Seven-bit digital attenuator based on GaAs technology

Abstract

This utility model discloses a seven-digit digitally controlled attenuator based on GaAs technology, belonging to the field of attenuator technology. It includes seven digitally controlled attenuator units connected in series and a drive control circuit that controls the operation of each digitally controlled attenuator unit. The seven digitally controlled attenuator units are connected sequentially in ascending order of attenuation. Each digitally controlled attenuator unit corresponds to a drive module, and the drive control method is used to control each digitally controlled attenuator unit, so that the digitally controlled attenuator operates at its corresponding attenuation position. Furthermore, sector capacitors are connected to the switches of the first, second, sixth, and seventh attenuator units, which helps to improve the attenuation flatness of the attenuator.

Description

Technical Field

[0001] This utility model relates to the field of attenuator technology, specifically to a seven-digit digitally controlled attenuator based on GaAs technology. Background Technology

[0002] Digitally controlled attenuator (DCA) chips are devices used for attenuating radio frequency (RF) signal power and are applied in products such as radar and base stations. DCA is a crucial component of phased array radar transceiver modules. DCA controls the attenuation amount in precise attenuation steps, generally offering better matching characteristics and attenuation accuracy than analog attenuators. Before the advent of GaAs pHEMTs, PIN diodes were primarily used to implement attenuators, but these were large, consumed a lot of power, and had slow control speeds. Therefore, DCA attenuators implemented using GaAs pHEMTs have gained widespread application due to their higher speed, lower loss, and smaller size. Utility Model Content

[0003] The purpose of this invention is to provide a seven-digit digitally controlled attenuator based on GaAs technology. The digitally controlled attenuation units are connected in series in order of increasing attenuation, and each digitally controlled attenuation unit corresponds to a drive module. The drive control method is used to control each digitally controlled attenuation unit so that the digitally controlled attenuator works at the corresponding attenuation position.

[0004] To achieve the above objectives, the present invention adopts the following solution:

[0005] This application provides a seven-digit digitally controlled attenuator based on GaAs technology, including seven digitally controlled attenuation units connected in series and a drive control circuit for controlling the operation of each digitally controlled attenuation unit. The seven digitally controlled attenuation units are connected in sequence according to the attenuation amount from smallest to largest.

[0006] In some specific implementations, the seven numerically controlled attenuation units include a first attenuation unit, a second attenuation unit, a third attenuation unit, a fourth attenuation unit, a fifth attenuation unit, a sixth attenuation unit, and a seventh attenuation unit arranged in ascending order of attenuation amount, wherein the attenuation amount between any two adjacent attenuation units differs by a factor of two.

[0007] In some specific implementations, the drive control circuit includes seven drive modules corresponding to seven numerically controlled attenuation units, wherein the first attenuation unit, the second attenuation unit, and the third attenuation unit are single-channel controlled, and the fourth attenuation unit, the fifth attenuation unit, the sixth attenuation unit, and the seventh attenuation unit are dual-channel controlled.

[0008] In some specific implementations, the first attenuation unit, the second attenuation unit, and the third attenuation unit have the same structure, each including a high-value gate resistor, a first switch, and a first ground resistor. One end of the high-value gate resistor is connected to the driving module, and the other end is connected to the gate of the first switch. The drain of the first switch is grounded through the first ground resistor, and the source of the first switch of the first attenuation unit and the source of the first switch of the second attenuation unit are connected. The source of the first switch of the second attenuation unit and the source of the first switch of the third attenuation unit are connected.

[0009] In some specific implementations, the drains of the first switches of both the first attenuation unit and the second attenuation unit are connected to a first sector capacitor.

[0010] In some specific implementations, the fourth, fifth, and sixth attenuation units each include a high-value gate resistor, a second switch, and a third switch. The driving module employs dual-path control for the fourth, fifth, and sixth attenuation units. The two control lines are respectively connected to the gates of the second and third switches. The source and drain of the second switch are both connected to the source of the third switch, and the drain of the third switch is grounded. The source of the second switch of the fourth attenuation unit is connected to the drain of the second switch of the fifth attenuation unit, and the source of the second switch of the fifth attenuation unit is connected to the drain of the second unit of the sixth attenuation unit.

[0011] In some specific implementations, the source of the second switch of the sixth attenuation unit is connected to the drain of the seventh attenuation unit, and a second sector capacitor is connected in parallel to the source of the second switch of the sixth attenuation unit.

[0012] In some specific implementations, the drain of the second switch of the fourth attenuation unit is connected to the source of the first switch of the third attenuation unit, and a ground matching capacitor is connected in parallel between the second switch and the first switch.

[0013] In some specific implementations, the seventh attenuation unit consists of two sixth attenuation units, wherein the two sixth attenuation units are connected by a second switch of the sixth attenuation unit.

[0014] The beneficial effects of this utility model are:

[0015] This invention discloses a seven-digit digitally controlled attenuator based on GaAs technology. Seven digitally controlled attenuation units are connected in series according to their attenuation values, from smallest to largest. Each digitally controlled attenuation unit corresponds to a drive module, and the attenuator is controlled by a drive control method to operate at its corresponding attenuation position. Furthermore, sector capacitors are connected to the switches of the first, second, sixth, and seventh attenuation units, which helps to improve the attenuation flatness of the attenuator. Attached Figure Description

[0016] Figure 1 A circuit connection diagram of a low-noise amplifier provided for an embodiment of this utility model;

[0017] Figure 2 Circuit simulation layout of the low-noise amplifier provided for embodiments of this utility model;

[0018] Figure 3 A schematic diagram of the attenuation of the seven basic bits provided in this embodiment of the utility model;

[0019] Figure 4 A simulation diagram of insertion loss provided for an embodiment of this utility model;

[0020] Figure 5 A simulation diagram of the input VSWR provided for an embodiment of this utility model;

[0021] Figure 6 A simulation diagram of the output VSWR provided for an embodiment of this utility model;

[0022] Figure 7 A simulation diagram of the seven-bit basic bit attenuation accuracy provided for an embodiment of this utility model;

[0023] Figure 8 A schematic diagram of RMS simulation of the attenuation accuracy of the seven basic bits provided for the embodiments of this utility model.

[0024] Explanation of reference numerals in the attached figures:

[0025] 1-RF input port, 2-RF output port, 3-Basic bit control port, 4-Negative power supply port, 51-First filter capacitor, 52-Second filter capacitor, 6-Drive control circuit; 71-First attenuation unit; 72-Second attenuation unit, 73-Third attenuation unit, 74-Fourth attenuation unit, 75-Fifth attenuation unit, 76-Sixth attenuation unit, 77-Seventh attenuation unit, 81-First sector capacitor, 82-Second sector capacitor, 9-Ground matching capacitor. Detailed Implementation

[0026] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the implementation of the present invention is not limited thereto.

[0027] In the description of this utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "longitudinal", "lateral", "horizontal", "inner", "outer", "front", "rear", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the utility model product is in use. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0028] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set up," "have," "install," "connect," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0029] The present invention will now be described in detail with reference to the accompanying drawings and embodiments:

[0030] Example 1:

[0031] like Figures 1-2 As shown, this embodiment provides a seven-digit digitally controlled attenuator based on GaAs technology, including seven cascaded digitally controlled attenuator units and a drive control circuit 6 for controlling the operation of each digitally controlled attenuator unit. The seven digitally controlled attenuator units are connected sequentially according to their attenuation values, from smallest to largest. The seven digitally controlled attenuator units include a first attenuator unit 71 (corresponding to a 0.25dB attenuation level), a second attenuator unit 72 (0.5dB attenuation level), a third attenuator unit 73 (1dB attenuation level), a fourth attenuator unit 74 (2dB attenuation level), a fifth attenuator unit 75 (4dB attenuation level), a sixth attenuator unit 76 (8dB attenuation level), and a seventh attenuator unit 77 (16dB attenuation level), arranged in ascending order of attenuation value. It can be seen that the attenuation value between any two adjacent attenuator units differs by a factor of two. The switching source of the first attenuator unit 71 is connected to the RF input port 1, and the switching source of the seventh attenuator unit 77 is connected to the RF output port 2.

[0032] Correspondingly, in order to better control each attenuation unit, the drive control circuit 6 includes seven drive modules corresponding to the seven numerically controlled attenuation units respectively. Since the first three attenuation units include a single switch, the first attenuation unit 71, the second attenuation unit 72 and the third attenuation unit 73 are single-channel controlled, while the fourth attenuation unit 74, the fifth attenuation unit 75, the sixth attenuation unit 76 and the seventh attenuation unit 77 are dual-channel controlled.

[0033] like Figure 2 As shown, to achieve a larger and more compact circuit layout, the seven attenuation units are arranged in ascending order of attenuation. The control ports of the seven drive modules, from left to right, are 0.25dB, 0.5dB, 1dB, 2dB, 4dB, 8dB, and 16dB. The drive control circuit 6 is connected to a first filter capacitor 51 and a second filter capacitor 52 at its two ends. Specifically, the first attenuation unit 71, the second attenuation unit 72, and the third attenuation unit 73 have identical structures, each including a high-value gate resistor, a first switch, and a first ground resistor. One end of the high-value gate resistor is connected to the drive module, and the other end is connected to the gate of the first switch. The drain of the first switch is grounded through the first ground resistor, and the source of the first switch in the first attenuation unit 71 and the first switch in the second attenuation unit 72 are connected. The source of the first switch in the second attenuation unit 72 and the first switch in the third attenuation unit 73 are also connected.

[0034] In order to improve the attenuation flatness of the first and second attenuation units 72, the drains of the first switches of the first attenuation unit 71 and the second attenuation unit 72 are both connected to a first sector capacitor 81.

[0035] Similarly, the fourth attenuation unit 74, the fifth attenuation unit 75, and the sixth attenuation unit 76 all include a high-value gate resistor, a second switch, and a third switch. The driving module employs dual-path control for the fourth attenuation unit and the fifth and sixth attenuation units. The two control lines are respectively connected to the gates of the second and third switches. The source and drain of the second switch are both connected to the source of the third switch, and the drain of the third switch is grounded. The source of the second switch in the fourth attenuation unit 74 is connected to the drain of the second switch in the fifth attenuation unit 75, and the source of the second switch in the fifth attenuation unit 75 is connected to the drain of the second unit in the sixth attenuation unit 76. The high-value gate resistor is typically greater than 7KΩ.

[0036] The seventh attenuation unit 77 consists of two sixth attenuation units 76, wherein the two sixth attenuation units 76 in the seventh attenuation unit 77 are connected through the second switches of the two sixth attenuation units 76. In order to improve the attenuation flatness of the sixth and seventh attenuation units 77, the source of the second switch of the sixth attenuation unit 76 is connected to the seventh attenuation unit 77, and a second sector capacitor 82 is connected in parallel to the source of the second switch of the sixth attenuation unit 76.

[0037] The control principle of this embodiment:

[0038] Please use negative voltage control. That is, when the power supply input is a negative -5V supply voltage, the control port input should be 0V or 5V. After conversion by the drive control circuit, it will be a control voltage of -5V or 0V. Taking the first attenuation control unit as an example, when the first attenuation control unit is working, the drive module outputs the control voltage to the first switch. The first switch is turned on, and the 0.25dB attenuation level is activated. For a dual-channel control attenuation unit, taking the fourth attenuation unit as an example, when the drive module controls the second switch to open and the third switch to close, the 2dB attenuation level is activated, and so on. Figure 3 The seven-bit attenuation of each attenuation unit is given. After connecting sector capacitors to the switches of the first, second, sixth, and seventh attenuation units, from... Figure 7 As can be seen from the attenuation accuracy of each attenuation unit, the sector capacitor helps adjust the attenuation accuracy of each attenuation unit to within a range of ±0.2. Figures 4-8 The other performance characteristics of this attenuator are given in the figure. It can be seen that in the frequency range of DC to 8GHz, the insertion loss of this CNC attenuator is less than 2dB, the input and output VSWR is less than 1.3, the attenuation accuracy is less than 0.2dB, and the attenuation accuracy RMS is less than 0.25.

[0039] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of this utility model, and the utility model is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of this utility model, and these modifications and improvements are also considered to be within the protection scope of this utility model.

Claims

1. A seven-digit digitally controlled attenuator based on GaAs technology, characterized in that, It includes seven CNC attenuation units connected in series and a drive control circuit that controls the operation of each CNC attenuation unit. The seven CNC attenuation units are connected in sequence according to the attenuation amount from smallest to largest.

2. The seven-digit digitally controlled attenuator based on GaAs technology according to claim 1, characterized in that, The seven numerically controlled attenuation units include the first attenuation unit, the second attenuation unit, the third attenuation unit, the fourth attenuation unit, the fifth attenuation unit, the sixth attenuation unit, and the seventh attenuation unit, arranged in ascending order of attenuation amount. The attenuation amount between any two adjacent attenuation units differs by a factor of two.

3. A seven-digit digitally controlled attenuator based on GaAs technology according to claim 2, characterized in that, The drive control circuit includes seven drive modules corresponding to seven numerically controlled attenuation units. The first, second, and third attenuation units are single-channel controlled, while the fourth, fifth, sixth, and seventh attenuation units are dual-channel controlled.

4. A seven-digit digitally controlled attenuator based on GaAs technology according to claim 3, characterized in that, The first attenuation unit, the second attenuation unit, and the third attenuation unit have the same structure, each including a high-value gate resistor, a first switch, and a first ground resistor. One end of the high-value gate resistor is connected to the driving module, and the other end is connected to the gate of the first switch. The drain of the first switch is grounded through the first ground resistor, and the source of the first switch of the first attenuation unit and the source of the first switch of the second attenuation unit are connected. The source of the first switch of the second attenuation unit and the source of the first switch of the third attenuation unit are connected.

5. A seven-digit digitally controlled attenuator based on GaAs technology according to claim 3, characterized in that, The drains of the first switches in both the first and second attenuation units are connected to a first sector capacitor.

6. A seven-digit digitally controlled attenuator based on GaAs technology according to claim 4, characterized in that, The fourth, fifth, and sixth attenuation units each include a high-value gate resistor, a second switch, and a third switch. The driving module uses dual-path control for the fourth, fifth, and sixth attenuation units. The two control lines are respectively connected to the gates of the second and third switches. The source and drain of the second switch are both connected to the source of the third switch, and the drain of the third switch is grounded. The source of the second switch of the fourth attenuation unit is connected to the drain of the second switch of the fifth attenuation unit, and the source of the second switch of the fifth attenuation unit is connected to the drain of the second unit of the sixth attenuation unit.

7. A seven-digit digitally controlled attenuator based on GaAs technology according to claim 6, characterized in that, The source of the second switch of the sixth attenuation unit is connected to the drain of the seventh attenuation unit, and a second sector capacitor is connected in parallel to the source of the second switch of the sixth attenuation unit.

8. A seven-digit digitally controlled attenuator based on GaAs technology according to claim 6, characterized in that, The drain of the second switch in the fourth attenuation unit is connected to the source of the first switch in the third attenuation unit, and a ground matching capacitor is connected in parallel between the second switch and the first switch.

9. A seven-digit digitally controlled attenuator based on GaAs technology according to claim 8, characterized in that, The seventh attenuation unit consists of two sixth attenuation units, which are connected by a second switch of the sixth attenuation unit.

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