JP5627514B2 - Variable temperature attenuation circuit - Google Patents

Description

  The present invention relates to a temperature variable attenuation circuit that compensates for temperature characteristics of an amplifier or the like in a high frequency circuit.

  In a high frequency circuit, a variable temperature attenuation circuit is used as a circuit for compensating temperature characteristics of an amplifier or the like (for example, Patent Documents 1 and 2).

  In Patent Document 1, a plurality of resistors and thermistors constitute a π-type attenuator, and by adjusting the resistance value of the resistor and the temperature characteristic of the thermistor, the temperature characteristic is opposite to that of the amplifier to be compensated. A variable temperature attenuation circuit has been proposed.

  Patent Document 2 discloses an example in which such a temperature variable attenuation circuit is configured by a single component, so that temperature compensation can be easily realized simply by surface mounting the component on a substrate.

JP 2001-144568 A Utility Model Registration No. 2544438

  However, the temperature characteristics of amplifiers and the like vary from individual to individual, and also vary depending on the production lot. Therefore, when increasing the accuracy of temperature compensation, it is necessary to individually adjust the temperature characteristics of the temperature compensation circuit in accordance with the temperature characteristics of an amplifier or the like. As means for realizing this adjustment relatively easily, there is a method of using a chip-type variable temperature attenuator as a temperature compensation circuit. In this case, a plurality of chip-type temperature variable attenuators having different temperature characteristics may be prepared, and the chip-type temperature variable attenuator may be selected in accordance with the temperature characteristics of an amplifier or the like. Specifically, there is a method in which temperature characteristics of an amplifier or the like are measured in advance, and a chip-type temperature variable attenuator is selected and mounted in accordance with the characteristics.

  However, this method increases the test cost because it is necessary to measure the temperature characteristics of a single unit such as an amplifier in addition to the temperature characteristics of the entire circuit. As a method of avoiding this, a chip-type variable attenuator with temperature characteristics centered on the design is incorporated in a circuit that requires temperature compensation, such as an amplifier, and the temperature characteristics of the entire circuit are measured. There is a way to replace it with a chip-type variable temperature attenuator with optimal temperature characteristics. In this case, it is not necessary to measure the temperature of a single unit such as an amplifier, but if the parts are replaced, the assembly cost increases. In either case, it is necessary to prepare a plurality of chips having different temperature characteristics, which increases the component cost. Thus, when the accuracy of temperature compensation is increased, the conventional method has a problem that the cost increases accordingly.

  The present invention has been made in view of the above, and an object of the present invention is to provide a temperature variable attenuation circuit that enables highly accurate temperature compensation without causing an increase in cost.

  In order to solve the above-described problems and achieve the object, the present invention includes a temperature variable attenuator whose attenuation varies with temperature, a first variable resistor provided in parallel with the temperature variable attenuator, and one end. Is connected to one input / output end of the temperature variable attenuator, the other end is a second variable resistor constituting one signal input / output end, and one end is connected to the other input / output end of the temperature variable attenuator. And a third variable resistor connected to the other end and constituting the other signal input / output end.

  According to the present invention, by changing the resistance values of the three variable resistors, it is possible to arbitrarily change the temperature characteristics of the attenuation amount while keeping the attenuation amount at the reference temperature of the entire circuit constant. . Then, the temperature characteristic of the temperature variable attenuation circuit can be easily adjusted according to the temperature characteristic of the circuit to be compensated. At this time, the temperature characteristic can be changed without preparing a plurality of temperature variable attenuators having different temperature characteristics. Therefore, it is possible to realize a temperature variable attenuation circuit that enables highly accurate temperature compensation without causing an increase in cost.

FIG. 1 is a circuit diagram showing a configuration of a temperature variable attenuation circuit according to Embodiment 1 of the present invention. FIG. 2 is a circuit diagram showing a configuration example of the temperature variable attenuator shown in FIG. FIG. 3 is a characteristic diagram showing a temperature characteristic example of the attenuation in the temperature variable attenuation circuit shown in FIG. FIG. 4 is a diagram illustrating the setting contents of the three variable resistors shown in FIG. 1 that obtain the three temperature characteristics shown in FIG. FIG. 5 is a conceptual diagram showing a mounting example of a temperature variable attenuation circuit that realizes the three temperature characteristics shown in FIG. FIG. 6 is a conceptual diagram showing a mounting example of a temperature variable attenuation circuit that realizes the temperature characteristic in the setting 1 shown in FIG. 3 using the configuration shown in FIG. FIG. 7 is a conceptual diagram illustrating an implementation example of a temperature variable attenuation circuit that realizes the temperature characteristics in the setting 2 illustrated in FIG. 3 using the configuration illustrated in FIG. FIG. 8 is a conceptual diagram showing a mounting example of a temperature variable attenuation circuit that realizes the temperature characteristics in setting 3 shown in FIG. 3 using the configuration shown in FIG. FIG. 9 is a circuit diagram showing a configuration of a temperature variable attenuation circuit according to the second embodiment of the present invention.

  Embodiments of a variable temperature attenuation circuit according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a circuit diagram showing a configuration of a temperature variable attenuation circuit according to Embodiment 1 of the present invention. In FIG. 1, a temperature variable attenuating circuit 1a according to the first embodiment includes a temperature variable attenuator 2 whose attenuation varies with temperature, a variable resistor R1 connected in parallel to the temperature variable attenuator 2, and a variable temperature. One end is connected to one input / output end of the attenuator 2 and the other end is one input / output terminal 3a, and one end is connected to the other input / output end of the temperature variable attenuator 2 and the other end is connected. It is comprised by the variable resistor R3 used as the other input / output terminal 3b.

  Here, FIG. 2 is a circuit diagram showing a configuration example of the temperature variable attenuator shown in FIG. A temperature variable attenuator 2 shown in FIG. 1 is connected to a resistor 6 in parallel with a temperature variable resistor (eg, a thermistor) 8 in a π-type attenuator composed of resistors 5, 6, and 7 as shown in FIG. This is the configuration.

  The circuit configuration of the temperature variable attenuating circuit 1a according to the first embodiment includes the temperature variable attenuator 2 and the variable resistor R1 by connecting the variable resistor R1 in parallel with the temperature variable attenuator 2. The amount of change in attenuation due to the circuit temperature can be reduced compared to the amount of change in the temperature variable attenuator 2 alone. At this time, by changing the resistance value of the variable resistor R1, the amount of change in attenuation due to temperature can be arbitrarily set to a value smaller than the amount of change in the temperature variable attenuator 2 alone.

  The attenuation amount at the reference temperature of the circuit constituted by the temperature variable attenuator 2 and the variable resistor R1 varies depending on the resistance value of the variable resistor R1, but the variable resistor is connected in series to both ends of the temperature variable attenuator 2. By connecting R2 and R3 and changing the resistance values of the variable resistors R2 and R3 in accordance with the resistance value of the variable resistor R1, the temperature of the entire circuit at the reference temperature is kept constant while maintaining the temperature constant. It is possible to arbitrarily set a change in the amount of attenuation due to.

  Next, FIG. 3 is a characteristic diagram showing an example of temperature characteristics of the attenuation in the temperature variable attenuation circuit shown in FIG. FIG. 4 is a diagram illustrating the setting contents of the three variable resistors shown in FIG. 1 that obtain the three temperature characteristics shown in FIG.

  In FIG. 3, when the normal temperature (25 ° C.) is the reference temperature and the attenuation at the normal temperature is 6 dB, the temperature characteristic 11 in setting 1, the temperature characteristic 12 in setting 2, and the temperature characteristic in setting 3 13 is shown. The temperature characteristic 11 in setting 1 is −0.007 dB / dB / ° C. The temperature characteristic 12 in setting 2 is -0.006 dB / dB / ° C. The temperature characteristic 13 in setting 3 is -0.005 dB / dB / ° C.

  In FIG. 4, in setting 1, the variable resistor R1 is open (open) setting, and the variable resistors R2 and R3 are each in short (short circuit) setting. That is, the temperature variable attenuation circuit 1a shown in FIG. Therefore, the temperature characteristic 11 indicates the temperature characteristic of the attenuation amount in the temperature variable attenuator 2. In setting 2, the variable resistor R1 is set to 90Ω, and the variable resistors R2 and R3 are each set to 5Ω. In setting 2, the variable resistor R1 is set to 5Ω, and the variable resistors R2 and R3 are each set to 16Ω.

  In this way, by selecting each of the resistance values of the variable resistors R1, R2, and R3 as setting 1, setting 2, and setting 3, the temperature characteristics of the attenuation amount can be obtained by maintaining the attenuation amount at room temperature at 6 dB. The characteristic 11 can be changed to “−0.007 dB / dB / ° C.”, the temperature characteristic 12 “−0.006 dB / dB / ° C.”, and the temperature characteristic 13 “−0.005 dB / dB / ° C.”.

  Next, a method for realizing a temperature variable attenuation circuit that realizes the three temperature characteristics shown in FIG. 3 will be described with reference to FIGS. FIG. 5 is a conceptual diagram showing a mounting example of a temperature variable attenuation circuit that realizes the three temperature characteristics shown in FIG. 6 to 8 are conceptual diagrams showing implementation examples of the variable temperature attenuation circuit that realizes the temperature characteristics in the setting 1, setting 2, and setting 3 shown in FIG. 3 using the configuration shown in FIG.

  FIG. 5 shows a case where a chip-type temperature variable attenuator 15 is used as the temperature variable attenuator 2 and thin film resistors R8 to R14 are used as the variable resistors R1, R2, and R3. In FIG. 5, RF (radio frequency) signal patterns 16 to 22 are formed on a thin film substrate. The RF signal pattern 16 is connected to the circuit ground through the through hole 23 to form a ground pattern. The ground plane of the chip-type variable temperature attenuator 15 is connected to the RF signal pattern 16.

  One end of the RF signal pattern 17 is connected to one input / output end of the chip-type temperature variable attenuator 15 together with one end of the RF signal pattern 18, and one end of the RF signal pattern 19 is connected to one end of the RF signal pattern 20 along with the chip-type temperature. The variable attenuator 15 is connected to the other input / output terminal. The RF signal pattern 17 is formed with thin film resistors R11 and R12 constituting the variable resistor R2, and the RF signal pattern 19 is formed with thin film resistors R13 and R14 constituting the variable resistor R3. Yes. Each resistance value of the thin film resistors R11 and R14 is 11Ω, and each resistance value of the thin film resistors R12 and R13 is 5Ω.

  The RF signal pattern 18 is formed such that one end of the RF signal pattern 18 abuts against one end side of the RF signal pattern 17 at an acute angle, and the other end is an RF signal pattern 21 bent in parallel with the RF signal pattern 19.

  Further, the RF signal pattern 20 is formed so that one end of the RF signal pattern 20 abuts against one end side of the RF signal pattern 19 at an acute angle, and the other end is an RF signal pattern 22 bent so as to be parallel to the RF signal pattern 17.

  A thin film resistor R8 is formed on the other end side of the RF signal pattern 18, a thin film resistor R10 is formed on the other end side of the RF signal pattern 20, and a thin film resistor R9 is formed on the RF signal pattern 22. . Each resistance value of the thin film resistors R8 and R10 is 42.5Ω, and the resistance value of the thin film resistor R9 is 5Ω. Although the thin film resistors R8, R9, and R10 constitute the variable resistor R1, the RF signal pattern 21 and the RF signal pattern 22 are not connected to each other, and the respective other ends are separated by a certain gap 24.

  In the above configuration, when realizing the temperature variable attenuation circuit having the temperature characteristic 11 in the setting 1 shown in FIG. 3, the thin film resistors R11 and R12 are short-circuited by the gold ribbon 25a as shown in FIG. Resistors R13 and R14 are short-circuited by the gold ribbon 25b. Then, in FIG. 1, the variable resistor R1 is set to open (open), and the variable resistors R2 and R3 are set to short (short circuit), respectively, set to 1 shown in FIG. 4, and have the temperature characteristic 11 shown in FIG. A variable temperature attenuation circuit is obtained.

  When realizing a temperature variable attenuation circuit having the temperature characteristic 12 in the setting 2 shown in FIG. 3, as shown in FIG. 7, the thin film resistor R11 is short-circuited by the gold ribbon 26a, and the thin film resistor R14 is connected. The gold ribbon 26b is short-circuited, and the gap 24 is short-circuited by the gold ribbon 26c. Then, in FIG. 1, the resistance value of the variable resistor R1 is set to R8 + R9 + R10 = 90Ω, and the resistance values of the variable resistors R2 and R3 are set to R12 = R13 = 5Ω, setting 2 shown in FIG. A temperature variable attenuation circuit having the temperature characteristic 12 shown is obtained.

  When realizing a temperature variable attenuation circuit having the temperature characteristic 13 in the setting 3 shown in FIG. 3, as shown in FIG. 8, the thin film resistor R8 is short-circuited by the gold ribbon 27a, and the gap 24 is formed by the gold ribbon. Short-circuit at 27b, and the thin film resistor R10 is short-circuited by the gold ribbon 27c. Then, in FIG. 1, the resistance value of the variable resistor R1 is set to R9 = 5Ω, and the resistance values of the variable resistors R2 and R3 are set to R11 + R12 = R13 + R14 = 16Ω, setting 3 shown in FIG. A temperature variable attenuation circuit having the temperature characteristic 13 shown is obtained.

  As described above, according to the first embodiment, the temperature characteristic of the attenuation amount can be easily changed to an arbitrary temperature characteristic only by changing the resistance values of the variable resistors R1, R2, and R3. Therefore, when forming a plurality of temperature variable attenuation circuits having different temperature characteristics of attenuation, it is not necessary to prepare a plurality of temperature variable attenuators having different temperature characteristics as in the prior art, and the number of parts can be reduced. Become.

  Further, according to the first embodiment, when a plurality of temperature variable attenuation circuits having different attenuation temperature characteristics are formed, the variable resistors R1, R2, and R3 are provided as shown in the mounting example of FIG. Each can be easily realized by composing a plurality of fixed resistors (for example, thin film resistors) and shorting unnecessary fixed resistors with a gold ribbon, a gold wire, etc. according to the desired temperature characteristics. it can. Therefore, it is possible to reduce the component cost and the assembly cost. In addition, the temperature characteristic of the temperature variable attenuation circuit can be easily adjusted in accordance with the temperature characteristic of the circuit to be compensated without increasing the cost, so that highly accurate temperature compensation can be realized.

Embodiment 2. FIG.
FIG. 9 is a circuit diagram showing a configuration of a temperature variable attenuation circuit according to the second embodiment of the present invention. In FIG. 9, the same reference numerals are given to the same or equivalent components as those shown in FIG. 1 (Embodiment 1). Here, the description will be focused on the portion related to the second embodiment.

  As shown in FIG. 9, the variable temperature attenuating circuit 1b according to the second embodiment deletes one of the variable resistor R2 and the variable resistor R3 in the configuration shown in FIG. 1 (first embodiment) (FIG. 9). 9, the variable resistor R3 is deleted).

  Compared to the first embodiment, the input / output terminal 3a side and the input / output terminal 3b side have different reflection characteristics, but the basic operation is the same as that of the first embodiment.

  According to the first embodiment, one variable resistor can be reduced, so that cost and circuit area can be reduced.

  As described above, the temperature variable attenuation circuit according to the present invention is useful as a temperature variable attenuation circuit that enables highly accurate temperature compensation without causing an increase in cost.

DESCRIPTION OF SYMBOLS 1a, 1b Temperature variable attenuation circuit 2 Temperature variable attenuator 3a, 3b Input / output terminal 5, 6, 7 Resistor which comprises pi type attenuator 8 Temperature variable resistor (thermistor)
11 Temperature characteristics at setting 1 12 Temperature characteristics at setting 2 13 Temperature characteristics at setting 3 15 Chip-type temperature variable attenuator 16-22 RF signal pattern 23 Through hole 24 Gap 25a, 25b, 26a, 26b, 26c, 27a 27b, 27c Gold ribbon R1, R2, R3 Variable resistor R8, R9, R10 Thin film resistor R11, R12 Thin film resistor R13, R14 Variable resistor R3 Construct thin film resistors

Claims (2)

A variable temperature attenuator whose attenuation changes with temperature,
A first variable resistor provided in parallel with the temperature variable attenuator;
A second variable resistor having one end connected to one input / output end of the temperature variable attenuator and the other end constituting one signal input / output end;
A temperature variable attenuating circuit comprising: a third variable resistor having one end connected to the other input / output end of the temperature variable attenuator and the other end constituting the other signal input / output end. A variable temperature attenuator whose attenuation changes with temperature,
A first variable resistor provided in parallel with the temperature variable attenuator;
A second variable resistor having one end connected to one input / output end of the temperature variable attenuator and the other end constituting one signal input / output end;
The other variable input / output terminal of the variable temperature attenuator constitutes the other signal input / output terminal.

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