JPH0544841B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to an integrated circuit high frequency amplification device, which is used for high frequency signal amplification in television tuner circuits, satellite broadcast receivers, etc. be.

Conventional Structure and Problems Conventionally, in a high-frequency amplifier circuit that processes high-frequency signals in the 100 MHz band or higher, a multistage connection circuit as shown in FIG. 1A is often used in order to obtain high gain. In order to integrate the circuit shown in FIG. 1A, it is necessary to encapsulate it in an IC package 1 as shown in FIG.
1b, 1c, 1d and the IC chips are connected by bonding wires, so L _io and
It will have wire inductance like L _G , L _put , and L _B . This wire inductance is
It usually has a value of 2.5nH to 5nH, and is negligible at low frequencies, but becomes non-negligible when it comes to high-frequency signals of 800MHz or higher. In the circuit shown in Figure 1, the influence can be removed by using an external circuit or resistors R ₁ , R ₃ , and R ₄ inside the IC for L _IN , L _B , and L _put , but they are inserted between the ground (GND) and Only the inductance L _G that occurs cannot be removed. In the example shown in the figure, a particular problem is that a common inductance component L is inserted into the emitters of transistors Q ₁ and Q ₂ , which creates a feedback loop and causes oscillation in the circuit, which is a serious drawback. . Figure 1C shows an attempt to improve the above oscillation phenomenon by inserting a resistor _R5 into the emitter of the transistor _Q2 in Figure B and grounding the bonding wire inductance _LG2 through a bypass capacitor C connected to the outside of the IC. However, if there is only one transistor _Q1 , there is no problem, but by connecting transistors _Q1 and _Q2 in multiple stages, the wire inductance L _G2
At the same time, since there is a wire inductance L _G1 caused by grounding the emitter of the transistor _Q1 to the ground inside the IC, the ground potential of the circuit becomes unstable, and although there is no problem with one L _G1 , multi-stage connection had the drawback of not being able to eliminate oscillation conditions.

OBJECTS OF THE INVENTION It is an object of the present invention to provide a means for obtaining stable operation without oscillation in such a multi-stage connected high frequency integrated circuit.

Structure of the Invention The high-frequency amplification device according to the present invention has an integrated circuit including a circuit in which grounded emitter amplifiers are DC-coupled and connected in multiple stages. A terminal is connected to the outside of the integrated circuit from the emitter of at least one of these transistors through a bonding wire of the integrated circuit, and a filter circuit including the inductance of the bonding wire is constructed from this terminal between the terminal and the ground. However, a specific frequency (800 MHz to 1 GHz) is grounded outside the integrated circuit using a filter circuit to prevent feedback due to the emitter resistor and increase gain.

DESCRIPTION OF THE EMBODIMENTS An example of the configuration of the present invention is shown in FIG. The illustrated example is a two-stage amplifier circuit using common emitter transistors Q ₁ and Q ₂ . The high frequency input signal is supplied from the input terminal IN, and the output terminal
Output from OUT. Here, a current flows from the power supply +B through the resistor _R11 to the collector of the transistor _Q1 , and that current is shunted to the base of the transistor _Q2 , and to the collector of the transistor _Q2 from the power supply +B through the resistor _R12. Current is supplied. The sum of the base current of transistor Q ₂ and the current flowing _through resistor R ₁₂ flows through the emitter of transistor _{Q 2, and flows through resistor R 13 to ground} (GND). A potential determined by the product of the current and the value of resistor _R13 is generated, and if this is fed back to the base of transistor _{Q1 through resistor R14 ,} the transistor
The base potential of Q ₁ increases, the collector potential of transistor Q ₁ decreases, the emitter potential of transistor Q ₂ decreases, the base potential of transistor Q ₁ stabilizes at a certain point, and resistors R ₁₁ , R ₁₃ , R ₁₄ ，
By selecting the value of R ₁₅ , desired currents can be passed through each of the transistors Q ₁ and Q ₂ . In such a state, the input signal is transmitted through transistors Q ₁ ,
_However , because the emitter resistance _R13 of transistor _Q2 makes it impossible to obtain a gain at high frequencies, a filter circuit 11 is inserted between the emitter of transistor _Q2 and the ground, and a specific frequency (800MHz This reduces the amount of feedback (~1GHz) and stabilizes circuit operation. Note that the resistor _R15 in the figure is inserted to adjust the amount of DC fed back by the resistor _R14 . By the way, if the circuit shown in Figure 2 is integrated and housed in an IC package, the configuration will be as shown in Figure 3. Since the integrated circuit chip and the package are connected by bonding wires, the lines shown in the figure are L _IN , L _OUT , L _B , L _G1 ,
It has a wire inductance of L _G2 .
This value, as mentioned above, will be a value between 2.5 and 5 nH,
As mentioned above, the effects of L _OUT , L _B , and L _IN can be removed, but the effects of L _G1 and L _G2 are large in terms of alternating current, and their mutual influence can lead to unstable operation. Since an oscillation state occurs, only at least one bonding inductance is allowed. Therefore, in the example of FIG. 3 of the present invention, the stability of the circuit is ensured by removing one inductance L _G2 , that is, the filter circuit 11 is installed outside the IC package. , has the function of resonating with the inductance of L _G2 and absorbing it.
The filter circuit 11 may have the shapes shown in FIGS. 5A, B, and C. In the example shown in Fig. 5A, a series resonant circuit is constructed with the bonding inductance L _G2 and the capacitor _C1 , and the influence of L _G2 is removed, and the emitter resistance _R13 of the transistor _Q2 is reduced near the desired frequency (800MHz to 1GHz). By eliminating the effects of In the 800MHz to 1GHz band, the appropriate value for capacitor _C1 is 15pF or less. If a capacitor _C1 of 1000 pF is used here, the characteristics will be as shown by the solid line A in Figure 4, and the gain at low frequencies will become too large and the inductance
Due to the influence of L _G2 , the circuit shown in Figure 3 becomes extremely susceptible to oscillation. For this reason, in a DC-coupled multi-stage amplifier circuit, the above-mentioned measures cannot be taken. In addition, if a damping resistor is inserted into the capacitor _C1 in FIG. 5A, a wide band can be secured and the desired effect can be obtained.

Figures 5B and 5C show other configuration examples of the filter circuit 11. Figure 5 shows a resonant circuit with L _G2 , Lx and _C1 , _C2, and Figure 5C shows a resonance circuit with L _G2 , Rx ₁ . C ₁ and C ₂ constitute a resonant circuit, and by developing the filter circuit in various ways, the characteristic B in FIG. 4 can be varied.

A second embodiment of the invention is shown in FIG. In the example of FIG. 6, an emitter follower circuit consisting of transistor Q ₃ and resistor R ₁₆ is inserted between the amplifier consisting of transistor Q 1 and the amplifier consisting of transistor Q ₂ in FIG. ₃ , and Q ₁ This improves the reverse transfer relationship between the Q2 amplifier and the _Q2 amplifier, which can further improve the stability of the circuit.

A third embodiment of the invention is shown in FIG. This example is similar to the emitter of transistor _Q1 in the example in Figure 3.
Insert a resistor _R16 between the ground inside the IC and connect the transistor
A terminal is brought out from the IC through the bonding wire L _G3 from the emitter of _Q1 , and a filter circuit 11' having the configuration shown in Fig. 5 is also inserted into that terminal.The filter circuits 11 and 11' are connected to transistors.
By connecting the emitters of Q ₁ and Q ₂ in two stages, the characteristics shown in FIG. 4B are made steeper.

A fourth embodiment of the invention is shown in FIG. In this device, in the example of FIG. 6 in which an emitter follower circuit is inserted, DC feedback to the base of transistor Q ₁ is applied from the emitter of emitter follower transistor Q ₃ using resistors R ₁₄ and R ₁₅ . , the same effect as the configuration shown in FIG. 6 can be obtained.

A fifth embodiment of the invention is shown in FIG. In the example shown in this figure, a DC-coupled multi-stage connected amplifier is configured.
A resistor is inserted between the internal ground of the IC in at least one emitter of the amplifier after the second stage, and a terminal is brought out from each emitter to the outside of the IC through the bonding wire _LGN , and the filter shown in Fig. 5 is connected between this terminal and the ground. By adding the circuit 11N, the operation of the circuit is stabilized. In the figure 1
The emitter follower circuit shown in 3 may or may not be inserted.

However, the direct current feedback to the base of the transistor _Q1 is to negatively feed back the divided potential with the resistor _RNG from the even-numbered emitters of the second and subsequent stage amplifiers through the resistor _RNB .

Although the first to fifth embodiments have been described above,
The DC feedback resistors R ₁₄ and R _NB may be configured outside the IC, and the potential of the DC feedback resistors does not necessarily need to be divided.

Furthermore, although the output signal in each embodiment is taken out directly from the collector of the emitter-grounded transistor, an emitter follower circuit may be inserted into the output of the emitter follower circuit to obtain the output from the emitter follower circuit.

Effects of the Invention By using the present invention, it is possible to stabilize the operation of a circuit in the integration of high-frequency DC connections and multi-stage coupling.

[Brief explanation of the drawing]

Figures 1A, B, and C are circuit diagrams of a high-frequency amplification device in a conventional example, Figure 2 is a circuit diagram of a high-frequency amplification device in an embodiment of the present invention, and Figure 3 is a circuit diagram of a high-frequency amplification device in an embodiment of the present invention, and Figure 3 shows the device of the present invention enclosed in an IC package. The equivalent circuit diagram when
Figure 4 is a frequency-amplitude characteristic diagram of a multistage amplifier;
Figures A, B, and C are circuit diagrams showing various specific examples of filter circuits used in the present invention, and Figure 6 is a circuit diagram showing various examples of filter circuits used in the present invention.
7 is a circuit diagram showing a third embodiment of the present invention, FIG. 8 is a circuit diagram showing a fourth embodiment of the present invention, and FIG. 9 is a circuit diagram showing a fourth embodiment of the present invention. FIG. 5 is a circuit diagram showing a fifth embodiment. Q ₁ , Q ₂ ... Amplification transistor, R ₁₃ , R ₁₄ ...
Resistor, 11...filter circuit.

Claims (1)

[Scope of Claims] 1. An integrated circuit is constructed by connecting emitter-grounded amplifiers in multiple stages by DC coupling, and a resistor is connected between the emitters of the transistors in the second and subsequent stages between the ground in the integrated circuit. A terminal is provided outside the integrated circuit through a bonding wire from the emitter terminal of at least one of the transistors, and a specified frequency (800MHz to 1G
1. A high frequency amplification device characterized by providing a filter circuit including an inductance of the bonding wire so as to have a low impedance in the vicinity of Hz. 2. The high frequency amplification device according to claim 1, wherein the emitter potential of the transistors in the second and subsequent stages is subjected to direct current negative feedback to the base of the input stage transistor through a resistor. 3. The high frequency amplification device according to claim 1, wherein an emitter follower circuit is inserted between each emitter grounded type amplifier circuit. 4. Insert a resistor between the emitter of the input stage transistor and the ground, connect an external terminal from the emitter via a bonding wire, and connect the desired frequency (800MHz to
2. The high frequency amplification device according to claim 1, further comprising a filter circuit including an inductance of the bonding wire so as to have a low impedance in the vicinity of 1 GHz. 5. The high frequency amplification device according to claim 3, wherein negative DC feedback is applied from the emitter terminal of the emitter follower circuit to the base of the transistor in the input stage via a resistor.