Numerical control attenuator with wide temperature range and regulation and control method thereof

Abstract

The invention discloses a digital control attenuator with a wide temperature range and a regulation and control method thereof, the digital control attenuator comprises a 0.5 dB attenuator, a 1dB attenuator, a 2dB attenuator, a 4dB attenuator, an 8dB attenuator and a digital control circuit, a radio frequency input signal sequentially passes through the 0.5 dB attenuator, the 1dB attenuator, the 2dB attenuator, the 4dB attenuator and the 8dB attenuator, is subjected to five times of signal attenuation processing and then is used as a radio frequency output signal, and the digital control circuit is connected with the digital control circuit. The 0.5 dB attenuator, the 1dB attenuator, the 2dB attenuator, the 4dB attenuator and the 8dB attenuator are respectively connected with power supply voltage; the digital control circuit is used for generating five control signals which are respectively provided for the 0.5 dB attenuator, the 1dB attenuator, the 2dB attenuator, the 4dB attenuator and the 8dB attenuator; the 0.5 dB attenuator, the 1dB attenuator, the 2dB attenuator and the 4dB attenuator are all T-type attenuation units with wide temperature ranges, and the 8dB attenuator is a pi-type attenuation unit with wide temperature ranges. According to the invention, the attenuation precision of the numerical control attenuator can be kept high within a wide temperature range.

Description

Technical Field

[0001] The invention belongs to the technical field of attenuators, and in particular relates to a digitally controlled attenuator with a wide temperature range and a control method thereof. Background Art

[0002] In phased array systems, digitally controlled attenuators are used as amplitude adjustment circuits with high linearity, low power consumption, broadband characteristics and convenient configurability, and are widely used. In practical applications, the system is usually under conditions where the ambient temperature changes dramatically, which requires the digitally controlled attenuator to have stable attenuation accuracy characteristics over a wide temperature range. In traditional attenuator circuits, the signal transmission characteristics of the transistor itself and the resistance value of the resistor will change with temperature, causing the attenuation accuracy of the digitally controlled attenuator to drift dramatically with temperature changes. Summary of the invention

[0003] The purpose of the present invention is to provide a digitally controlled attenuator with a wide temperature range and a control method thereof to address the problem that the attenuation accuracy of the digitally controlled attenuator in the prior art deteriorates significantly at different temperatures, so as to enable the attenuation accuracy of the digitally controlled attenuator to maintain high accuracy within a wide temperature range.

[0004] In order to achieve the above object, one aspect of the present invention provides a digitally controlled attenuator with a wide temperature range, comprising a 0.5dB attenuator, a 1dB attenuator, a 2dB attenuator, a 4dB attenuator, an 8dB attenuator and a digital control circuit, wherein a radio frequency input signal passes through the 0.5dB attenuator, the 1dB attenuator, the 2dB attenuator, the 4dB attenuator and the 8dB attenuator in sequence, and is used as a radio frequency output signal after five signal attenuation processes, and the 0.5dB attenuator, the 1dB attenuator, the 2dB attenuator, the 4dB attenuator and the 8dB attenuator are respectively connected to a power supply voltage;

[0005] The digital control circuit is used to generate 5 control signals, which are respectively provided to a 0.5dB attenuator, a 1dB attenuator, a 2dB attenuator, a 4dB attenuator, and an 8dB attenuator;

[0006] 0.5dB attenuator, 1dB attenuator, 2dB attenuator, 4dB attenuator are all T-type attenuation units with wide temperature range, and 8dB attenuator is a π-type attenuation unit with wide temperature range;

[0007] The wide temperature range T-type attenuation unit comprises a first voltage conversion circuit, a first control conversion circuit and a T-type attenuation circuit, and the wide temperature range π-type attenuation unit comprises a second voltage conversion circuit, a second control conversion circuit and a π-type attenuation circuit, and the first and second voltage conversion circuits are used to convert the power supply voltage into a voltage signal that increases with the increase of temperature, and output the voltage signal to the first and second control conversion circuits respectively as driving signals of the first and second control conversion circuits;

[0008] The first and second control conversion circuits output a high potential signal that increases with increasing temperature and a low potential signal of zero voltage under the action of the control signal. The low potential signal is used to control the transistors of the T-type attenuation circuit and the π-type attenuation circuit to turn off, and the high potential signal is used to control the transistors of the T-type attenuation circuit and the π-type attenuation circuit to turn on.

[0009] Preferably, the wide temperature range T-type attenuation unit includes a first transistor to a tenth transistor, a first capacitor, a first resistor to an eighth resistor, wherein the seventh transistor to the tenth transistor and the eighth resistor constitute a first voltage conversion circuit, the third transistor to the sixth transistor constitute a first control conversion circuit, and the first transistor, the second transistor, the first capacitor, the first resistor to the seventh resistor constitute a T-type attenuation circuit.

[0010] Preferably, the source of the first transistor is connected to the RF input signal and is connected to one end of the first resistor and one end of the second resistor; the drain of the first transistor serves as the RF output signal and is connected to the other end of the first resistor, one end of the third resistor, and one end of the fifth resistor, the other end of the fifth resistor is grounded, the gate of the first transistor is connected to one end of the sixth resistor, the source of the second transistor is connected to one end of the fourth resistor and one end of the first capacitor, the drain of the second transistor is connected to the other end of the second resistor and the other end of the third resistor, the gate of the second transistor is connected to one end of the seventh resistor, the other end of the fourth resistor and the other end of the first capacitor are grounded, the gate of the third transistor and the gate of the fourth transistor are connected and serve as the control signal output. The input end, the source of the third transistor is grounded, the drain of the third transistor, the drain of the fourth transistor, the gate of the fifth transistor, and the gate of the sixth transistor are connected and connected to the other end of the sixth resistor, the source of the fifth transistor is grounded, the drains of the fifth transistor and the sixth transistor are connected and connected to the other end of the seventh resistor, the source of the seventh transistor is grounded, its gate is connected to the drain, and is connected to the gate of the ninth transistor and the drain of the eighth transistor, and then connected to the source of the fourth transistor and the sixth transistor, the source of the ninth transistor is grounded through the eighth resistor, the drain is connected to the drain of the tenth transistor, the gate of the tenth transistor, and the gate of the eighth transistor, the source of the eighth transistor and the tenth transistor are connected, and connected to the power supply voltage.

[0011] Preferably, the wide temperature range π-type attenuation unit includes the eleventh to twenty-first transistors, a second capacitor, a third capacitor, and a ninth to sixteenth resistor, wherein the eighteenth to twenty-first transistors and the sixteenth resistor constitute a second voltage conversion circuit, the fourteenth to seventeenth transistors constitute a second control conversion circuit, and the eleventh to thirteenth transistors, the second capacitor, the third capacitor, and the ninth to fifteenth resistors constitute a π-type attenuation circuit.

[0012] Preferably, the source of the eleventh transistor is connected to the RF input signal and is connected to one end of the eleventh resistor and the drain of the twelfth transistor. The drain of the eleventh transistor serves as the RF output signal and is connected to the other end of the eleventh resistor and the drain of the thirteenth transistor. The ninth resistor and one end of the second capacitor are connected to the source of the twelfth transistor and the other end is grounded. The tenth resistor and one end of the third capacitor are connected to the source of the thirteenth transistor and the other end is grounded. The gates of the fourteenth transistor and the fifteenth transistor are connected and serve as the control signal input terminal. The source of the fourteenth transistor is grounded. The drains of the fourteenth transistor and the fifteenth transistor are connected and are connected to the gate of the eleventh transistor through the thirteenth resistor and are connected to the The gates of the sixteenth transistor and the seventeenth transistor are connected, the source of the sixteenth transistor is grounded, the drains of the sixteenth transistor and the seventeenth transistor are connected, connected to the gate of the twelfth transistor through the fourteenth resistor, connected to the gate of the thirteenth transistor through the fifteenth resistor, the source of the eighteenth transistor is grounded, its gate is connected to the drain, and is connected to the gate of the twentieth transistor and the drain of the nineteenth transistor, and then connected to the source of the fifteenth transistor and the seventeenth transistor, the source of the twentieth transistor is grounded through the sixteenth resistor, the drain is connected to the drain and gate of the twenty-first transistor and the gate of the nineteenth transistor, the sources of the nineteenth transistor and the twenty-first transistor are connected, and connected to the power supply voltage.

[0013] Another aspect of the present invention provides a control method for the wide temperature range digitally controlled attenuator, by adjusting and setting the circuit parameters of the wide temperature range T-type attenuation unit and the wide temperature range π-type attenuation unit, so that:

[0014] When the temperature rises, the output voltages of the first and second voltage conversion circuits rise, so that the first and second control conversion circuits output a control voltage or a zero voltage of the same amplitude as the output voltage of the first and second voltage conversion circuits under the action of the control signal, so as to control the on-off state of the transistors driving the T-type attenuation circuit and the π-type attenuation circuit. The threshold voltages of the transistors of the T-type attenuation circuit and the π-type attenuation circuit increase with the increase of temperature, so that the over-driving capability of the transistors of the T-type attenuation circuit remains substantially unchanged, thereby maintaining the stability of its attenuation characteristics.

[0015] When the temperature decreases, the output voltages of the first and second voltage conversion circuits decrease, so that the first and second control conversion circuits output control voltages or zero voltages of the same amplitude as the output voltages of the first and second voltage conversion circuits under the action of control signals, so as to control the on-off states of the transistors driving the T-type attenuation circuit and the π-type attenuation circuit. The threshold voltages of the transistors of the T-type attenuation circuit and the π-type attenuation circuit themselves decrease as the temperature decreases, so that the overdriving capabilities of the T-type attenuation circuit and the π-type attenuation circuit remain basically unchanged, thereby maintaining the stability of their attenuation characteristics.

[0016] The wide temperature range digitally controlled attenuator and the control method thereof according to the above aspects of the present invention can maintain high attenuation accuracy of the digitally controlled attenuator within a wide temperature range. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings used in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work:

[0018] Figure 1 A schematic diagram of the structure of a digitally controlled attenuator with a wide temperature range according to an embodiment of the present invention;

[0019] Figure 2 This is a circuit schematic diagram of a wide temperature range T-type attenuation unit according to an embodiment of the present invention;

[0020] Figure 3 This is a circuit schematic diagram of a wide temperature range π-type attenuation unit according to an embodiment of the present invention;

[0021] Figure 4 The attenuation accuracy of a digitally controlled attenuator with a wide temperature range varies with temperature according to an embodiment of the present invention. DETAILED DESCRIPTION

[0022] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] The embodiments of the present invention provide a digitally controlled attenuator with a wide temperature range, such as Figure 1As shown, the digitally controlled attenuator with a wide temperature range according to the embodiment of the present invention includes a 0.5 dB attenuator, a 1 dB attenuator, a 2 dB attenuator, a 4 dB attenuator, an 8 dB attenuator and a digital control circuit.

[0024] The RF input signal IN passes through the 0.5dB attenuator, 1dB attenuator, 2dB attenuator, 4dB attenuator, and 8dB attenuator in turn, and is processed by five controllable signal attenuation processes as the RF output signal OUT. The power supply voltage input signal provides the power supply voltage VDD for the 0.5dB attenuator, 1dB attenuator, 2dB attenuator, 4dB attenuator, and 8dB attenuator respectively. The digital control circuit generates five different control signals Vctrl, which are used as control drive signals for the 0.5dB attenuator, 1dB attenuator, 2dB attenuator, 4dB attenuator, and 8dB attenuator respectively. The 0.5dB attenuator, 1dB attenuator, 2dB attenuator, and 4dB attenuator are all T-type attenuation units with a wide temperature range, and the 8dB attenuator is a π-type attenuation unit with a wide temperature range.

[0025] The wide temperature range T-type attenuation unit includes a first voltage conversion circuit, a first control conversion circuit and a T-type attenuation circuit, and the wide temperature range π-type attenuation unit includes a second voltage conversion circuit, a second control conversion circuit and a π-type attenuation circuit. The first and second voltage conversion circuits are used to convert the power supply voltage into a voltage signal that increases with the increase of temperature, and output the voltage signal to the first and second control conversion circuits respectively as the driving signals of the first and second control conversion circuits. The circuit principles of the first and second voltage conversion circuits are the same, and for the convenience of description, they are also collectively referred to as voltage conversion circuits.

[0026] The first and second control conversion circuits respectively output a high potential signal that increases with the increase of temperature and a low potential signal of zero voltage under the action of the control signal, the low potential signal is used to control the transistors of the T-type attenuation circuit and the π-type attenuation circuit to turn off, and the high potential signal is used to control the transistors of the T-type attenuation circuit and the π-type attenuation circuit to turn on. The circuit principles of the first and second control conversion circuits are the same, and for the convenience of description, they are also collectively referred to as control conversion circuits below.

[0027] In a specific embodiment, Figure 2 As shown, the wide temperature range T-type attenuation unit includes the first transistor M1a to the tenth transistor M10a, the first capacitor C1a, the first resistor R1a to the eighth resistor R8a. The seventh transistor M7a to the tenth transistor M10a and the eighth resistor R8a constitute a first voltage conversion circuit, the third transistor M3a to the sixth transistor M6a constitute a first control conversion circuit, and the first transistor M1a, the second transistor M2a, the first capacitor C1a, the first resistor R1a to the seventh resistor R8a constitute a T-type attenuation circuit.

[0028] The source of the first transistor M1a is connected to the RF input signal IN, and is connected to one end of the first resistor R1a and one end of the second resistor R2a; the drain of the first transistor M1a is used as the RF output signal OUT, and is connected to the other end of the first resistor R1a, one end of the third resistor R3a, and one end of the fifth resistor R5a, and the other end of the fifth resistor R5a is grounded; the gate of the first transistor M1a is connected to one end of the sixth resistor R6a. The source of the second transistor M2a is connected to one end of the fourth resistor R4a and one end of the first capacitor C1a, the drain of the second transistor M2a is connected to the other end of the second resistor R2a and the other end of the third resistor R3a, and the gate of the second transistor M2a is connected to one end of the seventh resistor R7a. The other end of the fourth resistor R4a and the other end of the first capacitor C1a are grounded. The gate of the third transistor M3a and the gate of the fourth transistor M4a are connected and used as the input end of the control signal Vctrl, the source of the third transistor M3a is grounded, the drain of the third transistor M3a, the drain of the fourth transistor M4a, the gate of the fifth transistor M5a, and the gate of the sixth transistor M6a are connected and connected to the other end of the sixth resistor R6a, the source of the fifth transistor M5a is grounded, and the drains of the fifth transistor M5a and the sixth transistor M6a are connected and connected to the other end of the seventh resistor R7a. The source of the seventh transistor M7a is grounded, its gate is connected to the drain, and is connected to the gate of the ninth transistor M9a and the drain of the eighth transistor M8a, and then connected to the source of the fourth transistor M4a and the sixth transistor M6a. The source of the ninth transistor M9a is grounded through the eighth resistor R8a, and the drain is connected to the drain of the tenth transistor M10a, the gate of the tenth transistor M10a, and the gate of the eighth transistor M8a. The sources of the eighth transistor M8a and the tenth transistor M10a are connected and connected to the power supply voltage VDD.

[0029] In a specific embodiment, Figure 3 As shown, the wide temperature range π-type attenuation unit includes the eleventh transistor M1b to the twenty-first transistor M11b, the second capacitor C1b, the third capacitor C2b, and the ninth resistor R1b to the sixteenth resistor R8b. The eighteenth transistor M8b to the twenty-first transistor M11b and the sixteenth resistor R8b constitute a second voltage conversion circuit, the fourteenth transistor M4b to the seventeenth transistor M7b constitute a second control conversion circuit, and the eleventh transistor M1b to the twenty-first transistor M11b, the second capacitor C1b, the third capacitor C2b, and the ninth resistor R1b to the fifteenth resistor R7b constitute a π-type attenuation circuit.

[0030] The source of the eleventh transistor M1b is connected to the RF input signal IN, and is connected to one end of the eleventh resistor R3b and the drain of the twelfth transistor M2b. The drain of the eleventh transistor M1b is used as the RF output signal OUT, and is connected to the other end of the eleventh resistor R3b and the drain of the thirteenth transistor M3b. The ninth resistor R1b and one end of the second capacitor C1b are connected to the source of the twelfth transistor M2b, and the other end is grounded. The tenth resistor R2b and one end of the third capacitor C2b are connected to the source of the thirteenth transistor M3b, and the other end is grounded. The gates of the fourteenth transistor M4b and the fifteenth transistor M5b are connected and used as the input end of the control signal Vctrl, and the source of the fourteenth transistor M4b is grounded. The drains of the fourteenth transistor M4b and the fifteenth transistor M5b are connected, and are connected to the gate of the eleventh transistor M1b through the thirteenth resistor R5b, and are connected to the gates of the sixteenth transistor M6b and the seventeenth transistor M7b at the same time, and the source of the sixteenth transistor M6b is grounded. The drains of the sixteenth transistor M6b and the seventeenth transistor M7b are connected, connected to the gate of the twelfth transistor M2b through the fourteenth resistor R6b, and connected to the gate of the thirteenth transistor M3b through the fifteenth resistor R7b. The source of the eighteenth transistor M8b is grounded, its gate is connected to the drain, and is connected to the gate of the twentieth transistor M10b and the drain of the nineteenth transistor M9b, and then connected to the source of the fifteenth transistor M5b and the seventeenth transistor M7b. The source of the twentieth transistor M10b is grounded through the sixteenth resistor R8b, and the drain is connected to the drain and gate of the twenty-first transistor M11b and the gate of the nineteenth transistor M9b. The sources of the nineteenth transistor M9b and the twenty-first transistor M11b are connected, and are connected to the power supply voltage VDD.

[0031] The attenuation accuracy of the digital controlled attenuator in a wide temperature range of the above embodiment of the present invention was tested. Figure 4 As shown in the figure, under different temperature conditions, the attenuation accuracy changes very little compared to the traditional attenuator and presents a stable state.

[0032] The embodiment of the present invention also provides a control method for a wide temperature range digitally controlled attenuator, which realizes the temperature stability of the attenuation characteristics of the attenuator by adjusting and setting the circuit parameters of the wide temperature range T-type attenuation unit and the wide temperature range π-type attenuation unit. The principle is as follows:

[0033] The relationship between the output voltage V(T) of the voltage conversion circuit and the temperature T is:

[0034] V(T) = k1(T-T0) + V(T0) Formula (1)

[0035] Where T0 is the room temperature of 25°C, V(T0) is the output voltage of the voltage conversion circuit at the room temperature of 25°C, and k1 is the positive temperature coefficient of voltage conversion.

[0036] The relationship between the threshold voltage G(T) of the transistors in the T-type attenuation circuit and the π-type attenuation circuit and the temperature T is:

[0037] G(T) = k2(T-T0) + G(T0) Formula (2)

[0038] Wherein T0 is room temperature 25°C, G(T0) is the threshold voltage of the transistor at room temperature 25°C, and k2 is the transistor process parameter.

[0039] According to the output voltage V(T) of the voltage conversion circuit and the threshold voltage G(T) of the transistor, the overdrive capability of the transistor is obtained as follows:

[0040] V(T) - G(T) = (k1- k2)T + (k2- k1)T0 + V(T0) - G(T0) Formula (3)

[0041] When appropriate circuit parameters are set to satisfy k1≈k2, the overdrive capability of the transistor changes with temperature to a constant value, achieving temperature stability of the attenuator attenuation characteristics.

[0042] According to the above principle, the regulation of the wide temperature range T-type attenuation unit is specifically:

[0043] When the temperature rises, according to formula (1), the output voltage of the voltage conversion circuit in the attenuation unit rises, so that the first control conversion circuit outputs a control voltage (high potential) or zero voltage (low potential) equal to the output voltage V(T) of the first voltage conversion circuit under the action of the control signal VCtrl, so as to control the on-off state of the first transistor M1a and the second transistor M2a. The threshold voltage of the first transistor M1a and the second transistor M2a increases with the increase of temperature, so that the over-driving capability of the first transistor M1a and the second transistor M2a remains basically unchanged, thereby maintaining the stability of their attenuation characteristics.

[0044] When the temperature decreases, according to formula (1), the output voltage of the voltage conversion circuit in the attenuation unit decreases, so that the first control conversion circuit outputs a control voltage (high potential) or zero voltage (low potential) equal to the output voltage V(T) of the first voltage conversion circuit under the action of the control signal VCtrl, which is used to control the on-off state of the first transistor M1a and the second transistor M2a. The threshold voltage of the first transistor M1a and the second transistor M2a decreases as the temperature decreases, so that the over-driving capability of the first transistor M1a and the second transistor M2a remains basically unchanged, thereby maintaining the stability of its attenuation characteristics. In summary, regardless of whether the temperature increases or decreases, the attenuation characteristics of the first transistor M1a and the second transistor M2a can remain stable.

[0045] The regulation of the wide temperature range π-type attenuation unit is specifically:

[0046] When the temperature rises, according to formula (1), the output voltage of the voltage conversion circuit in the attenuation unit rises, so that the second control conversion circuit outputs a control voltage (high potential) or zero voltage (low potential) equal to the output voltage V(T) of the second voltage conversion circuit under the action of the control signal VCtrl, so as to control the on-off state of the eleventh transistor M1b, the twelfth transistor M2b, and the thirteenth transistor M3b. The threshold voltages of the eleventh transistor M1b, the twelfth transistor M2b, and the thirteenth transistor M3b themselves increase with the increase of temperature, so that the over-driving capabilities of the eleventh transistor M1b, the twelfth transistor M2b, and the thirteenth transistor M3b remain basically unchanged, thereby maintaining the stability of their attenuation characteristics;

[0047] When the temperature decreases, according to formula (1), the output voltage of the voltage conversion circuit in the attenuation unit decreases, so that the second control conversion circuit outputs a control voltage (high potential) or zero voltage (low potential) equal to the output voltage V(T) of the second voltage conversion circuit under the action of the control signal VCtrl, which is used to control the on-off state of the eleventh transistor M1b, the twelfth transistor M2b, and the thirteenth transistor M3b, and the threshold voltage of the eleventh transistor M1b, the twelfth transistor M2b, and the thirteenth transistor M3b itself decreases as the temperature decreases, so that the over-driving capability of the eleventh transistor M1b, the twelfth transistor M2b, and the thirteenth transistor M3b remains basically unchanged, thereby maintaining the stability of its attenuation characteristics. In summary, regardless of whether the temperature increases or decreases, the attenuation characteristics of the eleventh transistor M1b, the twelfth transistor M2b, and the thirteenth transistor M3b can maintain stability.

[0048] In summary, the digital controlled attenuator with a wide temperature range of the embodiment of the present invention sequentially attenuates the signal through a 0.5dB attenuator, a 1dB attenuator, a 2dB attenuator, a 4dB attenuator, and an 8dB attenuator, and adopts a wide temperature range T-type / π-type attenuation unit to implement the above 5 attenuators, thereby reducing the change in the attenuation accuracy of the digital controlled attenuator with temperature. The embodiment of the present invention adds a voltage conversion circuit and a control conversion circuit on the basis of the T-type / π-type attenuation circuit. The voltage conversion circuit converts the constant power supply voltage VDD into a voltage signal that increases with increasing temperature, outputs this signal to the control conversion circuit, and serves as the source drive signal of the control conversion circuit. Under the action of the control signal Vctrl, the control conversion circuit outputs a high potential signal that increases with increasing temperature and a low potential signal that is approximately equal to the ground potential (zero potential). The low potential signal controls the transistor driven by it to turn off, and the high potential signal controls the transistor driven by it to turn on. For transistors controlled by high-potential signals, when the temperature rises, the transconductance of the transistor itself decreases, resulting in a weakened signal transmission capability, while the characteristic of the high-potential signal increasing with increasing temperature increases the overdrive voltage of the transistor, thereby enhancing the signal transmission capability of the transistor. When the two factors reach a balance, the signal transmission capability of the transistor will present a basically unchanged stable characteristic with increasing temperature. For transistors controlled by low-potential signals, since the transistor is turned off, its signal transmission capability is extremely weak and basically has nothing to do with temperature. The wide temperature range T-type / π-type attenuation unit of the embodiment of the present invention, its attenuation characteristics are determined by the difference in signal transmission capability between the transistor controlled by the high-potential signal and the transistor controlled by the low-potential signal. Since the signal transmission capability of the two themselves is stable with temperature changes, the attenuation characteristics of the wide temperature range T-type / π-type attenuation unit are stable with temperature changes. In summary, the digitally controlled attenuator of the embodiment of the present invention can achieve flat and stable attenuation accuracy within a wide temperature range.

[0049] The above description is only by way of illustration of certain exemplary embodiments of the present invention. It is undoubted that those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A digitally controlled attenuator with a wide temperature range, characterized in that: Including 0.5dB attenuator, 1dB attenuator, 2dB attenuator, 4dB attenuator, 8dB attenuator and digital control circuit, The RF input signal passes through a 0.5 dB attenuator, a 1 dB attenuator, a 2 dB attenuator, a 4 dB attenuator, and an 8 dB attenuator in sequence, and is used as a RF output signal after five signal attenuation processes. The 0.5 dB attenuator, the 1 dB attenuator, the 2 dB attenuator, the 4 dB attenuator, and the 8 dB attenuator are respectively connected to the power supply voltage; The digital control circuit is used to generate 5 control signals, which are respectively provided to a 0.5dB attenuator, a 1dB attenuator, a 2dB attenuator, a 4dB attenuator, and an 8dB attenuator; 0.5dB attenuator, 1dB attenuator, 2dB attenuator, 4dB attenuator are all T-type attenuation units with wide temperature range, and 8dB attenuator is a π-type attenuation unit with wide temperature range; The wide temperature range T-type attenuation unit comprises a first voltage conversion circuit, a first control conversion circuit and a T-type attenuation circuit, and the wide temperature range π-type attenuation unit comprises a second voltage conversion circuit, a second control conversion circuit and a π-type attenuation circuit, and the first and second voltage conversion circuits are used to convert the power supply voltage into a voltage signal that increases with the increase of temperature, and output the voltage signal to the first and second control conversion circuits respectively as driving signals of the first and second control conversion circuits; The first and second control conversion circuits output a high potential signal that increases with increasing temperature and a low potential signal of zero voltage under the action of the control signal. The low potential signal is used to control the transistors of the T-type attenuation circuit and the π-type attenuation circuit to turn off, and the high potential signal is used to control the transistors of the T-type attenuation circuit and the π-type attenuation circuit to turn on.

2. The digitally controlled attenuator with a wide temperature range as claimed in claim 1, characterized in that: The wide temperature range T-type attenuation unit includes a first transistor to a tenth transistor, a first capacitor, and a first resistor to an eighth resistor, wherein the seventh transistor to the tenth transistor and the eighth resistor constitute a first voltage conversion circuit, the third transistor to the sixth transistor constitute a first control conversion circuit, and the first transistor, the second transistor, the first capacitor, and the first resistor to the seventh resistor constitute a T-type attenuation circuit.

3. The digitally controlled attenuator with a wide temperature range as claimed in claim 2, characterized in that: The source of the first transistor is connected to the RF input signal and is connected to one end of the first resistor and one end of the second resistor; the drain of the first transistor serves as the RF output signal and is connected to the other end of the first resistor, one end of the third resistor, and one end of the fifth resistor, the other end of the fifth resistor is grounded, the gate of the first transistor is connected to one end of the sixth resistor, the source of the second transistor is connected to one end of the fourth resistor and one end of the first capacitor, the drain of the second transistor is connected to the other end of the second resistor and the other end of the third resistor, the gate of the second transistor is connected to one end of the seventh resistor, the other end of the fourth resistor and the other end of the first capacitor are grounded, the gate of the third transistor and the gate of the fourth transistor are connected and serve as the control signal input end , the source of the third transistor is grounded, the drain of the third transistor, the drain of the fourth transistor, the gate of the fifth transistor, and the gate of the sixth transistor are connected and connected to the other end of the sixth resistor, the source of the fifth transistor is grounded, the drains of the fifth transistor and the sixth transistor are connected and connected to the other end of the seventh resistor, the source of the seventh transistor is grounded, its gate is connected to the drain, and is connected to the gate of the ninth transistor and the drain of the eighth transistor, and then connected to the source of the fourth transistor and the sixth transistor, the source of the ninth transistor is grounded through the eighth resistor, the drain is connected to the drain of the tenth transistor, the gate of the tenth transistor, and the gate of the eighth transistor, the source of the eighth transistor and the tenth transistor are connected, and connected to the power supply voltage.

4. The digitally controlled attenuator with a wide temperature range as claimed in any one of claims 1 to 3, characterized in that: The wide temperature range π-type attenuation unit includes the eleventh transistor to the twenty-first transistor, the second capacitor, the third capacitor, and the ninth resistor to the sixteenth resistor, wherein the eighteenth transistor to the twenty-first transistor and the sixteenth resistor constitute a second voltage conversion circuit, the fourteenth transistor to the seventeenth transistor constitute a second control conversion circuit, and the eleventh transistor to the thirteenth transistor, the second capacitor, the third capacitor, and the ninth resistor to the fifteenth resistor constitute a π-type attenuation circuit.

5. The digitally controlled attenuator with a wide temperature range as claimed in claim 4, characterized in that: The source of the eleventh transistor is connected to the RF input signal, and is connected to one end of the eleventh resistor and the drain of the twelfth transistor. The drain of the eleventh transistor serves as the RF output signal, and is connected to the other end of the eleventh resistor and the drain of the thirteenth transistor. The ninth resistor and one end of the second capacitor are connected to the source of the twelfth transistor, and the other end is grounded. The tenth resistor and one end of the third capacitor are connected to the source of the thirteenth transistor, and the other end is grounded. The gates of the fourteenth transistor and the fifteenth transistor are connected and serve as the control signal input end. The source of the fourteenth transistor is grounded. The drains of the fourteenth transistor and the fifteenth transistor are connected, and are connected to the gate of the eleventh transistor through the thirteenth resistor, and connected to the gate of the tenth transistor. The gates of the sixteenth transistor and the seventeenth transistor are connected, the source of the sixteenth transistor is grounded, the drains of the sixteenth transistor and the seventeenth transistor are connected, and are connected to the gate of the twelfth transistor through the fourteenth resistor, and are connected to the gate of the thirteenth transistor through the fifteenth resistor. The source of the eighteenth transistor is grounded, and its gate is connected to the drain, and is connected to the gate of the twentieth transistor and the drain of the nineteenth transistor, and then connected to the source of the fifteenth transistor and the seventeenth transistor. The source of the twentieth transistor is grounded through the sixteenth resistor, and the drain is connected to the drain and gate of the twenty-first transistor and the gate of the nineteenth transistor. The sources of the nineteenth transistor and the twenty-first transistor are connected and connected to the power supply voltage.

6. A control method for a digitally controlled attenuator with a wide temperature range according to any one of claims 1 to 5, characterized in that: By adjusting and setting the circuit parameters of the wide temperature range T-type attenuation unit and the wide temperature range π-type attenuation unit, the following is achieved: When the temperature rises, the output voltages of the first and second voltage conversion circuits rise, so that the first and second control conversion circuits output control voltages of equal amplitude to the output voltages of the first and second voltage conversion circuits or zero voltage under the action of the control signal, so as to control the on-off state of the transistors driving the T-type attenuation circuit and the π-type attenuation circuit. The threshold voltages of the transistors of the T-type attenuation circuit and the π-type attenuation circuit increase with the increase of temperature, so that the over-driving capability of the transistors of the T-type attenuation circuit remains substantially unchanged, thereby maintaining the stability of its attenuation characteristics. When the temperature decreases, the output voltages of the first and second voltage conversion circuits decrease, so that the first and second control conversion circuits output control voltages or zero voltages of the same amplitude as the output voltages of the first and second voltage conversion circuits under the action of control signals, so as to control the on-off states of the transistors driving the T-type attenuation circuit and the π-type attenuation circuit. The threshold voltages of the transistors of the T-type attenuation circuit and the π-type attenuation circuit themselves decrease as the temperature decreases, so that the overdriving capabilities of the T-type attenuation circuit and the π-type attenuation circuit remain basically unchanged, thereby maintaining the stability of their attenuation characteristics.

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