KR20000013184U - Output power detection circuit of dual band terminal - Google Patents

Abstract

The present invention is to provide an output power compensation circuit of a dual-band terminal that can meet the miniaturization of the terminal, and maximize the battery life by minimizing the current consumption, the output power by sensing the output power of the power amplifier An output power sensing circuit of a compensating dual band terminal, comprising: a first power amplifier having a frequency characteristic of a first band and amplifying a transmission output, and a second power amplifier having a frequency characteristic of a second band and amplifying a transmission output A first impedance unbalance preventing unit for preventing the output impedance of the first power amplifier from shaking, a second impedance unbalance preventing unit preventing the output impedance of the second power amplifier from shaking, the first impedance unbalance preventing unit and the first impedance unbalance preventing unit 2 Output power selector for selecting and outputting one of output power of impedance unbalance prevention part, phase A detection IC for converting the output power of the output power selector into a DC component, a DC stabilizer for removing the AC component from the DC component to stabilize the DC component, and an output power level of the corresponding power amplifier from the output signal of the DC stabilizer. And a CPU for recognizing and outputting a control signal for compensation, and an automatic gain controller for controlling the input power level of the power amplifier under the control of the CPU.

Description

Output power detection circuit of dual band terminal

The present invention relates to a dual band terminal. In particular, the output power detection of a dual band terminal suitable for minimizing the attenuation and interference of the final output of the dual band terminal operating in both the cellular and the 800 MHz band PCS of 1.8 GHz band It is about a circuit.

1 is a block diagram illustrating an output power sensing circuit used in a single band terminal.

In general, in the CDMA terminal, the CPU 12 recognizes whether the power amplifier 11 outputs the power corresponding to the strength of the reception signal of the receiver, and determines the power corresponding to the signal strength. If not, the output is compensated for and the final output power is obtained.

At this time, the function of converting the output power to a DC level that the CPU can detect is the output power detection circuit unit 13.

The output power sensing circuit unit 13 is connected between the power amplifier and the CPU, and its configuration is composed of a combination of diodes and a sensing IC 13a for converting the output signal of the power amplifier 11 to a DC level, and the power An impedance unbalance prevention unit 13b connected between an output terminal of the amplifier 11 and the sensing IC 13a to prevent the impedance between the power amplifier 11 and the isolator from changing, and the sensing IC ( After the AC component is extracted and removed from the output signal of 13a), it is composed of a DC stabilizing unit 13c for transferring it to the CPU 12.

Herein, reference numeral 14 denotes an automatic gain control unit, and when the CPU 12 that detects the output power of the power amplifier 11 determines that the output power is less than the strength of the received signal, the automatic gain control is performed. The gain of wealth 14 will be increased.

The isolator 15 is connected between the output terminal of the power amplifier 11 and the antenna, and serves to prevent the RF signal reflected from the antenna from being applied to the power amplifier 11.

Referring to the output power detection operation of the single-band terminal as follows.

The output of the power amplifier 11 is transmitted through an antenna via an isolator (ISL) 15.

At this time, in order to detect the output degree of the power amplifier 11, a part of the output is sent to the output power detection circuit unit 13.

The sensing IC 13a and the impedance unbalance prevention unit 13b of the output power sensing circuit unit 13 are very important components. If the device value is not found in this portion, the final output power loss cannot be very large. .

The impedance unbalance detection unit 13b is usually composed of a capacitor and a resistor. One terminal of the capacitor is connected to the power amplifier 11 and the other terminal is connected in series with the resistor.

As described above, the sensing IC 13a is composed of a combination of diodes and converts the RF signal output from the power amplifier 11 into a DC component.

The DC stabilizer 13c removes an AC component from the DC component output from the sensing IC 13a and transfers the AC component to the CPU 12.

Accordingly, the CPU 12 recognizes the intensity of the output power according to the high and low level of the input DC signal, and feeds it back to the automatic gain control unit 14 to determine the final output power. do.

When the output power detection circuit of the dual band terminal is configured using the above configuration, it is as shown in FIG.

2 is a block diagram illustrating an output power sensing circuit of a dual band terminal according to the prior art.

First, the output power is compensated through two paths of the output power detection circuit of the conventional dual band terminal.

That is, in order to satisfy the 800 MHz band and all of the 1.8 GHz band, output power must be compensated through different paths.

According to the configuration, the first impedance unbalance is formed of a CPU 21, a first power amplifier 22 having a frequency characteristic of the 800 MHz band, a capacitor and a resistor and connected to an output terminal of the first power amplifier 22. A first sensing IC 24 formed of a combination of a prevention part 23 and a diode and connected to an output terminal of the first impedance unbalance prevention part 23 to convert an RF signal into a DC component; A first DC stabilizer 25 configured between the CPU 24 and the CPU 21 to remove an AC component from the output of the first sensing IC 24, and having the gain adjusted by the CPU 21; A second power amplifier 22a connected to the gain control unit 26 and the output terminal of the automatic gain control unit 26 and having a frequency characteristic of the 1.8 GHz band, and a capacitor and a resistor, the second power amplifier unit ( A combination of a second impedance unbalance prevention unit 23a connected to the output terminal of 22a) and a diode And a second sensing IC 24a which is connected to an output terminal of the second impedance unbalance preventing unit 23a and converts an RF signal into a DC component, between the second sensing IC 24a and the CPU 21. And a second DC stabilizing section 25a for removing the AC component from the output of the second sensing IC 24a.

Here, reference numeral "27" is a first isolator and "27a" is a second isolator.

According to such a configuration, the automatic gain amplifier 26-the first power amplifier 22-the first impedance unbalance prevention unit 23-the first sensing IC 24-the first DC stabilizing unit 25- A path for compensating the output power of the terminal connected to the CPU 21 and using the 800 MHz band is made.

Then, the automatic gain amplifier 26, the second power amplifier 22a, the second impedance unbalance prevention unit 23a, the second sensing IC 24a, the second DC stabilizing unit 25a, and the CPU 21. A path is established to compensate the output power of the terminal using the 1.8 GHz band.

Operation along each path operates in the same way as in the output power compensation circuit of the single band terminal.

However, the output power compensation circuit of the dual band terminal according to the prior art has the following problems.

In order to satisfy the dual band, the output power is compensated through two paths, but the size becomes larger in view of the miniaturization trend of the portable terminal.

In addition, although the PCS service is off in the cellular service state of the 800 MHz band and the cellular service is in the off state in the PCS service state of the 1.8 GHz band, the service mode in the off state is also supplied with power. The consumption is larger than the single-band terminal has a problem that the battery life of the terminal is shortened by that much.

The present invention has been made to solve the above problems of the prior art, to meet the miniaturization of the terminal, to provide an output power compensation circuit of a dual-band terminal capable of maximizing the battery life by minimizing the current consumption. There is this.

The output power compensation circuit of the dual band terminal of the present invention for achieving the above object in the output power detection circuit of the dual band terminal for compensating the output power by sensing the output power of the power amplifier, frequency of the first band A first power amplifier having a characteristic and amplifying a transmission output, a second power amplifier having a frequency characteristic of a second band and amplifying a transmission output, a first impedance unbalance that prevents the output impedance of the first power amplifier from being shaken Selecting the output power to select and output any one of the output power of the prevention unit, the second impedance unbalance prevention unit, the first impedance unbalance prevention unit and the second impedance unbalance prevention unit to prevent the output impedance of the second power amplifier unit from shaking A sensing IC for converting an output power of the output power selector into a DC component, and an AC characteristic of the DC component A DC stabilizing unit for stabilizing the DC component by removing the DC component, a CPU for recognizing the output power level of the corresponding power amplifying unit from the output signal of the DC stabilizing unit, and outputting a control signal for compensation; It characterized in that it is configured to include an automatic gain control unit for adjusting the level of power.

1 is a block diagram illustrating an output power detection circuit of a single band terminal;

2 is a block diagram illustrating an output power detection circuit of a dual band terminal according to the prior art;

3 is a block diagram illustrating the output power detection circuit of the dual-band terminal of the present invention;

Explanation of symbols for main parts of the drawings

31,31a: first and second power amplifier 33: output power selector

32,32a: first and second impedance unbalance prevention unit 34: sensing IC

35: DC stabilization unit 36: CPU

37: automatic gain control unit 38,38a: first, second isolator

Hereinafter, the output power compensation circuit of the dual band terminal of the present invention will be described with reference to the accompanying drawings.

3 is a block diagram illustrating an output power compensation circuit of the dual band terminal of the present invention.

As shown in FIG. 3, the first power amplifier 31 having the frequency characteristic of the first band, the second power amplifier 31a having the frequency characteristic of the second band, and the respective power amplifiers ( First and second impedance unbalance prevention parts 32 and 32a connected to the output terminals of the first and second amplifiers 31 and 31a, respectively, and transferring the output power of the corresponding amplification part to the sensing IC, and the first impedance unbalance prevention parts 32 and the second. An output power selector 33 for selecting and outputting any one of the output power of the first power amplifier 31 and the output power of the second power amplifier 31a transmitted through the impedance unbalance prevention unit 32a; And a combination of diodes, the sensing IC 34 converting the output power selected by the output power selecting section 33 into a DC component, and removing the AC component from the output of the sensing IC 34 to remove the DC. DC stabilization section 35 for stabilizing the components, and the first, from the output signal of the DC stabilization section 35, The CPU 36 which determines the strength of the output power of the second power amplifiers 31 and 31a and the input levels of the first and second power amplifiers 31 and 31a under the control of the CPU 36. It is configured to include an automatic gain control unit 37 to adjust.

Here, the first isolator 38 of the first frequency band is further configured between the output terminal of the first power amplifier 31 and the antenna, and the second isolator between the output terminal of the second power amplifier 31a and the antenna. The second isolator 38a of the frequency band is further configured.

The operation description of the output power compensation circuit of the dual band terminal of the present invention configured as described above is as follows.

First, the dual band of the present invention refers to cellular in the 800 MHz band (first band) and PCS in the 1.8 GHz band (second band).

In the dual band terminal, the service of the PCS is off when the cellular is in the service state, and the service of the cellular is off when the PCS is in the service state.

In this case, when the first power amplifier 31 operates to generate an output, the second power amplifier 31a is turned off. On the contrary, when the second power amplifier 31a operates to generate an output. The power supply of the first power amplifier 31 is turned off.

At this time, as in the prior art, since the sense IC and the DC stabilizer are divided into bands, the current consumption is high. will be.

To this end, an output power selector 33 is configured between each of the impedance unbalance prevention units 32 and 32a and the sensing IC 34.

The output power selector 33 senses the output power of the first power amplifier 31 or the output power of the second power amplifier 31a according to the characteristics of each band pass filter using two band pass filters. To the IC 34.

Here, as described above, the output power selector 33 selects any one of the two output powers using a control signal of the CPU as a selection signal in addition to using two band pass filters. It is possible to configure as.

On the other hand, there is no passing loss due to the path difference from the first impedance unbalance prevention unit 32 to the sensing IC 34 and the path connected from the second impedance unbalance prevention unit 32a to the sensing IC 34. .

In addition, the path formed from the first impedance unbalance preventing portion 32 to the second impedance unbalance preventing portion 32a and the path formed from the second impedance unbalance preventing portion 32a to the first impedance unbalance preventing portion 32 are inserted. Loss has a large characteristic.

Here, the first impedance unbalance preventing unit 32 and the second impedance unbalance preventing unit 32a have a great influence on the output loss of the first power amplifier 31 and the second power amplifier 31a.

Since each of the power amplifiers 31 and 31a and the isolators 38 and 38a has an output impedance of about 50 ohms, a sense IC is provided between the power amplifiers 31 and 31a and the isolators 38 and 38a. Insertion causes the output impedance to shake, causing output loss in the power amplifier.

To prevent this, the first impedance unbalance preventing portion 32 and the second impedance unbalance preventing portion 32a should be designed to have a high impedance.

That is, in order not to affect the impedance between the first power amplifier 31 and the first isolator 38 and the second power amplifier 31a and the second isolator 38a, a capacitor having a high capacitance is connected. Next, to form a high impedance, connect a resistor larger than 50Ω in series with the capacitor.

By such a configuration, the output of the first power amplifier 31 is mostly transmitted to the first isolator 38, and the output of the second power amplifier 31a is mostly transmitted to the second isolator 38a.

The operation of each band will be described based on the above description.

In the cellular mode, the first power amplifier 31 is operated and this output is mostly transmitted through the antenna via the first isolator 38.

A part of the output of the first power amplifier 31 is transmitted to the first impedance unbalance prevention unit 32 having a high impedance.

When the first impedance unbalance prevention unit 32 transfers the RF signal output from the first power amplifier 31 to the output power selector 33, the band pass filter of the output power selector 33 is applied. Is passed to the sensing IC 34.

The RF signal transmitted to the sensing IC 34 is converted into a DC component in the sensing IC 34, and the unstable DC component is changed into a more stable DC component by the DC stabilizer 35.

When the signal of the stable DC component is transmitted to the CPU 36, the CPU 36 detects the level of the signal currently output from the first power amplifier 31.

That is, as the output level of the DC stabilizer 35 is high and low, the CPU 36 controls the automatic gain control unit 37 so that the output power of the first power amplifier 31 reaches a desired level. The input level of the power amplifier 31 is adjusted.

On the other hand, the output power selector 33 also serves to prevent the output of the first impedance unbalance prevention unit 32 from being transmitted to the second impedance unbalance prevention unit 32.

This is to prevent the output power of the first power amplifier 31 from being mistaken for the output power of the second power amplifier 31a in the off state.

In this manner, the cellular mode is turned off in the cellular mode, and conversely, the cellular mode is turned off in the PCS mode.

As described above, the output power detection circuit of the dual band terminal of the present invention has the following effects.

First, the miniaturization of the terminal can be realized by minimizing the occupied area of the chip by configuring a sensing IC and a DC stabilizer that can share two bands.

Second, by not sharing the sense IC and DC stabilizer for each band, power consumption can be reduced, thereby maximizing battery life.

Claims (3)

In the output power detection circuit of a dual band terminal for compensating the output power by sensing the output power of the power amplifier, A first power amplifier having a frequency characteristic of a first band and amplifying a transmission output; A second power amplifier having a frequency characteristic of a second band and amplifying a transmission output; A first impedance unbalance prevention unit for preventing the output impedance of the first power amplifier from being shaken, A second impedance unbalance prevention unit which prevents the output impedance of the second power amplifier from shaking; An output power selector configured to select and output any one of the output powers of the first impedance unbalance prevention unit and the second impedance unbalance prevention unit; A detection IC converting the output power of the output power selector into a DC component; DC stabilization unit for stabilizing the DC component by removing the AC component from the DC component, A CPU for recognizing the output power level of the corresponding power amplification part from the output signal of the DC stabilization part and outputting a control signal for compensation; And an automatic gain control unit configured to adjust the level of the input power of the corresponding power amplifier under the control of the CPU. The output power sensing circuit of claim 1, wherein the output power selector comprises first and second bandpass filters according to frequency characteristics of the first and second power amplifiers. The method of claim 1, wherein the output power selector comprises a multiplexer for selecting any one of the output of the first impedance unbalance prevention unit and the output of the second impedance unbalance prevention unit by using the control signal of the CPU as a selection signal. Output power detection circuit of a dual band terminal.