JP2006311305A - Passive polyphase filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a passive polyphase filter in which components arrangement and a wiring shape are simple and it is easy to uniformize influences by a parasitic element on characteristics. <P>SOLUTION: Four resistive elements R1 to R4, four capacitive elements C1 to C4, four input terminals I1 to I4 for inputting a four-phase signal and four output terminals O1 to O4 for outputting a four-phase signal are provided on one and the same substrate of an integrated circuit. The resistive elements and the capacitative elements are alternately connected so as to have a loop form, and the input terminals and the output terminals are sequentially and alternately connected to each node between the resistive elements and the capacitative elements. The input terminals and the output terminals are collectively arranged in a central area, the four resistive elements are arranged in an area surrounding the input terminals and the output terminals, the four capacitative elements are arranged in an area surrounding the four resistive elements, and the four resistive elements and the four capacitative elements are covered with an upper-layer wiring layer where a uniform conductor layer is formed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a passive polyphase filter (complex filter) used for image removal or the like in signal processing of an electronic apparatus, and more particularly to improvement in arrangement of resistors, capacitors, and input / output terminals as constituent elements.

  A passive polyphase filter used for image removal in signal processing of an electronic device has a circuit configuration as shown in FIG. This passive polyphase filter is configured by connecting resistors R1 to R4 and capacitors C1 to C4 alternately in a loop with resistors and capacitors. I1 to I4 are input terminals for inputting signals, and O1 to O4 are output terminals for outputting signals. The resistors R1 to R4 have the same resistance value, and the capacitors C1 to C4 have the same capacitance value.

  In the circuit of FIG. 6, as the signal processing from the input terminal I1 to the output terminal O1, a passive first-order low-pass filter is configured by the resistor R1 and the capacitor C4. On the other hand, as the signal processing from the output terminal O2 to the input terminal I1. The capacitor C1 and the resistor R1 constitute a passive primary high-pass filter. That is, the original input signal at the input terminal I1 and the signal from the output terminal O2 are combined and output to the output terminal O1. The signal relationship from the other signal input terminals to the output terminal has the same configuration.

  FIG. 7 shows an example of a layout (layout) of the passive polyphase filter having the above configuration on an integrated circuit. Each reference numeral is attached corresponding to the circuit diagram of FIG. In the arrangement of the conventional passive polyphase filter, consideration is given to meandering the wiring so that the wiring resistance becomes equal (see, for example, Non-Patent Document 1).

Further, FIG. 8 shows a layout (layout) of another conventional passive polyphase filter (see, for example, Patent Document 1). In the arrangement of the passive polyphase filter, the input terminal I1 and the input terminal I4 are shared, and the input terminal I2 and the input terminal I3 are shared to realize the arrangement on the integrated circuit in the case of two-phase input. The resistors R1 to R4 and the capacitors C1 to C4 are rotationally symmetrical by 90 degrees, and the resistors and the capacitors are arranged alternately so that the occurrence of parasitic capacitance is reduced.
IEEE JOURNAL OF SOLID-STATE CIRCUIT, VOL.36 NO.6, JUNE 2001, CMOS Mixers and Polyphase Filters for Large Image Rejection, Farbod Behbahani and 3 others JP 2003-234406 A (page 7, FIG. 1)

  Conventionally, in an arrangement method of a passive polyphase filter used for removing an image of signal processing of an electronic device, when it is realized on an integrated circuit, the arrangement of a plurality of stages is simplified, and characteristics due to parasitic elements resulting from the arrangement are reduced. The challenge was to make the effects uniform.

  On the other hand, in the case of the four-phase input passive polyphase filter shown in FIG. 7, the wiring connecting the resistor R2 and the capacitor C2 and the wiring connecting the resistor R3 and the capacitor C3 with respect to the wiring connecting the resistor R1 and the capacitor C1. In order to match the value of the wiring resistance which is a parasitic element by the wiring connecting the resistor R4 and the capacitor C4, the wiring connecting the resistor R2 and the capacitor C2, the wiring connecting the resistor R3 and the capacitor C3, and connecting the resistor R4 and the capacitor C4 The wiring is meandering. Therefore, it becomes a complicated shape as arrangement of a passive type polyphase filter.

  FIG. 9 shows a circuit diagram of a passive polyphase filter having two stages and four phases. This passive polyphase filter includes a first-stage passive polyphase filter including resistors R11 to R14, capacitors C11 to C14, input terminals I11 to I14, and output terminals O11 to O14, resistors R21 to R24, and capacitors C21 to C21. And a second-stage passive polyphase filter including C24, input terminals I21 to I24, and output terminals O21 to O24. The first stage output terminals O11 to O14 are respectively connected to the corresponding second stage input terminals I21 to I24.

  As an example of the arrangement of the passive polyphase filter on the integrated circuit, an arrangement diagram in the case where the passive polyphase filter is configured based on the arrangement method shown in FIG. 7 is shown in FIG. In this arrangement, in order to connect the output terminal of the first stage and the input terminal of the second stage, the wiring connecting the resistor R11 and the capacitor C14 is connected to the output O12 of the first stage, the input I22 of the second stage, and the output. It must cross each wiring connecting O13 and input I23, and output O14 and input I24. The value of the wiring capacitance, which is a parasitic element due to the intersection, changes the characteristics of the filter.

  On the other hand, in the arrangement of the four-phase input passive polyphase filter as shown in FIG. 8, since the directions of the resistors R1 and R3 and the resistors R4 and R2 are different, the relative variations are different and it is difficult to obtain the same resistance value. Moreover, when the passive polyphase filter having two stages and four phases input shown in FIG. 9 is configured based on the arrangement method as shown in FIG. 8, the shape becomes quite complicated as shown in FIG.

  The present invention solves the above-mentioned conventional problems, and the arrangement of components and the shape of wiring are simple, and it is easy to make uniform the influence on characteristics due to parasitic elements resulting from these arrangements. An object of the present invention is to provide a passive polyphase filter that can easily make the influence on characteristics due to parasitic elements uniform by suppressing complication of arrangement and wiring even when configured in a plurality of stages.

  The passive polyphase filter of the present invention has a basic configuration for inputting four resistance elements, four capacitance elements, and a four-phase signal formed on the same substrate of an integrated circuit. Four input terminals and four output terminals for outputting a four-phase signal, wherein the resistor element and the capacitor element are alternately connected in a loop, and between the resistor element and the capacitor element The input terminal and the output terminal are alternately connected to each node sequentially.

  To achieve the above object, the passive polyphase filter of the first configuration of the present invention is arranged such that the input end and the output end are gathered in a central region, and the four resistance elements are the input end and The four capacitance elements are arranged in a region surrounding the four resistance elements, and the four resistance elements and the four capacitance elements are uniform conductors. It is characterized by being covered with an upper wiring layer on which the layer is formed.

  In the passive polyphase filter of the second configuration of the present invention, the input end and the output end are arranged in a central area, and the four capacitive elements surround the input end and the output end. The four resistance elements are arranged in a region surrounding the four capacitance elements, and the four resistance elements and the four capacitance elements are formed with a uniform conductor layer. It is characterized by being covered with an upper wiring layer.

  According to the configuration of the passive polyphase filter having the above configuration, the arrangement of the resistive element and the capacitive element, which are the constituent elements, and the configuration of the wiring between the input and output terminals are simple, and the arrangement is made even when configured in multiple stages. In addition, it is easy to uniformize the influence of the parasitic elements on the characteristics without complicating the wiring.

  In the passive polyphase filter according to the present invention, it is preferable that each of the four resistance elements is divided into two, and the divided partial resistance elements are arranged so as to extend in directions orthogonal to each other. .

  In addition, a plurality of passive polyphase filters having a first or second configuration are provided, and each of the input terminals of the passive polyphase filter in the preceding stage corresponds to the passive polyphase filter in the subsequent stage. It can be configured to be connected to the output end.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 is a layout diagram of a passive polyphase filter according to the first embodiment. This arrangement realizes a four-phase input passive polyphase filter having the circuit configuration of FIG. The same elements as those of the conventional example in FIGS. 7 and 8 will be described with the same reference numerals.

  The passive polyphase filter of FIG. 1 includes four resistors R1 to R4 having the same resistance value, four capacitors C1 to C4 having the same capacitance value, and a four-phase signal on the same substrate of the integrated circuit. 4 input terminals I1 to I4 and four output terminals O1 to O4 for outputting a four-phase signal.

  The input terminals I1 to I4 and the output terminals O1 to O4 are arranged in a central area. In the present embodiment, the input terminals I1 to I4 are aligned on the left side, and the output terminals O1 to O4 are aligned on the right side. The resistors R1 to R4 are disposed clockwise in a region surrounding the input terminals I1 to I4 and the output terminals O1 to O4. Capacitors C1 to C4 are arranged clockwise in a region surrounding resistors R1 to R4. Further, each of the resistors R1 to R4 is divided into two and formed by partial resistors R1a and R1b, partial resistors R2a and R2b, partial resistors R3a and R3b, and partial resistors R4a and R4b. The partial resistors R1a and R1b forming the resistor R1 are arranged so as to extend in directions orthogonal to each other. The partial resistors that form the other resistors R2 to R3 are similarly arranged.

  Resistors R1 to R4 and capacitors C1 to C4 are alternately connected in a loop. The input terminals I1, I2, I3, and I4 and the output terminals O2, O3, O4, and O1 are alternately connected to the nodes between the resistors R1 to R4 and the capacitors C1 to C4 connected in a loop. ing. The wirings 1 to 8 connecting the input terminals I1 to I4 and the output terminals O1 to O4 and each node are adjusted so that the wiring lengths match. However, in the arrangement as described above, it is not necessary to greatly meander the wirings 1 to 8. Therefore, the arrangement of the elements constituting the passive polyphase filter results in a simple and simple shape.

  FIG. 2 shows a circuit diagram of a passive polyphase filter having three stages and four phases. This passive polyphase filter includes resistors R31 to R34, capacitors C31 to C34, input terminals I31 to I34, and output terminals O31 to O34 in addition to the two-stage four-phase input passive polyphase filter shown in FIG. A third-stage passive polyphase filter is added. The second stage output terminals O21 to O24 are connected to the corresponding third stage input terminals I31 to I34, respectively.

  FIG. 3 shows an example in which each element of this passive polyphase filter is arranged according to the present embodiment shown in FIG. In FIG. 3, the first-stage passive polyphase filter 9, the second-stage passive polyphase filter 10, and the third-stage passive polyphase filter 11 have the same configuration as the passive polyphase filter shown in FIG. Have

  The resistors and capacitors constituting each of the passive polyphase filters 9 to 11 are covered with an upper wiring layer 12. A uniform conductor layer is formed on the wiring layer 12. Further, on the upper layer of the wiring layer 12, input wirings 13 to 16 connected to the input terminals of the first-stage passive polyphase filter 9, and inter-stage wirings connecting the output terminals to the corresponding input terminals, respectively. 17 to 20 and interstage wirings 21 to 24 and output wirings 25 to 28 connected to the output terminals of the third-stage passive polyphase filter 11 are arranged.

  By covering the four resistors and four capacitors constituting the passive polyphase filter with the upper wiring layer 12, there is a parasitic capacitance between the wiring layer 12 and the resistor and between the wiring layer 12 and the capacitor. It is formed. The parasitic capacitance generated has the same capacitance value for each resistor and each capacitor by AC grounding the wiring layer 12, and acts equally on the phase between the signals. Therefore, there is no difference in filter characteristics between the signals. In addition, the wiring connecting the output terminal of the first stage and the input terminal of the second stage has no direct crossing between the wirings, so that no wiring capacitance as a parasitic element is generated, and a filter is provided between the phases. There is no difference in characteristics. Further, even if a plurality of stages are connected, the wiring length from the preceding stage output to the succeeding stage input can be made equal, so that the parasitic resistance value of each phase is uniform, and there is no difference in filter characteristics between the phases. Even if the number of stages is further increased, the same effect can be obtained.

  Although not shown in FIG. 1, a wiring layer similar to the wiring layer 12 is also provided in the upper layers of the resistors R1 to R4 and the capacitors C1 to C4 in FIG. Further, on the upper layer of the wiring layer 12, wirings from the outside for the input terminals I1 to I4 and the output terminals O1 to O4 are arranged.

  As described above, in the passive polyphase filter according to the first embodiment, four resistors are arranged in a region surrounding the input end and the output end, and four capacitors are arranged in a region surrounding the four resistors. It is characterized by a configuration in which four resistors and four capacitors are covered with an upper wiring layer. Accordingly, it is possible to realize an excellent passive polyphase filter in which the arrangement of the constituent elements is simplified and the influence of the parasitic elements resulting from the arrangement is uniform on the characteristics. In particular, when configured in a plurality of stages, the effect of suppressing the arrangement of elements and the complexity of wiring is great.

  In the multi-stage configuration shown in FIG. 3, the case where a plurality of stages having the same resistance and capacitor are connected has been described as an example. Can be different.

  In this embodiment, the case of using the three-layer wiring is shown. However, in order to reduce the parasitic capacitance with the resistance generation layer and the capacitor generation layer, it is also possible to use the upper layer wiring by the multilayer wiring. .

(Embodiment 2)
FIG. 4 is a layout diagram of the passive polyphase filter according to the second embodiment. This arrangement realizes a four-phase input passive polyphase filter having the circuit configuration of FIG. The same elements as those in the first embodiment in FIG. 1 are described with the same reference numerals.

  The input terminals I1 to I4 and the output terminals O1 to O4 are arranged in a row in a central area. The capacitors C1 to C4 are arranged counterclockwise in a region surrounding the input terminals I1 to I4 and the output terminals O1 to O4. The resistors R1 to R4 are arranged counterclockwise in a region surrounding the capacitors C1 to C4.

  The resistors R1 to R4 are each formed by partial resistors R1a and R1b, partial resistors R2a and R2b, partial resistors R3a and R3b, and partial resistors R4a and R4b divided into two. The partial resistors R1a and R1b forming the resistor R1 are arranged so as to extend in directions orthogonal to each other. The partial resistors that form the other resistors R2 to R3 are similarly arranged.

  The wirings 29 to 36 connecting the input terminals I1 to I4 and the output terminals O1 to O4, and the nodes between the resistors R1 to R4 and the capacitors C1 to C4 are adjusted so that the wiring lengths match. However, in the arrangement of the present embodiment, it is not necessary to meander the wirings 29 to 36 greatly. Therefore, as a result of arranging the elements constituting the passive polyphase filter, a simple and simple shape is obtained.

  Furthermore, FIG. 5 shows an example in which each element of the three-stage four-phase input passive polyphase filter shown in FIG. 2 is arranged according to the present embodiment shown in FIG. In FIG. 5, the first-stage passive polyphase filter 37, the second-stage passive polyphase filter 38, and the third-stage passive polyphase filter 39 have the same structure as the passive polyphase filter shown in FIG. Have

  The resistors and capacitors constituting each of the passive polyphase filters 37 to 39 are covered with a wiring layer 12 on which an upper uniform conductor layer is formed. On the upper layer of the wiring layer 12, the input wirings 40 to 43 respectively connected to the input ends of the first-stage passive polyphase filter 37 and the interstage wiring 44 connecting each output end and each corresponding input end. ˜47 and interstage wirings 48 ˜ 51, and output wirings 52 ˜ 55 connected to the output terminals of the third stage passive polyphase filter 39 are arranged.

  By covering the four resistors and four capacitors constituting the passive polyphase filter with the upper wiring layer 12, there is a parasitic capacitance between the wiring layer 12 and the resistor and between the wiring layer 12 and the capacitor. It is formed. The parasitic capacitance generated has the same capacitance value for each resistor and each capacitor by AC grounding the wiring layer 12, and acts equally on the phase between the signals. Therefore, there is no difference in filter characteristics between the signals. In addition, the wiring connecting the output terminal of the first stage and the input terminal of the second stage has no direct crossing between the wirings, so that no wiring capacitance as a parasitic element is generated, and a filter is provided between the phases. There is no difference in characteristics. Further, even if a plurality of stages are connected, the wiring length from the preceding stage output to the succeeding stage input can be made equal, so that the parasitic resistance value of each phase is uniform, and there is no difference in filter characteristics between the phases. Even if the number of stages is further increased, the same effect can be obtained.

  As described above, in the passive polyphase filter according to the second embodiment, four capacitors are arranged in a region surrounding the input end and the output end, and four resistors are arranged in a region surrounding the four capacitors. It is characterized by a configuration in which four resistors and four capacitors are covered with an upper wiring layer. Accordingly, it is possible to realize an excellent passive polyphase filter in which the arrangement of the constituent elements is simplified and the influence of the parasitic elements resulting from the arrangement is uniform on the characteristics. Moreover, even if it is configured in a plurality of stages, the arrangement of elements and the complexity of wiring are suppressed.

  In the multi-stage configuration shown in FIG. 5, the case where a plurality of stages having the same resistance and capacitor are connected has been described as an example. However, according to the required characteristics, the resistance and capacitor are connected between the stages. Can be different.

  In this embodiment, the case of using the three-layer wiring is shown. However, in order to reduce the parasitic capacitance with the resistance generation layer and the capacitor generation layer, it is also possible to use the upper layer wiring by the multilayer wiring. .

  The passive polyphase filter of the present invention has simple arrangement and wiring of elements, improved filter characteristics, and is useful for signal processing of electronic equipment, design of integrated circuits, and the like.

Arrangement diagram of 4-phase input passive polyphase filter in Embodiment 1 Circuit diagram of 3-stage 4-phase input passive polyphase filter Arrangement of 3-stage 4-phase input passive polyphase filter in the first embodiment Arrangement diagram of 4-phase input passive polyphase filter in embodiment 2 Arrangement of 3-stage 4-phase input passive polyphase filter in Embodiment 2 Circuit diagram of 4-phase input passive polyphase filter Arrangement of four-phase input passive polyphase filter in the conventional example Arrangement of four-phase input passive polyphase filter in another conventional example Circuit diagram of passive polyphase filter with two-stage four-phase input Arrangement of two-stage four-phase input passive polyphase filter in the conventional example Arrangement of two-stage four-phase input passive polyphase filter in another conventional example

Explanation of symbols

1-8, 29-36 Wiring 9, 37 First-stage passive polyphase filter 10, 38 Second-stage passive polyphase filter 11, 39 Third-stage passive polyphase filter 12 Wiring layers 13-16, 40- 43 Input wiring 17-24, 44-51 Interstage wiring 25-28, 52-55 Output wiring C1-C4, C11-C14, C21-C24, C31-C34 Capacitors I1-I5, I11-I14, I21-I24, I31 to I34 Input terminals O1 to O4, O11 to O14, O21 to O24, O31 to O34 Output terminals R1 to R4, R11 to R14, R21 to R24, R31 to R34 Resistors R1a, R1b, R2a, R2b, R3a, R3b, R4a, R4b Partial resistance

Claims (6)

Four resistor elements, four capacitor elements, four input terminals for inputting a four-phase signal, and four-phase signal output formed on the same substrate of the integrated circuit Four output terminals, and the resistance element and the capacitive element are alternately connected in a loop, and the input terminal and the output terminal are alternately arranged for each node between the resistive element and the capacitive element. In the passive polyphase filter connected to
The input end and the output end are arranged in a central region, the four resistance elements are arranged in a region surrounding the input end and the output end, and the four capacitance elements are the four capacitance elements. A passive polyphase, wherein the four resistive elements and the four capacitive elements are disposed in a region surrounding the resistive element, and are covered with an upper wiring layer on which a uniform conductor layer is formed. filter. Four resistor elements, four capacitor elements, four input terminals for inputting a four-phase signal, and four-phase signal output formed on the same substrate of the integrated circuit Four output terminals, and the resistance element and the capacitive element are alternately connected in a loop, and the input terminal and the output terminal are alternately arranged for each node between the resistive element and the capacitive element. In the passive polyphase filter connected to
The input end and the output end are arranged in a central area, the four capacitive elements are arranged in a region surrounding the input end and the output end, and the four resistance elements are the four resistance elements. A passive polyphase, wherein the four resistive elements and the four capacitive elements are disposed in a region surrounding the capacitive element, and are covered with an upper wiring layer on which a uniform conductor layer is formed. filter.   3. The passive polyphase filter according to claim 1, wherein each of the four resistance elements is divided into two, and the divided partial resistance elements are arranged to extend in directions orthogonal to each other.   A plurality of the passive polyphase filters according to any one of claims 1 to 3, wherein the input terminals of the passive polyphase filter at the front stage correspond to the passive polyphase filter at the rear stage. A passive polyphase filter connected to the output end.   An integrated circuit comprising the passive polyphase filter according to claim 1. A receiver comprising the integrated circuit according to claim 5.

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