JP2002176368A - Transmission power controller capable of controlling optimization of bias current of transmission output amplifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remarkably variably control transmission power like in a mobile terminal used in a CDMA mobile communication system and to extend the communication time in the mobile terminal using a battery for power source. SOLUTION: An IF signal Sa is variably amplified, attenuated, frequency- converted and band-restricted through a variable gain IF amplifier 11, a mixer 12, a local oscillator 13, a BPF 14 and a step attenuator 15 and is inputted to a power amplifier (FET) 16. A bias current measurement value signal Sd detected by a bias current detecting circuit 17 is subtracted (negative feedback loop) from a reference value signal Sc with which a conversion circuit 18 generates from a gain control signal Sb and an attenuator control signal Sc, and bias voltage Sn integrated by an integrator 20 is outputted to the power amplifier 16. The power amplifier 16 transmits transmission output power Se corresponding to the bias current point of the bias voltage Sn.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio transmission power control for variably controlling a transmission output by a transmission power amplifier using a battery as a power source for a portable telephone, and more particularly to an optimization of a bias current of a transmission output amplifier. The present invention relates to a transmission power control device capable of controlling activation.

[0002]

2. Description of the Related Art Conventionally, in this type of portable telephone, a rechargeable battery is used as a power source, and it is necessary to reduce current consumption in order to extend a usable time (talk time) for each charge. In this case, most of the current consumed during transmission (during a call) is a transmission power amplifier (high-frequency power IC).
Consumed by Therefore, it is most important to reduce power consumption in the transmission power amplifier.

In a CDMA mobile communication system such as IS95, which has been put into practical use as such a mobile phone (mobile terminal), the distance problem between the base station and the mobile terminal (located far from the base station). The mobile terminal is required to variably control the transmission power of the mobile terminal over 80 dB in order to avoid the problem of interference caused by transmission radio waves from nearby mobile terminals.

In the variable control of the transmission power in the CDMA mobile communication system, the circuit used for the variable control is complicated, and the scale of the apparatus and the new processing are increased, which has been regarded as a weak point of the CDMA mobile communication system. But this CD
In the MA mobile communication system, the average transmission power can be reduced by variably controlling the transmission power in the mobile terminal, so that the average current consumption of the transmission power amplifier is reduced. Therefore,
A long talk time becomes possible.

In mobile terminals other than CDMA mobile communication systems, conventional transmission power amplifiers (high-frequency power I
Even if the transmission power in (C) is reduced, the power consumption cannot be reduced because the bias current cannot be reduced. Japanese Patent Application Laid-Open No. 3-179926 is known as an example of performing the bias control in such a transmission power amplifier (high-frequency power IC).

FIG. 6 is a block diagram showing a configuration example of such a conventional radio transmission power control device.

[0007] This example is applied to a mobile terminal using multi-level digital modulation such as 16-level QAM. A multi-level QAM modulator 1 is applied to an analog multi-level signal of a transmission signal.
Modulates the high frequency signals of the I signal and the Q signal. This modulated signal is power-amplified by the power amplifier (HPA) 2 and transmitted from the antenna as transmission power.

[0008] An analog multi-level signal is input to the HPA saturation output control circuit 3. HPA saturation output control circuit 3
Indicates that the transmission signal point recognition circuit 3a identifies which transmission symbol is on the phase plane. The peak value of the transmission symbol is determined based on the identification result. Based on this determination, the bias control circuit 3b switches the power amplifier (HPA)
2. An optimum bias value (control signal) of 2 is set.

As a result, the average current consumption in the power amplifier (HPA) 2 when transmitting a multilevel digital signal is reduced.

[0010]

However, in the configuration shown in FIG. 6 of the conventional example, control for setting a bias value (control signal) corresponding to an instantaneous peak value of a transmission symbol by the multi-level digital modulation method is performed. Is going. That is,
Since this is not a bias control method for largely changing transmission power, it cannot be applied to a case where transmission power of a mobile terminal is variably controlled over 80 dB as in a CDMA mobile communication system. In other words, the conventional example has a drawback that the talk time cannot be further extended in a mobile terminal using a battery as a power supply.

The present invention has been made in view of the above points, and provides a transmission power control device capable of adjusting a bias current of a transmission power amplifier when performing large control of transmission output. Accordingly, it is an object to provide a transmission power control device that reduces the average current consumption by increasing the bias current at the time of high output and decreasing the bias current at the time of low output.

[0012]

To achieve the above object, a transmission power control apparatus capable of optimizing the bias current of a transmission output amplifier according to the present invention is capable of changing the level of an input transmission signal based on the control signal. And a transmission output amplifier using a transistor that amplifies a variable input transmission signal from the variable means and generates a transmission output signal, and outputs a detection value signal obtained by detecting a current flowing through the transistor of the transmission output amplifier. A detecting means, and a reference value serving as a bias current point each time the transmission output power is varied by converting the control signal to the variable means into a reference value corresponding to the level of the variable input transmission signal input to the transmission output amplifier. A conversion unit that outputs a signal, a detection value signal from the detection unit is compared with a reference value signal from the conversion unit, and based on the comparison value, It is characterized in that it comprises a bias current setting means for setting the bias current point.

Further, according to the present invention, a resistor inserted in a current path flowing from a power supply line to a transistor of a transmission output amplifier is used as the preferred detecting means, and a voltage drop at the resistor is output as a detection value signal. It is characterized by:

Further, the present invention provides a second transistor operating under the same DC bias current condition as the first transistor of the transmission output amplifier.
It is characterized by comprising a transistor and a resistor inserted into a current path flowing from the power supply line to the second transistor, and outputting a voltage drop at the resistor as a detection value signal.

Further, the present invention is characterized in that the first transistor and the second transistor of the transmission output amplifier are formed on the same semiconductor chip.

Further, the present invention provides, as the conversion means, a memory in which data of a reference value signal corresponding to a variable input transmission signal level input to a transmission output amplifier is stored in advance at an address for each level of a control signal, A D / A converter that converts the data of the reference value signal from the memory into an analog signal and outputs the analog signal to the bias current setting means.

Further, in the present invention, a data rewritable storage element is used as the memory, and data of a reference value signal corresponding to a bias current point matched with the operating characteristics of a transistor of a transmission output amplifier to be used is stored in advance. It is characterized by that.

Further, according to the present invention, as the bias current setting means, a comparison means for outputting a signal obtained by comparing a detection voltage detected by the detection means with a reference value signal from the conversion means, And an integrator for outputting a bias voltage corresponding to a bias current point of the transmission output amplifier to the transmission output amplifier.

Further, the present invention is characterized in that a subtraction means for subtracting a detection voltage detected by the detection means from a reference value signal output from the conversion means is used as the comparison means.

Further, according to the present invention, as the variable means, one or both of a variable amplifier for variably amplifying an input transmission signal in accordance with a control signal level and an attenuator for attenuating an input transmission signal in accordance with a control signal level And a gain control signal is input to a variable amplifier as a control signal, or an attenuator control signal is input to an attenuator.

Further, the present invention is characterized in that one or both of the gain control signal to the variable amplifier and the attenuator control signal to the attenuator are converted into a reference value signal and output.

Further, the present invention is characterized in that a frequency conversion means for converting the frequency of an input transmission signal is further provided between the variable means and the transmission output amplifier.

The present invention is further characterized by further comprising a band-pass filter between the frequency conversion means and the transmission output amplifier for band-limiting the frequency-converted signal to remove an unnecessary signal.

Further, the present invention is characterized in that the radio transmission power control device having the above configuration is provided in a mobile terminal using a battery as a power source in a CDMA mobile communication system.

In the configuration of the wireless transmission power control apparatus according to the present invention, the power amplifying means detects a current detection value signal corresponding to a variable state (level) by a control signal of an input transmission signal, and a power amplification signal from the input control signal. The reference value signal generated corresponding to the bias current point of the means is compared. For example,
A bias current point corresponding to a variable transmission output power is set in the transmission output amplifier based on a more accurate value obtained by subtracting the detection value signal from the reference value signal.

Therefore, when the transmission output power is reduced by changing the input transmission signal as in the conventional example, the bias current is not reduced and the power consumption does not decrease. That is, when the transmission output power of the transmission output amplifier is reduced by varying the input transmission signal to reduce the transmission output power, the bias current is also reduced and the power consumption is also reduced.

Further, in the present invention, the data of the reference value signal corresponding to the bias current point matching the operating characteristics of each transistor of the various transmission output amplifiers is stored by using a data rewritable storage element. .

Therefore, various types of transmission output amplifiers can be configured, and the degree of freedom in design is improved.

Further, the present invention is applied to a mobile terminal or the like having the above configuration used in a CDMA mobile communication system.

Therefore, a large variable control of the transmission power can be performed accurately and reliably, such as a mobile terminal used in a CDMA mobile communication system. In particular, the talk time at a mobile terminal using a battery as a power source can be reduced. You will be able to stretch it further.

[0031]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a configuration of an embodiment of a transmission power control apparatus capable of performing bias current optimization control according to the present invention.

This radio transmission power control device is provided with a variable gain IF amplifier 11 for variably amplifying an input intermediate frequency (IF) signal Sa based on a gain control signal Sb. On the output side of the variable gain IF amplifier 11, there is provided a mixer 12 for converting the IF signal Sa into a high frequency signal of a predetermined frequency and outputting the same. The mixer 12 is connected to a local oscillator 13 that outputs a local oscillation signal for frequency conversion.

Further, on the output side of the mixer 12, a band-pass filter (BPF) 14 for limiting the band of the high-frequency signal and removing unnecessary waves is provided, and the high-frequency signal from the BPF 14 is input to the BPF 14. A step attenuator (ATT) 15 that attenuates to a predetermined value and outputs the signal with an attenuator control signal Sc is connected. Furthermore, this ATT
A field-effect transistor (FET) for transmitting the transmission output power Se based on the bias voltage Sn is provided on the output side of the reference numeral 15.
Is provided.

A bias current detection circuit 17 for outputting a bias current measurement value signal Sd as a detection value signal based on a current flowing from a power supply is connected to the power amplifier 16. Further, based on the input gain control signal Sb and attenuator control signal Sc, I
The level of the F signal Sa, that is, the reference value signal Sv which is the reference value of the bias current point each time the transmission output power is varied
Is provided. Further, a subtractor (adder) 19 for subtracting (negative feedback loop) the measured bias current value signal Sd from the reference value signal Sv and outputting the subtracted signal is connected to the output side of the conversion circuit 18.
9 is a bias voltage Sn obtained by integrating the signal of the subtraction value on the output side.
Is provided to the power amplifier 16.

FIG. 2 is a circuit diagram showing a detailed configuration of the power amplifier 16 and the bias current detection circuit 17 in FIG.

The power amplifier 16 has an AT shown in FIG.
A matching circuit 24 for input impedance matching, which includes a tuning circuit (LC) for inputting the high-frequency signal from T15 to the gate of the FET Q1 for power amplification, is connected in series. Further, a matching circuit 25 for output impedance matching is connected to the drain of the FET Q1. The source of the FET Q1 is grounded, and the drain is provided with a coil L1 for preventing leakage of a high-frequency signal to the bias current detection circuit 17. Note that the coil L1 may be provided inside the bias current detection circuit 17. Further, the gate of the FET Q1 is provided with a coil L2 for preventing leakage of a high-frequency signal to the bias voltage Sn line and a capacitor C2 for bypassing the high-frequency signal.

The bias current detection circuit 17 has a resistor R1 connected between the power supply line (Vcc) and the FET Q1 of the power amplifier 16, and has a capacitor C1 for high frequency signal bypass. The configuration is such that the bias current measurement value signal Sd, which is a voltage drop, is output to the subtractor 19 shown in FIG.

FIG. 3 is a circuit diagram showing another detailed configuration example of the power amplifier 16 and the bias current detection circuit 17 shown in FIG.

In the power amplifier 16A and the bias current detection circuit 17A, an FET Q11 for power amplification and as a first transistor, and a FET Q11 as a second transistor having a proportionally reduced size, for example, a gate width set to 1/10, are used. The auxiliary FET Q12 is used. The auxiliary FET Q12 is configured as the same semiconductor chip 26 so as to obtain a precise proportional relationship with the FET Q11. That is, by making the DC bias current conditions of both the FET Q11 and the auxiliary FET Q12 the same, the auxiliary F
ETQ12 has approximately 1/1 of FET Q11 for power amplification.
A small bias current of 00 flows.

The power amplifier 16A has the same configuration as the power amplifier 16 shown in FIG.
4, an output-side matching circuit 25, an FET Q11, coils L1 and L2, and a capacitor C2 are provided. In the power amplifier 16A, the source of the FET Q11 is grounded, and the drain is connected to the power line (Vcc) through the coil L1. In addition, a high frequency signal bypass capacitor C4 is provided. The bias current detecting circuit 17A includes a resistor R1 and a high-frequency signal bypass capacitor C connected between the drain of the auxiliary FET Q12 and the drain of the auxiliary FET Q12.
1 is provided, and the bias current measurement value signal Sd, which is the voltage drop of the resistor R1, is output to the subtractor 19 shown in FIG.

FIG. 4 is a circuit diagram showing a detailed configuration of the conversion circuit 18 in FIG.

The gain control signal Sb and the attenuator control signal Sc of the digital value are input as addresses to the conversion circuit 18 having this configuration, and the FETs corresponding to the addresses are input.
The level of the IF signal Sa to Q1 (Q11),
The ROM 27 includes a conversion table for outputting a reference value signal Sv that is a reference value of a bias current point every time the transmission output power is changed. Furthermore, this ROM 27
A D / A converter 28 for converting the digital reference value signal Sv from the analog signal into an analog signal and sending the analog signal to the subtracter 19 is provided.

Next, the operation of this embodiment will be described.

FIG. 5 shows the power amplifier 16 in this operation.
FIG. 4 is a characteristic diagram of the bias voltage Sn versus the transmission output power Se of FIG. 1 and 5, the IF signal Sa has a variable gain I
The signal is input to the F amplifier 11. Variable gain IF amplifier 11
Is an IF signal Sa at an amplification factor corresponding to the gain control signal Sb.
Is amplified and output to the mixer 12. The mixer 12 outputs to the BPF 14 a high-frequency signal of a predetermined frequency which is mixed with the local oscillation signal from the local oscillator 13 and converted.

In the BPF 14, the high frequency signal from the mixer 12 is band-limited to remove unnecessary waves and output to the ATT 15. The ATT 15 is turned on / off (operation / non-operation) by the attenuator control signal Sc, and when turned on, attenuates the high-frequency signal from the BPF 14 to a predetermined value and outputs it to the power amplifier 16.

In this operation, the FE of the power amplifier 16
The current from the power supply line (Vcc) to TQ1 (Q11) is detected by the bias current detection circuit 17. The bias current detection circuit 17 sends a bias current measurement value signal Sd obtained by converting the detected current to a voltage to the subtractor 19.

On the other hand, the gain control signal Sb of digital value and the attenuator control signal Sc are input to the conversion circuit 18 as addresses. In accordance with this address, the conversion circuit 18 stores the level of the IF signal Sa to the FET Q1 (Q11), that is, the data of the reference value signal Sv, which becomes the reference value of the bias current point each time the transmission output power is varied, in the ROM.
The reference value signal Sv read out from the conversion table 27 and converted into an analog signal by the D / A converter 28 is output to the subtractor 19. In the subtracter 19, a signal of this value is output to the integrator 20 by a negative feedback loop for subtracting the measured bias current signal Sd from the reference value signal Sv, and is integrated there. The voltage of the integrated value of the integrator 20 is output to the gate of the power amplifier 16 as the bias voltage Sn shown in FIG. The transmission output power Se corresponding to the bias current point set by the bias voltage Sn is transmitted from the power amplifier 16.

As described above, with respect to the reference value signal Sv, FE
An accurate bias voltage Sn (bias current point) is obtained by subtracting (negative feedback loop) the bias current measurement value signal Sd corresponding to the current actually flowing to TQ1 (Q11).

Next, detailed operations of the power amplifier 16 and the bias current detection circuit 17 shown in FIG. 2 will be described.

1 and 2, a high-frequency signal (IF signal Sa) from the ATT 15 is input to the power amplifier 16 through the matching circuit 24 to the gate of the FET Q1. A bias voltage Sn is input to the gate of the FET Q1 through a coil L2 for preventing leakage of a high-frequency signal and a capacitor C2 for bypassing a high-frequency signal, and based on the bias voltage Sn, a high-frequency signal (IF signal Sa) from the ATT 15 And the transmission output power Se is amplified.
Through the matching circuit 25.

In this case, the bias current detection circuit 17
The current to the FET Q1 drops by the resistor R1, and the bias current measurement signal Sd, which is the drop voltage, is output to the subtractor 19 shown in FIG. The subtractor 19 subtracts (negative feedback loop) the measured bias current value signal Sd output from the bias current detection circuit 17 from the reference value signal Sv output from the conversion circuit 18, and further, the bias voltage S integrated by the integrator 20.
n is output to the gate of the FET Q1.

In the operation using the power amplifier 16 and the bias current detection circuit 17 shown in FIG. 2, a relatively large current flowing through the FET Q1 flows through the resistor R1 of the bias current detection circuit 17. Therefore, the resistance value of the resistor R1 needs to be extremely small. Therefore, the resistance value of the wiring and the like cannot be ignored, and the error of the bias current measurement value signal Sd increases. Further, since the voltage of the power supply line (Vcc) applied to the FET Q1 decreases due to the voltage drop of the resistor R1, characteristics such as the linearity of amplification of the power amplifier 16 are likely to deteriorate. This problem is caused by the power amplifier 16 shown in FIG.
The operation of the A and bias current detection circuit 17A solves the problem.

Next, the operation in the case of the power amplifier 16A and the bias current detection circuit 17A shown in FIG. 3 will be described.

The operation of power amplifier 16A is similar to that of power amplifier 16 shown in FIG. That is, ATT15
Signal Sa from the FE through the matching circuit 24
Input to the gate of TQ11. A bias voltage Sn is input to the gate of the FET Q11 through the coil L2 and the capacitor C2. Based on the bias current point of the bias voltage Sn, the IF signal that is variably amplified by the variable gain IF amplifier 11 and attenuated by the ATT15. Sa is amplified by power and the transmission output power Se is matched to the matching circuit 2
Send out through 5.

In this case, in the bias current detecting circuit 17A, the power amplifying FET Q11 and the auxiliary FE whose gate width is reduced to 1/10 by proportionally reducing the FET Q11.
TQ12 is used. FET Q11 and auxiliary FET Q
12 has the same DC bias current conditions, so that the auxiliary FET Q12 has a power amplification FET Q12.
A bias current of about 1/100 of 11 flows.

The auxiliary FE corresponds to the bias voltage Sn.
A current flows through the resistor R1 to the drain of TQ12,
A voltage drop occurs in the resistor R1. The bias current measurement value signal Sd, which is the voltage drop, is output to the subtractor 19 shown in FIG. The subtractor 19 subtracts the bias current measurement value signal Sd output from the bias current detection circuit 17 from the reference value signal Sv from the conversion circuit 18, and furthermore, applies the bias voltage Sn integrated by the integrator 20 to the gate of the FET Q1. Output to

In the operation of the power amplifier 16A and the bias current detection circuit 17A in this case, a current flows to the resistor R1 of the bias current detection circuit 17A and to the auxiliary FET Q12. The auxiliary FET Q12 includes a power amplification FET Q11.
Of the bias current flows. That is, the current flowing through the resistor R1 of the bias current detection circuit 17A decreases, and the resistance value of the resistor R1 can be increased. Therefore, the resistance value of the wiring and the like can be ignored, and the accurate bias current measurement signal S
d is obtained. The power line (Vc) is connected to the FET Q11.
Since the resistor R1 is not connected to the drain of the FET Q11 as in the configuration of the bias current detection circuit 17 shown in FIG. 2, the voltage applied from c) does not drop and the power amplifier 16A Characteristics such as amplification linearity do not deteriorate.

Next, the operation of the conversion circuit 18 will be described.

The conversion circuit 18 inputs the gain control signal Sb and the attenuator control signal Sc of the digital value to the ROM 27 as addresses. In the ROM 27, the FET Q1
A conversion table is provided which stores the level of the IF signal Sa to (Q11), that is, the data of the reference value signal Sv that becomes the reference value of the bias current point each time the transmission output power is varied. The data of this conversion table corresponds to the characteristics of the power amplifier 16 shown in FIG. 5, that is, the characteristics of the bias voltage Sn versus the transmission output power Se. ROM27
Subtracts the reference value signal Sv corresponding to the address value from the
Output to In this case, the data (reference value signal Sv) read from the conversion table of the ROM 27 using the digital value gain control signal Sb and the attenuator control signal Sc from the ROM 27 as addresses are converted into analog signals by the D / A converter 28 and subtracted. Send to 19.

As described above, in this embodiment, the bias current point of the power amplifier 16 (16A) is variably amplified by the variable gain IF amplifier 11 and is attenuated by the ATT 15
It changes according to the F signal Sa. Therefore, when the transmission output power Se is reduced, the power consumption is also reduced corresponding to the bias current point. That is, the transmission output power Se is always
The power amplifier 16 (16A) operates at the optimum bias voltage (bias current point) Sn.

Further, in this embodiment, the IF signal Sa is frequency-converted by the mixer 12 and the local oscillator 13, but the same effect as described above can be obtained even if this frequency conversion is not performed. In this embodiment, the IF signal Sa is variably amplified by the variable gain IF amplifier 11, and the ATT1
Although the transmission output power Se is changed by attenuating at 5,
The same effect as described above can be obtained with only one of them. In this case, the conversion circuit 18 generates the reference value signal Sv from one of the gain control signal Sb and the attenuator control signal Sc.

In this embodiment, the subtractor 19
The bias current measurement value signal Sd output from the bias current detection circuit 17 with respect to the reference value signal Sv from the conversion circuit 18
Has been described using an example of a negative return loop for subtracting. For example, the reference value signal Sv is connected to the FET Q1 (Q
11), the reference value signal Sv
And the bias current measurement value signal Sd, or
A configuration may be adopted in which the value of the reference value signal Sv is compared with the value of the bias current measurement value signal Sd, and the reference value signal Sv is added or subtracted based on the comparison value. In this case, the configuration uses a comparator for comparing the reference value signal Sv with the measured bias current value signal Sd and a voltage variable amplifier.

Further, in this embodiment, the ROM 27
When a storage element (EEPROM) in which data of a conversion table is rewritable is used, a variety of 16 (16
The configuration of A) becomes possible. That is, a wide variety of FETs
Can be adapted to the characteristics of the bias voltage Sn of the transistor including the transmission output power Se. In this case, the wireless transmission power control device can be designed freely.

[0065]

As described above, according to the radio transmission power control apparatus of the present invention, the current corresponding to the variable state of the input transmission signal detected by the power amplification means and the transmission output from the input control signal are determined. A bias current point corresponding to the transmission output power is set by comparing with a reference value signal generated corresponding to the bias current point of the transmission power control device capable of performing the bias current optimization control of the amplifier.

As a result, when the transmission output power of the transmission power control device capable of optimizing the bias current of the transmission output amplifier is reduced by reducing the transmission output power by changing the input transmission signal, the bias current decreases, and The power can be reduced. Also, according to the present invention, a bias current point matching the operating characteristics of each transistor of a transmission power control device capable of performing bias current optimization control of various transmission output amplifiers using a data rewritable storage element. Since the data of the reference value signal corresponding to the transmission power amplifier is stored, it is possible to configure a transmission power control device capable of performing bias current optimization control of various transmission output amplifiers, and the degree of freedom in design is improved.

Further, according to the present invention, the above structure
Since the present invention is applied to a mobile terminal used in an MA mobile communication system, a large variable control of transmission power can be performed accurately and reliably as in a mobile terminal used in a CDMA mobile communication system. , It is possible to further extend the call time at the mobile terminal.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a wireless transmission power control device according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a detailed configuration of a power amplifier and a bias current detection circuit shown in FIG.

FIG. 3 is a circuit diagram showing another detailed configuration of the power amplifier and the bias current detection circuit shown in FIG. 1;

FIG. 4 is a circuit diagram showing a detailed configuration of the conversion circuit shown in FIG.

FIG. 5 is a characteristic diagram of the power amplifier in the operation of the embodiment.

FIG. 6 is a block diagram illustrating a configuration example of a conventional wireless transmission power control device.

[Explanation of symbols]

 Reference Signs List 11 variable gain IF amplifier 12 mixer 13 local oscillator 14 BPF 15 ATT 16, 16A power amplifier 17, 17A bias current detection circuit 18 conversion circuit 19 subtractor 20 integrator 26 semiconductor chip 27 ROM 27 Q1, Q11 FET Q12 auxiliary FET Q R1 resistor R Sa IF signal Sb Gain control signal Sc Attenuator control signal Sd Bias current measurement value signal Se Transmission output power Sn Bias voltage Sv Reference value signal

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5J100 JA01 JA10 KA05 LA08 LA09 QA04 SA01 5K022 EE01 EE21 EE31 5K060 BB00 CC11 CC12 DD04 FF06 HH06 HH08 HH14 HH22 HH31 JJ02 JJ08 KK01 LL01 LL11 LL22 PP05

Claims (13)

[Claims] A variable means for varying a level of an input transmission signal based on a control signal; a transmission output amplifier using a transistor for amplifying a variable input transmission signal from the variable means to generate a transmission output signal; A detection unit that outputs a detection value signal that detects a current flowing through a transistor of the transmission output amplifier; and the control signal to the variable unit is set to a reference value corresponding to a level of the variable input transmission signal input to the transmission output amplifier. A conversion unit that outputs a reference value signal serving as a bias current point every time the transmission output power is changed by converting the signal; and comparing the detection value signal from the detection unit with the reference value signal from the conversion unit, Bias current setting means for setting a bias current point to the transmission output amplifier based on the comparison value. A transmission power control device that can perform current optimization control. 2. The method according to claim 1, wherein a resistor inserted in a current path flowing from a power supply line to a transistor of the transmission output amplifier is used as the detection unit, and a voltage drop at the resistor is output as a detection value signal. A transmission power control device according to claim 1, wherein the bias power optimization control is possible. 3. A detecting device comprising: a second transistor operating under the same DC bias current condition as a first transistor of a transmission output amplifier; and a resistor inserted into a current path flowing from a power supply line to the second transistor. The transmission power control device according to claim 1, further comprising: outputting a voltage drop at the resistor as a detection value signal. 4. The transmission power control device according to claim 3, wherein the first transistor and the second transistor of the transmission output amplifier are formed on the same semiconductor chip. 5. A memory in which data of a reference value signal corresponding to a variable input transmission signal level input to the transmission output amplifier is stored in advance at an address for each level of a control signal as the conversion means, And an A / D converter for converting the data of the reference value signal from the analog signal into an analog signal and outputting the analog signal to the bias current setting means. Control device. 6. A memory according to claim 6, wherein a data rewritable storage element is used as the memory, and the data of the reference value signal stored in advance in the memory is a bias current point matched to the operating characteristics of the transistor of the transmission output amplifier to be used. The transmission power control device capable of performing bias current optimization control according to claim 5, wherein the transmission power control device is data corresponding to (1). 7. A comparing means for outputting a signal obtained by comparing a detection voltage detected by the detecting means with a reference value signal from a converting means, wherein the bias current setting means comprises: The transmission device capable of performing the bias current optimization control according to claim 1, further comprising: an integration unit that outputs a bias voltage corresponding to a bias current point of a transistor of the transmission output amplifier to the transmission output amplifier. Power control device. 8. The bias current optimization control according to claim 7, wherein said comparing means uses a subtracting means for subtracting a detection voltage detected by said detecting means from a reference value signal output from a converting means. Transmission power control device capable of 9. The variable means includes one or both of a variable amplifier that variably amplifies an input transmission signal in accordance with a level of a control signal, and an attenuator that attenuates an input transmission signal in accordance with a level of a control signal. When only the attenuator is provided, an attenuator control signal is input to the attenuator as the control signal. 2. The transmission power control device according to claim 1, wherein a control signal is an attenuator control signal input to the attenuator. 10. The bias current optimization according to claim 9, wherein a converter converts one or both of a gain control signal to the variable amplifier and an attenuator control signal to the attenuator into a reference value signal and outputs the reference value signal. Transmission power control device that can control activation. 11. The bias current optimization control according to claim 1, further comprising frequency conversion means for frequency-converting an input transmission signal between the variable means and the transmission output amplifier. Possible transmission power control. 12. The apparatus according to claim 11, further comprising a band-pass filter between the frequency conversion unit and the transmission output amplifier for band-limiting a signal subjected to frequency conversion to remove an unnecessary signal. Transmission power control device capable of bias current optimization control. 13. A transmission power control capable of performing bias current optimization control, wherein the wireless transmission power control device according to claim 1 is provided in a mobile terminal powered by a battery in a CDMA mobile communication system. apparatus.