JP2004088520A - Mobile radio equipment, power amplifier vcc control method and program to be used therefor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide mobile radio equipment in which circuit scale is reduced by stabilizing an output power to enable even a circuit which does not incorporate an APC circuit to perform Vcc control. <P>SOLUTION: In a control part 4, a gain of an AGC amplifier 6 is adjusted by a D/A converter 5 to variably output an output power of a power amplifier 7. In the control part 4, an output voltage of a D/D converter 2 in accordance with an input voltage of a battery 1 is controlled by a D/A converter 3. An A/D converter 9 monitors an output voltage of the D/D converter 2 and feeds it back to the control part 4. When the fed-back output voltage is different from a set voltage, the control part 4 offsets a control signal to the D/A converter 3, such that the set output voltage and the fed-back voltage become equal. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a portable wireless device, a power amplifier Vcc control method used therefor, and a program thereof, and more particularly to a power amplifier Vcc control method in a portable wireless device.
[0002]
[Prior art]
Conventionally, in this type of Vcc control method, as shown in FIG. 3, a resistance value (R1, R2, R3, R4) around the D / D converter 2, a feedback voltage (Vfb) of the D / D converter 2, and Due to the variation with the control voltage (Vcont), the variation of the output voltage Vout of the D / D converter 2 serving as the power supply of the power amplifier 7 increases.
[0003]
Here, if the input current of the D / D converter 2 is Iin, the input current of the D / D converter 2 is Iin, the input voltage of the D / D converter 2 is Vin, and the efficiency of the D / D converter is η,
Iin = (Vout / Vin) · (1 / η) · Iout (1)
Vout = [(Vfb / R4) − ((Vcont−Vfb) / R3)] · [(R1 · R2) / (R1 + R2)] + Vfb (2)
Holds.
[0004]
For example, when the resistance values R1, R2, R3, R4, the feedback voltage Vfb, and the control voltage Vcont all vary by ± 5% [in the case of Vout (min), R1, R2, Vfb = −5%, R3, R4, Vcont = + 5%, and in the case of Vout (max), R1, R2, Vfb = + 5%, R3, R4, Vcont = −5%], although there is some variation depending on the voltage of the power supply Vout, the above ( When the calculation is performed with reference to the equation (2), the output voltage Vout greatly varies around 15 to 20% on the plus side and the minus side, respectively.
[0005]
In this case, since the output voltage Vout varies greatly, there is a concern that the output voltage Vout may affect the gain characteristics and distortion characteristics of the power amplifier 7. For example, when the output voltage Vout fluctuates on the minus side, deterioration of the distortion characteristic and a decrease in gain are apprehended when compared with the desired characteristics of the power amplifier 7, and when the output voltage Vout fluctuates on the plus side, the gain of the gain increases. There is a concern about the increase. For this reason, when an APC (Auto Power Control) circuit (a circuit that keeps the output power constant) is not built in the output of the power amplifier 7, the output power is not stabilized due to a large gain variation of the power amplifier 7.
[0006]
Further, there is a large variation in the peripheral circuits of the D / D converter 2 and the voltage applied to the power amplifier 7 at the moment when the power supply of the power amplifier 7 is switched to the bypass circuit (not shown), and the voltage applied to the D / D converter 2 If the potential difference from the supplied voltage immediately before switching is large, a discontinuous voltage is instantaneously applied to the power supply of the power amplifier 7, and the characteristic deterioration of the power amplifier 7 and the instantaneous fluctuation of the output power are reduced. This causes a deterioration in wireless characteristics.
[0007]
For this reason, in the conventional Vcc control method, when performing Vcc control, the detection circuit 11 is arranged on the output side of the power amplifier 7 as shown in FIG. 4, and the detected voltage is set to A so that the output power is stabilized. A / D converter 12 incorporates an APC circuit that feeds back the signal, an offset is added to D / A converter 5 using control signal # 1, power is adjusted by AGC (Auto Gain Control) amplifier 6, and power amplifier 7 Output power is kept constant.
[0008]
As a conventional Vcc control method, besides the above technique, in order to control the power supply voltage applied to the power amplifying means so that the power supply always has a low power loss irrespective of the affirmation of the transmission power, the power during amplification is controlled. If the transmission power causes loss, the power supply voltage is converted to a low level by a DC / DC converter and then applied to the power amplification means. If the transmission power does not cause a power loss to exceed a certain level during amplification, the power supply voltage is reduced to the power amplification means. There is also a technique of directly applying the voltage to the substrate (for example, see Patent Document 1).
[0009]
[Patent Document 1]
JP 2001-320288 A
[Problems to be solved by the invention]
In the above-described conventional Vcc control method, when the Vcc control is performed, if the output of the power amplifier does not include the APC circuit, the output power is not stabilized due to a large gain variation of the power amplifier. Problem. This problem cannot be solved even by using the technique described in Patent Document 1.
[0011]
Therefore, an object of the present invention is to solve the above-mentioned problems, and to provide a portable wireless device capable of stably controlling the output power and controlling the Vcc even in a circuit without a built-in APC circuit and reducing the circuit size, and a portable wireless device therefor. An object of the present invention is to provide a method of controlling a power amplifier Vcc to be used and a program therefor.
[0012]
[Means for Solving the Problems]
A portable wireless device according to the present invention is a portable wireless device in which power supplied from a battery is varied by a DC / DC converter and supplied to a power amplifier, and a monitor means for monitoring an output voltage of the DC / DC converter; And control means for controlling the output voltage of the D / D converter in accordance with the detection result of the monitor means.
[0013]
Another portable wireless device according to the present invention is a portable wireless device in which power supplied from a battery is varied by a DC / DC converter and supplied to a power amplifier, wherein the input voltage of the DC / DC converter is low and When the input power of the power amplifier is high, a bypass circuit that bypasses the DC / DC converter and directly supplies power to the power amplifier from the battery is provided.
[0014]
A power amplifier Vcc control method according to the present invention is a power amplifier Vcc control method for a portable wireless device in which power supplied from a battery is varied by a DC / DC converter and supplied to the power amplifier. Monitoring the output voltage; and controlling the output voltage of the D / D converter according to the monitoring result.
[0015]
Another power amplifier Vcc control method according to the present invention is a power amplifier Vcc control method for a portable wireless device in which power supplied from a battery is varied by a DC / DC converter and supplied to the power amplifier. Determining whether the input voltage of the converter is low and the input power of the power amplifier is high; and determining whether the input voltage of the DC / DC converter is low and the input power of the power amplifier is high, Causing the power amplifier to directly supply power from the battery by bypassing the DC / DC converter.
[0016]
The program of the power amplifier Vcc control method according to the present invention is a program of a power amplifier Vcc control method for a portable wireless device in which power supplied from a battery is varied by a DC / DC converter and supplied to the power amplifier. And a process of monitoring the output voltage of the DC / DC converter and a process of controlling the output voltage of the D / D converter according to the monitoring result.
[0017]
Another power amplifier Vcc control method program according to the present invention is a power amplifier Vcc control method program for a portable wireless device in which power supplied from a battery is varied by a DC / DC converter and supplied to the power amplifier. The computer determines whether the input voltage of the DC / DC converter is low and the input power of the power amplifier is high, and the input voltage of the DC / DC converter is low and the input power of the power amplifier is high. And determining that the power amplifier is directly supplied with power from the battery by bypassing the DC / DC converter by a bypass circuit.
[0018]
That is, the portable wireless device (including the entire device and the portable telephone) of the present invention has a power amplifier inside, and has a feature that it can operate even if the power amplifier can be varied up to about 1 V with the power supply voltage as a lower limit, A D / D (DC / DC) converter that varies a power supply voltage according to the input power of the power amplifier and a D / A (digital / analog) converter that controls the output voltage of the D / D converter are provided inside.
[0019]
Further, the portable wireless device of the present invention has a bypass circuit for avoiding a voltage drop generated in the D / D converter as a means for reducing distortion when the power amplifier input power is high, and the bypass circuit has a D / D converter. The power is supplied to the power amplifier without going through a converter to improve distortion.
[0020]
A feature of the present invention is that a D / D converter does not include an APC (Auto Power Control) circuit for maintaining a constant output power inside the device, and a D / D converter that controls a resistance of a peripheral circuit, a DC component of a coil, and an output voltage. By implementing control to reduce the occurrence of large voltage variations in the output voltage of the D / D converter due to variations in the A converter, variations in the power supply voltage applied to the power amplifier are reduced, and the characteristics of the power amplifier are reduced. It is possible to realize fine power supply voltage settings that can be used to the maximum.
[0021]
As described above, the power amplifier Vcc control method of the present invention stabilizes the output power of the power amplifier by controlling so as to reduce the variation of the power supply voltage of the power amplifier even when the APC circuit is not built-in. The deterioration of the distortion characteristic is also improved, the potential difference when the power supply of the power amplifier is switched to the bypass circuit is reduced, and the instantaneous fluctuation of the output power is also improved.
[0022]
That is, in the power amplifier Vcc control method of the present invention, the voltage of the output of the D / D converter serving as the power supply of the power amplifier is monitored by the A / D (analog / digital) converter, and the voltage greatly varies from the desired voltage. In this case, by controlling the amount of variation ΔV so as to be offset to the voltage control signal (Vcont), it is possible to reduce the variation of the voltage applied to the power amplifier, and the gain characteristic of the power amplifier is reduced. Can be kept constant, and even in a circuit without a built-in APC circuit, Vcc control can be performed with stable output power, and the circuit scale can be reduced.
[0023]
Further, according to the power amplifier Vcc control method of the present invention, the output voltage of the D / D converter can be precisely and finely controlled, so that the power supply voltage of the power amplifier is reduced to the maximum allowable distortion characteristic. In order to improve the current efficiency, it is possible to maximize the effect of reducing the current flowing from the battery by Vcc control using a D / D converter.
[0024]
For example, if the input power of the power amplifier is low and the output voltage Vout of the D / D converter is 1/3 of the input voltage Vin, but the influence on the distortion characteristics of the power amplifier is small, the efficiency η of the D / D converter is reduced. Assuming that the current is about 80%, the current (Iin) flowing from the battery to the D / D converter is about 42% of the current (Iout) flowing to the power amplifier when calculated with reference to the above equation (1).
[0025]
Further, in the power amplifier Vcc control method of the present invention, since the variation of the D / D converter is reduced, only the on-resistance of the D / D converter itself becomes a potential difference at the time of switching to the bypass circuit. Since the visible potential difference is small, the potential difference when the power supply is switched to the bypass circuit can be reduced as a measure against distortion of the power amplifier, and the instantaneous output power fluctuation can be improved.
[0026]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a Vcc control circuit according to one embodiment of the present invention. In FIG. 1, a Vcc control circuit according to an embodiment of the present invention does not include a conventional APC (Auto Power Control) circuit, but has a power amplifier 7 and an AGC (Auto Gain Control) amplifier 6 therein. 7 has a control unit 4 having a function of variably controlling the output voltage. The control unit 4 controls each unit by executing a computer-executable program stored in the recording medium 10.
[0027]
In the Vcc control circuit according to the present embodiment, the control unit 4 adjusts the gain of the AGC amplifier 6 by the D / A (digital / analog) converter 5 using the control signal # 1 and variably outputs the output power of the power amplifier 7. . At this time, in order to variably control the power supply voltage of the power amplifier 7 so that the distortion characteristics do not deteriorate with respect to the output power of the power amplifier 7, the Vcc control circuit according to the present embodiment uses a step-down type D / D (DC / DC) converter 2. The control unit 4 controls the output voltage of the D / D converter 2 with respect to the input voltage of the battery 1 by the D / A converter 3 using the control signal # 2.
[0028]
In this case, the output voltage of the step-down type D / D converter 2 is varied below the input voltage of the battery 1 with respect to the input voltage of the battery 1, thereby obtaining the D / D as shown in the above equation (1). The relationship between the input current Iin and the output current Iout of the converter 2 is established, and the higher the efficiency η of the D / D converter 2 and the lower the output voltage Vout, the more the current (input current Iin) flowing out of the battery 1 is reduced, and Energy saving.
[0029]
As shown in FIG. 3, in the circuit configuration around the D / D converter 2, when the circuit of the D / D converter 2 in which the output voltage Vout is varied by the feedback voltage Vfb is configured, the resistor R1 , R2, R3, and R4 and the D / D converter 2 due to individual variations of the feedback voltage Vfb and the output voltage (control voltage Vcont) of the D / A converter 3 that controls the output voltage Vout. The output voltage Vout of the converter 2 varies.
[0030]
In the Vcc control circuit according to the present embodiment, an A / D (analog / digital) converter 9 for monitoring the variation of the output voltage Vout of the D / D converter 2 in order to improve the variation of the output voltage Vout of the D / D converter 2. have. The A / D converter 9 monitors the output voltage of the D / D converter 2 and feeds it back to the control unit 4. At this time, when the feedback output voltage is different from the voltage set by the control unit 4, the control unit 4 controls the control signal so that the set output voltage is the same as the feedback voltage. It has a function of applying an offset to # 2.
[0031]
As a result, the desired power supply voltage with reduced variation is always applied to the power amplifier 7, and it is possible to improve the variation in the gain characteristic of the power amplifier 7 due to the voltage variation, and to stabilize the output power of the power amplifier 7. Can be achieved.
[0032]
In the Vcc control circuit according to the present embodiment, as a measure for improving the output power of the power amplifier 7 and deteriorating the distortion characteristics, the voltage drop due to the on-resistance of the D / D converter 2 is improved, and the power supply voltage of the power amplifier 7 is reduced. It has a bypass circuit to improve. This bypass circuit has a circuit configuration in which the battery voltage is directly applied to the power amplifier 7 from the battery 1 by a bypass SW (switch) 8.
[0033]
This bypass circuit operates only when the distortion characteristic of the power amplifier 7 is deteriorated, when the input power is high, and when the battery voltage serving as the power supply voltage is low, and the circuit is switched using the control signal # 3 in the control unit 4. Implemented.
[0034]
If the variation in the output voltage of the D / D converter 2 is large, the potential difference from when switching to the bypass circuit becomes large, and the voltage variation that occurs at the time of switching causes the characteristic deterioration of the power amplifier 7 (particularly, the gain characteristic variation). It becomes. In the present embodiment, in order to reduce the variation in the output voltage of the D / D converter 2, the voltage fluctuation when switching to the bypass circuit is represented by “on resistance of the D / D converter 2 × current flowing through the D / D converter 2”. If the ON resistance of the D / D converter 2 is low at this time, the voltage fluctuation can be improved, and the deterioration of the gain characteristic of the power amplifier 7 can be improved.
[0035]
FIG. 2 is a flowchart showing the Vcc control operation of the Vcc control circuit according to one embodiment of the present invention. The Vcc control operation of the Vcc control circuit according to one embodiment of the present invention will be described with reference to FIGS. Note that the Vcc control shown in FIG. 2 can also be realized by the control unit 4 executing a program (a program executable by a computer) on the recording medium 10.
[0036]
In the Vcc control circuit according to the present embodiment, the Vcc control is started at the same time as the transmission starts (step S1 in FIG. 2), and the control unit 4 sets the initial setting value of the output power of the AGC amplifier 6, which is the input power of the power amplifier 7. (Step S2 in FIG. 2), the output power of the power amplifier 7 having a constant gain characteristic is set.
[0037]
At this time, in the Vcc control circuit according to the present embodiment, the D / D converter 2 is designed to lower the power supply voltage of the power amplifier 7 in advance in accordance with the output power of the AGC amplifier 6 so that the distortion characteristic of the power amplifier 7 does not deteriorate. An initial value is set so that the output voltage is controlled from the control unit 4 via the D / A converter 3 (step S3 in FIG. 2), the power of the D / D converter 2 is turned on (step S4 in FIG. 2), and the power amplifier is turned on. 7 is turned on. In this case, since the D / D converter 2 is a step-down type, the output voltage does not become higher than the battery voltage.
[0038]
Next, in the Vcc control circuit according to the present embodiment, the output power of the AGC amplifier 6 and the battery voltage are monitored (Step S5 in FIG. 2). At this time, in the Vcc control circuit according to the present embodiment, when the output voltage of the AGC amplifier 6 is high and the battery voltage is low, the output voltage of the D / D converter 2 decreases and the distortion characteristic of the power amplifier 7 deteriorates. The bypass SW 8 is turned on by the unit 4 to bypass the D / D converter 2 (step S 6 in FIG. 2), thereby improving the voltage drop of the D / D converter 2 and improving the distortion characteristics of the power amplifier 7.
[0039]
On the other hand, the Vcc control circuit according to the present embodiment controls the power supply of the power amplifier 7 by the D / D converter 2 except when the output voltage of the AGC amplifier 6 is high and the battery voltage is low. When the output power of the AGC amplifier 6 is set again (step S7 in FIG. 2), the output voltage of the D / D converter 2 is set in accordance with the output power (step S8 in FIG. 2).
[0040]
In the above setting, the Vcc control circuit according to the present embodiment detects whether or not the transmission is in the transmission state (step S9 in FIG. 2). If the transmission is in the transmission state, the output voltage of the D / D converter 2 is checked, and the D / D converter is checked. A / D converter 9 detects a voltage variation due to a variation in the peripheral circuit of No. 2 and when the variation is significantly different from the set value (step S10 in FIG. 2), the output voltage of the D / D converter 2 is reduced in a direction to reduce the variation. (Step S11 in FIG. 2). In the case where the Vcc control circuit according to the present embodiment has no variation or the variation in the output voltage is reduced, the output power of the AGC amplifier 6 and the battery voltage are checked again (step S5 in FIG. 2), and the above-described Vcc control is performed. Repeat control.
[0041]
In the transmission state confirmation (step S9 in FIG. 2), the Vcc control circuit according to the present embodiment terminates the above-described Vcc control if the transmission state is completed (step S12 in FIG. 2).
[0042]
As described above, in the present embodiment, the output voltage of the D / D converter 2 serving as the power supply of the power amplifier 7 is monitored by the A / D converter 9, and when the voltage greatly varies from the desired voltage, the variation amount By converting and controlling 〓V to be offset to the voltage control signal (Vcont), it is possible to reduce the variation in the voltage applied to the power amplifier 7 and to keep the gain characteristic of the power amplifier 7 constant. Can be. Therefore, in this embodiment, even in a circuit without a built-in APC circuit, the output power can be stabilized and Vcc control can be performed, and the circuit scale can be reduced.
[0043]
Further, in this embodiment, since the output voltage of the D / D converter 2 can be precisely and finely controlled, the power supply voltage of the power amplifier 7 is reduced to the maximum allowable distortion characteristic, and the current efficiency is reduced. Therefore, the effect of reducing the current flowing from the battery 1 can be maximized by Vcc control using the D / D converter 2.
[0044]
For example, if the input power of the power amplifier 7 is low and the output voltage Vout of the D / D converter 2 is reduced to 1/3 of the input voltage Vin, the D / D converter Assuming that the efficiency η is about 80% and calculating by referring to the above equation (1), the input current Iin flowing from the battery 1 to the D / D converter 2 is about 42% of the output current Iout flowing to the power amplifier 7. It is.
[0045]
Furthermore, in this embodiment, since the variation of the D / D converter 2 is reduced, only the on-resistance of the D / D converter 2 itself becomes the potential difference when switching to the bypass circuit. Since it is small, as a measure against distortion of the power amplifier 7, the potential difference when the power supply is switched to the bypass circuit can be reduced, and the instantaneous fluctuation of the output power can be improved.
[0046]
【The invention's effect】
As described above, according to the present invention, the output voltage of the DC / DC converter serving as the power supply of the power amplifier is monitored by the A / D converter. By converting and controlling the voltage control signal to the DC converter so as to be offset, the output power can be stably controlled and the Vcc control can be performed even in a circuit without a built-in APC circuit, and the circuit scale can be reduced. The effect is obtained.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a Vcc control circuit according to one embodiment of the present invention.
FIG. 2 is a flowchart showing a Vcc control operation of a Vcc control circuit according to one embodiment of the present invention.
FIG. 3 is a block diagram illustrating a configuration example of a peripheral circuit of the D / D converter 2.
FIG. 4 is a block diagram showing a configuration of a conventional Vcc control circuit.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Battery 2 D / D converter 3, 5 D / A converter 4 Control part 6 AGC amplifier 7 Power amplifier 8 Bypass SW
9 A / D converter 10 Recording medium

Claims (12)

A portable wireless device in which power supplied from a battery is varied by a DC / DC converter and supplied to a power amplifier, wherein a monitor means for monitoring an output voltage of the DC / DC converter, and a detection result of the monitor means Control means for controlling an output voltage of the D / D converter in response to the request. 2. The portable wireless device according to claim 1, wherein the power amplifier is operable even when the power supply voltage from the battery is varied up to about 1 V as a lower limit. The control means controls the output voltage of the DC / DC converter based on the amount of variation when the output voltage of the DC / DC converter greatly varies from a desired voltage. The portable wireless device according to claim 1. When the input voltage of the DC / DC converter is low and the input power of the power amplifier is high, a bypass circuit that bypasses the DC / DC converter and directly supplies power from the battery to the power amplifier is included. The portable wireless device according to claim 1. A portable wireless device in which power supplied from a battery is varied by a DC / DC converter and supplied to a power amplifier, wherein the DC / DC converter has a low input voltage and a high input power to the power amplifier. A portable wireless device comprising: a bypass circuit for directly supplying power from the battery to the power amplifier while bypassing a / DC converter. A method for controlling a power amplifier Vcc of a portable wireless device in which power supplied from a battery is varied by a DC / DC converter and supplied to a power amplifier, the method comprising: monitoring an output voltage of the DC / DC converter; Controlling the output voltage of the D / D converter according to the result. 7. The power amplifier Vcc control method according to claim 6, wherein the power amplifier is operable even when the power supply voltage from the battery is varied up to about 1 V as a lower limit. The step of controlling the output voltage of the D / D converter includes, when the output voltage of the DC / DC converter greatly varies from a desired voltage, changing the output voltage of the DC / DC converter based on the amount of variation. 8. The power amplifier Vcc control method according to claim 6, wherein the control is performed. Determining whether the input voltage of the DC / DC converter is low and the input power of the power amplifier is high; and determining that the input voltage of the DC / DC converter is low and the input power of the power amplifier is high. 9. A power amplifier Vcc according to any one of claims 6 to 8, further comprising the step of: causing said DC / DC converter to be bypassed by a bypass circuit and directly supplying power from said battery to said power amplifier. Control method. A power amplifier Vcc control method for a portable wireless device in which power supplied from a battery is varied by a DC / DC converter and supplied to a power amplifier, wherein the input voltage of the DC / DC converter is low and the input of the power amplifier is low. Determining whether the power is high; and, when determining that the input voltage of the DC / DC converter is low and the input power of the power amplifier is high, bypassing the DC / DC converter by a bypass circuit to reduce the power. Controlling the amplifier to directly supply power from the battery. A program for controlling a power amplifier Vcc of a portable wireless device in which power supplied from a battery is varied by a DC / DC converter and supplied to a power amplifier, wherein a computer monitors an output voltage of the DC / DC converter. A program for executing a process and a process of controlling an output voltage of the D / D converter according to a result of the monitoring. A program for a power amplifier Vcc control method for a portable wireless device in which power supplied from a battery is varied by a DC / DC converter and supplied to a power amplifier, wherein a computer has a low input voltage of the DC / DC converter and A process for determining whether or not the input power of the power amplifier is high; and a bypass circuit for controlling the DC / DC converter by a bypass circuit when it is determined that the input voltage of the DC / DC converter is low and the input power of the power amplifier is high. Causing the power amplifier to directly supply power from the battery by bypassing the power amplifier.

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