlier, thereby reducing the output efficiency of the power amplifier circuit.

[0009] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a power amplifier circuit capable of suppressing a decrease in output efficiency.

[0010] Technical solutions to solve problems

[0011] To achieve such an object, one aspect of the present invention relates to a power amplifier circuit comprising: a first amplifier circuit, which is supplied with a first bias from a first bias circuit, amplifies a first signal, and outputs an output signal to a first output terminal; a first trigger circuit, which includes at least one diode having an anode electrically connected to the first output terminal, wherein when a voltage at the first output terminal exceeds a given threshold, the first trigger circuit outputs a first feedback signal corresponding to the voltage at the first output terminal; a first conversion circuit, which includes a first transistor connected in a diode-connected manner, a second transistor connected in a current mirror manner to the first transistor, and a second transistor connected in a current mirror manner to the first transistor. a first resistor connected in series with the collector or drain, a second resistor connected in series with the collector or drain of the second transistor, and a third resistor connected in series with the emitter or source of the second transistor, wherein the first feedback signal is input to the collector or drain of the first transistor and the collector or drain of the second transistor, and the resistance value of the third resistor is smaller than the resistance value of the second resistor; and a first adjustment circuit including a transistor having a base or gate inputted with the signal output from the first conversion circuit and a collector or drain electrically connected to the first bias circuit so as to adjust the first bias supplied from the first bias circuit.

[0012] To achieve this object, another aspect of the present invention relates to a power amplifier circuit comprising: a first amplifier circuit, supplied with a first bias from a first bias circuit, amplifying a first signal and outputting an output signal to a first output terminal; a second amplifier circuit, supplied with a second bias from a second bias circuit, electrically connected to the first amplifier circuit at a preceding stage of the first amplifier circuit, amplifying an input signal and outputting the first signal; a first trigger circuit, comprising at least one diode having an anode electrically connected to the first output terminal, wherein when a voltage at the first output terminal exceeds a predetermined threshold value, the first trigger circuit outputs a first feedback signal corresponding to the voltage at the first output terminal; and a first conversion circuit, comprising a first diode-connected transistor. , a second transistor current mirror-connected to the first transistor, a first resistor connected in series with the collector or drain of the first transistor, a second resistor connected in series with the collector or drain of the second transistor, and a third resistor connected in series with the emitter or source of the second transistor, wherein the first feedback signal is input to the collector or drain of the first transistor and the collector or drain of the second transistor, and the resistance value of the third resistor is smaller than the resistance value of the second resistor; and a first adjustment circuit including a transistor having a base or gate inputted with a signal output from the first conversion circuit and a collector or drain electrically connected to the second bias circuit so as to adjust the second bias supplied from the second bias circuit.

[0013] Effects of the Invention

[0014] According to the present invention, it is possible to provide a power amplifier circuit that can prevent breakdown of the amplifier circuit and achieve high output efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a diagram showing a configuration example of a power amplifier circuit according to the first embodiment.

[0016] Figure 2 This is a graph showing the voltage and current characteristics at the output terminal of a power amplifier circuit not provided with a conversion circuit, and a region where a power-stage transistor may break down.

[0017] Figure 3 This is a graph showing the characteristics of voltage and current at the output terminal of the power amplifier circuit disclosed in Patent Document 1 and a region where a power-stage transistor may break down.

[0018] Figure 4 Graph showing characteristics of voltage and current at the output terminal of a power amplifier circuit and a region where a power stage transistor may break down.

[0019] Figure 5 1 is a diagram showing an example of the relationship between a voltage Vting represented by a feedback signal S1 input to a conversion circuit and a voltage Von represented by a signal output from the conversion circuit.

[0020] Figure 6 It is a diagram showing the states of voltage and current at various points in the conversion circuit.

[0021] Figure 7 It is a diagram showing the states of voltage and current at various points in the conversion circuit.

[0022] Figure 8 It is a diagram showing the states of voltage and current at various points in the conversion circuit.

[0023] Figure 9 This is a graph showing the efficiency characteristics of the power amplifier circuit according to the first embodiment.

[0024] Figure 10 JP-A-2004-11465 is a graph showing the efficiency characteristics of the power amplifier circuit disclosed in Patent Document 1.

[0025] Figure 11 It is a diagram showing a configuration example of a power amplifier circuit according to a first modification.

[0026] Figure 12 It is a graph showing the relationship between voltage and current in a power-stage amplifier circuit.

[0027] Figure 13 Graph showing the voltage of the amplifier circuit of the driver stage.

[0028] Figure 14 A diagram showing a configuration example of a power amplifier circuit according to a second modification.

[0029] Figure 15 It is a diagram showing a configuration example of a power amplifier circuit according to the second embodiment.

[0030] Figure 16 A diagram showing a configuration example of a power amplifier circuit according to a third modification.

[0031] Figure 17 A diagram showing a configuration example of a power amplifier circuit according to a fourth modification.

[0032] Figure 18 This is a diagram showing a configuration example of a power amplifier circuit according to a modification of the third embodiment.

[0033] Figure 19 It is a diagram showing a configuration example of a power amplifier circuit according to a fourth embodiment.

[0034] Figure 20 This is a diagram showing a configuration example of a power amplifier circuit according to a fifth modification.

[0035] Figure 21 It is a diagram showing a configuration example of a power amplifier circuit according to the fifth embodiment.

[0036] Figure 22 This is a diagram showing a configuration example of a power amplifier circuit according to a sixth modification. DETAILED DESCRIPTION

[0037] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The same elements are denoted by the same reference numerals, and repeated descriptions are omitted.

[0038] ===Power Amplifier Circuit 100a According to First Embodiment===

[0039] Figure 1 1 is a diagram showing a configuration example of a power amplifier circuit 100 a according to the first embodiment. Figure 1The illustrated power amplifier circuit 100a is installed in a mobile communication device, such as a cellular phone, and is used to amplify the power of radio frequency (RF) signals transmitted to a base station. Power amplifier circuit 100a amplifies the power of signals based on communication standards such as 2G (second-generation mobile communication system), 3G (third-generation mobile communication system), 4G (fourth-generation mobile communication system), 5G (fifth-generation mobile communication system), LTE (Long Term Evolution)-FDD (Frequency Division Duplex), LTE-TDD (Time Division Duplex), LTE-Advanced, and LTE-Advanced Pro. The frequency of the RF signal ranges from several hundred MHz to several tens of GHz, for example. The communication standards and frequencies of the signals amplified by power amplifier circuit 100a are not limited to these.

[0040] <<Structure>>

[0041] Reference Figure 1 , an example of the structure of the power amplifier circuit 100a is described.

[0042] The power amplifier circuit 100 a includes, for example, matching circuits 110 and 120 , bias circuits 130 and 140 , amplifier circuits 150 and 160 , a trigger circuit 170 , a conversion circuit 180 , and an adjustment circuit 190 .

[0043] The matching circuit 110 is a circuit (MN: Matching Network) that matches the impedance of the circuit preceding the power amplifier circuit 100 a with the impedance of the amplifier circuit 150 . The matching circuit 120 is a circuit that matches the impedance of the amplifier circuit 150 with the impedance of the amplifier circuit 160 .

[0044] The bias circuit 130 is a circuit that supplies a bias current to the amplifier circuit 150. The bias circuit 130 is supplied with a constant current from a constant current source 132 via a resistor 131, for example, and supplies a bias to the base of a transistor 151 of the amplifier circuit 150.

[0045] The bias circuit 140 is a circuit that supplies a bias current to the amplifier circuit 160. The bias circuit 140 is supplied with a constant current from a constant current source 142 via a resistor 141, for example, and supplies a bias to the base of a transistor 161 of the amplifier circuit 160.

[0046] Amplifier circuit 150 amplifies input signal RFin input via matching circuit 110 and outputs signal RF1. Amplifier circuit 150 includes, for example, transistor 151, capacitor 152, and resistor 153. Transistor 151 receives input signal RFin at its base via capacitor 152, and is biased by bias circuit 130 via resistor 153.

[0047] Amplifier circuit 160 amplifies signal RF1 input via matching circuit 120 and outputs signal RF2. Amplifier circuit 160 includes, for example, transistor 161, capacitor 162, and resistor 163. Signal RF1 is input to the base of transistor 161 via capacitor 162, and a bias is supplied from bias circuit 140 via resistor 163.

[0048] Transistors 151 and 161 are, for example, bipolar transistors such as heterojunction bipolar transistors (HBTs). Alternatively, transistors 151 and 161 may include field-effect transistors (MOSFETs) instead of HBTs. The following description assumes that transistors 151 and 161 are bipolar transistors.

[0049] In the power amplifier circuit 100a, the bias supplied from the bias circuit 140 to the amplifier circuit 160 can be adjusted by the adjustment circuit 190 described later. Thus, in the power amplifier circuit 100a, the voltage of the output terminal 102 can be appropriately adjusted according to temperature.

[0050] The trigger circuit 170 is a circuit that outputs a feedback signal S1 corresponding to the voltage of the output terminal 102 to the conversion circuit 180 when the voltage of the output terminal 102 exceeds a predetermined threshold value.

[0051] Trigger circuit 170 is comprised of, for example, at least one diode. Specifically, in trigger circuit 170, multiple diodes are connected in series. The anode of any of the multiple diodes (here, the anode at one end of the multiple diodes) is electrically connected to output terminal 102, and the cathode of any of the multiple diodes (the cathode of the diode located closer to the reference potential than the diode electrically connected to output terminal 102) is electrically connected to a reference potential (here, ground). Trigger circuit 170 only needs to include at least one diode.

[0052] In the trigger circuit 170, any node between the plurality of diodes connected in series ( Figure 1 The trigger circuit 170 is electrically connected to the conversion circuit 180 (“node N1”). In other words, the feedback signal S1 is output from the node N1 between two adjacent diodes among the plurality of diodes in the trigger circuit 170.

[0053] That is, the trigger circuit 170 can set a threshold value by the number of diodes 171 located closer to the output terminal 102 than the node N1 , and output the feedback signal S1 through the node N1 when the voltage of the output terminal 102 exceeds the threshold value.

[0054] Furthermore, the diode 172 located closer to the reference potential than the node N1 in the trigger circuit 170 can protect the trigger circuit 170 from ESD (Electro Static Discharge), which is a high voltage spike.

[0055] Here, in the trigger circuit 170 , due to the properties of a diode, the threshold value decreases as the temperature increases. That is, at a high temperature, the trigger circuit 170 operates at a lower voltage at the output terminal 102 than at a low temperature.

[0056] The power amplifier circuit 100 a includes a conversion circuit 180 to improve the temperature-dependent operation tendency of the trigger circuit 170 .

[0057] The conversion circuit 180 includes transistors 181 and 182 and resistors 183, 184, and 185. In the conversion circuit 180, the transistor 181 and the transistor 182 are connected in a current mirror manner.

[0058] The transistor 181 is a diode-connected transistor. The collector of the transistor 181 is electrically connected to the node N1 of the trigger circuit 170, and the feedback signal S1 is inputted via the resistor 183. The emitter of the transistor 181 is electrically connected to a reference potential.

[0059] The collector of transistor 182 is electrically connected to node N1 of trigger circuit 170 and receives feedback signal S1 via resistor 184. The emitter of transistor 182 is electrically connected to a reference potential via resistor 185. The base of transistor 182 is electrically connected to the base of transistor 181.

[0060] The resistor 183 is connected in series between the node N1 of the trigger circuit 170 and the collector of the transistor 181. The resistor 184 is connected in series between the node N1 of the trigger circuit 170 and the collector of the transistor 182.

[0061] The resistor 185 is connected in series between the emitter of the transistor 181 and the reference potential. The resistor 185 has a smaller resistance value than the resistor 184.

[0062] That is, conversion circuit 180 is a so-called Widlar current mirror circuit. Conversion circuit 180 determines the level of signal S2 output to adjustment circuit 190 by the ratio of the resistance values of resistor 184 to resistor 185. The operation of conversion circuit 180 will be described later.

[0063] The adjustment circuit 190 is a circuit for adjusting the bias output from the bias circuit 140 based on the signal S2 input from the conversion circuit 180 .

[0064] Adjustment circuit 190 includes transistor 191 and resistors 192 and 193. Transistor 191 has a base electrically connected to the collector of transistor 182 via resistor 192, an emitter electrically connected to a reference potential, and a collector electrically connected to bias circuit 140 to suppress a bias outputted from bias circuit 140.

[0065] Transistors 181, 182, and transistor 191 are, for example, bipolar transistors such as heterojunction bipolar transistors (HBTs). Alternatively, transistors 181, 182, and transistor 191 may include field-effect transistors (MOSFETs) instead of HBTs. The following description assumes that transistors 181, 182, and transistor 191 are bipolar transistors.

[0066] <<Action>>

[0067] Next, refer to Figures 1 to 11 The operation of the power amplifier circuit 100a will be described. First, the effectiveness of the power amplifier circuit 100a compared with the power amplifier circuit of the comparative example will be described, and then the specific operation of the power amplifier circuit 100a will be described.

[0068] Figure 2 1 is a graph showing the voltage and current characteristics at the output terminal of the power amplifier circuit without the trigger circuit 170, the conversion circuit 180 and the adjustment circuit 190, and the region Rd where the power stage transistor may be broken down. Figure 2 In FIG, the horizontal axis shows the voltage of the output terminal, and the vertical axis shows the current of the output terminal. Figure 2 (A) is a graph showing the characteristics (one-dot chain line) when the temperature is -30 degrees Celsius. Figure 2 (B) is a graph showing the characteristics (dashed line) when the temperature is +25 degrees Celsius. Figure 2(C) is a graph showing the characteristics (solid line) when the temperature is +85 degrees Celsius.

[0069] Figure 3 This is a graph showing the voltage and current characteristics at the output terminal of the power amplifier circuit disclosed in Patent Document 1 and the region Rd where the power stage transistor may break down. In other words, this is a graph showing the voltage and current characteristics and the region Rd where the power stage transistor may break down in the power amplifier circuit obtained by removing the conversion circuit 180 from the power amplifier circuit 100a according to the first embodiment. Figure 3 In FIG, the horizontal axis shows the voltage of the output terminal, and the vertical axis shows the current of the output terminal. Figure 3 The area Rd shown is Figure 2 The region Rd shown is the same. Figure 3 In FIG, the maximum voltage value of the output terminal in the power amplifier circuit is shown by a dotted line (voltage suppression line L1 described later). Figure 3 (A) is a graph showing the characteristics (one-dot chain line) when the temperature is -30 degrees Celsius. Figure 3 (B) is a graph showing the characteristics (dashed line) when the temperature is +25 degrees Celsius. Figure 3 (C) is a graph showing the characteristics (solid line) when the temperature is +85 degrees Celsius.

[0070] Figure 4 1 is a graph showing the characteristics of the voltage and current at the output terminal 102 of the power amplifier circuit 100a and the region Rd where the transistor 161 may be broken down at a power level. Figure 4 In FIG, the horizontal axis shows the voltage of the output terminal 102, and the vertical axis shows the current of the output terminal 102. Figure 4 The area Rd shown is Figure 2 The region Rd shown is the same. Figure 4 In FIG. 1 , the maximum voltage value of the output terminal 102 in the power amplifier circuit 100 a is shown by a dotted line (voltage suppression line L1 described later). Figure 4 (A) is a graph showing the characteristics (one-dot chain line) when the temperature is -30 degrees Celsius. Figure 4 (B) is a graph showing the characteristics (dashed line) when the temperature is +25 degrees Celsius. Figure 4 (C) is a graph showing the characteristics (solid line) when the temperature is +85 degrees Celsius.

[0071] like Figures 2 to 4 As shown, the lower the temperature (here, -30 degrees Celsius), the lower the voltage in the region Rd where the transistor may break down. In other words, the higher the temperature, the higher the voltage at which the transistor may break down.

[0072] This shows a tendency opposite to the above situation, that is, as the temperature becomes higher, the diode in the trigger circuit 170 operates earlier. Figure 3 as well as Figure 10 As shown in FIG. 1 , the characteristics of the power amplifier circuit deteriorate. The conversion circuit 180 is a circuit that can improve this characteristic degradation. A detailed description will be given below.

[0073] like Figure 2 As shown, in a power amplifier circuit without conversion circuit 180, the collector voltage (output terminal voltage) of the power-stage transistor may sometimes show the voltage in region Rd, where the transistor may break down. In other words, as the output voltage in this power amplifier circuit increases, the risk of transistor breakdown increases.

[0074] like Figure 3 As shown, in the power amplifier circuit disclosed in Patent Document 1, a protection circuit equivalent to the trigger circuit 170 and the adjustment circuit 190 of the power amplifier circuit 100a is provided in order to suppress the voltage of the output terminal. Figure 3 As shown by the voltage suppression line L1, the higher the temperature becomes, the more the protection circuit operates at a low voltage (low voltage at the output terminal). Figure 3 (B) Figure 3 As shown in region Rd in (C), region Rd shifts toward higher voltages as the temperature increases. Therefore, in this power amplifier circuit, as the temperature increases, the deviation between the voltage at the output terminal when the protection circuit is activated and the voltage shown in region Rd increases. This degrades the characteristics of the power amplifier circuit, reducing output efficiency.

[0075] like Figure 4 As shown in FIG. 1 , in the power amplifier circuit 100a, the higher the temperature becomes, the higher the adjustment circuit 190 can be operated when the voltage of the output terminal 102 is high. Figure 4 As shown in (A) to (C) of FIG1 , in power amplifier circuit 100a, as the temperature increases, the voltage at output terminal 102 during operation of adjustment circuit 190 shifts toward a higher voltage. Therefore, in power amplifier circuit 100a, the difference between the voltage at output terminal 102 during operation of adjustment circuit 190 and the voltage shown in region Rd can be significantly reduced (or made consistent).

[0076] Below, refer to Figures 5 to 8 The operation of the conversion circuit 180 will be described, in which the voltage of the output terminal 102 when the adjustment circuit 190 is operated shifts to a higher voltage as the temperature increases.

[0077] Figure 5: is a diagram showing an example of the relationship between the voltage Vtrig represented by the feedback signal S1 input to the conversion circuit 180 and the voltage Von represented by the signal output from the conversion circuit 180. Figure 5 In FIG, the horizontal axis shows the voltage Vtrig, and the vertical axis shows the voltage Von.

[0078] exist Figure 5 In FIG, as an example, the characteristic at -30 degrees Celsius is shown by a single-dot chain line, the characteristic at +25 degrees Celsius is shown by a dotted line, and the characteristic at +85 degrees Celsius is shown by a solid line. Figure 5 In FIG. 1 , for convenience of explanation, the operation region of the conversion circuit 180 is divided into (i), (ii), and (iii).

[0079] Figure 6 、 Figure 7 、 Figure 8 1 is a diagram showing states of voltage and current at various points in the conversion circuit 180 .

[0080] First, refer to Figure 5 、 Figure 6 , the operation of the conversion circuit 180 in the operation region (i) will be described.

[0081] exist Figure 5 In the region where the voltage Vtrig is less than 1.2 V, the transistor 181 and the transistor 182 do not operate. Figure 6 As shown, no current (here, current I1 and current I2) flows through transistors 181 and 182. Therefore, no voltage drop occurs across resistor 184. Consequently, voltage Von and voltage Vtrig, which are the base potentials of transistor 191, are substantially equal.

[0082] Next, refer to Figure 5 、 Figure 7 , the operation of the conversion circuit 180 in the operation region (ii) will be described.

[0083] exist Figure 5 In the region where the voltage Vtrig exceeds 1.2 V as shown in the operation region (ii), Figure 7 As shown, current I1 begins to flow through transistor 181. The current value of current I1 is the difference between voltage Vtrig and base-emitter voltage Vbe1 of transistor 181, divided by the resistance value of resistor 183. Here, base-emitter voltage Vbe3 of transistor 191 is equal to voltage Vbe1, so current I2 flowing through transistor 182 is equal to current I1. In operating region (ii), transistor 182 operates in the saturation region, so voltage Von is approximately 0.2V.

[0084] Next, refer to Figure 5 、 Figure 8 , the operation of the conversion circuit 180 in the operation region (iii) will be described.

[0085] exist Figure 5 In the region where the voltage Vtrig exceeds 3.0 V, as shown in the operation region (iii), Figure 5 As shown in FIG. 1 , the current I2 changes logarithmically with respect to the voltage Vtrig. This is because the transistor 182 operates in the active region. Figure 8 As shown, resistor 185 is connected in series with the emitter of transistor 182 (Vbe2 of transistor 182 is the value obtained by subtracting the product of resistor R185 and current I2 from Vbe1 of transistor 181). Furthermore, in a region where voltage Vtrig is higher (an active region completely out of saturation), voltage Vtrig increases significantly compared to the voltage drop across resistor 184. Therefore, voltage Von increases approximately proportionally to voltage Vtrig.

[0086] At this time, in transistor 182, the lower the temperature, the greater the current flowing toward the reference potential. Therefore, the lower the temperature, the higher the collector-emitter voltage of transistor 182 needs to be. Specifically, in power amplifier circuit 100a, the lower the temperature, the higher the collector-emitter voltage Vce in the active region of transistor 182 becomes. Consequently, voltage Von rises at a lower voltage Vtrig (voltage Von rises earlier).

[0087] Therefore, if Figure 5 As shown in the operating region (iii), for the same voltage Vtrig, the voltage Von at a low temperature (e.g., -30 degrees Celsius) becomes higher than the voltage Von at a high temperature (e.g., +85 degrees Celsius). That is, as the temperature increases, the voltage Von rises to the desired voltage (e.g., voltage Von is 0.7V) at a higher voltage than the voltage Vtrig. Therefore, as mentioned above, Figure 4 As shown, as the temperature increases, the transistor 191 of the adjustment circuit 190 can be operated when the voltage of the output terminal 102 (here, voltage Vtrig) is higher. Thus, the power amplifier circuit 100a can optimally suppress the voltage of the output terminal 102 according to the temperature.

[0088] That is, Figure 3As shown, in the power amplifier circuit disclosed in Patent Document 1, as the temperature increases, the transistor operates more in a state where the voltage at the output terminal is low. However, in the power amplifier circuit 100a, through the conversion circuit 180, as the temperature increases, the transistor 191 of the adjustment circuit 190 can operate more in a state where the voltage at the output terminal 102 is high.

[0089] In addition, the resistance value of the resistor 185 is smaller than the resistance value of the resistor 184. Figure 5 In the operation region (iii) shown, the voltage Von is increased at an appropriate voltage Vtrig. In addition, the larger the ratio of the resistance value of the resistor 185 to the resistance value of the resistor 184, the Figure 5 As the logarithmic curve of the graph in the operation region (iii) becomes flatter, the difference of the voltage Vtrig from the same voltage Von becomes larger.

[0090] That is, in the power amplifier circuit 100 a , by adjusting the resistance value of the resistor 185 , the operation timing of the transistor 191 of the adjustment circuit 190 with respect to the voltage Vtrig can be adjusted.

[0091] Here, refer to Figure 9 as well as Figure 10 , a case will be described in which the power amplifier circuit 100a can improve the output efficiency compared with the power amplifier circuit disclosed in Patent Document 1. Figure 9 Graph showing the efficiency characteristics of the power amplifier circuit 100 a according to the first embodiment. Figure 10 Graph showing the efficiency characteristics of the power amplifier circuit disclosed in Patent Document 1. Figure 9 、 Figure 10 In the figure, (A) shows the efficiency characteristics at -30 degrees Celsius, (B) shows the efficiency characteristics at +25 degrees Celsius, and (C) shows the efficiency characteristics at +85 degrees Celsius. Figure 9 、 Figure 10 In the figure, the horizontal axis shows the level of the input signal and the vertical axis shows the efficiency. Figure 9 、 Figure 10 In FIG. 1 , lines L2 to L4 show the efficiency of the power amplifier circuit without the trigger circuit 170 , the conversion circuit 180 , and the adjustment circuit 190 .

[0092] like Figure 9 As shown in (A) to (C), compared with the power amplifier circuit without the conversion circuit 180, in the power amplifier circuit 100a, the trigger circuit 170, the conversion circuit 180, and the adjustment circuit 190 do not cause a decrease in efficiency even when the temperature changes. This is because Figure 4As shown, in the power amplifier circuit 100 a , the conversion circuit 180 can make the maximum value of the voltage at the output terminal 102 approach the voltage indicated by the region Rd of the transistor according to the temperature.

[0093] On the other hand, Figure 10 As shown in (A) to (C), compared with the power amplifier circuit without the conversion circuit 180, in the power amplifier circuit disclosed in Patent Document 1, the efficiency decreases as the temperature increases ( Figure 10 This is because, if Figure 3 As shown, in the power amplifier circuit disclosed in Patent Document 1, the protection circuit operates when the voltage at the output terminal becomes lower as the temperature becomes higher.

[0094] <<First Modification>>

[0095] Reference Figure 11 Next, a power amplifier circuit 100b1 according to a modified example of the first embodiment will be described. Figure 11 This figure shows a configuration example of a power amplifier circuit 100b1 according to a first modification. Note that the following description of matters common to the power amplifier circuit 100a according to the first embodiment will be omitted, and only the differences will be described. In particular, similar functions and effects based on similar configurations will not be mentioned individually.

[0096] Compared with the power amplifier circuit 100a, the power amplifier circuit 100b1 is also provided with a trigger circuit 170b1, a conversion circuit 180b1, and a regulating circuit 190b1 at the collector of the amplifier circuit 150 of the driver stage.

[0097] The trigger circuit 170b1 is a circuit that outputs a feedback signal S1b corresponding to the collector voltage to the conversion circuit 180b1 when the collector voltage of the transistor 151 of the amplifier circuit 150 exceeds a predetermined threshold value.

[0098] Trigger circuit 170b1 is comprised of, for example, at least one diode 171b1 or 172b1. Specifically, multiple diodes are connected in series in trigger circuit 170b1. Each of the diodes has an anode (in this case, the anode at one end) electrically connected to the collector of transistor 151, and a cathode electrically connected to a reference potential (in this case, ground).

[0099] In the trigger circuit 170b1, any node between the plurality of diodes connected in series (in Figure 1 In other words, in the trigger circuit 170, the feedback signal S1b is output from the node N2 between two diodes connected in series among the plurality of diodes.

[0100] That is, the trigger circuit 170b1 can set a threshold value by the number of diodes 171b1 on the collector side of the node N2, and output the feedback signal S1b through the node N2 when the collector voltage exceeds the threshold value.

[0101] Furthermore, the diode 172 b 1 located on the reference potential side of the node N2 in the trigger circuit 170 b 1 can protect the trigger circuit 170 b 1 from ESD (Electro Static Discharge), which is a high voltage spike.

[0102] Here, in the trigger circuit 170b1, due to the properties of the diode, the threshold value becomes lower as the temperature increases. That is, the trigger circuit 170 is more likely to start up at a high temperature than at a low temperature.

[0103] The power amplifier circuit 100b1 includes a conversion circuit 180b1 to improve the temperature-dependent operation tendency of the trigger circuit 170b1.

[0104] The conversion circuit 180b1 includes transistors 181b1 and 182b1 and resistors 183b1, 184b1, and 185b1. The conversion circuit 180b1 has the same structure as the conversion circuit 180a, and therefore its description is omitted.

[0105] The adjustment circuit 190b1 is a circuit for suppressing the bias output from the bias circuit 130 based on the signal S2b input from the conversion circuit 180b1.

[0106] The adjustment circuit 190b1 includes a transistor 191b1, a resistor 192b1, and a resistor 193b1. The adjustment circuit 190b1 has the same structure as the adjustment circuit 190, and therefore its description is omitted.

[0107] Next, refer to Figures 11 to 13 , the operation of the power amplifier circuit 100b1 is described.

[0108] Figure 12 1 is a graph showing the relationship between the voltage and current of the amplifier circuit 160 at the power stage. Figure 12 In (A), the horizontal axis shows time, and the vertical axis shows the collector voltage of the amplifier circuit 160. Figure 12 In (B), the horizontal axis represents time, and the vertical axis represents the base current of the amplifier circuit 160 .

[0109] Figure 13 is a graph showing the voltage of the amplifier circuit 150 of the driver stage. Figure 13 In FIG. 1 , the horizontal axis represents time, and the vertical axis represents the collector voltage of the amplifier circuit 150 .

[0110] In addition, the following describes the driving stage of the power amplifier circuit 100b1. Figures 5 to 10 The operation in the power stage of the power amplifier circuit 100a is the same as that in the power amplifier circuit 100b1, and its description is omitted. That is, the following describes the further operation of the power amplifier circuit 100b1 compared with the power amplifier circuit 100a.

[0111] like Figure 12 As shown, in the power amplifier circuit 100b1, the phase difference between the collector voltage and the base current of the amplifier circuit 160 in the power stage is approximately 180 degrees.

[0112] In the power amplifier circuit 100b1, the conversion circuit 180 operates to suppress Figure 12 The voltage at the time when the voltage amplitude shown in (A) becomes the maximum ( Figure 12 (A) Vmax1), to prevent the breakdown of the amplifier circuit 160 at the power stage. However, simply setting the conversion circuit 180 at the power stage cannot suppress Figure 12 (B) shows the current at the time when the current amplitude becomes the maximum ( Figure 12 (B) Imax).

[0113] In the power amplifier circuit 100b1, a conversion circuit 180b1 is also provided in the driver stage, thereby preventing the breakdown of the transistor caused by the voltage of the driver stage and preventing the breakdown of the transistor caused by the current in the power stage.

[0114] Specifically, if Figure 13 As shown, the phase of the voltage at the driver stage is approximately 180 degrees different from the phase of the voltage at the power stage. In other words, the phase of the voltage at the driver stage is approximately the same as the phase of the current at the power stage. In this way, in the power amplifier circuit 100b1, the operation of the conversion circuit 180b1 can suppress the voltage at which the voltage amplitude of the amplifier circuit 150 at the driver stage reaches its maximum ( Figure 13 Vmax2), thereby suppressing the current at the time when the current amplitude of the power stage becomes the maximum ( Figure 12 (B) Imax).

[0115] <<Second Modification>>

[0116] Reference Figure 14 Next, a power amplifier circuit 100b2 according to a modified example of the first embodiment will be described. Figure 14 This figure shows a configuration example of a power amplifier circuit 100b2 according to a second modification. Note that the following description of matters common to the power amplifier circuit 100a according to the first embodiment will be omitted, and only the differences will be described. In particular, similar functions and effects based on similar configurations will not be mentioned individually.

[0117] Compared with the power amplifier circuit 100a, the power amplifier circuit 100b2 further includes an adjustment circuit 190b2 for suppressing the offset of the amplifier circuit 150 in the driver stage.

[0118] Adjustment circuit 190b2 is a circuit for suppressing the bias output from bias circuit 130 to amplifier circuit 150 based on signal S1 input from conversion circuit 180. Adjustment circuit 190b2 includes transistor 191b2, resistor 192b2, and resistor 193b2. Adjustment circuit 190b2 has the same configuration as adjustment circuit 190, and therefore its description is omitted.

[0119] Next, the operation of the power amplifier circuit 100b2 will be described. The power amplifier circuit 100b2 performs the same operation as the power amplifier circuit 100b1 according to the first modification, which suppresses the voltage amplitude of the collector and the current amplitude of the base of the amplifier circuit 160 of the power stage (the phase is approximately 180 degrees different from the voltage amplitude of the collector). Therefore, in the following, referring to Figure 12 as well as Figure 13 The operation of the power amplifier circuit 100b2 will be described.

[0120] In the power amplifier circuit 100b2, the conversion circuit 180 operates to suppress Figure 12 The voltage at the time when the voltage amplitude shown in (A) becomes the maximum is used to prevent the breakdown of the amplifier circuit 160 in the power stage. However, the conversion circuit 180 and the adjustment circuit 190 provided in the power stage cannot suppress the breakdown of the amplifier circuit 160 in the power stage. Figure 12 (B) shows the current at the time when the current amplitude becomes the maximum ( Figure 12 (B) Imax).

[0121] Therefore, in the power amplifier circuit 100b2, the adjustment circuit 190b2 is provided in parallel with the adjustment circuit 190. Thus, when the conversion circuit 180 is in operation, the adjustment circuit 190b2 can suppress the voltage (the time when the voltage amplitude of the amplifier circuit 150 in the driver stage (the phase difference of which is approximately 180 degrees from the voltage amplitude of the collector of the amplifier circuit 160 in the power stage) becomes the maximum. Figure 13 Thus, in the power amplifier circuit 100b2, the current at the time when the current amplitude of the power stage becomes the maximum can be suppressed ( Figure 12 Furthermore, the power amplifier circuit 100b2 has a simpler structure than the power amplifier circuit 100b1 and produces the same effect as the power amplifier circuit 100b1.

[0122] ===Power Amplifier Circuit 100c According to Second Embodiment===

[0123] Reference Figure 15 , a power amplifier circuit 100c according to the second embodiment will be described. Figure 15 This figure shows an example configuration of a power amplifier circuit 100c according to the second embodiment. Note that the following description of matters common to the power amplifier circuit 100a according to the first embodiment will be omitted, and only the differences will be described. In particular, similar functions and effects based on similar configurations will not be mentioned individually.

[0124] Compared to power amplifier circuit 100a, power amplifier circuit 100c has a differential amplifier circuit formed by amplifier circuits 160a and 160b in power stage 160. Furthermore, power amplifier circuit 100c has trigger circuits 170c1 and 170c2 for amplifier circuits 160a and 160b, respectively.

[0125] The power amplifier circuit 100c includes a distributor 160c that distributes the signal RF1 output from the amplifier circuit 150 into a signal RF11 and a signal RF12 having a phase difference of approximately 180 degrees from the signal RF11. The distributor 160c is, for example, a balun transformer.

[0126] The amplifier circuit 160a amplifies the signal RF11 and outputs the signal RF21 to the output terminal 102a. The amplifier circuit 160b amplifies the signal RF12 and outputs the signal RF22 to the output terminal 102b.

[0127] The trigger circuit 170 c 1 is a circuit that outputs a feedback signal Sc1 corresponding to the voltage of the output terminal 102 a to the conversion circuit 180 when the voltage of the output terminal 102 a exceeds a predetermined threshold value.

[0128] Trigger circuit 170c1 is composed of, for example, at least one diode 171c1 or 172c1. Specifically, multiple diodes are connected in series in trigger circuit 170c1. Each of the diodes has an anode (in this case, the anode at one end) electrically connected to output terminal 102a, and a cathode electrically connected to a reference potential (in this case, ground).

[0129] In the trigger circuit 170c1, any node between the plurality of diodes connected in series (in Figure 14 The trigger circuit 170c1 is electrically connected to the conversion circuit 180 (referred to as "node Nc1" in FIG). In other words, the feedback signal Sc1 is output from the node Nc1 between two diodes connected in series among the plurality of diodes in the trigger circuit 170c1.

[0130] The trigger circuit 170 c 2 is a circuit that outputs a feedback signal Sc2 corresponding to the voltage of the output terminal 102 b to the conversion circuit 180 when the voltage of the output terminal 102 b exceeds a predetermined threshold value.

[0131] Trigger circuit 170c2 is comprised of, for example, at least one diode 171c2 or 172c2. Specifically, multiple diodes are connected in series in trigger circuit 170c2. Each of the diodes has an anode (in this case, the anode at one end) electrically connected to output terminal 102b, and a cathode electrically connected to a reference potential (in this case, ground).

[0132] In the trigger circuit 170c2, any node between the plurality of diodes connected in series (in Figure 14 The trigger circuit 170c2 is electrically connected to the conversion circuit 180. In other words, the feedback signal Sc2 is output from the node Nc2 between two diodes connected in series among the plurality of diodes in the trigger circuit 170c2.

[0133] Feedback signals Sc1 and Sc2 output from flip-flop circuits 170c1 and 170c2 are combined at node Nc3. In power amplifier circuit 100c, the combined signal is input to conversion circuit 180c. The configuration of conversion circuit 180c is identical to that of conversion circuit 180, so its description will be omitted.

[0134] The adjustment circuit 190c suppresses the bias output from the bias circuit 140c based on the signal S2 input from the conversion circuit 180c. The configuration of the adjustment circuit 190c is the same as that of the adjustment circuit 190, and therefore its description is omitted.

[0135] In the adjustment circuit 190c, the collector is electrically connected to the bias circuit 140c so as to adjust the bias outputted from the bias circuit 140c to the amplifier circuits 160a and 160b, respectively. Furthermore, when the bias circuits 140c are independently provided for the amplifier circuits 160a and 160b, the collector of the adjustment circuit 190c may be connected to a common portion of the inputs of the respective bias circuits (e.g., at Figure 14 (in the middle is a node between the resistor 141 and the bias circuit 140c) is electrically connected.

[0136] The power amplifier circuit 100c is configured as a noise-resistant circuit by being composed of differential amplifier circuits. This allows for common conversion circuits without providing conversion circuits for the respective amplifier circuits of the differential amplifier circuits, thereby achieving miniaturization and preventing breakdown of the amplifier circuits.

[0137] <<3rd Modification>>

[0138] Reference Figure 16 Next, a power amplifier circuit 100d1 according to a modified example of the second embodiment will be described. Figure 16 This figure shows a power amplifier circuit 100d1 according to a third variation. Note that the following description of matters common to the power amplifier circuit 100c according to the second embodiment will be omitted, and only the differences will be described. In particular, similar functions and effects based on similar structures will not be mentioned one by one.

[0139] Compared with the power amplifier circuit 100c, the power amplifier circuit 100d1 according to the third modification also includes a trigger circuit 170d1, a conversion circuit 180d, and a regulation circuit 190d at the collector of the amplifier circuit 150 at the driver stage.

[0140] The trigger circuit 170d1 is a circuit that outputs a feedback signal S1d corresponding to the collector voltage to the conversion circuit 180d when the collector voltage of the transistor 151 of the amplifier circuit 150 exceeds a predetermined threshold. Figure 11 The trigger circuit 170b1 shown is the same, so its description is omitted.

[0141] In the power amplifier circuit 100d, the conversion circuit 180d is also provided in the driver stage of the power amplifier circuit 100c, thereby preventing the breakdown of the transistor caused by the voltage of the driver stage and the breakdown of the transistor caused by the current of the power stage compared to the power amplifier circuit 100c.

[0142] <<Fourth Modification>>

[0143] Reference Figure 17 Next, a power amplifier circuit 100d2 according to a modified example of the second embodiment will be described. Figure 17 This figure shows a configuration example of a power amplifier circuit 100d2 according to a fourth modification. Note that the following description of matters common to the power amplifier circuit 100c according to the second embodiment will be omitted, and only the differences will be described. In particular, similar functions and effects based on similar configurations will not be mentioned individually.

[0144] Compared with the power amplifier circuit 100c, the power amplifier circuit 100d2 according to the fourth modification further includes an adjustment circuit 190d2 for suppressing the offset of the amplifier circuit 150 in the driver stage.

[0145] Adjustment circuit 190d2 is a circuit for suppressing the bias output from bias circuit 130 to amplifier circuit 150 based on signal S2 input from conversion circuit 180. Adjustment circuit 190d2 includes transistor 191d2, resistor 192d2, and resistor 193d2. Adjustment circuit 190d2 has the same configuration as adjustment circuit 190, and therefore its description is omitted.

[0146] Next, the operation of the power amplifier circuit 100d2 will be described. The power amplifier circuit 100d2 performs the same operation as the power amplifier circuit 100d1 according to the third modification, which suppresses the voltage amplitude of the collector and the current amplitude of the base of the amplifier circuit 160a and the amplifier circuit 160b in the power stage (the phase is approximately 180 degrees different from the voltage amplitude of each collector). Therefore, in the following, referring to Figure 12 as well as Figure 13 The operation of the power amplifier circuit 100b2 will be described.

[0147] In the power amplifier circuit 100d2, the conversion circuit 180 operates to suppress Figure 12 The voltage at the time when the voltage amplitude shown in (A) becomes the maximum is used to prevent the breakdown of the amplifier circuit 160a and the amplifier circuit 160b in the power stage. However, the conversion circuit 180 and the adjustment circuit 190 provided in the power stage cannot suppress the breakdown of the amplifier circuit 160a and the amplifier circuit 160b in the power stage. Figure 12 (B) shows the current at the time when the current amplitude becomes the maximum ( Figure 12 (B) Imax).

[0148] Therefore, in the power amplifier circuit 100d2, the adjustment circuit 190d2 is provided in parallel with the adjustment circuit 190. When the conversion circuit 180 is in operation, the adjustment circuit 190d2 can suppress the voltage (the voltage at which the voltage amplitude of the amplifier circuit 150 in the driving stage becomes the maximum) at the time when the conversion circuit 180 is in operation. Figure 13 Thus, in the power amplifier circuit 100b2, the current at the time when the current amplitude of the power stage becomes the maximum can be suppressed ( Figure 12 Furthermore, the power amplifier circuit 100 d 2 has a simpler structure than the power amplifier circuit 100 d 1 and produces the same effects as the power amplifier circuit 100 d 1 .

[0149] ===Power Amplifier Circuit 100e According to Third Embodiment===

[0150] Reference Figure 18 , a power amplifier circuit 100e according to a third embodiment will be described. Figure 18This figure shows an example configuration of a power amplifier circuit 100e according to the third embodiment. Note that the following description of matters common to the power amplifier circuit 100a according to the first embodiment will be omitted, and only the differences will be described. In particular, similar functions and effects based on similar configurations will not be mentioned individually.

[0151] Compared to the power amplifier circuit 100a, the power amplifier circuit 100e has an adjustment circuit 190e that suppresses the bias output from the bias circuit 130. That is, the power amplifier circuit 100e prevents breakdown of the amplifier circuit 160 by suppressing the output voltage of the amplifier circuit 150 in the driver stage.

[0152] Components other than the adjustment circuit 190e in the power amplifier circuit 100e are the same as those in the power amplifier circuit 100a, and therefore their description is omitted.

[0153] Specifically, adjustment circuit 190e includes transistor 191e and resistors 192e and 193e. Transistor 191e has a base electrically connected to the collector of transistor 182 via resistor 192e, an emitter electrically connected to a reference potential, and a collector electrically connected to bias circuit 130 to adjust the bias output from bias circuit 130.

[0154] ===Power Amplifier Circuit 100f According to Fourth Embodiment===

[0155] Reference Figure 19 , a power amplifier circuit 100f according to a fourth embodiment will be described. Figure 19 This figure shows an example configuration of a power amplifier circuit 100f according to a fourth embodiment. Note that the following description of matters common to the power amplifier circuit 100a according to the first embodiment will be omitted, and only the differences will be described. In particular, similar functions and effects based on similar configurations will not be mentioned individually.

[0156] Compared with the power amplifier circuit 100a, the power amplifier circuit 100f is a circuit including a transistor 103f and a resistor 104f. In the transistor 103f, the base and any node between the plurality of diodes of the trigger circuit 170 (in Figure 19 The collector is electrically connected to the collector of the transistor 161 of the amplifier circuit 160 through the resistor 104f, and the emitter is electrically connected to the collectors of the transistors 181 and 182 of the conversion circuit 180.

[0157] Transistor 103f supplies a signal obtained by amplifying feedback signal S1 to conversion circuit 180. Specifically, in power amplifier circuit 100f, conversion circuit 180 operates based on feedback signal Sf, which represents a current value obtained by dividing the current value of feedback signal S1 in power amplifier circuit 100a by the current amplification factor Hfe of transistor 103f. Thus, in power amplifier circuit 100f, conversion circuit 180 operates based on feedback signal Sf, which represents a current value smaller than that of feedback signal S1. Consequently, power amplifier circuit 100f can improve the operational sensitivity of conversion circuit 180.

[0158] <<Fifth Modification>>

[0159] Reference Figure 20 Next, a power amplifier circuit 100f1 according to a modified example of the fourth embodiment will be described. Figure 20 This figure shows a configuration example of a power amplifier circuit 100f1 according to a fifth modification. Note that the following description of matters common to the power amplifier circuit 100f according to the fourth embodiment will be omitted, and only the differences will be described. In particular, similar functions and effects based on similar configurations will not be mentioned individually.

[0160] Compared with the power amplifier circuit 100f, the power amplifier circuit 100f1 according to the fifth modification further includes an adjustment circuit 190f1 for suppressing the offset of the amplifier circuit 150 in the driving stage.

[0161] Adjustment circuit 190f1 is a circuit for suppressing the bias output from bias circuit 130 to amplifier circuit 150 based on signal S2 input from conversion circuit 180. Adjustment circuit 190f1 includes transistor 191f1, resistor 192f1, and resistor 193f1. Adjustment circuit 190f1 has the same configuration as adjustment circuit 190, and therefore its description is omitted.

[0162] Next, the operation of the power amplifier circuit 100f1 will be described. The power amplifier circuit 100f1 performs the same operation as the power amplifier circuit 100b1 according to the first modification, which suppresses the voltage amplitude of the collector and the current amplitude of the base of the amplifier circuit 160 of the power stage (the phase is approximately 180 degrees different from the voltage amplitude of the collector). Therefore, in the following, referring to Figure 12 as well as Figure 13 The operation of the power amplifier circuit 100b2 will be described.

[0163] In the power amplifier circuit 100f1, the conversion circuit 180 operates to suppress Figure 12The voltage at the time when the voltage amplitude shown in (A) becomes the maximum is used to prevent the breakdown of the amplifier circuit 160 in the power stage. However, the conversion circuit 180 and the adjustment circuit 190 provided in the power stage cannot suppress the breakdown of the amplifier circuit 160 in the power stage. Figure 12 (B) shows the current at the time when the current amplitude becomes the maximum ( Figure 12 (B) Imax).

[0164] Therefore, in the power amplifier circuit 100f1, the adjustment circuit 190f1 is provided in parallel with the adjustment circuit 190. When the conversion circuit 180 is in operation, the adjustment circuit 190f1 can suppress the voltage (the time when the voltage amplitude of the amplifier circuit 150 of the driver stage (the phase difference of which is approximately 180 degrees from the voltage amplitude of the collector of the amplifier circuit 160 of the power stage) becomes the maximum. Figure 13 Thus, in the power amplifier circuit 100f1, the current at the time when the current amplitude of the power stage becomes the maximum can be suppressed ( Figure 12 (B) Imax).

[0165] ===Power Amplifier Circuit 100g According to Fifth Embodiment===

[0166] Reference Figure 21 , a power amplifier circuit 100g according to a fifth embodiment will be described. Figure 21 This figure shows an example configuration of a power amplifier circuit 100g according to the fifth embodiment. Note that the following description of matters common to the power amplifier circuit 100c according to the second embodiment will be omitted, and only the differences will be described. In particular, similar functions and effects based on similar configurations will not be mentioned individually.

[0167] Compared with the power amplifier circuit 100c, the power amplifier circuit 100g is a circuit including a transistor 103g, a resistor 104g, and a capacitor 105g. In the transistor 103g, the base and any node between the plurality of diodes of the trigger circuit 170c1 (in Figure 21 "node Nc1" in the figure) and any node between the multiple diodes of the trigger circuit 170c2 (in Figure 21 The collector is electrically connected to the collector of the transistor 161b of the amplifier circuit 160b through the resistor 104g, and the emitter is electrically connected to the collectors of the transistors 181 and 182 of the conversion circuit 180.

[0168] The capacitor 105g is a capacitor for smoothing the potential of the collector of the transistor 103G. One end of the capacitor 105g is connected to a node (between the collector of the transistor 103g and the collector of the transistor 161b of the amplifier circuit 160b) Figure 21The node Ng1 is electrically connected to one end of the transistor 104g (referred to as "node Ng1" in the figure), and the other end is electrically connected to a reference potential. Node Ng1 is provided, for example, between the resistor 104g and the collector of the transistor 103g. Alternatively, node Ng1 may be provided, for example, between the resistor 104g and the collector of the transistor 61B.

[0169] However, it is more preferable to place node Ng1 between resistor 104g and the collector of transistor 103g than between resistor 104g and the collector of transistor 61B. This is because placing node Ng1 between resistor 104g and the collector of transistor 103g improves the isolation of capacitor 105g from the path through which signal RF22 passes. Consequently, the capacitance of capacitor 105g can be increased, resulting in more appropriate potential smoothing and, consequently, improved sensitivity of the breakdown protection function.

[0170] In transistor 103g, feedback signal Sc1 rectified by trigger circuit 170c1 and feedback signal Sc2 rectified by trigger circuit 170c2, whose phase is approximately 180 degrees different from feedback signal Sc1, are supplied to the base. Transistor 103g supplies feedback signal Sg, which is an amplification of feedback signal Sc1 and feedback signal Sc2, to converter circuit 180. Thus, similar to power amplifier circuit 100f, power amplifier circuit 100g can improve the operational sensitivity of converter circuit 180.

[0171] Here, capacitor 105g smoothes the collector voltage of transistor 103g generated when feedback signals Sc1 and Sc2 are supplied to the base of transistor 103g. In this way, in power amplifier circuit 100g, two trigger circuits 170c1 and 170c2 can function by one transistor 103g.

[0172] In contrast, when power amplifier circuit 100g is not provided with capacitor 105g, a transistor connected to trigger circuit 170c1 and a transistor connected to trigger circuit 170c2 are required to function. In this case, the provision of two transistors complicates wiring. In other words, by providing capacitor 105g in power amplifier circuit 100g, the number of transistors can be reduced, allowing both trigger circuits 170c1 and 170c2 to function with simplified wiring.

[0173] <<Sixth Modification>>

[0174] Reference Figure 22 Next, a power amplifier circuit 100g1 according to a modified example of the fifth embodiment will be described. Figure 22This figure shows a configuration example of a power amplifier circuit 100g1 according to a sixth modification. Note that the following description of matters common to the power amplifier circuit 100g according to the fifth embodiment will be omitted, and only the differences will be described. In particular, similar functions and effects based on similar configurations will not be mentioned individually.

[0175] Compared to the power amplifier circuit 100g, the power amplifier circuit 100g1 according to the sixth modification further includes an adjustment circuit 190g1 for suppressing the offset of the amplifier circuit 150 in the driver stage.

[0176] Adjustment circuit 190g1 is a circuit for suppressing the bias output from bias circuit 130 to amplifier circuit 150 based on signal Sg input from conversion circuit 180. Adjustment circuit 190g1 includes transistor 191g1, resistor 192g1, and resistor 193g1. Adjustment circuit 190g1 has the same configuration as adjustment circuit 190, and therefore its description is omitted.

[0177] Next, the operation of the power amplifier circuit 100g1 will be described. The power amplifier circuit 100g1 performs the same operation as the power amplifier circuit 100d1 according to the third modification, which suppresses the voltage amplitude of the collector and the current amplitude of the base of the amplifier circuit 160a and the amplifier circuit 160b in the power stage (the phase is approximately 180 degrees different from the voltage amplitude of each collector). Therefore, the following refers to Figure 12 as well as Figure 13 The operation of the power amplifier circuit 100g1 will be described.

[0178] In the power amplifier circuit 100g1, the conversion circuit 180 operates to suppress Figure 12 The voltage at the time when the voltage amplitude shown in (A) becomes the maximum is used to prevent the breakdown of the amplifier circuit 160a and the amplifier circuit 160b in the power stage. However, the conversion circuit 180 and the adjustment circuit 190 provided in the power stage cannot suppress the breakdown of the amplifier circuit 160a and the amplifier circuit 160b in the power stage. Figure 12 (B) shows the current at the time when the current amplitude becomes the maximum ( Figure 12 (B) Imax).

[0179] Therefore, in the power amplifier circuit 100g1, the adjustment circuit 190g1 is provided in parallel with the adjustment circuit 190. When the conversion circuit 180 is in operation, the adjustment circuit 190g1 can suppress the voltage (the voltage at which the voltage amplitude of the amplifier circuit 150 in the driving stage reaches the maximum) at the time when the conversion circuit 180 is in operation. Figure 13 Thus, in the power amplifier circuit 100g1, the current ( Figure 12 (B) Imax).

[0180] ===Summary===

[0181] <1>

[0182] The power amplifier circuit 100a according to an exemplary embodiment of the present disclosure includes: an amplifier circuit 160 (first amplifier circuit) supplied with a first bias from a bias circuit 140 (first bias circuit), amplifying a signal RF1 (first signal) and outputting a signal RFout (output signal) to an output terminal 102 (first output terminal); a trigger circuit 170 (first trigger circuit) including at least one diode having an anode electrically connected to the output terminal 102 (first output terminal), wherein when a voltage at the output terminal 102 (first output terminal) exceeds a predetermined threshold value, the trigger circuit 170 (first trigger circuit) outputs a feedback signal S1 (first feedback signal) corresponding to the voltage at the output terminal 102 (first output terminal); and a conversion circuit 180 (first conversion circuit) including a diode-connected transistor 181 (first transistor), a transistor 182 (second transistor) connected in a current mirror connection with the transistor 181 (first transistor), and a diode-connected transistor 183 (second transistor). A resistor 183 (first resistor) connected in series with the collector or drain of a transistor 181 (first transistor); a resistor 184 (second resistor) connected in series with the collector or drain of a transistor 182 (second transistor); and a resistor 185 (third resistor) connected in series with the emitter or source of the transistor 182 (second transistor). A feedback signal S1 (first feedback signal) is input to the collector or drain of the transistor 181 (first transistor) and the collector or drain of the transistor 182 (second transistor), and the resistance value of the resistor 185 (third resistor) is smaller than the resistance value of the resistor 184 (second resistor). An adjustment circuit 190 (first adjustment circuit) includes a transistor 191 having a base or gate receiving a signal S2 output from the conversion circuit 180 (first conversion circuit) and having a collector or drain electrically connected to the bias circuit 140 (first bias circuit) so as to adjust a first bias supplied from the bias circuit 140 (first bias circuit). Thus, the power amplifier circuit 100 a can prevent breakdown of the amplifier circuit and achieve high output efficiency.

[0183] <2>

[0184] according to <1> In the power amplifier circuit 100a according to the exemplary embodiment of the present disclosure, adjustment circuit 190 (first adjustment circuit) further includes resistor 192 (fourth resistor) and resistor 193 (fifth resistor). In transistor 191, signal S2 output from conversion circuit 180 (first conversion circuit) is input to the base or gate via resistor 192 (fourth resistor), and the collector or drain is electrically connected to bias circuit 140 (first bias circuit) via resistor 193 (fifth resistor) to adjust the first bias supplied from bias circuit 140 (first bias circuit). Consequently, power amplifier circuit 100a can isolate harmonic signals and DC components while preventing breakdown of the amplifier circuit, achieving high output efficiency.

[0185] <3>

[0186] according to <1> or <2> In the power amplifier circuit 100a according to the exemplary embodiment of the present disclosure, trigger circuit 170 (first trigger circuit) includes a plurality of diodes 171 and 172 connected in series. The anodes of the plurality of diodes 171 are electrically connected to the output terminal 102 (the first output terminal), and the cathodes of the plurality of diodes 172 are electrically connected to a reference potential. A feedback signal S1 (first feedback signal) is output from a node N1 between two adjacent diodes 171 and 172. Thus, power amplifier circuit 100a can be protected from ESD, a high-voltage spike, by diodes 172, and can achieve high output efficiency while preventing breakdown of the amplifier circuit.

[0187] <4>

[0188] according to <1> to <3> The power amplifier circuit described in any one of the preceding claims, wherein the power amplifier circuit 100a according to the exemplary embodiment of the present disclosure further includes an amplifier circuit 150 (second amplifier circuit) supplied with a second bias from a bias circuit 130 (second bias circuit), electrically connected to amplifier circuit 160 (first amplifier circuit) at a stage preceding amplifier circuit 160 (first amplifier circuit), and amplifying signal RFin (input signal) and outputting signal RF1 (first signal). Thus, in power amplifier circuit 100a, breakdown of the amplifier circuit can be effectively prevented in a multi-stage amplifier circuit, while achieving high output efficiency.

[0189] <5>

[0190] according to <4> The power amplifier circuit described above, wherein the power amplifier circuit 100b1 according to an exemplary embodiment of the present disclosure includes: a trigger circuit 170b1 (second trigger circuit), including at least one diode having an anode electrically connected to the collector or drain (second output terminal) of the amplifier circuit 150 (second amplifier circuit), wherein when the voltage of the collector or drain (second output terminal) exceeds a predetermined threshold value, the trigger circuit 170b1 (second trigger circuit) outputs a feedback signal Sb1 (second feedback signal) corresponding to the voltage of the collector or drain (second output terminal); a conversion circuit 180b (second conversion circuit), including a transistor 181b (third transistor) connected in diode connection, a transistor 182b (fourth transistor) in current mirror connection with the transistor 181b (third transistor), a resistor 183b (sixth resistor) connected in series with the collector or drain of the transistor 181b (third transistor), and a resistor 184b (sixth resistor) connected in series with the collector or drain of the transistor 184b (third transistor). 2b (fourth transistor); and a resistor 185b (eighth resistor) connected in series with the emitter or source of transistor 182b (fourth transistor). The feedback signal Sb1 (second feedback signal) is input to the collector or drain of transistor 181b (third transistor) and the collector or drain of transistor 182b (fourth transistor), and the resistance value of resistor 185b (eighth resistor) is smaller than the resistance value of resistor 184b (seventh resistor). An adjustment circuit 190b (second adjustment circuit) includes a transistor 191b having a signal output from the conversion circuit 180b (second conversion circuit) input to its base or gate via a resistor 192b (ninth resistor), and having a collector or drain electrically connected to the bias circuit 130 (second bias circuit) via a resistor 193b (tenth resistor) so as to adjust the second bias supplied from the bias circuit 130 (second bias circuit). Thus, the power amplifier circuit 100b can suppress the voltage at which the voltage amplitude of the driver-stage amplifier circuit 150 reaches its maximum, thereby suppressing the current at which the current amplitude of the power stage reaches its maximum. Consequently, the power amplifier circuit 100b can prevent breakdown of the amplifier circuit and achieve high output efficiency.

[0191] <6>

[0192] according to <1> to <5> The power amplifier circuit according to any one of the preceding claims, wherein the power amplifier circuit 100c according to the exemplary embodiment of the present disclosure includes a distributor 160c that distributes a signal RF1 (a first signal) into a signal RF11 (a second signal) and a signal RF12 (a third signal) having a phase difference of approximately 180 degrees from the signal RF11 (a second signal); the amplifier circuit 160 (a first amplifier circuit) includes an amplifier circuit 160a (a third amplifier circuit) that amplifies the signal RF11 (a second signal) and outputs the signal RFout1 (an output signal) to the output terminal 102a (a third output terminal); and an amplifier circuit 160b (a fourth amplifier circuit) that amplifies the signal RF12 (a third signal) and outputs the signal RFout2 (an output signal) to the output terminal 102b (a fourth output terminal); and the trigger circuit 170 (a first trigger circuit) includes a trigger circuit 170c1 (a third trigger circuit) having an anode connected to the output terminal 102a (a third output terminal). ), wherein when the voltage of the output terminal 102a (the third output terminal) exceeds a given threshold value, the trigger circuit 170c1 (the third trigger circuit) outputs a feedback signal Sc1 (the third feedback signal) corresponding to the voltage of the output terminal 102a (the third output terminal); and the trigger circuit 170c2 (the fourth trigger circuit) includes at least one diode whose anode is electrically connected to the output terminal 102b (the fourth output terminal), wherein when the voltage of the output terminal 102b (the fourth output terminal) exceeds a given threshold value, the trigger circuit 170c2 (the fourth trigger circuit) outputs a feedback signal Sc2 (the fourth feedback signal) corresponding to the voltage of the output terminal 102b (the fourth output terminal), and the conversion circuit 180 (the first conversion circuit) receives a signal obtained by synthesizing the feedback signal Sc1 (the third feedback signal) and the feedback signal Sc2 (the fourth feedback signal) as the feedback signal S1 (the first feedback signal). Thus, the power amplifier circuit 100 c is a circuit resistant to noise and uses a common conversion circuit, thereby being able to prevent breakdown of the amplifier circuit while achieving miniaturization.

[0193] <7>

[0194] The power amplifier circuit 100e according to the exemplary embodiment of the present disclosure includes: an amplifier circuit 160 (first amplifier circuit) to which a first bias is supplied from a bias circuit 140 (first bias circuit), amplifies a signal RF1 (first signal) and outputs a signal RFout (output signal) to an output terminal 102 (first output terminal); an amplifier circuit 150 (second amplifier circuit) to which a second bias is supplied from a bias circuit 130 (second bias circuit), is electrically connected to the amplifier circuit 160 (first amplifier circuit) at a stage preceding the amplifier circuit 160 (first amplifier circuit), and amplifies the signal RF1 (first signal) and outputs the signal RFout (output signal) to an output terminal 102 (first output terminal); The trigger circuit 170 (first trigger circuit) amplifies the input signal RFin and outputs the signal RF1 (first signal); the trigger circuit 170 (first trigger circuit) includes at least one diode whose anode is electrically connected to the output terminal 102 (first output terminal), wherein when the voltage of the output terminal 102 (first output terminal) exceeds a given threshold value, the trigger circuit 170 (first trigger circuit) outputs a feedback signal S1 (first feedback signal) corresponding to the voltage of the output terminal 102a (first output terminal); the conversion circuit 180 (first conversion circuit) includes a diode-connected transistor 181 (first transistor), a transistor 182 (second transistor) current mirror-connected to the transistor 181 (first transistor), a resistor 183 (first resistor) connected in series with the collector or drain of the transistor 181 (first transistor), a resistor 184 (second resistor) connected in series with the collector or drain of the transistor 182 (second transistor), and a resistor 185 (third resistor) connected in series with the emitter or source of the transistor 182 (second transistor), wherein the collector or drain of the transistor 181 (first transistor) and the transistor 182 (second transistor) are connected in series. The power amplifier circuit 100e includes a transistor (100e) having a feedback signal S1 (first feedback signal) input to its collector or drain; resistor 185 (third resistor) having a resistance value smaller than that of resistor 184 (second resistor); and an adjustment circuit 190 (first adjustment circuit) including a transistor having a signal output from the conversion circuit 180 (first conversion circuit) input to its base or gate via resistor 192 (fourth resistor); and a transistor having a collector or drain electrically connected to the bias circuit 130 (second bias circuit) via resistor 193 (fifth resistor) to adjust the second bias supplied from the bias circuit 130 (second bias circuit). Thus, the power amplifier circuit 100e prevents breakdown of the amplifier circuit 160 by suppressing the output voltage of the amplifier circuit 150 in the driver stage.

[0195] <8>

[0196] according to <1> to <3> The power amplifier circuit according to any one of the preceding claims, wherein the power amplifier circuits 100b2, 100d2, 100f1, and 100g1 according to the exemplary embodiment of the present disclosure further include: an amplifier circuit 150 (a second amplifier circuit) to which a second bias is supplied from a bias circuit 130 (a second bias circuit), electrically connected to the amplifier circuit 160 (a first amplifier circuit) at a preceding stage of the amplifier circuit 160 (a first amplifier circuit), and amplifying a signal RFin (an input signal) and outputting a signal RF1 (a first signal); and a second adjustment circuit including transistors 191b2, 191d2, 191f1, and 191g1, each of which receives a signal output from the conversion circuit 180 (a first conversion circuit) at its base or gate and is electrically connected to the bias circuit 130 (a second bias circuit) at its collector or drain so as to adjust the second bias supplied from the bias circuit 130 (a second bias circuit). Thus, in the power amplifier circuits 100b2, 100d2, 100f1, and 100g1, the voltage and current at the time when the voltage amplitude and current amplitude of the power stage are maximum can be suppressed, thereby preventing breakdown of transistors in the power stage.

[0197] The various embodiments described above are intended to make the present invention easy to understand and are not intended to limit the present invention. The present invention can be changed or improved without departing from its purport, and the present invention also includes its equivalents. That is, as long as those skilled in the art have the characteristics of the present invention, the embodiments to which design changes are appropriately applied to the various embodiments are also included in the scope of the present invention. For example, the various elements and their configurations, materials, conditions, shapes, sizes, etc. possessed by the various embodiments are not limited to the illustrated contents and can be appropriately changed. In addition, as long as it is technically possible, the various elements possessed by the various embodiments can be combined, and the embodiments to which they are combined are also included in the scope of the present invention as long as they include the characteristics of the present invention.

[0198] Description of Reference Numerals

[0199] 100a, 100b1, 100b2, 100c, 100d1, 100d2, 100e, 100f, 100f1, 100g, 100g1: power amplifier circuit;

[0200] 110: matching circuit;

[0201] 120: matching circuit;

[0202] 130: bias circuit;

[0203] 140, 140c: bias circuit;

[0204] 150: amplifier circuit;

[0205] 160: amplifier circuit;

[0206] 170, 170b1, 170c1, 170c2, 170d1: trigger circuit;

[0207] 180, 180b, 180d: conversion circuit;

[0208] 190, 190b, 190d: Adjustment circuit.

Claims

1. A power amplifier circuit comprising: a first amplifier circuit which is supplied with a first bias from a first bias circuit, amplifies a first signal, and outputs an output signal to a first output terminal; The first trigger circuit includes at least one diode whose anode is electrically connected to the first output terminal, wherein: When the voltage of the first output terminal exceeds a given threshold, the first trigger circuit outputs a first feedback signal corresponding to the voltage of the first output terminal; a first conversion circuit comprising a first transistor in a diode connection, a second transistor in a current mirror connection with the first transistor, a first resistor connected in series with the collector or drain of the first transistor, a second resistor connected in series with the collector or drain of the second transistor, and a third resistor connected in series with the emitter or source of the second transistor, wherein the first feedback signal is input to the collector or drain of the first transistor and the collector or drain of the second transistor, and a resistance value of the third resistor is smaller than a resistance value of the second resistor; and The first adjustment circuit includes a transistor having a base or a gate input with a signal output from the first conversion circuit and a collector or a drain electrically connected to the first bias circuit so as to adjust the first bias supplied from the first bias circuit.

2. The power amplifier circuit according to claim 1, wherein: The first adjustment circuit further includes a fourth resistor and a fifth resistor. In the transistor, the signal output from the first conversion circuit is input to the base or gate via the fourth resistor, and the collector or drain is electrically connected to the first bias circuit via the fifth resistor to adjust the first bias supplied from the first bias circuit.

3. The power amplifier circuit according to claim 1 or claim 2, wherein: The first trigger circuit includes a plurality of diodes connected in series, anodes of the plurality of diodes being electrically connected to the first output terminal, and cathodes of the plurality of diodes being electrically connected to a reference potential. The first trigger circuit outputs the first feedback signal from a node between two adjacent diodes among the plurality of diodes.

4. The power amplifier circuit according to any one of claims 1 to 3, wherein: Also features: The second amplifier circuit is supplied with a second bias from a second bias circuit, is electrically connected to the first amplifier circuit at a preceding stage of the first amplifier circuit, amplifies an input signal, and outputs the first signal.

5. The power amplifier circuit according to claim 4, wherein: have: a second trigger circuit comprising at least one diode having an anode electrically connected to a second output terminal of the second amplifier circuit, wherein when a voltage at the second output terminal exceeds a predetermined threshold, the second trigger circuit outputs a second feedback signal corresponding to the voltage at the second output terminal; a second conversion circuit comprising a third transistor in diode connection, a fourth transistor in current mirror connection with the third transistor, a sixth resistor connected in series with the collector or drain of the third transistor, a seventh resistor connected in series with the collector or drain of the fourth transistor, and an eighth resistor connected in series with the emitter or source of the fourth transistor, wherein the second feedback signal is input to the collector or drain of the third transistor and the collector or drain of the fourth transistor, and a resistance value of the eighth resistor is smaller than a resistance value of the seventh resistor; and The second adjustment circuit includes a transistor having a base or a gate input with a signal output from the second conversion circuit via a ninth resistor and a collector or a drain electrically connected to the second bias circuit via a tenth resistor so as to adjust the second bias supplied from the second bias circuit.

6. The power amplifier circuit according to claim 1 or claim 5, wherein: further comprising: a distributor for distributing the first signal into a second signal and a third signal having a phase difference of 180 degrees from the second signal; The first amplifier circuit includes: a third amplifier circuit that amplifies the second signal and outputs a first output signal to a third output terminal; and a fourth amplifier circuit that amplifies the third signal and outputs a second output signal to a fourth output terminal. The first trigger circuit includes: a third trigger circuit comprising at least one diode having an anode electrically connected to the third output terminal, wherein when the voltage of the third output terminal exceeds a given threshold, the third trigger circuit outputs a third feedback signal corresponding to the voltage of the third output terminal; and a fourth trigger circuit comprising at least one diode having an anode electrically connected to the fourth output terminal, wherein when the voltage of the fourth output terminal exceeds a given threshold, the fourth trigger circuit outputs a fourth feedback signal corresponding to the voltage of the fourth output terminal; A signal synthesized from the third feedback signal and the fourth feedback signal is input to the first conversion circuit as the first feedback signal.

7. A power amplifier circuit comprising: a first amplifier circuit which is supplied with a first bias from a first bias circuit, amplifies a first signal, and outputs an output signal to a first output terminal; a second amplifier circuit supplied with a second bias from a second bias circuit, electrically connected to the first amplifier circuit at a preceding stage of the first amplifier circuit, amplifying an input signal and outputting the first signal; The first trigger circuit includes at least one diode whose anode is electrically connected to the first output terminal, wherein: When the voltage of the first output terminal exceeds a given threshold, the first trigger circuit outputs a first feedback signal corresponding to the voltage of the first output terminal; a first conversion circuit comprising a first transistor in a diode connection, a second transistor in a current mirror connection with the first transistor, a first resistor connected in series with the collector or drain of the first transistor, a second resistor connected in series with the collector or drain of the second transistor, and a third resistor connected in series with the emitter or source of the second transistor, wherein the first feedback signal is input to the collector or drain of the first transistor and the collector or drain of the second transistor, and a resistance value of the third resistor is smaller than a resistance value of the second resistor; and The first adjustment circuit includes a transistor having a base or a gate input with a signal output from the first conversion circuit and a collector or a drain electrically connected to the second bias circuit so as to adjust the second bias supplied from the second bias circuit.

8. The power amplifier circuit according to any one of claims 1 to 3, wherein: Also features: a second amplifier circuit supplied with a second bias from a second bias circuit, electrically connected to the first amplifier circuit at a preceding stage of the first amplifier circuit, amplifying an input signal and outputting the first signal; and The second adjustment circuit includes a transistor having a base or a gate input with a signal output from the first conversion circuit and a collector or a drain electrically connected to the second bias circuit so as to adjust the second bias supplied from the second bias circuit.

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