JP2001007601A - Power supply circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a power supply circuit small and to reduce manufacturing cost by forming a transmission line which is a longitudinal arm of a T-shaped impedance conversion circuit to be a capacitor, consisting of two-layered conductors connected to different power supplies and a discrimination circuit layer interposed between the two-layered conductors, and providing two capacitors, respectively connected to a ground electrode at the other end of the transmission line to the transmission line. SOLUTION: A short-circuit transmission line with a length L3 is formed with a structure consisting of two-layered conductors (1st and 2nd conductor layers) and a dielectric layer interposed between the two-layered conductors and which acts as a capacitor C3. That is, the two-layered conductors whose length is L3, which have the same potential with respect to a high frequency signal, acts as a short-circuit transmission line on the high frequency signal on one hand, which it acts as separate conductors for supplying power on a power supply voltage because a capacitor C1 supplies a voltage for the pre-stage to the 1st conductor layer and a capacitor C2 supplies a voltage for the post- stage to the 2nd conductor layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention is used as a circuit for a microwave band or a millimeter wave band. Although the present invention has been developed as an interstage coupling circuit for a semiconductor integrated circuit, it can be widely used for other purposes.
The circuit of the present invention is a passive four-terminal circuit itself, performs impedance matching between two high-frequency circuits coupled by the four-terminal circuit, and supplies a power supply voltage to each of the two high-frequency circuits. Use for

[0002]

2. Description of the Related Art Conventionally, in a circuit for handling a frequency in a microwave region or higher, two or more T-shaped impedance conversion circuits are provided between two active circuits, and these impedance conversion circuits are connected through these circuits. In two active circuits,
Techniques for supplying power supply voltages are known.

[0003] To explain this briefly, FIG.
Pre-stage circuit A₁ The post-stage circuit A, which is the same active circuit as
_TwoAnd the interstage circuit A which is a passive circuit_Three Establish this
Interstage circuit A_ThreeAnd the former circuit A₁ of
Output impedance and post-stage circuit A_Two Input impedance
With the terminal V₁ From the preceding circuit A ₁ 
DC voltage to the collector electrode of_Two Later
Circuit A_Two DC voltage to the base electrode
You. Terminal V₁And terminal V_Two Is the frequency
Two capacitors with sufficiently low impedance
C₁And C_Two Are connected to ground potential by
Transmission line T of two vertical arms₃₁And T₃₂Is equally well
Low impedance capacitor C_ThreeBy high frequency signal
It is configured to be connected in parallel to the signal. Connection
Transmission line T shorted from the point₃₁And T₃₂Looking at
Reactance X₃₁, X₃₂Looks like. Accordingly
Therefore, the equivalent circuit at the used frequency is the reactance X
_ThreeTransmission line T indicating_ThreeCan be replaced with
As shown in FIG. 9, each transmission line
Road (T₁, T_Two, T_Three) Characteristic impedance value and line
By setting the length appropriately, the pre-stage circuit A₁ Output
Impedance and subsequent circuit A_TwoAdjust the input impedance of
Can be combined.

Here, it is difficult to implement a desired impedance converter as a lumped circuit on a small integrated circuit at a frequency in the microwave band or higher. Therefore, this interstage circuit itself is made of a transmission line that can freely design the characteristic impedance and the amount of phase change,
The desired impedance converter is realized in the design of the distributed constant circuit. As a transmission line, for example, CPW
(Coplanar Waveguide).

[0005] The relationship between the length of a transmission line formed on a semiconductor integrated circuit and the impedance value (or admittance value) apparently generated at that point is determined in advance by the dielectric constant and other characteristics of the material used at the frequency used. If you know, you can design using the Smith chart. That is, the output impedance of the preceding circuit,
An interstage circuit for determining the input impedance of the subsequent circuit and matching the input impedance can be realized with practically sufficient accuracy. Since this technique is already well known, a detailed description of its design method and the like is omitted here.

[0006]

Here, as shown in FIG. 8 described above, when power is supplied from the interstage circuit to the front stage and the rear stage, the vertical arm of the T-shaped impedance matching circuit is used. Two transmission lines (T ₃ ) (T ₃₁ and T ₃₂ )
Must be separated. That is, since the power supply circuit has different DC voltages for the former stage and the latter stage, they cannot be formed as the same conductor. Therefore, two transmission lines (T ₃₁ and T ₃₁₎ have conventionally been used for this purpose.
₃₂ ) are formed separately, and the two are connected to each other by a further formed capacitor (C ₃ ).

As described above, the transmission lines (T ₃₁ and T ₃₂ ) of the two vertical arms are formed on the integrated circuit board so as not to interfere with each other. C ₃ ) must be formed,
The area of the interstage circuit increases. This lowers the yield of circuit chips and increases manufacturing costs. Also, a standing wave is generated on the short-circuited transmission line of the vertical arm, and it becomes a kind of antenna that dissipates and absorbs electromagnetic wave energy. This can cause bonding.

SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and has as its object to reduce the number of vertical transmission lines formed in an inter-stage circuit, thereby reducing the size of the circuit and lowering the manufacturing cost. And An object of the present invention is to provide a small power supply circuit. An object of the present invention is to provide a power supply circuit that can reduce manufacturing costs. An object of the present invention is to provide a power supply circuit that reduces energy dissipation and does not generate unnecessary circuit coupling.

[0009]

According to the present invention, a transmission line serving as a vertical arm of a conversion circuit on a distributed constant circuit is formed by two layers of conductors sandwiching a dielectric material therebetween. It is characterized in that it functions as a signal line of one transmission line for a high-frequency signal, and a supply path for two different power supply voltages for a power supply voltage.

That is, according to the present invention, as shown in the principle diagram of FIG. 1, transmission lines (T ₁ , T
_2. A T-shaped impedance conversion circuit including a transmission line (T ₃ ) of a vertical arm whose one end is connected to a connection point of the transmission lines of both horizontal arms is denoted by reference numeral of the embodiment drawing, the same applies hereinafter. A power supply voltage is supplied to two circuits respectively connected to the two lateral arms via the impedance conversion circuit, and the three transmission lines (T ₁ , T ₂ , and T ₃ ) are used at respective frequencies to be used. In a power supply circuit formed by a distributed constant circuit exhibiting a desired characteristic impedance value and a phase change amount, the transmission line (T ₃ ) of the vertical arm is supplied with different power supply voltages for supplying the two circuits. and connected thereto a two-layer conductor, are formed in the form of a capacitor (C ₃₎ including a dielectric layer interposed between the conductors of the two layers, the transmission line of each of the conductors of the two-layer the longitudinal arm (T ₃₎ capacitor connected to the respective ground electrode at a position corresponding to the other end of the (C _1, C ₂₎
It is characterized by having. When the supply voltage of either the _first circuit (A ₁ ) or the second circuit (A ₂ ) is the ground voltage, one of the capacitors (C ₁ , C ₂ ) can be omitted. In the following description, reference numerals of the embodiment drawings are displayed in parentheses for easy understanding.
This does not limit the invention to the examples. FIG. 2 shows an equivalent circuit of the circuit shown in FIG. 1 with respect to the use frequency, and FIG. 3 shows an equivalent circuit with respect to the power supply voltage.

According to such a configuration, it is not necessary to replace one transmission line with a vertical arm with a transmission line with two vertical arms, so that the entire area can be reduced and unnecessary signal transmission can be achieved. Radiation or absorption can be reduced. Manufacturing cost is also improved by reducing the area.

The three transmission lines (T ₁ , T ₂ , and T ₃ ) and the three capacitors (C ₁ , C ₂ , and C ₃ ) are integrally formed as an integrated circuit on the surface of the semiconductor substrate. It is desirable to take the form.

The three transmission lines (T ₁ , T ₂ , and T ₃ ) are more specifically CPW (Coplanar Waveguide).
e) or a microstrip line.

[0014]

FIG. 4 is a structural view of an embodiment of the present invention.
You. This figure shows the layout from the top of the semiconductor integrated circuit
It is a pattern.
is there. By this first conductor layer, between the ground conductors in a plane
A center conductor is sandwiched between them, providing a constant characteristic impedance
A CPW having a capacitance (50Ω) is formed. Falling right
The hatched area is the second conductor layer. Small squares are vias
A hole (via-hole), wherein the first conductive layer and the second conductive layer
Formed by filling conductive material into holes that pass through
It is. The vertical stripes in FIG. 4 indicate the first conductive layer and the second conductive layer.
The dielectric layer sandwiched between the body layers forms a capacitor
To indicate that Capacitor C₁ , C_Two And C _Three Part of
In this way, a dielectric layer was sandwiched between two conductor layers like this
It has a three-layer structure. The first conductor layer that is at ground potential is
Rilliage B₁ , B_Two And B_Three Electrically connected by
Is done.

FIG. 5 schematically shows the form of the three-layer structure. FIG. 5A is a top view, and FIG. 5B is a cross-sectional view.
Forming a first conductor layer (Au) on a semiconductor substrate (GaAs),
After a polyimide isolation layer is formed around the dielectric layer, a dielectric layer (Ta ₂ O ₅ ) is formed, and a second conductor layer (Au) is further formed thereon. The via hole has a shape in which the dielectric layer of FIG. 5 does not exist, and is formed so as to electrically connect the first conductor layer and the second conductor layer at required positions.

In the structure of FIG. 4, the length L₁ Part equivalent to
Transmission line T₁ Is formed and the length L _Two Transmission line
T_Two Is formed. This transmission line T₁ Transmission line T_Two But
They are arranged to be connected in series. The desired phase change is
Each length L₁ And L_TwoSet by adjusting
Is done. In this embodiment, the transmission line T₁ And transmission line
T_TwoAt the connection point with_Three Transmission line T_Three Is connected
Is done.

Here, the feature of the present invention is that a portion of the short-circuit transmission line having a length L ₃ is formed by a structure in which a dielectric layer is sandwiched between two conductor layers (a first conductor layer and a second conductor layer). formed, there is to be utilized as a capacitor C _3. That is, length of the L ₃ made of a conductor layer of two layers, the conductive layer of the two layers relative to the high-frequency signal becomes the same potential to act as a short-circuit transmission line with respect to the supply voltage , voltages V ₁ for the preceding stage is supplied from the capacitor C ₁ to the first conductor layer, by the voltage V ₂ for the subsequent stage is supplied from the capacitor C ₂ to the second conductive layer, another conductor of each power supply voltage supply Act as

In the conventional example, as described with reference to FIG. 8, it is necessary to disassemble the vertical transmission line T ₃ in parallel to provide two transmission lines T ₃₁ and T ₃₂ . Moreover, it is necessary to arrange the two transmission lines so as not to interfere with each other. On the other hand, in the present invention, since it can be formed by one short-circuited transmission line, the area occupied by the circuit is reduced and the whole is compact.

(First Embodiment) FIG. 6A shows an example of such a practical design. In the case where a transistor amplifier having a frequency of 30 GHz (wavelength on a substrate of 4 mm) is used as an interstage circuit, , L ₁ is 110 [mu] m, L2 is 357μ
m and L3 are 1255 μm. Figure 6 for comparison
FIG. 3B shows a circuit having the same characteristics realized by the conventional technique. 6 (a) and 6 (b) are on the same scale, and it can be well understood that the area is reduced by the present invention.

(Second Embodiment) FIG. 7 shows an embodiment of the present invention in which a distributed constant circuit is realized by a microstrip line. A microstrip line is a transmission line using a metal layer provided on the back surface of a substrate and a metal layer provided on the front surface. Therefore, when the metal layer on the back surface of the substrate is included, the metal layer has a three-layer structure. In the portion forming the capacitor C ₁ and C _2, the metal layer of the intermediate layer connected to the lowermost metal layer by a via hole, forming a capacitor between the intermediate layer and the top layer. In the portion forming the capacitor C _3, the structure to form a capacitor between the uppermost layer and the intermediate layer CP
The same as in the case of W, the potential of the top layer and the intermediate layer is the same for the use frequencies, (see FIG. 1) the top layer to the terminal V ₂ to the power supply voltage, the intermediate layer is connected to the terminal V _1.

[0021]

As described above, the power supply circuit can be reduced in size according to the present invention. By reducing the size, the manufacturing cost can be reduced. In addition, by reducing the number of transmission lines of the vertical arm to be short-circuited, there is an effect that energy dissipation is reduced and unnecessary coupling can be avoided.

[Brief description of the drawings]

FIG. 1 is a circuit diagram illustrating the principle of the present invention.

FIG. 2 is an equivalent circuit diagram for a use frequency (microwave) of the present invention.

FIG. 3 is an equivalent circuit diagram for a power supply voltage (DC voltage) of the present invention.

FIG. 4 is a structural diagram when the present invention is implemented by CPW.

FIG. 5 is a diagram illustrating a layer structure when the present invention is implemented by CPW.

FIG. 6A is a pattern configuration diagram of the first embodiment of the present invention.
(B) is a diagram showing a pattern configuration according to a conventional technique according to the same standard. The scales of (a) and (b) are equal.

FIG. 7 is a pattern configuration diagram of a second embodiment of the present invention.

FIG. 8 is a circuit diagram showing the principle of a conventional circuit.

FIG. 9 is a high-frequency equivalent circuit diagram of a conventional circuit.

Claims (4)

[Claims] 1. A transmission line (T ₁ , T ₂ ) of two horizontal arms connected in series and a transmission line (T ₃ ) of a vertical arm connected at one end to a connection point of the transmission lines of both horizontal arms. A power supply voltage is supplied to two circuits respectively connected to the two lateral arms via the T-shaped impedance conversion circuit, and the three transmission lines (T ₁ , T ₂ , T ₃ ) is a power supply circuit formed by a distributed constant circuit exhibiting a desired characteristic impedance value and a desired amount of phase change at a used frequency, and the transmission line (T ₃ ) of the vertical arm is supplied to each of the two circuits. Formed in the form of a capacitor (C ₃ ) that includes two layers of conductors connected to different power supply voltages to each other and a dielectric layer interposed between the two layers of conductors. Each Kitateude transmission line of (T
Power supply circuit comprising the two capacitors respectively corresponding located at the other end connected to the ground electrode (C _1, C _{2) 3).} 2. The three transmission lines (T ₁ , T ₂ , and T ₃ ) and the three capacitors (C ₁ , C ₂ , and C ₃ ) are formed as integrated circuits on a surface of a semiconductor substrate. The power supply circuit according to claim 1. 3. The power supply circuit according to claim ₂ , wherein said three transmission lines (T ₁ , T ₂ , and T ₃ ) are formed by a CPW (Coplanar Waveguide). 4. The power supply circuit according to claim ₂ , wherein said three transmission lines (T ₁ , T ₂ , and T ₃ ) are formed by microstrip lines.