KR101094274B1 - Mode-Locking Power Amplifier Using Transmission Line Transformer - Google Patents

Abstract

The present invention relates to a power amplifier using a mode-locking technique using a transformer. More specifically, in a power amplifier structure having a differential structure, a gate of a transistor added for mode-injection is a transmission line transformer. The present invention relates to a power amplifier that receives power from the drain of an existing transistor through. According to the present invention, since the drain of the existing transistor and the gate of the transistor added for the mode-injection are separated by DC, the drain voltage of the existing transistor and the gate voltage of the transistor added for the mode-injection can be easily Detachable.

Semiconductor Integrated Circuits, High Frequency, Transformers, Transmission Lines, Mode-Locking

Description

Mode-Locking Power Amplifier Using Transmission Line Transformer

The present invention relates to a power amplifier, and more particularly, to a power amplifier using a mode-injection technique.

1 shows a simplified embodiment of a general power amplifier. 1 shows an amplifier stage operating in a differential structure, in which 101A and 101B represent MOSFETs driven by differential signals. Therefore, a high frequency signal having a phase difference of 180 ° is applied to the gates of 101A and 101B. Accordingly, the output signals at the drains of 101A and 101B also differ from each other by 180 °. At this time, the phase of the signal at the gate of 101A and the drain of 101B is almost the same, and the phase of the signal at the gate of 101B and the drain of 101A is almost the same.

FIG. 2 illustrates a cascode amplifier stage applied to the power amplifier of FIG. 1, in which 202A and 101A correspond to each other, and 202B and 101B correspond to each other. By adding 201A and 201B to this, the amplifier stage shown in FIG. 2 shows higher gain characteristics than the amplifier stage shown in FIG. In addition, the amplification stage of FIG. 2 has an advantage that a source of 201A and a drain of 202A are connected to each other, and a source of 201B and a drain of 202B are connected to each other, so that a higher power supply voltage can be used than the amplification stage of FIG. 1. . Even if the same power supply voltage is used, the drain-source voltage drop of each MOSFET used in the amplifier stage of FIG. 2 becomes smaller than that of the amplifier stage of FIG. You have this advantage.

In general, a DC voltage is applied to the gates of the 201A and 201B transistors of the amplifier according to FIG. 2.

3 illustrates an amplification stage structure using a mode-locking technique using the amplification stage according to FIG. 1. In the amplification stage structure shown in FIG. 3, a transistor of 301B and 302B was added to use a mode-injection technique, and the drain of 301B is connected to the drain of 301A and the gate of 302B, and the gate of 301B is connected to the drain of 302A and 302B. do. Similarly, the drain of 302B is connected to the drain of 302A and the gate of 301B, and the gate of 302B is connected to the drain of 301A and 301B.

At this time, since the gate signal of 301A and the drain signal of 302A and 302B to which the gate of 301B is connected are substantially in phase with each other, 301A and 301B have almost similar operations. Similarly, since the gate signal of 302A and the drain signals of 301A and 301B to which the gate of 302B is connected are substantially in phase with each other, 302A and 302B have almost similar operations. As a result, when RFIN + and RFIN − signals of the same magnitude are applied to the amplifier of FIG. 1 and the amplifier of FIG. 3, the amplifier of FIG. 3 is added to the amplifier of FIG. 1 because the transistors of 301B and 302B are added. Compared with the high gain characteristics. As a result, even if a weak RFIN +/- signal is applied to the amplifier according to FIG. 1, a positive feedback loop is formed by the transistors 301B and 302B and 301A and 302A for the mode-injection technique. You can expect power. Here, 303 was used as a switch for turning on / off the operation of the amplifier according to FIG. 3 by controlling such a positive feedback loop.

FIG. 4 illustrates an amplifier stage structure using a mode-locking technique using the amplifier stage shown in FIG. 2. In the amplifier stage structure of FIG. 4, the transistors of 401B and 402B were added to use the mode-injection technique, and the amplifier stage of FIG. 4 can be analyzed similarly to the analysis process of the amplifier stage of FIG. 3. The drain of 401B is connected to the drain of 401A and the source of 401C, and the gate of 401B is connected to the 402C drain. Similarly, the drain of 402B is connected to the drain of 402A and the source of 402C, and the gate of 402B is connected to the 401C drain.

At this time, since the gate signal of 401A and the drain signal of 402C to which the gate of 401B is connected are substantially in phase with each other, 401A and 401B have almost similar operations. Similarly, since the gate signal of 401A and the drain signal of 402C to which the gate of 401B are connected are substantially in phase with each other, 401A and 401B have almost similar operations. As a result, when RFIN + and RFIN − signals having the same magnitude are applied to the amplifier of FIG. 2 and the amplifier of FIG. 4, the amplifier of FIG. 4 is added to the amplifier of FIG. 2 because the transistors of 401B and 402B are added. Compared with the high gain characteristics. As a result, even though a weak RFIN +/- signal is applied to the amplifier according to FIG. 2, a positive feedback loop is formed by the transistors 401B and 402B and 401A and 402A for the mode-injection technique. You can expect output power. By controlling the DC voltages of 401C and 402C in the amplifier of FIG. 4, the role of 303 in the amplifier of FIG. 3 can be substituted.

As can be seen from the amplification stage structure using the mode-injection technique according to Figs. It is connected to the drain of DC. Therefore, the amplifier stage structure using the conventional mode-injection technique has the gate bias voltage of the transistor added for the mode-injection having a characteristic that is dependent on the drain voltage of the existing transistors 301A, 302A, 401C and 402C. do. In general, however, in the amplifier stage, the bias voltage of the gate has an optimum voltage, and this gate voltage is one of the variables that change the gain characteristics of the entire amplifier stage. That is, the conventional amplifier structure using the mode-injection technique has a problem that it is difficult to easily adjust the gate bias voltage of the transistor added for the mode-injection.

Accordingly, a technical problem of the present invention is to make it possible to easily change the gate bias voltage of a transistor added for the mode-injection technique in designing an amplifier using the mode-injection technique.

According to an aspect of the present invention, an amplifier includes a first transistor and a second transistor connected in parallel between a power supply voltage and a ground terminal to receive a differential signal having a phase difference of 180 °, and a third transistor. A mode-injection amplifier in which a source terminal and a drain terminal of a transistor and a fourth transistor are connected to corresponding source and drain terminals of the first transistor and the second transistor, respectively, wherein the gates of the third and fourth transistors are used. The terminals are electrically connected to the drain terminals of the second transistor and the first transistor with respect to the AC power, respectively, and are isolated from the DC power.

Preferably, the first transistor is electrically coupled to the gate terminal of the fourth transistor with respect to the AC power source of the drain terminal of the first transistor, and the second transformer is connected to the AC power source of the drain terminal of the second transistor. And electrically coupled to the gate terminal of the third transistor.

According to an aspect of the present invention, an amplifier includes a first transistor and a second transistor connected in parallel between a power supply voltage and a ground terminal to receive a differential signal having a phase difference of 180 °. A source terminal connected to the drain terminal of the first transistor, a gate terminal to which the DC voltage is applied, a first-first transistor to output the drain terminal, a source terminal connected to the drain terminal of the second transistor, and a gate to which the DC voltage is applied A mode in which the source terminal and the drain terminal of the 2-1 transistor, the third transistor, and the fourth transistor, to which the terminal and the drain terminal are output, are respectively connected to the corresponding source terminal and the drain terminal of the first transistor and the second transistor, respectively. In the injection amplifier, the gate terminals of the third transistor and the fourth transistor are respectively the same for the AC power source. 2, electrically connected to the transistor and the drain terminal of the first transistor being characterized in that the isolation for the DC supply.

Preferably, the first power transistor is electrically coupled to the gate terminal of the fourth transistor through the first transformer, and the first power source is connected to the AC power source of the drain terminal of the first transistor. It is characterized in that coupled to the gate terminal of the third transistor through a two transformer.

Preferably, the first transformer and the second transformer is characterized in that the spiral transformer.

Preferably, the number of turns on the primary side and the number of turns on the secondary side of the helical transformer are different from each other.

As described above, according to the present invention, since the drain of the transistor constituting the general high frequency amplifier and the gate of the transistor added for the mode-injection are DC separated, the gate bias voltage of the transistor added for the mode-injection. Can be easily adjusted independently of the supply voltage.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings. This embodiment is not intended to limit the scope of the invention, but is presented by way of example only.

(Example 1)

5 is a view for explaining a first embodiment of the mode-injection amplifier stage using the transmission line transformer according to the present invention. Unlike in FIG. 3, the amplifying stage structure according to the present invention is not directly connected to the drain of 502A, but is coupled to each other through a transformer. Thus, the AC signal at drain 502A is coupled to the gate of 501B through a transformer, but the DC voltage at drain 502A is isolated from the gate of 501B. Likewise, the gates of 502B are not directly connected to the drain of 501A, but are coupled to each other through a transformer. Thus, the AC signal at drain 501A is coupled to the gate of 502B through a transformer, but the DC voltage at drain 501A is isolated from the gate of 502B. Accordingly, when viewed from the side of the AC signal, FIGS. 3 and 5 have the same operation, and thus the amplifier structure of FIGS. 3 and 5 has the same AC characteristic. AC characteristic also includes gain characteristics. On the other hand, unlike the gates of 301B and 302B of FIG. 5, the gates of 501B and 502B of FIG. Regardless, there is an advantage that an independent gate bias voltage can be applied to the gates of 501B and 502B. Accordingly, in FIG. 5, it is easy to appropriately adjust the gate voltages of 501B and 502B to maximize the gain of the amplifier.

In this case, the transformer may be formed of a transmission line transformer often used in a high frequency circuit. This case is mainly useful when the operating frequency band is 1 GHz or more. As a variant of this, the transformer may be a general helical transformer, in which the winding ratio of the primary side and the secondary side constituting the transformer are adjusted to each other, so that the AC is coupled to 502B (or 501B) at the drain of 501A (or 502A). You can also adjust the size of the signal.

(Example 2)

6 is a view for explaining a second embodiment of the mode-injection amplifier stage using the transmission line transformer according to the present invention. Unlike in FIG. 4, the amplification stage structure according to the present invention is not directly connected to the drain of 602C, but is coupled to each other through a transformer. Thus, the AC signal at 602C drain is coupled to the gate of 601B through a transformer, but the DC voltage at 602C drain is isolated from the gate of 601B. Likewise, the gates of 602B are not directly connected to the drain of 601C, but are coupled to each other via a transformer. Thus, the AC signal of the 601C drain is coupled to the gate of 602B through a transformer, but the DC voltage of the 601C drain is isolated from the gate of 602B. Accordingly, when viewed from the side of the AC signal, since FIG. 4 and FIG. 6 perform the same operation, the amplifier structures of FIG. 4 and FIG. 6 have the same AC characteristics. AC characteristic also includes gain characteristics. On the other hand, unlike the gates of 401B and 402B of FIG. 6, the gates of 601B and 602B of FIG. 6 are isolated from each other in DC and drains of 601C and 602C, and thus are different from the power supply voltage applied to the drains of 601C and 602C. Regardless, there is an advantage that an independent gate bias voltage can be applied to the gates of 601B and 602B. Therefore, in FIG. 6, it is easy to appropriately adjust the gate voltages of 601B and 602B to maximize the gain of the amplifier.

In this case, the transformer may be formed of a transmission line transformer often used in a high frequency circuit. This case is mainly useful when the operating frequency band is 1 GHz or more. As a variant of this, the transformer may be a general helical transformer, in which the winding ratios of the primary side and the secondary side constituting the transformer are adjusted to each other, and are coupled to 602B (or 601B) at the drain of 601C (or 602C). You can also adjust the size of the AC signal.

1 is a view for explaining an amplifier having a conventional differential structure;

2 is a diagram for explaining an amplifier having a conventional differential structure and a cascode structure;

3 is a view for explaining an amplifier of a differential structure using a conventional mode-locking technique;

4 is a diagram for explaining an amplifier using a conventional mode-injection technique and employing a cascode and a differential structure;

5 is a view for explaining a first embodiment of a mode-injection amplifier using a transmission line transformer according to the present invention;

6 is a view for explaining a second embodiment of a mode-injection amplifier using a transmission line transformer according to the present invention.

Claims (6)

A first transistor and a second transistor connected in parallel between a power supply voltage and a ground terminal to receive a differential signal having a phase difference of 180 ° include a source terminal and a drain terminal of the third and fourth transistors. A mode-injection amplifier connected to a corresponding source terminal and a drain terminal of a transistor and the second transistor, respectively, And the gate terminals of the third transistor and the fourth transistor are electrically connected to the drain terminals of the second transistor and the first transistor with respect to an AC power supply, and are isolated from the DC power supply, respectively. The method of claim 1, The first transistor is electrically coupled to the gate terminal of the fourth transistor with respect to the AC power of the drain terminal of the first transistor, and the second transistor is connected to the gate terminal of the fourth transistor with respect to the AC power of the drain terminal of the second transistor. An amplifier electrically coupled with the gate terminal. It is composed of a first transistor and a second transistor connected in parallel between a power supply voltage and a ground terminal to receive a differential signal having a phase difference of 180 °, and a source terminal and a DC voltage connected to the drain terminal of the first transistor are applied. A first-first transistor outputting a gate terminal and a drain terminal, a source terminal connected to the drain terminal of the second transistor, a gate terminal to which a DC voltage is applied, and a second-1 transistor outputting a drain terminal; A mode-injection amplifier in which source and drain terminals of a third transistor and a fourth transistor are connected to corresponding source and drain terminals of the first transistor and the second transistor, respectively, And the gate terminals of the third transistor and the fourth transistor are electrically connected to the drain terminals of the second transistor and the first transistor with respect to an AC power supply, and are isolated from the DC power supply, respectively. The method of claim 3, Electrically coupled to the gate terminal of the fourth transistor with respect to the AC power supply of the drain terminal of the 1-1 transistor, and through the second transformer with respect to the AC power supply of the drain terminal of the 2-1 transistor. And an amplifier coupled to the gate terminal of the third transistor. The method according to claim 2 or 4, And the first transformer and the second transformer are helical transformers. The method of claim 5, And the number of turns on the primary side and the number of turns on the secondary side of the spiral transformer are different from each other.

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