Transformer circuit for output synthesis

Abstract

A transformer circuit (10) for output synthesis combines in-phase output signals (RF_I, RF_IB), which are obtained by modulating an in-phase baseband signal with a first local oscillator signal, with quadrature output signals (RF_Q, RF_QB), which are obtained by modulating a quadrature baseband signal with a second local oscillator signal orthogonal to the first local oscillator signal. An output inductor (21) comprises a wiring section (211) adjacent to a first input inductor (11), a wiring section (212) adjacent to a second input inductor (12), and connection wiring (CN) connecting the wiring sections (211, 212). Output terminals (RF, RFB) are provided at locations other than the connection wiring (CN) and wiring on the side continuous with the connection wiring (CN) for the wiring sections (211, 212).

Description

Output combining transformer circuit

[0001] The present disclosure relates to a transformer circuit, and more particularly to the structure of an output combining transformer circuit for combining two quadrature modulated signals.

[0002] Non-Patent Document 1 discloses a circuit in which a two-stage transformer circuit is used to combine quadrature-modulated in-phase and quadrature signals, and its layout structure.

[0003] J. Yoo et al., “A 28-nm Bulk-CMOS IC for Full Control of a Superconducting Quantum Processor Unit-Cell”, ISSCC2023, pp.506-508, Feb. 2023

[0004] However, the circuit in Non-Patent Document 1 requires three separate transformers, which increases the area occupied by the transformers and increases costs. Furthermore, unwanted signals input to the input inductors are combined in the transformer circuit, which reduces the quality of the output signal.

[0005] The present disclosure provides a layout structure for an output combining transformer circuit that is effective in suppressing degradation in the signal quality of an output signal.

[0006] A first aspect of the present disclosure is an output combining transformer circuit that combines an in-phase output signal obtained by modulating an in-phase baseband signal with a first local oscillation signal, and a quadrature output signal obtained by modulating a quadrature baseband signal with a second local oscillation signal that is orthogonal to the first local oscillation signal, the transformer circuit comprising: a first input inductor having wiring configured in a loop shape and to which the in-phase output signal is input; a second input inductor having wiring configured in a loop shape and to which the quadrature output signal is input; and an output inductor having an output terminal and outputting a combined output signal from the output terminal, the output inductor comprising: a first wiring section that is adjacent to the first input inductor and is made up of wiring configured in a polygonal shape; a second wiring section that is adjacent to the second input inductor and is made up of wiring configured in a polygonal shape; and a first connection wiring that connects the first wiring section and the second wiring section, the output terminal of the output inductor being provided at a location other than the first connection wiring and wiring of the first and second wiring sections that corresponds to sides that are continuous with the first connection wiring.

[0007] According to this aspect, unwanted signals of the same phase are input to the first input inductor, and unwanted signals of the same phase but opposite in phase to the unwanted signal input to the first input inductor are input to the second input inductor. Therefore, the unwanted signals generated in the output inductor are also opposite in phase between the first wiring section and the second wiring section. Therefore, the first connection wiring connecting the first wiring section and the second wiring section serves as a virtual ground point where the voltage amplitude of the unwanted signals is zero. A current flows into the virtual ground point to eliminate the potential difference, resulting in a large current amplitude. Therefore, if an output terminal is provided at this location, unwanted signals are generated due to the current flowing to the load connected to the output terminal, and the potential difference increases, resulting in significant degradation of the quality of the output signal. Therefore, in this aspect, the output terminal is provided at a location other than the first connection wiring and the wiring of the first and second wiring sections that are adjacent to the first connection wiring. This reduces the current amplitude of the unwanted signals at the output terminal, thereby suppressing degradation of signal quality.

[0008] A second aspect of the present disclosure is an output combining transformer circuit that combines an in-phase output signal obtained by modulating an in-phase baseband signal with a first local oscillation signal and a quadrature output signal obtained by modulating a quadrature baseband signal with a second local oscillation signal that is orthogonal to the first local oscillation signal, the output combining transformer circuit comprising: a first input inductor to which the in-phase output signal is input; a second input inductor to which the quadrature output signal is input; and an output inductor having an output terminal and outputting a combined output signal from the output terminal; the first input inductor comprising a first loop portion made of wiring configured in a loop shape; and a second loop portion also made of wiring configured in a loop shape, the loop having a winding direction opposite to that of the first loop portion; the second input inductor comprising a third loop portion made of wiring configured in a loop shape; and a third loop portion also made of wiring configured in a loop shape, the loop having a winding direction opposite to that of the third loop portion. and a fourth loop portion comprising a first wiring portion adjacent to the first loop portion and consisting of wiring configured in a polygonal shape, a second wiring portion adjacent to the second loop portion and consisting of wiring configured in a polygonal shape, a third wiring portion adjacent to the third loop portion and consisting of wiring configured in a polygonal shape, a fourth wiring portion adjacent to the fourth loop portion and consisting of wiring configured in a polygonal shape, a first connection wiring connecting the first wiring portion and the third wiring portion, and a second connection wiring connecting the second wiring portion and the fourth wiring portion, and in the output inductor, the output terminal is provided at a location other than the first connection wiring and the wiring of the first and third wiring portions that corresponds to a side continuous with the first connection wiring, and the second connection wiring and the wiring of the second and fourth wiring portions that corresponds to a side continuous with the second connection wiring.

[0009] According to this aspect, unwanted signals of the same phase are input to the first input inductor, and unwanted signals of the same phase but opposite in phase to the unwanted signals input to the first input inductor are input to the second input inductor. Therefore, the unwanted signals generated in the output inductor are opposite in phase between the first wiring section and the third wiring section, and opposite in phase between the second wiring section and the fourth wiring section. The first connecting wiring connecting the first wiring section and the third wiring section and the second connecting wiring connecting the second wiring section and the fourth wiring section serve as virtual ground points where the voltage amplitude of the unwanted signals is zero. A current flows into the virtual ground point to eliminate the potential difference, resulting in a large current amplitude. Therefore, if an output terminal is provided at this location, unwanted signals will be generated due to the current flowing through the load connected to the output terminal, and the potential difference will increase, significantly degrading the quality of the output signal. Therefore, in this aspect, the output terminal is provided at a location other than the first connection wiring, the wiring of the first and third wiring sections that is on a side continuous with the first connection wiring, and the second connection wiring, and the wiring of the second and fourth wiring sections that is on a side continuous with the second connection wiring, thereby reducing the current amplitude of unwanted signals at the output terminal and suppressing deterioration of signal quality.

[0010] According to the present disclosure, it is possible to provide a layout structure for an output combining transformer circuit that is effective in suppressing degradation in the signal quality of the output signal.

[0011] Example of a circuit configuration including an output combining transformer circuit according to an embodiment Example of a layout structure of an output combining transformer circuit Another example of a layout structure of an output combining transformer circuit

[0012] Hereinafter, embodiments will be described with reference to the drawings. In the following description, the same reference numerals may be used to refer to terminals and signals input to or output from those terminals.

[0013] Fig. 1 shows an example of a circuit configuration including an output combining transformer circuit (referred to as a transformer circuit as appropriate) according to an embodiment. The circuit in Fig. 1 includes a transformer circuit 10. The transformer circuit 10 includes a first input inductor 11 and a second input inductor 12 on the primary side, and an output inductor 21 electromagnetically coupled to the first and second input inductors 11 and 12 on the secondary side.

[0014] The differential input signals BB_I and BB_IB are in-phase baseband signals. The differential input signals BB_Q and BB_QB are quadrature baseband signals. Local oscillation signals LO_I, LO_IB, LO_Q, and LO_QB of the same frequency (assumed to be frequency f) are generated from a local oscillator (not shown). LO_I and LO_IB are in opposite phase, and LO_Q and LO_QB are in opposite phase. LO_I and LO_IB and LO_Q and LO_QB are in orthogonal phase to each other.

[0015] Differential input signals BB_I and BB_IB are modulated by local oscillation signals LO_I and LO_IB. The modulated in-phase output signals RF_I and RF_IB are input to a transformer circuit 10 and provided to a first input inductor 11. Differential input signals BB_Q and BB_QB are modulated by local oscillation signals LO_Q and LO_QB. The modulated quadrature output signals RF_Q and RF_QB are input to the transformer circuit 10 and provided to a second input inductor 12. A combined differential output signal RF and RFB is output from an output inductor 21.

[0016] Here, unnecessary signals of frequency 2f that are in phase with each other are generated in the in-phase output signals RF_I and RF_IB due to charge injection of gate capacitance caused by the local oscillation signals LO_I and LO_IB and clock feedthrough of gate overlap capacitance. Similarly, unnecessary signals of frequency 2f that are in phase with each other are generated in the quadrature output signals RF_Q and RF_QB due to charge injection of gate capacitance caused by the local oscillation signals LO_Q and LO_QB and clock feedthrough of gate overlap capacitance.

[0017] These unwanted signals are combined in the transformer circuit 10, increasing their amplitude and possibly degrading the quality of the differential output signals RF and RFB. Below, an example of a layout structure of the transformer circuit 10 that can suppress degradation in the quality of the differential output signals RF and RFB is shown.

[0018] (First Structure Example) Figure 2 shows an example of the layout structure of the transformer circuit 10. In Figure 2, a first input inductor 11 to which in-phase output signals RF_I and RF_IB are applied is arranged on the left side of the drawing, and a second input inductor 12 to which quadrature output signals RF_Q and RF_QB are applied is arranged on the right side of the drawing. The first and second input inductors 11 and 12 are each made of wiring in the first to third metal layers (M1 to M3) and form a double loop shape. Note that the first and second input inductors 11 and 12 need only be loop-shaped and are not limited to a double configuration.

[0019] The output inductor 21 includes a loop-shaped wiring that is disposed adjacent to the first and second input inductors 11 and 12. In Fig. 2, the output inductor 21 is made of wiring on the fourth metal layer (M4), and is disposed adjacent to the wiring portion of the third metal layer that constitutes the first and second input inductors 11 and 12. Note that the wiring layer of the wiring that constitutes the output inductor 21 is not limited to the fourth metal layer, and may be configured using, for example, wiring on the first and second metal layers, which are layers below the third metal layer, or wiring on the same third metal layer.

[0020] The output inductor 21 includes a first wiring portion 211 adjacent to the first input inductor 11 and made of rectangular wiring, and a second wiring portion 212 adjacent to the second input inductor 12 and made of rectangular wiring. In FIG. 2 , the first and second wiring portions 211, 212 are configured to surround the peripheries of the first and second input inductors 11, 12, respectively. The first wiring portion 211 corresponds to the portion magnetically coupled to the first input inductor 11. The second wiring portion 212 corresponds to the portion magnetically coupled to the second input inductor 12. The output inductor 21 also includes a connection wiring CN that connects the first wiring portion 211 and the second wiring portion 212.

[0021] Here, unwanted signals of frequency 2f that are in phase with each other are input to the terminals RF_I and RF_IB of the first input inductor 11. Unwanted signals of frequency 2f that are in phase with each other and are opposite in phase to the unwanted signal input to the first input inductor 11 are input to the terminals RF_Q and RF_QB of the second input inductor 12.

[0022] The unwanted signal generated in the output inductor 21 has a phase corresponding to the magnetically coupled first and second input inductors 11, 12. Therefore, the unwanted signal generated in the first wiring part 211 by magnetic coupling in response to the unwanted signal input to the first input inductor 11 and the unwanted signal generated in the second wiring part 212 by magnetic coupling in response to the unwanted signal input to the second input inductor 12 are signals of opposite phases to each other.

[0023] As described above, the connection wiring CN connects the first wiring portion 211 magnetically coupled to the first input inductor 11 and the second wiring portion 212 magnetically coupled to the second input inductor 12 in the output inductor 21. For this reason, the connection wiring CN short-circuits the points where the unwanted signals are signals of opposite phases, and therefore serves as a virtual ground point where the voltage amplitude is zero.

[0024] At the virtual ground point, the voltage amplitude is zero, while a current flows in to eliminate the potential difference, resulting in a large current amplitude. Therefore, if this portion were cut and the output terminals RF and RFB were connected to both ends of the cut, an unwanted signal would be generated due to the current flowing through the load connected to the output terminals RF and RFB, increasing the potential difference and significantly degrading the quality of the output signal. This problem occurs not only at the virtual ground point but also in the vicinity of the virtual ground point. Specifically, in FIG. 2 , even if the output terminals RF and RFB are provided on the wiring (output terminal NG portions NG1 and NG2) on the sides of the first and second wiring portions 211 and 212 that are continuous with the connection wiring CN, the unwanted signal would be large and the signal quality would be significantly degraded.

[0025] 2, the output terminals RF and RFB are provided at the position farthest from the connection wiring CN, for example, at a position diagonally opposite the connection wiring CN in the second wiring section 212. This reduces the current amplitude of unwanted signals, suppressing degradation of signal quality. Furthermore, even if the output terminals RF and RFB are provided at a position other than the above-described output terminal NG sections NG1 and NG2, degradation of signal quality is suppressed.

[0026] As described above, in this structural example, in the output inductor 21, the connection wiring CN connecting the first wiring portion 211 and the second wiring portion 212 serves as a virtual ground point where the voltage amplitude of unwanted signals is zero. If the output terminals RF and RFB are provided at the virtual ground point, unwanted signals are generated due to the current flowing through the load connected to the output terminals RF and RFB, and the potential difference between the unwanted signals increases, resulting in significant degradation of the quality of the output signals. Therefore, in this structural example, the output terminals RF and RFB are provided at locations other than the connection wiring CN and the wiring (output terminal NG portions NG1 and NG2) on the sides of the first and second wiring portions 211 and 212 that are continuous with the connection wiring CN. This reduces the current amplitude of unwanted signals at the output terminals RF and RFB, thereby suppressing degradation of signal quality.

[0027] In this structural example, the first and second wiring portions 211, 212 of the output inductor 21 are formed of wiring having a rectangular shape, but this is not limited thereto. For example, the first and second wiring portions 211, 212 may be formed of wiring having another polygonal shape, such as an octagon. In addition, in this structural example, the first and second wiring portions 211, 212 of the output inductor 21 are formed to surround the peripheries of the first and second input inductors 11, 12, respectively, but this is not limited thereto. For example, the first and second wiring portions 211, 212 may be formed inside the first and second input inductors 11, 12, or may be formed to overlap the first and second input inductors 11, 12 in a plan view.

[0028] (Second Structure Example) Figure 3 shows another example of the layout structure of the transformer circuit 10. In Figure 3, a first input inductor 11, to which in-phase output signals RF_I and RF_IB are applied, is arranged on the left side of the drawing. The first input inductor 11 is made up of wiring in the first to third metal layers (M1 to M3) and has two loop portions 11a and 11b. The loop portion 11a on the upper side of the drawing and the loop portion 11b on the lower side of the drawing have opposite loop winding directions. This makes it possible to suppress leakage magnetic flux in the inductor and reduce the impact on the surrounding circuits.

[0029] 3, a second input inductor 12 to which orthogonal output signals RF_Q and RF_QB are applied is located on the right side of the drawing. Similar to the first input inductor 11, the second input inductor 12 is made of wiring from the first to third metal layers and has two loop portions 12a and 12b. The loop portion 12a on the upper side of the drawing and the loop portion 12b on the lower side of the drawing have opposite winding directions. This makes it possible to suppress leakage magnetic flux in the inductor and reduce the impact on surrounding circuits.

[0030] The loop portions 11a and 12a have the same winding direction, and the loop portions 11b and 12b have the same winding direction. The loop shapes and the number of turns of the loop portions 11a, 11b, 12a, and 12b are not limited to those shown in FIG.

[0031] The output inductor 21 is composed of wiring on the fourth metal layer (M4) with some exceptions, and the wiring on the fourth metal layer of the output inductor 21 is disposed adjacent to the wiring portions of the third metal layer constituting the first and second input inductors 11 and 12. The output inductor 21 has wiring portions 21a, 21b, 21c, and 21d adjacent to the loop portions 11a and 11b of the first input inductor 11 and the loop portions 12a and 12b of the second input inductor 12, respectively. In FIG. 3 , the wiring portions 21a, 21b, 21c, and 21d are each composed of rectangular wiring and are configured to surround the peripheries of the loop portions 11a, 11b, 12a, and 12b, respectively. The wiring portions 21a and 21c on the upper side of the drawing and the wiring portions 21b and 21d on the lower side of the drawing have opposite loop winding directions corresponding to the first and second input inductors 11 and 12.

[0032] It should be noted that the wiring layer of the output inductor 21 adjacent to the wiring portions of the first and second input inductors 11 and 12 is not limited to the fourth metal layer, but may be configured using, for example, wiring in the first and second metal layers, which are layers below the third metal layer, or wiring in the same third metal layer.

[0033] The wiring portion 21a corresponds to the location magnetically coupled to the loop portion 11a of the first input inductor 11. The wiring portion 21b corresponds to the location magnetically coupled to the loop portion 11b of the first input inductor 11. The wiring portion 21c corresponds to the location magnetically coupled to the loop portion 12a of the second input inductor 12. The wiring portion 21d corresponds to the location magnetically coupled to the loop portion 12b of the second input inductor 12. The output inductor 21 also includes a connection portion CN2 that includes a connection wiring 41 that connects the wiring portions 21a and 21c, and a connection wiring 42 that connects the wiring portions 21b and 21d.

[0034] Here, similar to the connection wiring CN in the first structural example, the connection portion CN2 is a location that shorts out points where the unwanted signals are signals of opposite phase to each other, and therefore serves as a virtual ground point where the voltage amplitude is zero. Therefore, as described in the first structural example, in the connection wirings 41 and 42 included in the connection portion CN2 and the wiring (output terminal NG portion NG3) that is on the side of the wiring portions 21a, 21b, 21c, and 21d that is continuous with the connection wirings 41 and 42, if the output terminals RF and RFB are provided, unwanted signals will be generated due to the current flowing through the loads connected to the output terminals RF and RFB, and the potential difference will increase, resulting in significant degradation in the quality of the output signal.

[0035] 3, the output terminals RF and RFB are provided at a position sufficiently far from the connection portion CN2, for example, at a position on the lower side of the fourth wiring portion 21d in the drawing. This reduces the current amplitude of unwanted signals at the output terminals RF and RFB, thereby suppressing degradation of signal quality. Furthermore, even if the output terminals RF and RFB are provided at a position other than the output terminal NG portion NG3, even if they are not at the positions shown in FIG. 3, degradation of signal quality is suppressed.

[0036] 3, the points XCN where the wiring in the output inductor 21 cross, i.e., the wiring connecting the wiring portion 21a and the wiring portion 21d, and the wiring connecting the wiring portion 21b and the wiring portion 21c, do not become virtual ground points. This point will be explained below.

[0037] In the first input inductor 11, there is a phase difference between the loop portions 11a and 11b due to a time difference in the propagation of signals from the input terminals RF_I and RF_IB. Therefore, in the output inductor 21, a phase difference also occurs between the wiring portion 21a adjacent to the loop portion 11a and the wiring portion 21b adjacent to the loop portion 11b. At this time, signals with a phase difference of nearly 180 degrees are induced in the wiring portions 21a and 21b due to the interaction of magnetic coupling.

[0038] Similarly, in the second input inductor 12, there is a phase difference between the loop portions 12a and 12b due to a time difference in the propagation of signals from the input terminals RF_Q and RF_QB. Therefore, in the output inductor 21, a phase difference also occurs between the wiring portion 21c adjacent to the loop portion 12a and the wiring portion 21d adjacent to the loop portion 12b. At this time, signals with a phase difference of nearly 180 degrees are induced in the wiring portions 21c and 21d due to the interaction of magnetic coupling.

[0039] Therefore, with respect to the unwanted signals, the wiring portions 21a and 21d have the same phase relationship, and the wiring portions 21b and 21c have the same phase relationship. Therefore, the point XCN does not become a virtual ground point.

[0040] In this structural example, the virtual ground point is the connection CN2. That is, the connection wiring 41 connecting the wiring portion 21a adjacent to the loop portion 11a of the first input inductor 11 and the wiring portion 21c adjacent to the loop portion 12a of the second input inductor 12, and the connection wiring 42 connecting the wiring portion 21b adjacent to the loop portion 11b of the first input inductor 11 and the wiring portion 21d adjacent to the loop portion 12b of the second input inductor 12, serve as the virtual ground points.

[0041] As described above, in this structural example, in the output inductor 21, the connection wiring 41 connecting the wiring portions 21a and 21c and the connection wiring 42 connecting the wiring portions 21b and 21d serve as virtual ground points where the voltage amplitude of unwanted signals is zero. If an output terminal were provided at the virtual ground point, unwanted signals would be generated due to the current flowing through the load connected to the output terminal, and the potential difference would increase, significantly degrading the quality of the output signal. Therefore, the output terminal is provided at a location other than the connection wirings 41 and 42, as well as the wiring on the sides of the wiring portions 21a and 21c that are continuous with the connection wiring 41, and the wiring on the sides of the wiring portions 21b and 21d that are continuous with the connection wiring 42 (output terminal NG portion NG3). This reduces the current amplitude of unwanted signals at the output terminal, thereby suppressing degradation of signal quality.

[0042] In this structural example, the wiring portions 21a, 21b, 21c, and 21d of the output inductor 21 are rectangular, but this is not limiting. For example, the wiring portions 21a, 21b, 21c, and 21d may be octagonal or other polygonal shapes. In this structural example, the wiring portions 21a, 21b, 21c, and 21d of the output inductor 21 are configured to surround the loop portions 11a, 11b, 12a, and 12b, respectively, but this is not limiting. For example, the wiring portions 21a, 21b, 21c, and 21d may be configured inside the loop portions 11a, 11b, 12a, and 12b, or may be configured to overlap the loop portions 11a, 11b, 12a, and 12b in a plan view.

[0043] The present disclosure can provide a layout structure for an output combining transformer circuit that is effective in suppressing degradation of the signal quality of the output signal, and is therefore useful, for example, for improving the performance of products that use output combining transformer circuits.

[0044] 10 Output combining transformer circuit 11 First input inductor 11a First loop section 11b Second loop section 12 Second input inductor 12a First loop section 12b Second loop section 21 Output inductor 21a, 21b, 21c, 21d Wiring section 211 First wiring section 212 Second wiring section 41, 42 Connection wiring BB_I, BB_IB In-phase baseband signal BB_Q, BB_QB Quadrature baseband signal CN Connection wiring CN2 Connection section LO_I, LO_IB, Local oscillation signal NG1, NG2, NG3 Output terminal NG section RF, RFB Output signal, output terminal RF_I, RF_IB In-phase output signal RF_Q, RF_QB Quadrature output signal

Claims

1. An output combining transformer circuit that combines an in-phase output signal obtained by modulating an in-phase baseband signal with a first local oscillation signal, and a quadrature output signal obtained by modulating a quadrature baseband signal with a second local oscillation signal that is orthogonal to the first local oscillation signal, comprising: a first input inductor having wiring configured in a loop shape and to which the in-phase output signal is input; a second input inductor having wiring configured in a loop shape and to which the quadrature output signal is input; and an output inductor having an output terminal and outputting a combined output signal from the output terminal, wherein the output inductor comprises: a first wiring section adjacent to the first input inductor and consisting of wiring configured in a polygonal shape; a second wiring section adjacent to the second input inductor and consisting of wiring configured in a polygonal shape; and a first connection wiring that connects the first wiring section and the second wiring section, wherein the output terminal of the output inductor is provided other than the first connection wiring and the wiring of the first and second wiring sections that is continuous with the first connection wiring.

2. An output combining transformer circuit according to claim 1, wherein the first and second wiring sections have wiring configured in a rectangular or octagonal shape.

3. An output combining transformer circuit that combines an in-phase output signal obtained by modulating an in-phase baseband signal with a first local oscillation signal, and a quadrature output signal obtained by modulating a quadrature baseband signal with a second local oscillation signal that is orthogonal to the first local oscillation signal, comprising: a first input inductor to which the in-phase output signal is input; a second input inductor to which the quadrature output signal is input; and an output inductor having an output terminal and outputting a combined output signal from the output terminal; the first input inductor comprising: a first loop portion made of wiring configured in a loop shape; and a second loop portion also made of wiring configured in a loop shape, the loop winding direction being opposite to that of the first loop portion; the second input inductor comprising: a third loop portion made of wiring configured in a loop shape; and a fourth loop portion also made of wiring configured in a loop shape, the loop winding direction being opposite to that of the third loop portion; and the output inductor comprising: a first wiring portion adjacent to the first loop portion and made of wiring configured in a polygonal shape; an output combining transformer circuit comprising: a second wiring section adjacent to the second loop section, the second wiring section being made up of wiring configured in a polygonal shape; a third wiring section adjacent to the third loop section, the third wiring section being made up of wiring configured in a polygonal shape; a fourth wiring section adjacent to the fourth loop section, the fourth wiring section being made up of wiring configured in a polygonal shape; a first connection wiring connecting the first wiring section and the third wiring section; and a second connection wiring connecting the second wiring section and the fourth wiring section; wherein in the output inductor, the output terminal is provided at a location other than the first connection wiring and the wiring of the first and third wiring sections that is on a side continuous with the first connection wiring, and the second connection wiring and the wiring of the second and fourth wiring sections that is on a side continuous with the second connection wiring.

4. An output combining transformer circuit according to claim 3, wherein the first to fourth wiring sections have wiring configured in a rectangular or octagonal shape.

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