JP2001127651A - Transmitter and portable telephone set - Google Patents

Abstract

PROBLEM TO BE SOLVED: To surely enhance the power efficiency of a transmitter by properly reducing current consumption. SOLUTION: A power amplifier circuit 16 has a property that current consumption is nearly constant in a region where a power level of the output power is about 0 dBm or below when a bias current is supplied to both a pre- stage power amplifier circuit 17 and a post-stage power amplifier circuit 18. A control circuit 13 controls a bias current supply circuit 14 so that the circuit 14 does not supply a bias current to the post-stage power amplifier circuit 18 when the power level of the transmission power to be transmitted is about 0 dBm or below thereby correcting the gain of a variable gain amplifier 15. The current consumption of the power amplifier 16 can surely be decreased by the bias current not supplied to the post-stage power amplifier circuit 18 thereby properly enhancing the power efficiency.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmitter having variable gain amplifying means for varying the gain, and a power amplifying means having a plurality of stages of power amplifying circuits, and a portable telephone having the above transmitter. .

[0002]

In recent years, with the advance of telecommunication technology, portable wireless communication devices such as mobile phones have become widespread. FIG. 5 schematically shows a configuration of a main part of a transmitter applied to a transmission unit of a mobile phone.

In FIG. 5, a control circuit 1 calculates a power level of transmission power to be transmitted, determines a gain of a variable gain amplifier 2 according to the calculation result, and
Operates with a gain determined by the control circuit 1 by inputting a control command from the control circuit 1. The bias current supply circuit 3 supplies a bias current to each of the power amplifier circuits (power amplifiers) 5 and 6 of the power amplifier 4 by inputting a bias current supply command from the control circuit 1, and Operate with a preset gain when a bias current is supplied from the bias current supply circuit 3.

According to such a configuration, the variable gain amplifier 2 receives the transmission power having the power level P 1,
By amplifying the input transmission power, the power level P
2 and a power amplifier 4
When the transmission power having the power level P2 is input, the power level P3 is amplified by amplifying the input transmission power.
Is generated. And the antenna 7
The transmission power having the power level P3 is radiated as a transmission radio wave.

[0005] In the prior art, a bias current is always supplied from the bias current supply circuit 3 to each of the power amplifier circuits 5 and 6. Here, the power level of the output power output from the power amplifier 4 and the current consumption of the power amplifier 4 have a relationship shown in FIG.

That is, the power level of the output power output from the power amplifier 4 exceeds a predetermined level (in FIG. 6,
In the region where the output power exceeds about 0 dBm, the current consumption decreases in accordance with the decrease in the power level of the output power. On the other hand, the power level of the output power is equal to or lower than a predetermined level (FIG. 6). In the area of about 0 dBm or less),
Since the bias current is always supplied from the bias current supply circuit 3 to the power amplifier circuits 5 and 6, the current consumption is maintained at a constant level regardless of the decrease in the power level of the output power.

However, in a region where the power level of the output power output by the power amplifier 4 is equal to or lower than a predetermined level, the output power level normally follows the decrease in the output power level by the decrease in the output power level. Therefore, it is desirable that current consumption be reduced. Therefore, as described above, when the current consumption is maintained at a certain level,
There is a problem that power efficiency is poor.

The present invention has been made in view of the above circumstances, and has as its object to reduce the current consumed by the power amplifying means in a region where the power level of the output power output by the power amplifying means is equal to or lower than a predetermined level. It is an object of the present invention to provide a transmitter capable of accurately reducing power consumption and thereby accurately increasing power efficiency, and a mobile phone including the transmitter.

[0009]

According to the transmitter of the present invention, the variable gain amplifying means can vary the gain and amplify the transmission power having the first power level. Generates the transmission power having the second power level. The power amplifying means includes a plurality of stages of power amplifying circuits, and amplifies transmission power having a second power level to generate transmission power having a third power level. Have a property that the current consumption is substantially constant in a region where the power level of the transmission power having the third power level corresponding to the output power is equal to or lower than a predetermined level in a state where the bias current is supplied to all of I have.

When the power level of the transmission power to be transmitted is equal to or lower than a predetermined level, the control means supplies the bias current from the bias current supply means to at least one of the power amplification circuits of the plurality of stages. Control is performed so as not to be supplied, and the gain of the variable gain amplifying means is controlled so that the power level of the transmission power to be transmitted matches the third power level.

That is, according to this, when the power level of the transmission power to be transmitted falls below a predetermined level, the bias current is supplied from the bias current supply means to at least one of the power amplification circuits of the plurality of stages. Since the power is controlled not to be supplied and the gain of the variable gain amplifying means is controlled so that the power level of the transmission power to be transmitted matches the third power level, the power amplification circuit of the plurality of stages Since the bias current is not supplied from at least one power amplification circuit to the power amplification circuit, the current consumption of the power amplification means can be accurately reduced, and the power efficiency can be accurately improved.

According to the second aspect of the present invention, the control means controls the bias current supply means so that the bias current is not supplied from the bias current supply means to the power amplification circuit having the largest current consumption among the plurality of power amplification circuits. .

That is, according to this, when the power level of the transmission power to be transmitted falls below a predetermined level, the bias current supply means supplies the bias current from the bias current supply means to the power consumption circuit having the largest current consumption among the plurality of power amplification circuits. Since the current is controlled so as not to be supplied and the gain of the variable gain amplifying means is controlled so that the power level of the transmission power to be transmitted matches the third power level, the power amplifier circuit of the plurality of stages is controlled. Since the bias current is not supplied from the bias current supply unit to the power amplification circuit having the largest current consumption, the current consumption in the power amplification unit can be reduced to the maximum, and the effect can be enhanced.

According to the third aspect of the present invention, when the power level of the transmission power to be transmitted falls below a predetermined level, the current consumption in the power amplifying means can be accurately reduced, and the power efficiency can be accurately improved. be able to.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a transmitting section of a portable telephone will be described below with reference to FIGS. First, FIG. 1 shows a functional block diagram of an electrical configuration of a main part of a transmission unit of a mobile phone.
In the mobile phone 11, the transmission unit 12 (transmitter according to the present invention) includes a control circuit 13 (control means according to the present invention), a bias current supply circuit 14 (bias current supply means according to the present invention), and a variable gain amplifier 15. (Variable gain amplifying means according to the present invention) and power amplifier 16 (power amplifying means according to the present invention).

The control circuit 13 determines the gain in the variable gain amplifier 15 and the gain in the power amplifier 16 based on the calculated power level calculated as the power level of the transmission power to be transmitted, and outputs a control command to the variable gain amplifier 15. At the same time, a bias current supply command is output to the bias current supply circuit 14.

When the transmission power having the power level P 1 is input to the variable gain amplifier 15, the variable gain amplifier 15 amplifies the input transmission power according to the gain determined by the control circuit 11 in accordance with the control command input from the control circuit 13. P
Generate a transmission power having

The bias current supply circuit 14 includes the control circuit 1
When a bias current supply command is input from 3, it controls whether or not to supply a bias current to each of the power amplifier circuit 17 at the preceding stage and the power amplifier circuit 18 at the subsequent stage in the power amplifier 16.

When the transmission power having the power level P 2 is input from the variable gain amplifier 15 to each of the power amplification circuit 17 at the preceding stage and the power amplification circuit 18 at the subsequent stage in the power amplifier 16, the bias current is supplied from the bias current supply circuit 14. Depending on whether or not the transmission power has been set, the input transmission power is amplified according to a preset gain to generate a transmission power having a power level P3. Then, the antenna 19 radiates transmission power having the power level P3 as transmission radio waves.

Now, the gain and current consumption in each of the power amplifier circuit 17 in the front stage and the power amplifier circuit 18 in the rear stage in the power amplifier 16 will be described with reference to FIG.

The power amplifier 17 at the preceding stage has a gain of 20 dB when a bias current is supplied, and has a gain of -25 dB when no bias current is supplied. The power amplifier circuit 17 in the preceding stage has a property that the current consumption is approximately 35 mA and is substantially constant in a region where the power level of the output power is 0 dBm or less.

The power amplifier circuit 18 at the subsequent stage has a gain of 10 dB when a bias current is supplied, and has a gain of -15 dB when no bias current is supplied. The power amplifier circuit 18 at the subsequent stage has a property that the current consumption is approximately 85 mA and is substantially constant in a region where the power level of the output power is 0 dBm or less.

Therefore, the gain of the entire power amplifier 16 is 30 dB when the bias current is supplied to both the power amplifier circuit 17 of the preceding stage and the power amplifier circuit 18 of the subsequent stage. In the power amplifier 16 as a whole, FIG.
As shown in (1), in the region where the power level of the output power is 0 dBm or less, the current consumption is approximately 120 mA, which is substantially constant.

Next, the operation of the above configuration will be described with reference to FIG.
This will be described with reference to FIG. Here, the power level P1 of the transmission power input to the variable gain amplifier 15 is
Assume 0 dBm.

The control circuit 13 calculates a calculated power level as the power level of the transmission power to be transmitted, and compares the calculated calculated power level Pc with a reference power level Ps set in advance as a threshold (step S1). ).

Here, the reference power level Ps will be described. The reference power level Ps is the maximum power level at which the power consumption of the power amplifier 16 keeps a constant level, and here is 0 dBm as shown in FIG.

If the calculated power level Pc exceeds the reference power level Ps, the control circuit 13 determines "NO" in step S1 and outputs a bias current supply command to the bias current supply circuit 14. Thus, control is performed such that the bias current is supplied from the bias current supply circuit 14 to both the current amplifier circuit 17 in the preceding stage and the current amplifier circuit 18 in the subsequent stage (step S2). At this time, since the bias current is supplied to both the current amplifier circuit 17 in the preceding stage and the current amplifier circuit 18 in the subsequent stage, the gain of the entire power amplifier 16 is 30 dB, and the current consumption of the entire power amplifier 16 is 120 mA.

Next, the control circuit 13 controls the power amplifier 16
The power level P3 of the transmission power to be transmitted, that is, the power level of the output power output from the power amplifier 16 and the calculated power level Pc are considered in consideration of the gain in The gain is calculated (corrected) and a control command is output to the variable gain amplifier 15 (step S3). Then, the variable gain amplifier 15 operates with a gain determined by the control circuit 1 thereafter by inputting a control command from the control circuit 13.

More specifically, the control circuit 13 calculates the calculated power level P as the power level of the transmission power to be transmitted.
If c is calculated as, for example, 25 dBm, the power level P1 of the transmission power input to the variable gain amplifier 15 becomes 0 dBm.
And the gain in the power amplifier 16 is 30 dB.
Therefore, the gain of the variable gain amplifier 15 is-
It is calculated as 5 dB.

Thus, when the transmission power having the power level P1 of 0 dBm is input, the variable gain amplifier 15 amplifies the input transmission power by -5 dB, thereby generating the transmission power having the power level P2 of -5 dBm. Then, when the power amplifier 16 receives the transmission power having the power level P2 of -5 dBm, the power amplifier 16 amplifies the input transmission power by 30 dB to generate the transmission power having the power level P3 of 25 dBm. Then, the antenna 19 sets the power level P3 to 2
The transmission power having 5 dBm is radiated as a transmission radio wave.

On the other hand, if the calculated power level Pc is equal to or lower than the reference power level Ps, the control circuit 13 determines “YES” in step S 1 and sends a bias current supply command to the bias current supply circuit 14. By output, the bias current is supplied from the bias current supply circuit 14 to the current amplification circuit 17 in the preceding stage, and the bias current supply circuit 14 is controlled so that the bias current is not supplied to the current amplification circuit 18 in the subsequent stage (step). S
4). At this time, the bias current is supplied to the current amplifier circuit 17 in the preceding stage, but the bias current is not supplied to the current amplifier circuit 18 in the subsequent stage. Therefore, the gain of the power amplifier 16 as a whole is 5 dB, and the power amplifier 16 as a whole is The current consumption is 35 mA.

Next, the control circuit 13 controls the power amplifier 16
In consideration of the gain of the variable gain amplifier 15, the power level P of the transmission power to be transmitted, that is, the power level of the output power output from the power amplifier 16 matches the calculated power level Pc. The gain is calculated (corrected) and a control command is output to the variable gain amplifier 15 (step S5). Then, the variable gain amplifier 15 receives the control command from the control circuit 13 and thereafter,
The control circuit 13 operates with the determined gain.

More specifically, the control circuit 13 calculates the calculated power level P as the power level of the transmission power to be transmitted.
If c is calculated as, for example, 0 dBm, the power level P1 of the transmission power input to the variable gain amplifier 15 is 0 dBm, and the gain in the power amplifier 16 is 5 dB.
B is calculated.

When the transmission power having the power level P1 of 0 dBm is input, the variable gain amplifier 15 amplifies the input transmission power by -5 dB, thereby generating the transmission power having the power level P2 of -5 dBm. Then, when the power amplifier 16 receives the transmission power having the power level P2 of -5 dBm, the power amplifier 16 amplifies the input transmission power by 5 dB to generate the transmission power having the power level P3 of 5 dBm. The antenna 19 has a power level P3 of 5 dBm.
Is radiated as transmission radio waves.

That is, in this case, the power amplifier 16
In FIG. 4, the bias current is supplied to the current amplification circuit 17 at the preceding stage, but the bias current is not supplied to the current amplification circuit 18 at the subsequent stage. Can save money.

As described above, according to the present embodiment,
Power amplification circuit 17 of the preceding stage and power amplification circuit 18 of the subsequent stage
In the state where the bias current is supplied to both of the power amplifiers and the power amplifier 16 having the characteristic that the current consumption is substantially constant in the region where the power level of the output power is about 0 dBm or less, the transmission power to be transmitted is Is controlled so that the bias current is not supplied from the bias current supply circuit 14 to the power amplifier circuit 18 at the subsequent stage when the power level is about 0 dBm or less, and the gain in the variable gain amplifier 15 is corrected. Subsequent power amplifier circuit 1
Since no bias current is supplied to the power amplifier 8, the power consumption of the power amplifier 16 can be accurately reduced, and the power efficiency can be accurately improved.

In particular, in this case, instead of preventing the bias current from being supplied to the power amplifier circuit 17 of the preceding stage, the bias current is supplied to the power amplifier circuit 18 of the subsequent stage which consumes more power than the power amplifier circuit 17 of the preceding stage. Is not supplied, the power consumption in the power amplifier 16 can be reduced to the maximum, and the effect can be enhanced.

The present invention is not limited to the above embodiment, but can be modified or expanded as follows. The configuration is not limited to the configuration applied to the transmission unit of the mobile phone, and may be a configuration applied to the transmission unit of another device as long as the configuration includes a power amplifier including a plurality of power amplification circuits. . The number of stages of the power amplifier circuit in the power amplifier is not limited to two, and may be another number. The gain of the power amplifier circuit may be another value.

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing gain and current consumption in each power amplifier circuit.

FIG. 3 is a flowchart showing control contents.

FIG. 4 is a diagram showing a relationship between a power level of output power and a current consumption in a power amplifier.

FIG. 5 is a diagram corresponding to FIG.

FIG. 6 is a diagram corresponding to FIG. 4;

[Explanation of symbols]

In the drawings, 11 is a mobile phone, 12 is a transmitting unit (transmitter),
13 is a control circuit (control means), 14 is a bias current supply circuit (bias current supply means), 15 is a variable gain amplifier (variable gain amplification means in the present invention), 16 is a power amplifier (power amplification means), Reference numeral 18 denotes a power amplifier circuit.

Claims (3)

[Claims] A variable gain amplifying means capable of changing a gain, amplifying a transmission power having a first power level to generate a transmission power having a second power level, A multi-stage power amplifier circuit, amplifying the transmission power having the second power level to generate transmission power having a third power level, and biasing all of the multi-stage power amplification circuits. Power amplifying means having a property that current consumption is substantially constant in a region where the power level of the transmission power having the third power level corresponding to the output power is equal to or lower than a predetermined level in a state where the current is supplied; A transmitter comprising: a bias current supply unit capable of individually supplying a bias current to each of the plurality of power amplification circuits; When the power level is equal to or lower than the constant level, control is performed such that the bias current is not supplied from the bias current supply unit to at least one of the power amplification circuits of the plurality of stages, and the power level of the transmission power to be transmitted is determined. A transmitter comprising control means for controlling a gain of the variable gain amplifying means so that the third power level matches the third power level. 2. The control unit controls the bias current supply unit so that a bias current is not supplied from the bias current supply unit to the power amplifier circuit having the largest current consumption among the power amplifier circuits of the plurality of stages. Item 7. The transmitter according to Item 1. 3. A mobile phone comprising the transmitter according to claim 1 or 2 as a transmitter, and transmitting radio waves to a base station by the transmitter.