JP2003060444A - Bias circuit for amplifier and high-frequency field effect transistor amplifier - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a bias circuit for an amplifier, capable of incorporating large temperature characteristics in an output voltage according to a single negative voltage. SOLUTION: The bias circuit for the amplifier comprises resistors 44 and 45, connected in series between a power source terminal 41 and a ground and having temperature characteristics different from each other, a field effect transistor 43 having a gate connected between the resistors 44 and 45, a resistor 45 connected between the power source terminal 41 and the source of the transistor 43, a resistor 47 connected between the drain of the transistor 43 and the ground, and an output voltage terminal 42 for generating on output voltage between the drain of the transistor 43 and the resistor 47.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bias circuit for an amplifier and a high frequency field effect transistor amplifier for reducing temperature characteristics of gain of an amplifier and reducing gain characteristic variation due to process variation.

[0002]

2. Description of the Related Art Conventionally, in order to reduce the temperature characteristic of gain of a semiconductor amplifier, a diode and a fixed resistor constitute a gate bias circuit of a high frequency amplification field effect transistor. Further, in order to reduce the variation in gain due to the variation in process, the constant current circuit is configured.

FIG. 8 shows, for example, (2001 Interna
regional Microwave Symposium
Digest P. 1071) is a circuit diagram showing a conventional temperature characteristic compensation bias circuit for a microwave integrated circuit, in which 1 is a Vgc terminal, 2 is a diode, 3 is a resistor, 4 is a Vr terminal, and 5 is Vg. Terminals, 6 are coils, 7 is an RFIN terminal, 8 is a high frequency amplification field effect transistor, and 9 is an RFOUT terminal.

Next, the operation will be described. In general, the high frequency amplification field effect transistor is characterized in that the gain decreases as the temperature rises, so it is necessary to adjust the gate bias voltage so as to compensate for the decrease in the gain due to the temperature rise. In FIG. 8, a negative voltage is supplied to both the Vgc terminal 1 and the Vr terminal 4, and Vgc, Vr and the resistor 3 are set so that an appropriate forward current flows through the diode 2.
The value of R has been determined. When the temperature rises, the gate voltage Vg of the high frequency amplification field effect transistor 8 rises due to the temperature characteristic of the diode 2 and compensates for the decrease in gain due to the temperature rise.

FIG. 9 shows, for example, Japanese Unexamined Patent Publication No. 7-21214.
It is a circuit diagram which shows the conventional high frequency amplifier shown by Unexamined-Japanese-Patent No. 4 in a figure, 11 is a 1st signal amplifier, 12 is a 2nd signal amplifier which also serves as a constant current circuit. Reference numeral 13 is a signal input terminal, 14 is a signal output terminal, and 15 is a power supply terminal to which a positive voltage is supplied. 16 is a field effect transistor, 17 is a bipolar transistor, 18 to 20 are coupling capacitors, 21 to 24 are bias resistors, 25 and 26.
Is an impedance matching coil, 27 to 30 are bypass capacitors, 31 and 32 are choke coils, 3
3 is a diode.

Next, the operation will be described. In FIG. 9, the second signal amplifier 12 operates as a constant current circuit. Therefore, even if the static characteristics of the field effect transistor 16 vary due to process variations, the drain current can be kept constant. In addition, a diode 33 is provided to cancel the temperature characteristic of the bipolar transistor 17, and acts to reduce the temperature dependence of the drain current of the field effect transistor 16.

[0007]

Since the conventional temperature characteristic compensating bias circuit is configured as described above, the circuit shown in FIG. 8 can compensate the temperature characteristic of the gain of the high frequency amplification field effect transistor 8. Have advantages. However, since it is necessary to prepare two types of voltages as the power supply to the Vgc terminal 1 and the Vr terminal 4, there is a problem that the external circuit that generates these voltages becomes large. In particular, the bias circuit of FIG.
gh Electron Mobility Tran
When applied to a field effect transistor having a shallow gate voltage setting value such as a system, a voltage not lower than the threshold voltage (~ 0.5V) of the diode 2 is required to fully develop the temperature characteristics of the diode 2. However, there is a problem in that it is necessary to prepare two types of positive and negative voltages because the voltages need to be applied to both ends of the diode 2. Also, FIG.
The temperature characteristic compensating bias circuit shown in (4) has no effect of correcting the gain variation due to the process variation of the high frequency amplification field effect transistor 8.

The high frequency amplifier shown in FIG. 9 has the effect of keeping the drain current of the field effect transistor 16 constant against temperature changes, but has no effect of compensating the gain temperature characteristic. Further, since two types of transistors, the field effect transistor 16 and the bipolar transistor 17, are used, there is a problem that it is difficult to realize the whole as one integrated circuit.

The present invention has been made to solve the above problems, and is not limited to the threshold voltage of a diode, and an arbitrary output voltage can be generated by a single negative voltage, and the output voltage can be changed. An object is to obtain a bias circuit for an amplifier that can have a large temperature characteristic. Further, the present invention compensates for the temperature characteristic of the gain of the high frequency amplification field effect transistor, and due to the similarity of the electric characteristics of the field effect transistors produced in close proximity,
An object of the present invention is to obtain a high-frequency field-effect transistor amplifier that can alleviate variations in the gain of the high-frequency amplification field-effect transistor due to process variations.

[0010]

A bias circuit for an amplifier according to the present invention comprises a first resistor and a second resistor which are connected in series between a negative voltage supply section and a ground and have different temperature characteristics.
Of the field effect transistor, a field effect transistor having a gate connected between the first resistance and the second resistance, a third resistance connected between the negative voltage supply section and the source of the field effect transistor, and A fourth resistor connected between the drain and the ground, and a voltage output unit for generating an output voltage from between the drain of the field effect transistor and the fourth resistor are provided.

A bias circuit for an amplifier according to the present invention is connected in series between a negative voltage supply section and a ground, and has a first resistor and a forwardly connected first diode having different temperature characteristics, and a first diode. A field effect transistor having a gate connected between the resistor and the first diode, a third resistor connected between the negative voltage supply unit and the source of the field effect transistor, and a drain connected between the drain and the ground of the field effect transistor. And a voltage output unit for generating an output voltage from between the drain of the field effect transistor and the fourth resistor.

A bias circuit for an amplifier according to the present invention comprises a fifth resistor connected between the source of the field effect transistor and the ground.

In the bias circuit for the amplifier according to the present invention, the temperature characteristics of the third resistor and the fifth resistor are different from each other.

A bias circuit for an amplifier according to the present invention is provided with a second diode connected in the forward direction between the source of the field effect transistor and the ground.

A high frequency field effect transistor amplifier according to the present invention comprises a bias circuit for an amplifier and a high frequency amplification field effect transistor whose gate is connected to a voltage output portion of the bias circuit. The bias circuit and the high frequency amplification field effect transistor are provided. Are integrated in the same chip by the same process.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below. Embodiment 1. 1 is a circuit diagram showing a bias circuit for a semiconductor amplifier according to a first embodiment of the present invention. In the figure, 41 is a power supply terminal (negative voltage supply section) for applying a negative voltage, and 42 is an output voltage terminal (voltage output). Section). 43
Is a field effect transistor, 44 is a resistor whose one end is grounded (first resistor), 45 is a resistor whose one end is connected in series to the other end of the resistor 44 and whose other end is connected to the power supply terminal 41 (second resistor). ). The resistors 44 and 45 have different temperature characteristics. The gate of the field effect transistor 43 is connected between the resistors 44 and 45. Reference numeral 46 is a resistance (third resistance) connected between the power supply terminal 41 and the source of the field effect transistor 43, and 47 is a resistance (fourth resistance) connected between the drain of the field effect transistor 43 and the ground.

Next, the operation will be described. In FIG. 1, when the environmental temperature changes, the gate-source voltage of the field effect transistor 43 changes due to the difference in temperature characteristics of the resistors 44 and 45. As a result, the drain current of the field effect transistor 43 changes, and the voltage output to the output voltage terminal 42 changes. Therefore, the resistor 44
By appropriately selecting the temperature characteristic of the resistor 45, the voltage output to the output voltage terminal 42 can have a desired temperature characteristic. For example, if a resistor 44 having a positive temperature coefficient and a resistor 45 having a negative temperature coefficient are selected, the gate-source voltage of the field effect transistor 43 increases negatively when the temperature rises, and thus the field effect transistor 43. Drain current is reduced. This allows the negative voltage output to the output voltage terminal 42 to have a positive temperature coefficient.

As described above, according to the first embodiment, the output voltage from the output voltage terminal 42 can have a desired temperature characteristic by appropriately selecting the temperature characteristics of the resistors 44 and 45. it can. Further, unlike the conventional technique, without being limited to the threshold voltage of the diode 2,
An arbitrary output voltage can be generated by a single negative voltage supplied from the power supply terminal 41, and the output voltage can have a large temperature characteristic.

Embodiment 2. 2 is a circuit diagram showing a bias circuit for a semiconductor amplifier according to a second embodiment of the present invention. In the figure, 48 is a resistor 45, an anode is connected in series to the other end of the resistor 44, and a cathode is a power source. It is a diode (first diode) connected to the terminal 41. The gate of the field effect transistor 43 is connected between the resistor 44 and the diode 48. Other configurations are the same as those in FIG.

Next, the operation will be described. When the environmental temperature changes, the gate-source voltage of the field effect transistor 43 changes due to the temperature characteristic of the diode 48.
As a result, the drain current of the field effect transistor 43 changes, and the voltage output to the output voltage terminal 42 changes. For example, when the temperature rises, the gate-source voltage of the field effect transistor 43 increases negatively, and the drain current of the field effect transistor 43 decreases. This allows the voltage output to the output voltage terminal 42 to have a positive temperature coefficient.

As described above, according to the second embodiment, the output voltage from the output voltage terminal 42 can have a desired temperature characteristic by appropriately selecting the temperature characteristics of the resistor 44 and the diode 48. it can. Further, unlike the conventional technique, an arbitrary output voltage is generated by a single negative voltage supplied from the power supply terminal 41 without being limited by the threshold voltage of the diode 2, and the output voltage has a large temperature characteristic. You can have it. Furthermore, since the two types of resistors 44 and 45 having different temperature characteristics are not used, when the semiconductor integrated circuit is configured, the manufacturing thereof can be facilitated.

Embodiment 3. 3 is a circuit diagram showing a bias circuit for a semiconductor amplifier according to a third embodiment of the present invention, in which 49 is a field effect transistor 43.
A resistor connected between the source and ground (fifth resistor)
Is. Other configurations are the same as those in FIG.

Next, the operation will be described. As in the second embodiment, the voltage output to the output voltage terminal 42 changes due to the change in the environmental temperature. In the third embodiment, by adding the resistor 49 connected between the source of the field effect transistor 43 and the ground, the rate of change of the current flowing through the resistor 46 can be reduced. Thereby, the rate of change of the voltage output to the output voltage terminal 42 can be increased.

As described above, according to the third embodiment, the change rate of the current flowing through the resistor 46 is reduced by the current flowing through the resistor 49, and the change rate of the output voltage is increased, whereby the output voltage is further increased. Can have great temperature characteristics. In the third embodiment, the example in which the resistor 49 is added to the circuit configuration of FIG. 2 has been shown, but the same effect can be obtained even if the resistor 49 is added to the circuit configuration of FIG.

Fourth Embodiment In the fourth embodiment of the present invention, the temperature characteristics of the resistor 46 and the resistor 49 in FIG. 3 shown in the third embodiment are made different from each other.

As described above, according to the fourth embodiment, due to the difference in the temperature characteristics of the resistors 46 and 49,
Since the temperature characteristic of the gate-source voltage of the field effect transistor 43 can be further increased, the temperature change rate of the voltage output to the output voltage terminal 42 can be further increased.

Embodiment 5. Fourth Embodiment FIG. 4 is a circuit diagram showing a bias circuit for a semiconductor amplifier according to a fifth embodiment of the present invention, in which 50 is a field effect transistor 43.
Is a diode (second diode) connected in the forward direction between the source and the ground. Other configurations are the same as those in FIG.

Next, the operation will be described. As in the second embodiment, the voltage output to the output voltage terminal 42 changes due to the change in the environmental temperature. In the fifth embodiment, the non-linearity of the resistance of the diode 50 suppresses the change in the source potential of the field effect transistor 43 due to the change in the drain current of the field effect transistor 43, and the field effect due to the temperature characteristic of the diode 50 itself. Since the temperature characteristic of the gate-source voltage of the transistor 43 can be further increased, the temperature change rate of the voltage output to the output voltage terminal 42 can be further increased.

As described above, according to the fifth embodiment, the temperature characteristic of the gate-source voltage of the field effect transistor 43 can be further increased due to the difference in temperature characteristic of the resistor 46 and the diode 50. The temperature change rate of the voltage output to the output voltage terminal 42 can be further increased. Further, since the two types of resistors 46 and 49 having different temperature characteristics are not used, when the semiconductor integrated circuit is configured, its manufacture can be facilitated. Although the fifth embodiment has shown the example in which the diode 50 is added to the circuit configuration of FIG. 2, the same effect can be obtained by adding the diode 50 to the circuit configuration of FIG.

Sixth Embodiment 5 is a circuit diagram showing a high frequency field effect transistor amplifier according to a sixth embodiment of the present invention. In the figure, 51 is a bias circuit for the semiconductor amplifier shown in the fifth embodiment, and 52 is an output of the bias circuit 51. A high frequency amplification field effect transistor having a gate connected to the voltage terminal 42. The bias circuit 51 and the high frequency amplification field effect transistor 52 are manufactured by being integrated in the same chip by the same process. FIG. 6 is a characteristic diagram showing the ambient temperature-output voltage characteristic of the bias circuit, and FIG. 7 is the threshold voltage of the field effect transistor.
It is a characteristic view which shows a drain current and a mutual conductance characteristic.

Next, the operation will be described. As in the fifth embodiment, the voltage output to the output voltage terminal 42 changes due to the change in the environmental temperature. In FIG. 5, since the voltage output to the output voltage terminal 42 gives the gate voltage of the high frequency amplification field effect transistor 52, it acts so as to compensate the temperature characteristic of the gain of the high frequency amplification field effect transistor 52. Further, since the field effect transistor 43 and the high frequency amplification field effect transistor 52 are formed in the vicinity of the same integrated circuit by the same process, the change of the threshold voltage due to the process variation is interlocked. At this time, the change in the drain current flowing through the field effect transistor 43 due to the process variation and the accompanying change in the voltage output to the output voltage terminal 42 cause the variation in the drain current of the high frequency amplification field effect transistor 52 due to the process variation. Acts to compensate.

Calculation examples of the effects of the sixth embodiment are shown in FIGS. 6 and 7. 6 is the same as that of FIG.
Is -1.4 V, the standard temperature of the high-frequency amplification field-effect transistor 52 under standard process conditions (2
5 ° C), that is, the gate voltage, that is, the voltage of the output voltage terminal 42 is -0.1 V, and the ambient temperature is -25 ° C to 75 °.
It shows a change in the voltage of the output voltage terminal 42 when changing to C. Further, FIG. 7 shows changes in the drain current and the transconductance of the high-frequency amplification field-effect transistor 52 when it is assumed that the threshold voltages of the field-effect transistor 43 and the high-frequency amplification field-effect transistor 52 change by ± 0.1 V due to process variations. It is shown. In order to compensate the temperature characteristic of the gain of the high frequency amplification field effect transistor 52, it is necessary to set the gate voltage shallower as the temperature becomes higher, but such setting of the gate voltage is realized by the bias circuit 51 of FIG. It can be confirmed from FIG. 6 that this is done. Further, the drain current and the transconductance of the high-frequency amplification field-effect transistor 52 vary with the variation of the threshold voltage of the high-frequency amplification field-effect transistor 52. However, by applying the bias circuit 51, the variation amount can be reduced. It can be confirmed from FIG. 7 that this can be done.

As described above, according to the sixth embodiment, the gain temperature characteristic of the high frequency amplification field effect transistor 52 is compensated, and the electric characteristic similarity of the field effect transistor 43 produced in close proximity is obtained. The variation in the gain of the high frequency amplification field effect transistor 52 due to the variation in the process can be reduced. In the sixth embodiment, the example in which the circuit configuration shown in the fifth embodiment is applied as the bias circuit 51 is shown, but the circuit configurations shown in the other embodiments may be applied.

[0034]

As described above, according to the present invention, the first resistance and the second resistance, which are connected in series between the negative voltage supply portion and the ground and have different temperature characteristics, the first resistance and the first resistance, are provided. A field effect transistor having a gate connected between the two resistors, a third resistor connected between the negative voltage supply unit and the source of the field effect transistor, and a fourth resistor connected between the drain of the field effect transistor and ground. And a voltage output section for generating an output voltage between the drain of the field effect transistor and the fourth resistance, the temperature characteristics of the first resistance and the second resistance should be appropriately selected. As a result, the output voltage from the voltage output section can have desired temperature characteristics. Further, unlike the conventional technique, the output voltage is not limited to the threshold voltage of the diode, an arbitrary output voltage is generated by a single negative voltage supplied from the negative voltage supply unit, and the output voltage has a large temperature characteristic. There is an effect that you can have.

According to the present invention, the first resistance and the first diode connected in the forward direction, which are connected in series between the negative voltage supply section and the ground and have different temperature characteristics, and the first resistance and the first diode are connected. A field effect transistor having a gate connected between the diodes, a third resistor connected between the negative voltage supply unit and the source of the field effect transistor, and a fourth resistor connected between the drain of the field effect transistor and ground. And a voltage output section for generating an output voltage between the drain of the field effect transistor and the fourth resistor, the temperature characteristics of the first resistor and the first diode are appropriately selected. The output voltage from the voltage output section can have a desired temperature characteristic. Further, unlike the conventional technique, the output voltage is not limited to the threshold voltage of the diode, an arbitrary output voltage is generated by a single negative voltage supplied from the negative voltage supply unit, and the output voltage has a large temperature characteristic. You can have it. Further, since two types of first resistance and second resistance having different temperature characteristics are not used, there is an effect that the manufacturing thereof can be facilitated when the semiconductor integrated circuit is configured.

According to the present invention, since the fifth resistor connected between the source of the field effect transistor and the ground is provided, the current flowing through the fifth resistor causes
By decreasing the rate of change of the current flowing through the third resistor and increasing the rate of change of the output voltage, there is an effect that the output voltage can have a larger temperature characteristic.

According to the present invention, the third resistor and the fifth resistor
Since the temperature characteristics of the resistance of are different from each other,
Due to the difference in the temperature characteristics of the third resistance and the fifth resistance,
By further increasing the rate of change of the output voltage, there is an effect that the output voltage can have a larger temperature characteristic.

According to the present invention, since the second diode connected in the forward direction is provided between the source of the field effect transistor and the ground, the non-linearity of the resistance of the second diode causes the field effect transistor. The change in the source potential of the field effect transistor due to the change in the drain current of the field effect transistor can be suppressed, and the temperature characteristic of the gate-source voltage of the field effect transistor can be further increased by the temperature characteristic of the second diode. The voltage can have a large temperature characteristic. Also,
Two types of third resistance and fifth type having different temperature characteristics
Since the resistor is not used, there is an effect that the manufacturing thereof can be facilitated when the semiconductor integrated circuit is configured.

According to the present invention, the bias circuit for the amplifier and the high frequency amplification field effect transistor whose gate is connected to the voltage output part of the bias circuit are provided, and the bias circuit and the high frequency amplification field effect transistor are provided in the same chip. Since the temperature characteristics of the gain of the high frequency amplification field effect transistor are compensated for by the same process, the high frequency amplification field effect transistor due to the process variation is caused by the similarity of the electric characteristics of the field effect transistor which is manufactured in close proximity. There is an effect that variation in gain of the effect transistor can be reduced.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a bias circuit for a semiconductor amplifier according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing a bias circuit for a semiconductor amplifier according to a second embodiment of the present invention.

FIG. 3 is a circuit diagram showing a bias circuit for a semiconductor amplifier according to a third embodiment of the present invention.

FIG. 4 is a circuit diagram showing a bias circuit for a semiconductor amplifier according to a fifth embodiment of the present invention.

FIG. 5 is a circuit diagram showing a high frequency field effect transistor amplifier according to a sixth embodiment of the present invention.

FIG. 6 is a characteristic diagram showing an environmental temperature-output voltage characteristic of a bias circuit.

FIG. 7 is a characteristic diagram showing threshold voltage-drain current and mutual conductance characteristics of a field effect transistor.

FIG. 8 is a circuit diagram showing a conventional temperature characteristic compensation bias circuit for a microwave integrated circuit.

FIG. 9 is a circuit diagram showing a conventional high frequency amplifier.

[Explanation of symbols]

1 Vgc terminal, 2 diode, 3 resistor, 4 Vr
Terminal, 5 Vg terminal, 6 coil, 7 RFIN terminal,
8 high frequency amplification field effect transistor, 9 RFOUT
Terminal, 11 first signal amplifier, 12 second signal amplifier, 13 signal input terminal, 14 signal output terminal, 15
Power supply terminal, 16 field effect transistor, 17 bipolar transistor, 18 to 20 coupling capacitor, 21
-24 bias resistance, 25, 26 matching coil, 27-30 bypass capacitor, 31, 32 choke coil, 33 diode, 41 power supply terminal (negative voltage supply section), 42 output voltage terminal (voltage output section), 4
3 field effect transistor, 44 resistance (first resistance), 45 resistance (second resistance), 46 resistance (third resistance), 47 resistance (fourth resistance), 48 diode (first diode), 49 resistance (fifth resistance), 5
0 diode (second diode), 51 bias circuit, 52 high frequency amplification field effect transistor.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kazuhisa Yamauchi             2-3 2-3 Marunouchi, Chiyoda-ku, Tokyo             Inside Ryo Electric Co., Ltd. (72) Inventor Kazutomi Mori             2-3 2-3 Marunouchi, Chiyoda-ku, Tokyo             Inside Ryo Electric Co., Ltd. (72) Inventor Yukio Ikeda             2-3 2-3 Marunouchi, Chiyoda-ku, Tokyo             Inside Ryo Electric Co., Ltd. (72) Inventor Naoki Takagi             2-3 2-3 Marunouchi, Chiyoda-ku, Tokyo             Inside Ryo Electric Co., Ltd. F-term (reference) 5J090 AA01 AA58 CA02 CA15 CA81                       CA91 CA92 CN01 FA10 FN06                       HA02 HA09 HA12 HA18 HA19                       HA25 HA29 HA32 HA33 KA12                       MA21 TA02 TA04                 5J092 AA01 AA58 CA02 CA15 CA81                       CA91 CA92 FA10 HA02 HA09                       HA12 HA18 HA19 HA25 HA29                       HA32 HA33 KA12 MA21 TA02                       TA04

Claims (6)

[Claims] 1. A gate is connected between a first resistance and a second resistance, which are connected in series between a negative voltage supply section and a ground and have different temperature characteristics, and the first resistance and the second resistance. A field effect transistor, a third resistor connected between the negative voltage supply section and the source of the field effect transistor, a fourth resistor connected between the drain of the field effect transistor and ground, and the field effect. A bias circuit for an amplifier, comprising: a drain of a transistor and a voltage output unit that generates an output voltage from between the fourth resistor. 2. A first diode connected in series between a negative voltage supply section and ground and having different temperature characteristics from each other and a first diode connected in a forward direction, and the first resistance and the first diode. A field-effect transistor having a gate connected to it, a third resistor connected between the negative voltage supply section and the source of the field-effect transistor, and a fourth resistor connected between the drain of the field-effect transistor and ground. And a voltage output section for generating an output voltage from between the drain of the field effect transistor and the fourth resistor, and a bias circuit for an amplifier. 3. A bias circuit for an amplifier according to claim 1, further comprising a fifth resistor connected between the source of the field effect transistor and the ground. 4. The bias circuit for an amplifier according to claim 3, wherein the temperature characteristics of the third resistor and the fifth resistor are different from each other. 5. A bias circuit for an amplifier according to claim 1, further comprising a second diode connected in a forward direction between the source of the field effect transistor and ground. 6. A bias circuit for an amplifier according to any one of claims 1 to 5, and a high frequency amplification field effect transistor having a gate connected to a voltage output section of the bias circuit, A high frequency field effect transistor amplifier, characterized in that the bias circuit and the high frequency amplification field effect transistor are integrated in the same chip by the same process.