JP6288607B2 - Power amplification module - Google Patents

Description

  The present invention relates to a power amplification module.

  In a mobile communication device such as a mobile phone, a power amplification module is used to amplify the power of a radio frequency (RF) signal transmitted to a base station. Such a power amplifying module includes a bias circuit for supplying a bias current to the transistors constituting the amplifier circuit in addition to the amplifier circuit for amplifying the RF signal.

  In the power amplification module, for example, when the bias current changes due to manufacturing variations of elements such as transistors, the characteristics of the power amplification module also change. Therefore, it is important to suppress the influence of manufacturing variations in the power amplification module. For example, Patent Document 1 discloses a configuration in which a bias current is controlled by comparing a bias current supplied to a transistor included in an amplifier circuit with a reference current.

JP-A-11-330866

  In the configuration disclosed in Patent Document 1, it is possible to control the bias current by comparing the bias current with the reference current. However, since it is necessary to provide a current generation circuit for generating the reference current and a comparison circuit for comparing the bias current and the reference current for each amplifier circuit, the circuit scale increases.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a power amplification module capable of suppressing a variation in bias current due to manufacturing variations and suppressing an increase in circuit scale.

  A power amplification module according to one aspect of the present invention includes a first transistor that amplifies and outputs a radio frequency signal, a first resistor that is supplied with a bias control voltage at one end, and the other end of the first resistor. A radio frequency amplifier circuit including a first bias circuit that supplies a first bias current to the first transistor in accordance with the voltage of the first resistor, a second resistor having one end grounded, and a second resistor An adjustment current generating circuit for generating a bias adjustment current according to the resistance value of the second resistor based on the current flowing through the second resistor by supplying the first reference voltage to the end; and according to the bias adjustment current A bias control circuit including a control voltage generation circuit for generating a bias control voltage.

  According to the present invention, it is possible to provide a power amplification module capable of suppressing fluctuations in bias current due to manufacturing variations and suppressing increase in circuit scale.

It is a figure which shows the structural example of the transmission unit containing the power amplification module which is one Embodiment of this invention. It is a figure which shows an example of a structure of a power amplification module. It is a figure which shows an example of a structure of RF amplification circuit. It is a figure which shows an example of a structure of a bias control circuit. It is a simulation result which shows an example of the relationship between the change rate of the resistance value of the resistor included in the bias circuit, and the bias control voltage V _BIAS . It is a simulation result which shows an example of the relationship between the rate of change of the resistance value of the resistor included in the bias circuit and the voltage V _B. It is a figure which shows another example of a structure of a bias control circuit. Is a diagram showing an example of a relationship between the temperature and the reference voltage V _T. It is a figure which shows an example of a structure of a temperature compensation circuit. Is a diagram illustrating an example of a change in current I _T. It is a figure which shows an example of a structure of a temperature compensation circuit when changing the reference voltage _VT by a secondary change characteristic. Is a diagram showing an example of a relationship between the current I _t3 and the current I _111. It is a figure which shows an example of the change of electric current _Iht0 . Is a diagram showing an example of a relationship between the current I _ht1 and the current I _T. Is a diagram showing an example of a relationship between the temperature and the reference voltage V _T. It is a figure which shows another example of a structure of a bias control circuit. It is a figure which shows an example of a structure of a temperature compensation circuit. It is a figure which shows an example of the other structure of a bias control circuit. It is a figure which shows an example of the other structure of a power amplification module.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram illustrating a configuration example of a transmission unit including a power amplification module according to an embodiment of the present invention. The transmission unit 100 is used for transmitting various signals such as voice and data to a base station in a mobile communication device such as a mobile phone. Although the mobile communication device also includes a receiving unit for receiving signals from the base station, description thereof is omitted here.

  As shown in FIG. 1, the transmission unit 100 includes a modulation unit 101, a transmission power control unit 102, a power amplification module 103, a front end unit 104, and an antenna 105.

  Modulation section 101 modulates an input signal based on a modulation scheme such as HSUPA (High Speed Uplink Packet Access) or LTE (Long Term Evolution), and generates a radio frequency (RF) signal for wireless transmission. . The RF signal is, for example, about several hundred MHz to several GHz.

  The transmission power control unit 102 adjusts and outputs the power of the RF signal based on the transmission power control signal. The transmission power control signal is generated based on, for example, an adaptive power control (APC) signal transmitted from the base station. For example, the base station transmits an APC signal to the mobile communication device as a command for adjusting the transmission power in the mobile communication device to an appropriate level by measuring the received signal from the mobile communication device. Can do.

The power amplification module 103 amplifies the power of the RF signal (RF _IN ) output from the transmission power control unit 102 to a level necessary for transmission to the base station, and outputs an amplified signal (RF _OUT ).

  The front end unit 104 performs filtering on the amplified signal, switching with a reception signal received from the base station, and the like. The amplified signal output from the front end unit 104 is transmitted to the base station via the antenna 105.

  FIG. 2 is a diagram illustrating an example of the configuration of the power amplification module 103 (power amplification module 103A). The power amplification module 103A includes an RF amplification circuit 201 (radio frequency amplification circuit), a bias control circuit 202, and a matching circuit (MN: Matching Network) 203.

  In the configuration shown in FIG. 2, the RF amplifier circuit 201 and the bias control circuit 202 are formed on different substrates. For example, the RF amplifier circuit 201 is configured as an integrated circuit using a bipolar transistor such as a heterojunction bipolar transistor (HBT). Further, for example, the bias control circuit 202 is configured as an integrated circuit using a MOSFET (MOS Field-Effect Transistor).

  The RF amplifier circuit 201 includes a bias circuit 211 (first bias circuit), an amplifier circuit 212, a matching circuit 213, and a resistor 214 (second resistor).

The bias circuit 211 supplies a bias current to the transistors constituting the amplifier circuit 212 based on the bias control voltage V _BIAS supplied from the bias control circuit 202.

The amplifier circuit 212 amplifies the input RF signal (RF _IN ) and outputs an amplified signal (RF _OUT ). The matching circuits 213 and 203 are for matching impedances with circuits provided before and after the amplifier circuit 212, and are configured using, for example, capacitors or inductors.

  The resistor 214 is provided to suppress fluctuations in the bias current due to manufacturing variations of the resistors included in the bias circuit 211. Details will be described later.

The bias control circuit 202 generates a bias control voltage V _BIAS supplied to the bias circuit 211 using the battery voltage V _BAT . The bias control circuit 202 can detect a manufacturing variation in resistance in the RF amplifier circuit 201 by applying a reference voltage of a predetermined level (for example, a band gap voltage V _BG ) to the resistor 214. The bias control circuit 202 can adjust the bias control voltage V _BIAS so that fluctuations in the bias current due to manufacturing variations in resistance are suppressed. Details will be described later.

  Configuration examples of the RF amplifier circuit 201 and the bias control circuit 202 will be described.

  FIG. 3 is a diagram illustrating an example of the configuration of the RF amplifier circuit 201. As described above, the RF amplifier circuit 201 includes the bias circuit 211 (first bias circuit), the amplifier circuit 212, the matching circuit 213, and the resistor 214.

  The bias circuit 211 includes a transistor 301 (third transistor), resistors 302 to 304, and diodes 305 and 306. Here, the transistor 301 is a bipolar transistor such as an HBT, for example.

In the bias circuit 211, the bias control voltage V _BIAS is applied to one end of the resistor 302 (first resistor). The other end of the resistor 302 is connected to the diodes 305 and 306 connected in series and to one end of the resistor 303. The other end of the resistor 303 is connected to the base of the transistor 301. A battery voltage V _BAT is applied to the collector of the transistor 301. The emitter of the transistor 301 is connected to one end of the resistor 304, and the other end of the resistor 304 is connected to the amplifier circuit 212 as a bias output to the amplifier circuit 212.

  The amplifier circuit 212 includes a transistor 311 (first transistor) and an inductor 313. Here, the transistor 311 is, for example, a bipolar transistor such as an HBT.

As shown in FIG. 3, an RF signal (RF _IN ) is input to the base of the transistor 311 via the matching circuit 213 and a bias current from the bias circuit 211 is supplied. In addition, the battery voltage V _BAT is applied to one end of the inductor 313, and the other end of the inductor 313 is connected to the collector of the transistor 311. Then, the amplified signal RF _OUT is output from the collector of the transistor 311 via the matching circuit 203.

A reference voltage of a predetermined level (for example, a band gap voltage V _BG ) (first reference voltage) supplied from the bias control circuit 202 is applied to one end of the resistor 214. The other end of the resistor 214 is grounded. In the RF amplifier circuit 201, the resistor 302 and the resistor 214 can be formed over the same substrate, and thus can be formed using resistance elements having the same size and shape. Here, the size of the resistor refers to a film thickness and a width. For example, when the resistor 214 is composed of one resistor element, the resistor 302 can be configured by connecting a plurality of the resistor elements in parallel.

  FIG. 4 is a diagram illustrating an example of the configuration of the bias control circuit 202 (bias control circuit 202A). As shown in FIG. 4, the bias control circuit 202 </ b> A includes a band gap (BG) circuit 401, an adjustment current generation circuit 402, and a control voltage generation circuit 403.

The bandgap circuit 401 generates a bandgap voltage _VBG that does not depend on temperature and power supply voltage fluctuations from a power supply voltage such as the battery voltage _VBAT . The band gap voltage V _BG is, for example, about 1.2V.

The adjustment current generation circuit 402 is a circuit that generates a bias adjustment current I _ADJ according to the resistance value of the resistor 214. The adjustment current generation circuit 402 includes an operational amplifier 411 and transistors (P-type MOSFETs) 412 and 413.

A band gap voltage V _BG is applied to the non-inverting input terminal of the operational amplifier 411. The inverting input terminal of the operational amplifier 411 is connected to the drain of the transistor 412 and one end of the resistor 214. The output terminal of the operational amplifier 411 is connected to the gates of the transistors 412 and 413.

In the transistor 412, the battery voltage V _BAT is applied to the source, and the drain is connected to one end of the resistor 214. In the transistor 413, the battery voltage V _BAT is applied to the source, and the drain is connected to the control voltage generation circuit 403.

In the adjustment current generation circuit 402, the voltage at the inverting input terminal of the operational amplifier 411 becomes V _BG due to an imaginary short between the non-inverting input terminal and the inverting input terminal of the operational amplifier 411. Assuming that the resistance value of the resistor 214 is R _ADJ and the current flowing through the transistor 412 is I ₄₁ , I ₄₁ = V _BG / R _ADJ . When the ratio of the sizes of the transistors 412 and 413 (the exclusive area of the gate width and the gate length) is m ₄₁ : m ₄₂ , the bias adjustment current I _ADJ flowing through the transistor 413 is (m ₄₂ / m ₄₁ ) × (V _BG / R _ADJ ).

  The control voltage generation circuit 403 includes an operational amplifier 421, a resistor 422 (fourth resistor), and a resistor 423 (fifth resistor).

A band gap voltage V _BG (second reference voltage) is applied to the non-inverting input terminal of the operational amplifier 421. The resistor 422 has one end connected to the inverting input terminal of the operational amplifier 421 and the other end grounded. The resistor 423 has one end connected to the inverting input terminal of the operational amplifier 421 and the other end connected to the output terminal of the operational amplifier 421. Further, the bias adjustment current I _ADJ is supplied to the connection point between the resistors 422 and 423.

The operational amplifier 421 and the resistors 422 and 423 constitute a non-inverting amplifier circuit. When the resistance values of the resistors 422 and 423 are R ₄₁ and R ₄₂ , respectively, the bias control voltage V _BIAS output from the output terminal of the operational amplifier 421 is {1+ (R _{42 /} R ₄₁ )} × V _BG −I _ADJ × R ₄₂ = {1+ (R ₄₂ / R ₄₁ )} × V _BG − (m ₄₂ / m ₄₁ ) × (V _BG / R _ADJ ) × R ₄₂ Therefore, the bias control voltage V _BIAS increases or decreases with the resistance value R _ADJ of the resistor 214. That is, as the resistance value R _ADJ changes due to manufacturing variations, the bias control voltage V _BIAS also changes. The resistor 214 is provided on a substrate of an integrated circuit that constitutes the RF amplifier circuit 201. Therefore, the change rate of the resistance value R _ADJ of the resistor 214 and the change rate of the resistance value of the resistor 302 of the bias circuit 211 are approximately the same. Therefore, when the resistance value of the resistor 302 changes due to manufacturing variations, the bias control voltage V _BIAS is adjusted according to the change in the resistance value of the resistor 302. Thereby, the fluctuation | variation of a bias current can be suppressed.

5 and 6 are simulation results showing an example of the relationship between the change rate of the resistance value of the resistor 302 and the bias control voltage V _BIAS and the voltage V _B. Note that the resistance value of the resistor 214 also changes in the same manner as the resistance value of the resistor 302. The voltage V _B in FIG. 6 is a voltage applied to one end of the resistor 303 connected to the base of the transistor 301 as shown in FIG. FIG. 5 and FIG. 6 show simulation results when there is no adjustment with the bias adjustment current I _ADJ and when there is no adjustment.

In FIG. 5, the horizontal axis represents the rate of change (%) of the resistance value of the resistor 302, and the vertical axis represents the bias control voltage V _BIAS (V). When there is no adjustment by the bias adjustment current I _ADJ , the bias control voltage V _BIAS is constant because the voltage amplification factor of the control voltage generation circuit 403 is constant. On the other hand, when there is adjustment by the bias adjustment current I _ADJ , the bias control voltage V _BIAS increases as the resistance value of the resistor 302 increases.

In FIG. 6, the horizontal axis indicates the rate of change (%) of the resistance value of the resistor 302, and the vertical axis indicates the voltage V _B (V). When there is no adjustment by the bias adjustment current I _ADJ , the bias control voltage V _BIAS is constant as shown in FIG. 5, so the voltage V _B decreases as the resistance value of the resistor 302 increases. On the other hand, when there is adjustment by the bias adjustment current I _ADJ , the bias control voltage V _BIAS changes according to the change in the resistance value of the resistor 302 as shown in FIG. 5, and therefore the voltage V _B is substantially constant.

As described above, by adjusting the bias control voltage V _BIAS according to the change in the resistance value of the resistor 302 due to manufacturing variations, the fluctuation of the voltage V _B can be suppressed and the fluctuation of the bias current can be suppressed. Further, since it is not necessary to provide the adjustment current generating circuit 402 for adjusting the bias control voltage V _BIAS for each amplifier circuit, it is possible to suppress an increase in circuit scale.

  FIG. 7 is a diagram showing another example of the configuration of the bias control circuit 202 (bias control circuit 202B). It should be noted that the same elements as those shown in FIG. Bias control circuit 202B includes a temperature compensation circuit 701 in addition to the configuration shown in FIG.

The temperature compensation circuit 701 is a circuit for suppressing a change in bias current due to temperature, and generates a reference voltage V _T (second reference voltage) based on the band gap voltage V _BG (fourth reference voltage). To do. When the bias circuit 211 has the configuration shown in FIG. 3, the bias current may be affected by the temperature characteristics of the forward voltage of the diodes 305 and 306. Specifically, when the forward voltage of the diodes 305 and 306 increases at a low temperature, the base current of the transistor 301 decreases, and as a result, the bias current output from the bias circuit 211 also decreases.

Therefore, the temperature compensation circuit 701 generates a reference voltage V _T that changes according to the temperature characteristics of the forward voltage of the diodes 305 and 306. FIG. 8 is a diagram illustrating an example of the relationship between the temperature T and the reference voltage V _T. In FIG. 8, the relationship between the temperature T and the reference voltage V _T is indicated by a straight line, but the relationship between the temperature T and the reference voltage V _T is not limited to this, and may be a curve, for example.

FIG. 9 is a diagram illustrating an example of the configuration of the temperature compensation circuit 701 (temperature compensation circuit 701A). The temperature compensation circuit 701A includes a constant current generation circuit 901, a compensation current generation circuit 902, and a current-voltage conversion circuit 903. The constant current generation circuit 901 is a circuit that generates a constant current regardless of temperature. The compensation current generation circuit 902 is a circuit that generates a compensation current that changes according to temperature. The current-voltage conversion circuit 903 converts the current I _T that changes according to the constant current generated by the constant current generation circuit 901 and the compensation current generated by the compensation current generation circuit 902 into a reference voltage V _T. Circuit.

The constant current generation circuit 901 includes an operational amplifier 911, transistors (P channel MOSFETs) 912 and 913, and a resistor 914. The operational amplifier 911 has a band gap voltage V _BG applied to a non-inverting input terminal, an inverting input terminal connected to a connection point between the transistor 912 and the resistor 914, and an output terminal connected to the gates of the transistors 912 and 913.

The compensation current generation circuit 902 includes an operational amplifier 921, transistors (P-channel MOSFETs) 922 and 923, transistors (N-channel MOSFETs) 924 and 925, a resistor 926, and a diode 927. In the operational amplifier 921, the band gap voltage V _BG is applied to the non-inverting input terminal, the inverting input terminal is connected to the connection point between the transistor 922 and the resistor 926, and the output terminal is connected to the gates of the transistors 922 and 923. The transistor 924 is diode-connected in series with the transistor 923 and is current-mirror connected to the transistor 925. The drain of the transistor 925 is connected to the drain of the transistor 913 of the constant current generation circuit 901. The resistor 926 has one end connected to the drain of the transistor 922 and the other end grounded via a diode 927. Note that the temperature characteristics of the diode 927 are equivalent to the temperature characteristics of the diodes 305 and 306.

  The current / voltage conversion circuit 903 includes a resistor 931. One end of the resistor 931 is connected to the drain of the transistor 913 of the constant current generation circuit 901 and the drain of the transistor 925 of the compensation current generation circuit 902, and the other end is grounded.

In the configuration shown in FIG. 9, when the resistance value of the resistor 914 is R ₉₀ , the current I ₉₀ flowing through the transistor 912 is V _BG / R ₉₀ (constant current). The current I ₉₁ flowing through the transistor 913 is k ₁ × I ₉₀ (constant current). Note that k ₁ is a coefficient corresponding to the size ratio of the transistors 912 and 913.

Further, when the resistance value of the resistor 926 R _91, the forward voltage of the diode 927 and V _F, a current I _t0 flowing through the transistor 922 becomes _{(V BG -V F) / R} 91. The current I _t1 flowing through the transistor 923 is k ₂ × I _t0 . Note that k ₂ is a coefficient corresponding to the size ratio of the transistors 922 and 923. Further, the current flowing through the transistor 925 is I _t2 = k ₃ × I _t1 . Note that k ₃ is a coefficient corresponding to the size ratio of the transistors 924 and 925. Here, V _F is because changes according to temperature, so that the current I _t0 ~I _t2 also changes depending on the temperature.

Figure 10 is a diagram showing an example of a change in current I _T. Forward voltage V _F of the diode 927 is, when it becomes lower with an increase in temperature, current I _t2 becomes possible to increase with increasing temperature. Note that since the current I _t2 is opposite in direction to the current I _T flowing through the resistor 931, the current I _t2 is shown by a negative temperature characteristic in FIG. Since the current I _T flowing through the resistor R ₉₂ is obtained by subtracting the current I _t2 from the current I ₉₁ , the current I _T decreases as the temperature rises as shown in FIG. By converting such a current I _T into a voltage by the resistor 931, as shown in FIG. 8, it is possible to generate a reference voltage V _T that decreases as the temperature rises. That is, the reference voltage V _T that changes according to the temperature characteristics of the forward voltage of the diodes 305 and 306 can be generated.

Returning to FIG. 7, in the bias control circuit 202B, the bias control voltage V _BIAS is generated based on the reference voltage V _T generated in this way. Therefore, the bias control voltage V _BIAS changes according to the temperature characteristics of the forward voltage of the diodes 305 and 306. Thereby, even if the forward voltage of the diodes 305 and 306 fluctuates due to temperature change, the bias control voltage V _BIAS also changes in conjunction with it, so that fluctuation of the bias current can be suppressed.

Although FIG. 9 shows an example of a configuration for changing the reference voltage V _T with a primary (straight line) change characteristic, the change characteristic of the reference voltage V _T may be secondary or higher. FIG. 11 is a diagram illustrating an example of the configuration of the temperature compensation circuit 701 (temperature compensation circuit 701B) when the reference voltage V _T is changed with a secondary change characteristic. In addition, the same code | symbol is attached | subjected to the element same as the structure shown in FIG. 9, and description is abbreviate | omitted. The temperature compensation circuit 701B includes a secondary correction circuit 1101 in addition to the configuration shown in FIG.

  The secondary correction circuit 1101 includes transistors (P-channel MOSFETs) 1111 to 1113 and a transistor 1114 (N-channel MOSFET). The transistor 1111 has a gate connected to the output terminal of the operational amplifier 911 and a drain connected to the drain of the transistor 1114. The transistor 1112 is diode-connected and also connected to the transistor 1113 in a current mirror. The drain of the transistor 1112 is connected to the drain of the transistor 1111. The drain of the transistor 1113 is connected to one end of the resistor 931. The transistor 1114 is current-mirror connected to the transistor 924.

In the temperature compensation circuit 701B, the current flowing through the transistor 1114 is I _t3 = k ₄ × I _t1 . Note that k ₄ is a coefficient corresponding to the size ratio of the transistors 924 and 1114. Further, the current flowing through the transistor 1111 is I ₁₁₁ = k ₅ × I ₉₀ . Note that k ₅ is a coefficient corresponding to the size ratio of the transistors 912 and 1111. The current flowing in the transistor 1112 is I _ht0 = I _t3 −I ₁₁₁ (where I _ht0 ≧ 0). The current flowing through the transistor 1113 is I _ht1 = k ₆ × I _ht0 . Note that k ₆ is a coefficient corresponding to the size ratio of the transistors 1112 and 1113.

Figure 12 is a diagram showing an example of the relationship between the current I _t3 and the current I _111. FIG. 13 is a diagram illustrating an example of a change in the current _Iht0 . In the example shown in FIG. 12, constant current I ₁₁₁ is set to the value of the current I _t3 at 25 ° C.. If the temperature is lower than 25 ° C., for a constant current I ₁₁₁ is larger than the current I _t3, the transistor 1111 becomes saturated operation, no current flows through the transistor 1112 (I _ht0 = 0). On the other hand, if the temperature is higher than 25 ° C., for a constant current I ₁₁₁ is less than the current I _t3, current I _ht0 the difference flows through the transistor 1112. Therefore, as shown in FIG. 13, the current I _ht0 (= I _t3 −I ₁₁₁ ) is zero up to 25 ° C., and increases as the temperature rises above 25 ° C.

Figure 14 is a diagram showing an example of the relationship between the current I _ht1 and the current I _T. When the current I _ht0 changes as shown in FIG. 13, the current I _ht1 changes similarly. Therefore, as shown in FIG. 14, the slope of the current I _T (= (I ₉₁ −I _t2 ) + I _ht1 ) changes at a certain temperature (for example, 25 ° C.). That is, the current I _T changes with secondary change characteristics. Therefore, the reference voltage V _T corresponding to the current I _T also changes with secondary change characteristics as shown in FIG. This makes it possible to adjust the reference voltage V _BIAS in accordance with the temperature characteristics of the forward voltage of the diodes 305 and 306 with higher accuracy.

FIG. 16 is a diagram illustrating another example of the configuration of the bias control circuit 202 (bias control circuit 202C). Note that the same elements as those shown in FIG. 7 are denoted by the same reference numerals and description thereof is omitted. The bias control circuit 202C includes an adjustment current generation circuit 1601 and a temperature compensation circuit 1602 instead of the adjustment current generation circuit 402 and the temperature compensation circuit 701 shown in FIG. Unlike the configuration shown in FIG. 7, the bias adjustment current I _ADJ output from the adjustment current generation circuit 1601 is supplied to the temperature compensation circuit 1602.

Adjustment current generation circuit 1601 includes transistors (N-channel MOSFETs) 1611 and 1612 in addition to the configuration of adjustment current generation circuit 402 shown in FIG. The transistor 1611 is diode-connected in series with the transistor 413 and is current-mirror connected to the transistor 1612. The drain of the transistor 1612 is connected to the temperature compensation circuit 1602. Note that the characteristics of the bias adjustment current I _ADJ flowing in the transistor 1612 are the same as those in FIG.

The temperature compensation circuit 1602 generates a reference voltage V _T (third reference voltage) based on the band gap voltage V _BG (fourth reference voltage) and the bias adjustment current I _ADJ . FIG. 17 is a diagram illustrating an example of the configuration of the temperature compensation circuit 1602. Note that the same components as those in the temperature compensation circuit 701B shown in FIG. Temperature compensation circuit 1602, except that the bias adjustment current I _ADJ as the current to reduce the current I _T supplied, the same configuration as the temperature compensation circuit 701B.

In the structure shown in FIG. 17, a current I _T decreases with increasing bias adjustment current I _ADJ. That is, the reference voltage V _T decreases as the bias adjustment current I _ADJ increases. In the bias control circuit 202C shown in FIG. 16, the reference voltage V _T that changes in accordance with the bias adjustment current I _ADJ in this way is amplified by the control voltage generation circuit 403, and the bias control voltage V _BIAS is output. Here, as the resistance value of the resistor 302 increases, the bias adjustment current I _ADJ decreases and the current I _T and the reference voltage V _T increase. Therefore, similarly to the simulation result shown in FIG. 5, the bias control voltage V _BIAS increases as the resistance value of the resistor 302 increases. Thereby, the same effect as the case of FIG. 7 can be acquired.

  FIG. 18 is a diagram illustrating an example of another configuration of the bias control circuit 202 (bias control circuit 202D). It should be noted that the same elements as those shown in FIG. The bias control circuit 202D includes a control voltage generation circuit 1801 instead of the control voltage generation circuit 403 shown in FIG. The control voltage generation circuit 1801 includes resistors 1811 and 1812 and an amplification factor control circuit 1820 in addition to the configuration of the control voltage generation circuit 403 shown in FIG. The amplification factor control circuit 1820 includes switches 1821 to 1823.

  One end of the resistor 422 is connected to the inverting input terminal of the operational amplifier 421, and the other end of the resistor 422 is grounded via the switch 1821. One end of the resistor 1811 is connected to the other end of the resistor 422, and the other end of the resistor 1811 is grounded via the switch 1822. One end of the resistor 1812 is connected to the other end of the resistor 1811, and the other end of the resistor 1812 is grounded via the switch 1823.

  The amplification factor control circuit 1820 controls the voltage amplification factor in the operational amplifier 421 by controlling on / off of the switches 1821 to 1823 based on a power mode control signal for controlling the power mode of the power amplification module 103. For example, in the low power mode, the amplification factor control circuit 1820 can reduce the voltage amplification factor by turning off the switches 1821 and 1822 and turning on the switch 1823. For example, in the high power mode, the amplification factor control circuit 1820 can increase the voltage amplification factor by turning off the switches 1822 and 1823 and turning on the switch 1821. Similarly, for example, in the middle power mode, the amplification factor control circuit 1820 can turn off the switches 1821 and 1823 and turn on the switch 1822.

  Note that the connection form of the resistor and the switch illustrated in FIG. 18 is an example, and any configuration that can change the resistance value can be employed. In addition, in the configuration for performing temperature compensation shown in FIGS. 7 and 16, a configuration for controlling the voltage amplification factor can be employed.

  FIG. 19 is a diagram illustrating an example of another configuration of the power amplification module 103 (power amplification module 103B). Note that the same elements as those shown in FIG. 2 are denoted by the same reference numerals and description thereof is omitted. The power amplification module 103B includes an RF amplification circuit 1901 instead of the RF amplification circuit 201 of the power amplification module 103A shown in FIG. The RF amplifier circuit 1901 includes a bias circuit 1911 (second bias circuit), an amplifier circuit 1912, and a matching circuit 1913 in addition to the configuration of the RF amplifier circuit 201.

The bias circuit 1911 has a configuration equivalent to that of the bias circuit 211. That is, the bias circuit 1911 includes a resistor (third resistor) to which the bias control voltage V _BIAS is supplied, like the resistor 302 of the bias circuit 211, and supplies a bias current (second bias current) to the amplifier circuit 1912. Supply. The amplifier circuit 1912 has a configuration equivalent to that of the amplifier circuit 212. That is, the amplifier circuit 1912 includes an amplifying transistor (second transistor) similarly to the transistor 311 of the amplifier circuit 212. The matching circuit 1913 is provided to match the impedance between the amplifier circuits 212 and 1912.

As shown in FIG. 19, the RF amplifier circuit 1901 forms a two-stage amplifier circuit. Even in such a configuration, fluctuations in the bias current output from the bias circuits 211 and 1911 can be suppressed by the bias control voltage V _BIAS output from the bias control circuit 202. Although FIG. 19 shows an example of a two-stage amplifier circuit, the number of stages of amplifier circuits may be three or more.

The present embodiment has been described above. According to the present embodiment, a change in resistance value due to manufacturing variation of the resistor 302 included in the bias circuit 211 can be detected by the resistance value of the resistor 214. Then, by adjusting the bias control voltage V _BIAS according to the resistance value of the resistor 214, it is possible to suppress fluctuations in the bias current. Further, according to the present embodiment, it is not necessary to provide a circuit for adjusting the bias control voltage V _BIAS for each amplifier circuit, so that an increase in circuit scale can be suppressed.

  In the present embodiment, an example is shown in which the resistor 214 is provided in the integrated circuit constituting the RF amplifier circuit 201 or the RF amplifier circuit 1901. However, the resistor 214 may be, for example, a surface mount component. In the case where the resistor 214 is a surface mount component, the resistance value of the resistor 214 may be set in accordance with a change in the resistance value of the resistor 302 in the integrated circuit.

  Note that, as shown in this embodiment, by providing the resistor 214 in the integrated circuit constituting the RF amplifier circuit 201 or the RF amplifier circuit 1901, adjustment of the resistance value of the resistor 214 is not necessary, and the manufacturing cost is reduced. It becomes possible.

  In the present embodiment, the size and shape of the resistance element that configures the resistor 302 can be the same as the size and shape of the resistance element that configures the resistor 214. Thereby, the deviation between the change rate of the resistance value of the resistor 302 and the change rate of the resistance value of the resistor 214 due to manufacturing variations can be reduced.

In the present embodiment, the bias control voltage V _BIAS can be adjusted according to the temperature characteristics of the diodes 305 and 306 included in the bias circuit 211. Thereby, the fluctuation | variation of the bias current by the temperature characteristic of the diodes 305 and 306 can be suppressed.

Further, in the present embodiment, even in a configuration in which the voltage amplification factor when generating the bias control voltage V _BIAS is controlled according to the power mode, fluctuations in the bias current can be suppressed.

  Note that this embodiment is intended to facilitate understanding of the present invention and is not intended to limit the present invention. The present invention can be changed / improved without departing from the spirit thereof, and the present invention includes equivalents thereof.

DESCRIPTION OF SYMBOLS 100 Transmission unit 101 Modulation part 102 Transmission power control part 103 Power amplification module 104 Front end part 105 Antenna 201, 1901 RF amplification circuit 202 Bias control circuit 203, 213, 1913 Matching circuit 211, 1911 Bias circuit 212, 1912 Amplification circuit 214, 302,303,304,312,422,423,914,926,931,1811,1812 resistance 301,311,412,413,912,913,922,923,924,925,1111,1112,1113,1114 1611, 1612 Transistors 305, 306, 927 Diode 313 Inductor 401 Band gap circuit 402, 1601 Adjustment current generation circuit 403 Control voltage generation circuit 411, 421, 91 , 921 operational amplifier 701 the temperature compensation circuit 901 constant current generation circuit 902 compensating current generating circuit 903 current-voltage conversion circuit 1101 secondary correction circuit 1820 gain control circuit 1821,1822,1823 switch

Claims (9)

A first transistor for amplifying and outputting a radio frequency signal;
A first bias circuit including a first resistor to which a bias control voltage is supplied at one end, and supplying a first bias current to the first transistor according to a voltage at the other end of the first resistor;
A radio frequency amplifier circuit including:
A second resistor having one end grounded;
An adjustment current that generates a bias adjustment current according to a resistance value of the second resistor based on a current flowing through the second resistor by supplying a first reference voltage to the other end of the second resistor. A generation circuit;
A control voltage generation circuit for generating the bias control voltage according to the bias adjustment current;
A bias control circuit including:
A power amplification module comprising: The power amplification module according to claim 1,
The radio frequency amplifier circuit is an integrated circuit including the second resistor.
Power amplification module. The power amplification module according to claim 1 or 2,
The resistive element that constitutes the first resistor and the resistive element that constitutes the second resistor have the same size and shape.
Power amplification module. The power amplification module according to any one of claims 1 to 3,
The radio frequency amplifier circuit includes:
A second transistor for amplifying and outputting the radio frequency signal amplified by the first transistor;
A second bias circuit including a third resistor to which the bias control voltage is supplied at one end, and supplying a second bias current to the second transistor according to the voltage at the other end of the third resistor; ,
A power amplification module further comprising: The power amplification module according to any one of claims 1 to 4,
The control voltage generation circuit includes an operational amplifier, a fourth resistor, and a fifth resistor,
A second reference voltage is supplied to a non-inverting input terminal of the operational amplifier;
The fourth resistor has one end connected to the inverting input terminal of the operational amplifier and the other end grounded.
The fifth resistor has one end connected to the inverting input terminal of the operational amplifier and the other end connected to the output terminal of the operational amplifier.
The bias adjustment current is supplied to a connection point between the fourth and fifth resistors.
Power amplification module. The power amplification module according to any one of claims 1 to 4,
The control voltage generation circuit includes an operational amplifier, a fourth resistor, and a fifth resistor,
A third reference voltage of a level corresponding to the bias adjustment current is supplied to a non-inverting input terminal of the operational amplifier;
The fourth resistor has one end connected to the inverting input terminal of the operational amplifier and the other end grounded.
The fifth resistor has one end connected to the inverting input terminal of the operational amplifier and the other end connected to the output terminal of the operational amplifier.
Power amplification module. The power amplification module according to claim 5,
The first bias circuit includes:
A third transistor for supplying a voltage at the other end of the first resistor to a base and outputting the first bias current from an emitter;
A diode provided between the base of the third transistor and ground;
Further including
The bias control circuit includes:
A temperature compensation circuit for generating the second reference voltage that changes according to a temperature characteristic of the diode based on a fourth reference voltage;
Power amplification module. The power amplification module according to claim 6,
The first bias circuit includes:
A third transistor for supplying a voltage at the other end of the first resistor to a base and outputting the first bias current from an emitter;
A diode provided between the base of the third transistor and ground;
Further including
The bias control circuit includes:
A temperature compensation circuit for generating the third reference voltage that is at a level corresponding to the bias adjustment current and changes according to a temperature characteristic of the diode, based on a fourth reference voltage and the bias adjustment current; ,
Power amplification module. The power amplification module according to any one of claims 5 to 8,
The control voltage generation circuit includes:
An amplification factor control circuit for controlling a voltage amplification factor in the operational amplifier based on a power mode control signal;
Power amplification module.

Images