JPS60177710A - High frequency amplifier - Google Patents

Abstract

PURPOSE:To ensure the stable working of a circuit which is obtained through integration of the high frequency DC connected multi-stage coupling, by leading a terminal outside an IC through a bonding wire of said IC and forming a filter circuit containing the inductance of the bonding wire from said terminal between the counter earths. CONSTITUTION:A sum current of the base current of a transistor (TR) Q2 and the current flowing through a resistance R12 is supplied to the emitter of the TRQ2. This sum current is also supplied to an earth (GND) through a resistance R13. Thus a potential decided by the product of the emitter current of the TRQ2 and the value of a resistance R13 is produced at the R13. This potential is fed back to the base of a TRQ1 through a resistance R14 and therefore the base potential of the TRQ1 is stabilized at a certain fixed point. Under such conditions, the input signals are amplified by both TRQ1 and Q2. However it is impossible to increase the gain by the emitter resistance R13 of the TRQ2 in terms of a high frquency. In this respect, a filter circuit 11 is inserted between earths from the emitter of the TRQ2. This reduces the feedback amount of a specific frequency and then stabilizes the circuit working.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application 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 broadcasting receivers, etc. It is.

Conventional Structure and Problems Conventionally, in a high frequency amplifier circuit that processes high frequency signals of 100 MH2 band or higher, a multistage connection circuit as shown in FIG. 1 is often used to obtain high gain. In order to integrate a circuit in FIG. 1, it is necessary to encapsulate it in an IC package 1 as shown in FIG.

1b, 10, 1d and the IC chip are connected by bonding wires, so they are not shown in Figure B, but L1n+LG,
One with wire inductance like Lout, t, B. This wire inductance usually has a value of 2.6 mH to 6 mH, and is a value that can be ignored at low frequencies, but becomes a value that cannot be ignored when it comes to high frequency signals of 800 MHz or more. In the circuit of FIG. 1, LIN, LB, and Lout are external circuits or resistors R1! inside the IC. By R31”4,
Although that influence can be removed, only the inductance LG inserted between the ground and ground (GND) cannot be removed.

In the example shown in the figure, a particular problem is that a common interface component is inserted into the emitters of transistors Q+ and Q2, which creates a feedback loop and causes oscillation in the circuit, which is a serious drawback.

In Figure 1C, a resistor R5 is inserted into the emitter of the transistor Q2 in Figure 1B, and the bonding wire inductance LG2 is grounded through a bypass capacitor C connected to the outside of the IC in order to improve the above oscillation phenomenon. However, if there is only one transistor Q, there is no problem, but by connecting transistors Q1 and 92 in multiple stages, the wire inductance LG2 (!: both transistor Q1
Due to the presence of wire inductance LG, which is caused by grounding the emitter of k+ to the ground inside the IC, the ground potential of the circuit becomes unstable, and even if there is only one k+, there is no problem, but when connected in multiple stages, an oscillation state may occur. It had the disadvantage that it could not be removed.

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

Composition of the Invention The high-frequency amplification device according to the present invention is constituted by an integrated circuit of a circuit in which emitter-grounded amplifiers are DC-coupled and connected in multiple stages. and from the emitter of at least one of those transistors, a terminal is brought out of the integrated circuit through a bonding wire of the integrated circuit, and from this terminal a filter circuit including the inductance of the bonding wire is constructed between the terminal and ground. However, a specific frequency is grounded outside the integrated circuit using a filter circuit, thereby preventing feedback due to the emitter resistance and increasing gain.

DESCRIPTION OF THE EMBODIMENTS An example of the structure of the present invention is shown in FIG. The illustrated example is a two-stage amplifier circuit using seven transistors with common emitters, Q+ and Q2. The commercial frequency input signal is supplied from the input terminal IN and output from the output terminal 0LIT. Here, the collector of the transistor Q is connected to the power supply terminal B.
A current flows through the resistor R1+, and the current is shunted to the base of the transistor Q2, and the current flows through the transistor Q2.
A current is supplied to the collector of No. 2 from 1JRR 1B through resistor R+2.

The sum of the base current of the transistor Q2 and the current flowing through the resistor R12 flows through the emitter of the transistor Q2, and flows through the resistor R13 to the ground (GND). When a potential determined by the product of the value is generated and is fed back to the base of the transistor Q1 through the resistor R14, the base potential of the transistor Q+(7) rises, the collector potential of the transistor Q falls, and the emitter of the transistor Q2 The potential decreases, the base potential of transistor Q1 becomes stable at a certain point, and resistor RIT + R13
+ "+4 + By selecting the value of R16, desired currents can be made to flow through transistors Q+, Qz, and Qz. In such a state, the input signal - is amplified by transistors Q+ and Q2. However, since it is not possible to obtain gain at high frequencies due to the emitter resistor R13 of the transistor Q2, a filter circuit 11 is inserted between the emitter of the transistor Q2 and the ground to reduce the amount of feedback at a specific frequency and improve the circuit operation. Note that the resistor Rss in the figure is inserted to adjust the amount of DC to be fed back using 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. Indicates LrN, Lout, LB, LC
, I, LC2. As mentioned above, this value is 2.5 to 5 mH, and as mentioned above, the influence can be removed for Lout, LB, and Lrn, but for LGI, L
The two C2 have a large influence in terms of alternating current, and because they influence each other, the operation becomes unstable and oscillates, so at least one bonding inductance is allowed.
There will be no. Therefore, in the example of FIG. 3 of the present invention,
The purpose is to ensure the stability of the circuit by removing one inductance LG2, that is, by installing a filter circuit 11 outside the IC path socket 7,
It has a function to absorb the interftance and resonance of LC2. As the filter circuit 11, the sixth
Figures A and B.

A shape as shown in C is possible. In the example shown in FIG. 5A, the bonding inductance LG2 and the capacitor C constitute a series resonant circuit to eliminate the influence of LC2 and the influence of the emitter resistor R13 of the transistor Q2 in the vicinity of the desired frequency. It is possible to obtain the characteristics shown by the broken line B and suppress the gain in the low frequency band. In the 800 MHz to 1 GHz band, a suitable value for the capacitor C7 is 15 pF or less. Here, if a capacitor C of 1000 pF is used, 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 due to the influence of the inductances I and G2, the characteristics will be as shown in Figure 3. The circuit becomes extremely susceptible to oscillation. For this reason, the above-mentioned solution is not acceptable in a DC-coupled multi-stage amplifier circuit. In addition,
In FIG. 6A, if a damping resistor is inserted into the capacitor C1, a wide band can be secured and the desired effect can be obtained.

6B and 6C show other configuration examples of the filter circuit 11. FIG. 5B shows a resonance circuit using LC2, LX and CI+02, and FIG. 6C shows a resonance circuit using LC2, RXI and CI+C2. It constitutes a resonant circuit, and by developing the filter circuit in various ways as described above, 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 a transistor Q3 and a resistor Ft+6 is inserted between the amplifier rl+ consisting of the transistor Q1 and the amplifier consisting of the transistor Q2 in FIG. This improves the reverse transfer relationship between the amplifiers, which can further improve the stability of the circuit.

A third embodiment of the invention is shown in FIG. In this example, the third
A resistor R16 is inserted between the emitter of the transistor Q1 in the example in the figure and the ground inside the IC, and a terminal is brought out from the emitter of the transistor Q1 to the outside of the IC through the bonding wire LG3, and the filter circuit with the configuration shown in Figure 6 is also connected to that terminal. 1
1' is inserted, and the characteristic shown in FIG. 4B is made steeper by connecting filter circuits 11 and 11' in two stages to the emitters of each of transistors Ql and Q2.

A fourth embodiment of the invention is shown in FIG. This device is the 6th
In the example of inserting the emitter follower circuit shown in the figure, the DC feedback to the base of the transistor Q1 is connected from the emitter of the emitter follower transistor Q3 to the resistor R14r'' +5.
It is possible to obtain the same effect as the structure shown in FIG. 6.

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, and a resistor is inserted between the ground in the IC in at least one emitter of the second and subsequent amplifiers, and a terminal is connected from each emitter to ICIIJ through the bonding wire LGN. By connecting the filter circuit 11N shown in FIG. 5 between this terminal and the ground, the operation of the circuit is stabilized. The emitter follower circuit indicated by 13 in the figure 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 E (yB).

Although the first to fifth embodiments have been described above, the DC feedback resistor R+<, RNB may be configured outside the IC, and the potential of the DC feedback resistor does not necessarily need to be divided.

Furthermore, although the output signal in each embodiment is taken out directly from the collector of the common emitter 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 connection 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 embodiments of the present invention, and Figure 3 is a circuit diagram of a high-frequency amplification device according to embodiments of the present invention, and Figure 3 shows a device of the present invention enclosed in an IC package. Figure 4 is a frequency-amplitude characteristic diagram of a multistage amplifier. Figures 6A, B, and C are circuit diagrams showing specific examples of filter circuits used in the present invention. Figure 6 is a diagram of the present invention. A circuit diagram showing the second embodiment of the invention, FIG. 7 is a circuit diagram showing the third embodiment of the invention.
FIG. 8 is a circuit diagram showing a fourth embodiment of the present invention, and FIG. 9 is a circuit diagram showing a fifth embodiment of the present invention. Ql, Q2 ・Amplification transistor, "+3 + "+4
・Resistor, 11・-filter circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person 2nd
Figure 3 Figure 4 Figure 5

Claims (4)

[Claims] (1) An integrated circuit is constructed by connecting emitter-grounded amplifiers in multiple stages using DC coupling, and a resistor is connected between the emitters of the transistors in the second and subsequent stages to the ground in the integrated circuit. A high frequency device that is characterized by providing a terminal outside the integrated circuit through a bonding wire from one emitter terminal, and installing a filter circuit between that terminal and external ground to provide low impedance in the vicinity of a specific frequency. Amplifier. (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 negative feedback through the base KW flow 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 amplification circuit. (4) Insert a resistor between the emitter of the transistor in the input stage and the ground, provide an external terminal from the emitter via a bonding wire, and provide a low impedance in the vicinity of the desired frequency between the external terminal and the external ground. 2. The high frequency amplification device according to claim 1, further comprising a filter circuit such that: 3. 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 input stage transistor via a resistor.