JPS62278823A - Electric power control circuit - Google Patents

Abstract

PURPOSE:To optimize a response characteristic, namely, the control at the time of the rise of a transmitter output by providing a memory circuit and a control circuit, storing the data of the period when a feedback is stable and controlling an electric power by memory data when the feedback loop is not stable. CONSTITUTION:A transmitting command signal is received, converted to a suitable signal, written to a memory circuit 14 and the command of reading is executed. The memory circuit 14 to receive the command writes a comparing circuit output when the feedback loop is stable, and outputs a written information based upon the command from a control circuit 13 from when a comparing circuit 9 comes to be essentially a non-action up to when a transmitting output is sent again and a feedback loop is stable. A control circuit selects a comparing circuit output while the feedback loop is stable, selects a memory circuit output while the feedback loop is not stable on the basis of the transmitting command signal, and connects them to a direct current amplifying circuit 10 of the next step. By a series of the action, since the input level or the electric power gain of an electric power amplifier 5 when the feedback loop is not stable can be set to the value equal to the time when the feedback loop is stable, the response characteristic of the transmitter can be optimized.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a wireless communication device, particularly a digital data communication system, etc., in which the timing of output transmission is controlled by a transmission command signal. The present invention relates to a transmission output power control device suitable for communication devices.

[Conventional technology]

Conventionally, this type of device generally converts a part of the transmission output power into a DC voltage proportional to the output, and converts this into a DC voltage that corresponds to the set output power, as described in Japanese Patent Application Laid-Open No. 60-41821. A gain control method is used in which a reference voltage is compared and amplified, and the input level or gain of a power amplifier is controlled by the output thereof using feedback loop control. An example of a power control device using such a gain control method using loop control will be described with reference to FIG. In the figure, 1 is an input terminal to which a transmission signal from a modulator (not shown) etc. is applied, 2 is an output terminal from which a transmission signal output is obtained, 3 is a control input terminal to which a control signal for setting the transmission output is applied; Reference numeral 4 denotes a voltage variable attenuator formed of a pin diode or the like, and is configured so that a transmission signal from the input terminal 1 is introduced into the voltage variable attenuator 4.

Then, the transmission signal that has undergone the required attenuation set by the voltage variable attenuator 4 is power amplified by the power amplifier 5, and its output reaches the output terminal 2 via the directional coupler 6, and the transmission output signal is is emitted as a transmission wave from an antenna through an antenna duplexer (not shown), for example.

On the other hand, a part of the transmission output signal branched by the directional coupler 6, which is a detection circuit that takes out a part of the output of the power amplifier 5, is detected by a detection circuit 7 composed of a diode, etc., and is proportional to the transmission output power. is converted into a DC voltage. This DC voltage is then compared in a comparison circuit 9 with the output voltage of a reference voltage generation circuit 8 which is driven by a control signal from the control input terminal 3 and generates a reference voltage corresponding to the set output.

The error voltage is extracted. This error voltage is applied to the DC amplifier 10
After being amplified by the above-mentioned voltage variable attenuator 4, the voltage is fed back as a control voltage to form a feedback loop.

Power control circuits configured in this way are widely used in general radio equipment because they can maintain constant power over a wide range of frequencies, are less susceptible to environmental conditions, and can be constructed economically. There is.

[Problem that the invention seeks to solve]

However, the above-mentioned conventional technology does not take into consideration the period until the feedback loop that controls the input level or power gain of the power amplifier operates and stabilizes, and the control is not performed until the feedback loop stabilizes. It becomes unstable and the output power becomes too high or too low. That is, there is a drawback that the response characteristics of the transmitter output are unstable.

An object of the present invention is to optimize this response characteristic, that is, the control at the rise of the transmitter output.

[Means for solving problems]

The above purpose is to provide a memory circuit and a control circuit in the prior art described above, to store data when the feedback loop is stable, and to control power using the stored data when the feedback loop is unstable. This is achieved by

[Action of the invention]

The power control circuit of the present invention receives a transmission command signal.

The memory circuit that received the command writes the comparator circuit output when the feedback loop is stable, and writes the comparator output when the feedback loop is stable, and when the transmission command signal is negative, i.e. From the time when the transmission output is cut off, there is no detection output, and the comparator circuit becomes essentially inactive, until the transmission command signal becomes positive again, the transmission output is sent out, and the feedback loop is stabilized, the control circuit described above Outputs the information written based on the command.

On the other hand, the control circuit uses the transmission command signal as a reference, and as mentioned above, as long as the feedback loop is stable, the comparison circuit output is
While the feedback loop is unstable, the memory circuit output is selected and connected to the primary stage DC amplifier circuit.

Through this series of operations, the input level or power gain of the power amplifier when the feedback loop is unstable can be set to the same value as when the feedback loop is stable, so the response characteristics of the transmitter can be optimized. It can be made into something.

〔Example〕

An embodiment of the present invention will be described below based on the drawings.

FIG. 1 is a block diagram showing a power control circuit according to the present invention, showing only the parts necessary for explanation.

In this Fig. 1, those with the same numbers as in Fig. 3 (1 to lO
) indicates the corresponding part, 11 is the transmission command signal input terminal, 1
2 is an A/D conversion circuit that converts the error voltage from the comparator circuit 9 into a digital signal and always outputs the digital signal to the switching circuit 15 and the control circuit 13; 13 is an A/D conversion circuit that converts the error voltage from the comparison circuit 9 into a digital signal; Conversion and switching circuit 15
a control circuit that outputs a control signal to the A/D conversion circuit 12, calculates the signal of the A/D conversion circuit 12, and outputs the result to the storage circuit 14;
14 is a storage circuit that stores the output of the control circuit and outputs the stored data to the switching circuit 15; 15 is a storage circuit that stores the output of the control circuit and outputs the stored data to the switching circuit 15; A control circuit selects one of them and outputs it to a D/A conversion circuit 16, and 16 is a D/A conversion circuit that converts this digital signal into a proportional voltage.

Next, the operation of the embodiment shown in FIG. 1 will be explained with reference to FIG. 2.

This FIG. 2 is a timing chart with the horizontal axis as the time axis and showing the relationship of the operations of each part with respect to time. First, as an initial setting, the switching circuit 15 is set to select the output data of the A/D conversion circuit 12. At 1+, a modulated input signal is applied to the input terminal 1 at the same time as the transmission command signal rises, and this input It is applied to the voltage variable attenuator 4 through the terminal 1. However, since there is no output from the detection circuit 7 at this point, the feedback loop is not applied and the voltage variable attenuator 4 is inactive, and the modulated input signal is power amplified by the power amplifier 5 without being attenuated, resulting in an excessive output. . The operation after this until time tz is the same as in the conventional example, so the explanation here will be omitted. Next, at time tz, the feedback loop is stabilized and the power is controlled to the set power level. At time t3, when a minute time Δt has passed since this feedback loop became stable, the control circuit 13
Read the output data of the conversion circuit 12, set the number of times,
Or calculate the average value of data over a period of time. This arithmetic operation is performed to correct the fact that the output of the comparator circuit 9 always fluctuates due to the operating characteristics of the control circuit 13. This calculated average value is output to the storage circuit 14 at time t4, and the storage circuit 14 that receives it rewrites the previously stored data and outputs this new data to the switching circuit 15. However, time t4 explained here must be at least before the transmission command signal, and then time t5, that is, at the same time as the transmission command signal is cut off, the transmission power and the output of the detection circuit 7 disappear and the feedback loop becomes inactive. becomes. Therefore, at the same time, a switching signal is sent from the control circuit 13 to the switching circuit 15 to switch the output of the switching circuit 15 to the data in the storage circuit 14. Due to this operation, even when there is no transmission command signal, the same voltage as when the feedback loop is stable is applied to the voltage variable attenuator 4, and a constant attenuation amount can always be maintained, and the transmission is performed again at time t6. Even when the command signal rises and a detection input is applied to the voltage variable attenuator 4, the desired attenuation is performed and the set power is obtained. Due to this stable rise characteristic, the feedback loop of the power control circuit is also stabilized in a short time. Therefore, at time t7, a minute time Δt' has passed since time t6, a switching signal is sent from the control circuit 13 to the switching circuit 15, and the switching circuit 15 The output of the A/D conversion circuit 12 is switched to the output of the A/D conversion circuit 12. Since the subsequent operation repeats the operation after time t3 described above, a description thereof will be omitted.

As described above, according to this embodiment, the response characteristics of the transmitter output can be improved.

〔Effect of the invention〕

According to the present invention, the response characteristics of the transmitter output, that is, the control at the time of the rise of the transmitter output, can be optimized, so that highly reliable wireless communication is possible.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing one embodiment of the present invention. FIG. 2 is a time chart showing the time relationship of the operations of each part to explain the operation of FIG. 1, and FIG. 3 is a block diagram showing an example of a conventional power control circuit. 12...A/D conversion circuit, 13...control circuit, 14
...Memory circuit, 15...Switching circuit, 16...D/
A conversion circuit. Patent Applicant: Hitachi Shonan Electronics Co., Ltd. Representative Patent Attorney Tadashi Akimoto Jitsuhatsu No. 2 No. 51EI

Claims (1)

[Claims] 1. A power amplifier that amplifies the transmitted signal, a detection circuit that takes out a part of the output of this power amplifier, and a detection circuit that converts the detection signal from this detection circuit into a voltage or sign proportional to the detection signal, as specified. a reference voltage generation circuit that generates a reference signal corresponding to the output; a comparison circuit that compares the output signal of the detection circuit with the reference signal of the voltage generation circuit and outputs an error signal; a memory circuit that stores and outputs an error signal; a control circuit that switches between the output of the comparator circuit and the output of the memory circuit; and a control circuit that converts either of the outputs into a DC voltage proportional to the output. , comprising a DC amplification circuit for amplifying and outputting, and means for controlling at least one of the input level and power gain of the power amplifier based on the output of the DC amplification circuit, and the storage circuit based on the transmission command signal. A power control circuit characterized by controlling.