JP3097601B2 - High output power amplifier - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a power amplifier,
In particular, the present invention relates to a power amplifier that obtains high output by combining respective output powers using a plurality of semiconductor elements.

[0002]

2. Description of the Related Art Microwave solid-state transmitters are replacing conventional traveling-wave tube amplifiers because of their high reliability and long life. For this reason, the output power of the solid-state transmitter has been increasing, and accordingly, the output power of the high-output amplifier used in the solid-state transmitter has to be further increased.

In order to increase the output power of a high-output amplifier (transistor), a method is generally used in which a plurality of semiconductor elements (transistor chips) having a small output power are used and their output powers are combined.

FIG. 5 shows a conventional power amplifier. Referring to FIG. 5, this conventional power amplifier is a power amplifier in which a power distribution / combination circuit is formed in a power amplifier and a plurality of transistor chips 1 are connected and operated in parallel. Are arranged to have the same phase change using suspended lines 3 and 4 corresponding to the circuit length.

The suspended lines 3 and 4 have a width W
The wavelength shortening rate and the impedance change due to the increase and decrease of the wavelength. The transistor chips 1 are arranged in a straight line in a direction perpendicular to the straight lines of the input / output terminals A and B, and branch circuits are formed in a divergent manner for distribution / combination, and are connected to the respective transistor chips 1.

The lengths of the branch circuits are different from each other. However, the lengths of the branch circuits are made up of the suspended lines 3, and the line width and the distance from the ground plane are selected to be optimum values in the respective branch circuits. A and the output end B are set at the same wavelength.

Thus, the input signal from the input terminal A is
The input terminals of all the transistor chips 1 have the same phase. The signal amplified by the transistor 1 is combined in the same phase at the output terminal B via the suspended line 4 of the branch circuit, and the output power of each transistor is combined.

For details of the high-frequency power amplifier circuit having the above-described circuit configuration, reference is made to, for example, Japanese Patent Application Laid-Open No. 63-281502.

[0009]

However, in the conventional power amplifier shown in FIG. 5, as the output power increases, the number of transistor chips used also increases. As a result, the distance from one end of the linearly arranged transistor chip to the other end of the transistor chip becomes long horizontally, which causes a problem that the transistor chip cannot be accommodated in the housing.

Furthermore, the difference between the length of the center branch circuit and the line length of the outermost branch circuit must be the same at the input and output ends of the transistor chip by increasing or decreasing the line width W.
If the difference is too large, the range of the wavelength shortening rate due to the increase and decrease of the line width W is limited, so that it is impossible to generate the difference in the wavelength shortening rate by the difference in the line length.

Further, when the wavelength shortening rate is selected, it is not always possible to achieve matching by the line impedance.

As described above, in the conventional high-frequency power amplifier circuit, when the output power increases, the distance between the transistor chips arranged vertically in the input / output terminals increases, and the various problems described above occur.

SUMMARY OF THE INVENTION Therefore, the present invention has been made to solve the above-mentioned problems of the prior art, and has as its object to reduce the number of transistor chips due to an increase in output power in a direction perpendicular to the input / output direction. The spread in various directions,
An object of the present invention is to provide a power amplifier that can supply the same phase to each transistor chip.

[0014]

In order to achieve the above-mentioned object, the present invention provides a plurality of stages of each amplifying element such that a bonding wire connecting between each amplifying element and a distribution / combination transmission line does not contact. The difference between the propagation phases caused by the bonding wires connected to each of the amplifying elements is set as the length of the transmission line where the total propagation phase of the signal is the same for all the amplifying elements.

[0015]

Embodiments of the present invention will be described below. According to a preferred embodiment of the present invention, there is provided a high-power amplifier which distributes an input signal, connects the plurality of power amplifiers via a transmission line, and combines the outputs to obtain a high output. A plurality of power amplification elements are arranged in a plurality of stages along the input / output direction so that bonding wires connecting the power transmission / combination transmission line and the power distribution / combination transmission line do not contact each other, and connected to the input / output of each of these power amplification elements. The difference in the propagation phase caused by the length of the bonding wire is defined as the length of the transmission line such that the total propagation phase of the signal is the same in all power amplification elements.

In order to describe the above-mentioned embodiment of the present invention in more detail, an embodiment of the present invention will be described below with reference to the drawings.

Embodiment 1 FIG. 1 is an explanatory diagram showing a configuration of a power amplifier according to a first embodiment of the present invention.
1A is a top view of the power amplifier, and FIG. 1B is a side view. 1, the same or equivalent parts as those in FIG. 5 are denoted by the same reference numerals.

In FIG. 1, reference numerals 1a to 1d denote amplification elements,
0, 11, 20, 21 are transmission lines, Lg1, Lg2,
Ld1 and Ld2 indicate bonding wires. Referring to FIG. 1, the present embodiment is different from the conventional power amplifier shown in FIG. 5 in that the amplifying elements 1a to 1d are each configured to amplify in a direction perpendicular to the straight line of the input terminal A and the output terminal B. Elements 1a and 1b and elements 1c and 1d are arranged in two stages.

The input and output bonding wires Lg1 and Lg2 of each of the amplifying elements 1a to 1d are shifted left and right so that they do not overlap, and they are respectively connected to the input-side transmission lines 10 and 11 and the output-side transmission line 20. , 21.

The signal input to the input terminal A is the transmission line 1
The power is distributed by 0 and 11, and a signal is guided to the end face A1 of the substrate. The transmission line 10 terminates the line here,
The transmission line 11 is further turned up to extend the line length and become a terminal.

A bonding wire Lg2 is connected from the transmission line 10 to the amplifying element 1c. Similarly, the amplifying element 1a is connected from the transmission line 11 by a bonding wire Lg1.

At this time, it is necessary to supply signals of the same phase to the amplification elements 1a and 1c. In other words, if the phases added to the amplification element 1 are different, when the signals are amplified and then combined, the combining efficiency due to the phase difference decreases.

Further, since the phase of the signal reflected from the amplifying element is also different, there arises a problem that the input reflection coefficient of the power amplifier is deteriorated by the phase difference.

In order to solve this, all signals applied to the amplifying element 1 must have the same phase.

The details will be described below with reference to FIG. 2 in which the vicinity of the transmission lines 10 and 11 and the amplification element 1 is partially enlarged.

The signal input from the input terminal A is transmitted on the transmission line 1
The light propagates through 0 and 11 and comes to the bonding end face A1 in the same phase.

From there, the bonding wire Lg1 is
It is directly connected to the amplification element 1c. On the other hand, the bonding wire Lg2 is formed by extending the transmission line further from the end face A1.
2 to the amplifying element 1a.

In order to transmit a signal to the amplifying elements 1a and 1c in the same phase, the impedance when the amplifying element 1c is viewed from A1 of the transmission line 10 and the impedance when the amplifying element 1a is viewed from the A1 of the transmission line 11 Should be the same.

The input impedance of the amplifying element 1 is Z1,
If the inductance of the bonding wires Lg1 / Lg2 is L1 / L2, the length from A1 to A2 of the transmission line 11 is 1 and the impedance is Z0, the transmission line 1
0, the impedance when the amplification element 1 side is viewed from A1 of the transmission line 11 is given by the following equations (1) and (2), respectively.

The impedance of A1 on the transmission line 10 side: Z1 + Jω × L2 (1) The impedance of A1 on the transmission line 11 side: Z0 × (Zt + JZ0 × tan (β × 1)) / (Z0 +
JZt × tan (β × 1))… (2)

Here, Zt = Z1 + Jω × L1 (where J ² = −1).

Generally, the input / output impedance of the high-power amplifier 1 is small, and the bonding wires Lg1, Lg
Since 2 is short with respect to wavelength, the following approximation applies:

Z1 << Z0, β × 1 << 1 / (2π), ωL1, ωL2 << Z0

Therefore, Zt << Z0, and the above equation (2)
Is approximated as Z1 + J (ω × L1 + Z0 × tan (β × 1)) (3)

Therefore, if the above equations (1) and (3) become the same, a signal is inputted to the amplifier 1a and the amplifier 1b in the same phase.

Therefore, the bonding wires Lg1, Lg2, Z0, L are determined so as to satisfy the following conditions.

Ω × L2 = ω × L1 + Z0 × tan (β × 1) (4)

That is, since the bonding wire Lg2 is longer than the bonding wire Lg1, the bonding wire Lg1 is formed by making the transmission line 11 longer than the transmission line 10 by one. Will be added.

The output side is shorter when the bonding wire of the same input as the input side is longer, and the output side is longer when the bonding wire of the input is shorter.

If the mounting satisfying this condition is performed, all the amplifying elements 1a to 1d have the same phase even if two stages of amplifying elements are provided perpendicular to the input terminal A and the output terminal B. Therefore, the spread in the horizontal direction described in the conventional example is reduced to about half by making the two stages, and it becomes possible to supply signals to the amplifying element 1 with the same phase.

If the lengths of A1 and A2 are determined so as to satisfy the above expression (4) even if the number of stages is further increased, instead of only two stages, the same effect can be obtained. Lateral spread can be further suppressed.

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 3 shows an amplifying element 13 having a plurality of bonding pads 13G and 13D.
It is explanatory drawing which shows the Example about the case of.

When the output power of the amplifier increases, the number of amplifying elements becomes too large, which increases the number of assembling steps and makes it difficult to determine the position of the amplifying elements. On the other hand, in order to increase the output power with one amplifying element, a multi-cell amplifying element in which a large number of unit amplifying elements are arranged to constitute one amplifying element is often used because it is small and can increase the output power. .

Referring to FIG. 3, amplifying elements 13 are arranged in two stages, and bonding pads 13G and bonding pads 13D of each amplifying element are arranged at alternate positions.

The length of each bonding wire Lg1, bonding wire Lg2, transmission line 10 and transmission line 1
The length of 1 is the same as that described in the first embodiment, and the bonding wires are connected to all of the plurality of bonding pads 13G and 13D.

Also in the case of the present embodiment, the spread in the horizontal direction is about １ ／ compared to the case where the amplifying elements 13 are arranged in a straight line.
Thus, there is an advantage that the mounting efficiency is improved.

Third Embodiment Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 4 is an explanatory diagram showing an embodiment in which the bonding pads of the amplifying element having the plurality of bonding pads 14G and 14D are alternately arranged to configure two amplifying elements as one amplifying element 14. is there. The function of the present embodiment is the same as that of the second embodiment, but the advantage of improving the assemblability can be obtained by using one amplifier element 14.

Further, since the position of the amplifying element is fixed, there is an advantage that variations due to assembly are eliminated.

[0049]

As described above, according to the present invention,
With the increase in the number of amplifying elements used in accordance with the increase in the output power of the amplifier, it is possible to suppress the spread in the vertical direction between the input terminal and the output terminal, and it is possible to improve the mounting efficiency.

The reason for this is that, in the present invention, amplifying elements are arranged in a plurality of stages, and the bonding pads of the respective amplifying elements are arranged so as not to overlap in the direction of the input terminal and the output terminal. This is because the lengths of the transmission line and the bonding wire are combined so as to be the same.

Further, according to the present invention, by using the amplifier elements arranged on one chip so that the bonding pads of the unit amplifier elements arranged in a plurality of stages do not overlap in the direction of the input terminal and the output terminal. This has the effect of suppressing the spread in the horizontal direction, reducing the number of assembly steps, and suppressing product variations.

[Brief description of the drawings]

FIG. 1 is a diagram showing a first embodiment of the present invention, and FIG.
Is a top view, and (B) is a side view.

FIG. 2 is a partially enlarged view of the first embodiment of the present invention.

FIG. 3 is a diagram showing a second embodiment of the present invention.

FIG. 4 is a diagram showing a third embodiment of the present invention.

FIG. 5 is a diagram showing a conventional high-frequency power amplifier.

[Explanation of symbols]

 1, 13, 14 Amplifying element 10, 11, 20, 21 Transmission line Lg1, Lg2 Ld1, Ld2 Bonding wire

Claims (3)

(57) [Claims] 1. A high-output power amplifier for distributing an input signal, connecting to a plurality of amplifying elements via a transmission line, and synthesizing the outputs to obtain a high output. Arranged in a plurality of stages, and the propagation phase difference caused by the length of the bonding wire connected to the amplification element is the length of the transmission line where the total propagation phase of the signal is the same for all the amplification elements. High output power amplifier. 2. A high-output power amplifier for distributing an input signal, connecting the plurality of power amplification elements via a transmission line, and synthesizing the outputs to obtain a high output. The plurality of power amplifying elements are arranged in a plurality of stages along the input / output direction so that bonding wires connecting the transmission lines do not contact each other. A high output power amplifier characterized in that a difference in propagation phase caused by the transmission line length is such that a total propagation phase of a signal is the same in all power amplification elements. 3. An amplifying element arranged on one chip so that bonding pads of unit amplifying elements arranged in a plurality of stages do not overlap in the direction of an input end and an output end. High output power amplifier.