A control circuit based on gallium arsenide material and a radio frequency front-end chip to which the control circuit is applied

Abstract

The present invention discloses a control circuit based on gallium arsenide material and a radio frequency front-end chip to which the control circuit is applied. The control circuit receives the voltage VEN as a control signal and outputs the voltage Vout for controlling the switching of the operating state to the power amplifier. As an innovation, the control circuit is composed of a resistor, a HEMT transistor made of gallium arsenide material, and a diode, and the power supply voltage is provided by VDD. Moreover, the control circuit includes a multi-stage amplifier circuit with a control signal driving stage, a control signal reverse driving stage, and a control signal output stage. The present invention designs and manufactures the control circuit using gallium arsenide material, which can integrate the control circuit, a low-noise amplifier, and a switch on the same gallium arsenide wafer, simplifies the complexity of the R & D design, and is conducive to shortening the R & D time, reducing the chip size, and saving the manufacturing cost.

Description

Technical Field

[0001] The present invention relates to the field of power amplifiers, and particularly to a control circuit and a radio frequency front-end chip to which the control circuit is applied. Background Art

[0002] In recent years, WiFi communication technology has achieved great success, with upgrades every few years. It has developed from WiFi2 (IEEE 802.11a / b) through WiFi3 (IEEE 802.11g), WiFi4 (IEEE 802.11n), WiFi5 (IEEE802.11ac), WiFi6 (IEEE 802.11ax) to WiFi7 (IEEE 802.11be). Significant progress has also been made in WiFi radio frequency chip technology, evolving from a separately packaged radio frequency power amplifier chip to integrating power amplifier wafers, low-noise amplifiers, switch wafers, and control circuit wafers into a radio frequency front-end chip module of a few square millimeters.

[0003] In current WiFi communication, radio frequency power amplifiers usually adopt HBT (heterojunction bipolar transistor) integrated circuit technology based on gallium arsenide materials, and switches and low-noise amplifiers mostly use HMET (high electron mobility transistor) integrated circuit technology based on gallium arsenide materials. Since the control circuit requires the use of OPA (operational amplifier), CMOS devices based on silicon-based materials are commonly used. Therefore, the control circuit of the WiFi radio frequency front-end chip cannot be directly integrated with other circuits (power amplifier, low-noise amplifier, and switch) into the same wafer, resulting in an extended R & D design cycle, an increased size and area, and an increased production cost.

[0004] As Figure 1 shown, it is a typical scheme of the control circuit in the prior art. The main body of this control circuit is composed of a low-dropout regulator 01, and is paired with current sources (see 02 and 03 in Figure 1 and current comparators (see 04 and 05 in Figure 1 ) to achieve the required control functions. There are also implementation schemes with an output driving NMOS transistor to control the voltage of the power amplifier, and implementation schemes with a temperature stabilization circuit.

[0005] Figure 1The low-dropout regulator 01 is composed of an operational amplifier OPA, a PMOS transistor T01, resistors R1' and R2'. The voltage VEN of the control signal is directly applied to the inverting input terminal of the operational amplifier OPA. The output terminal of the operational amplifier OPA is connected to the gate of the PMOS transistor T01. The source of the PMOS transistor T01 is connected to the power supply voltage, and the drain serves as the output voltage Vout of the entire control circuit and is also connected to the resistor R1'. The other end of the resistor R1' is connected to the resistor R2', and the other end of the resistor R2' is grounded. The connection point FB of the resistor R1' and the resistor R2' is used as a feedback point, which is connected to the non-inverting input terminal of the operational amplifier OPA and is also connected to the current comparators 04 and 05 to provide a reference current. According to the working principle of the operational amplifier, the output voltage Vout of the low-dropout regulator 01 can be expressed as: Vout = VEN × (1 + R1' / R2'). That is, when the ratio of the resistors R1' and R2' is fixed, the control signal can linearly control the output voltage Vout, thereby controlling the working state of the power amplifier.

[0006] The operational amplifier OPA and the PMOS transistor T01 that make up the above low-dropout regulator 01, including the PMOS transistors T02 and T03 in the two current comparators, are all made by the CMOS device process of silicon-based materials and cannot be fabricated on a gallium arsenide substrate. That is, the low-dropout regulator needs to be fabricated on a separate CMOS wafer and cannot be integrated with the power amplifier, low-noise amplifier, and switch fabricated on the gallium arsenide substrate onto the same wafer. Therefore, the module size of the chip increases and the types of wafers increase, resulting in an increase in the design complexity and manufacturing cost of the entire radio frequency front-end chip. Summary of the Invention

[0007] The object of the present invention is to propose a control circuit based on gallium arsenide material and its applied radio frequency front-end chip, which simplifies the wafer composition and manufacturing process of the radio frequency front-end chip.

[0008] The technical solution for the present invention to achieve the above object is a control circuit based on gallium arsenide material, which receives the voltage VEN as a control signal and outputs the voltage Vout for controlling the working state switching to the power amplifier. The characteristics are as follows: The control circuit is composed of resistors, HEMT transistors of gallium arsenide material, and diodes, and the power supply voltage is provided by VDD. The control circuit includes a multi-stage amplifier circuit of a control signal driving stage, a control signal reverse driving stage, and a control signal output stage.

[0009] The above control circuit based on gallium arsenide material. Further, in the control circuit, the amplifier circuit of the control signal driving stage is composed of resistor R1, R2, R3 and HEMT transistor T1, the amplifier circuit of the control signal reverse driving stage is composed of resistor R4, R5 and HEMT transistor T2, and the amplifier circuit of the control signal output stage is composed of HEMT transistors T3, T4 and gallium arsenide diodes D1, D2. The voltage VEN is connected to one end of resistor R1, the other end of resistor R1 is connected to the gates of resistor R2 and HEMT transistor T1, the other end of resistor R2 is connected to the source of HEMT transistor T1 and grounded together, the drain of HEMT transistor T1 is connected to resistor R3 and resistor R4 at a point, the other end of resistor R3 is connected to power supply VDD, the other end of resistor R4 is connected to the gate of HEMT transistor T2, the source of HEMT transistor T2 is grounded and the drain is connected to resistor R5 and the gate of HEMT transistor T3, the other end of resistor R5 and the drain of HEMT transistor T3 are both connected to power supply VDD, the source of HEMT transistor T3 is connected to the drain and gate of HEMT transistor T4 together as the output terminal of the control circuit voltage Vout, and the source of HEMT transistor T4 is grounded through a group of two gallium arsenide diodes D1 and D2 connected in series in the forward direction.

[0010] The above control circuit based on gallium arsenide material. Further still, the resistors R1, R2, R3 are all high-impedance resistors of 10KΩ or more.

[0011] The above control circuit based on gallium arsenide material. Further still, the conduction voltages of the gallium arsenide diodes D1, D2 are close to 1.25V, and the conduction voltage between the gate and source of the HEMT transistor T4 is close to 0.5V.

[0012] The above control circuit based on gallium arsenide material. Further, the control circuit is made by gallium arsenide chip processing technology, including a substrate with a thickness of 75μm, a bottom Au metal grounding film with a thickness of 4μm, a first Au metal connection line with a thickness of 1μm, a second Au metal connection line with a thickness of 4μm, HEMT transistors with a gate length of 0.5μm, gallium arsenide diodes and resistors, and a 0.1μm thick silicon nitride insulating layer is formed between the two Au metal connection lines and is locally electrically connected through the solid holes in the silicon nitride insulating layer.

[0013] One of the technical solutions for the present invention to achieve the above - mentioned another object is a radio - frequency front - end chip, which is characterized in that it is composed of a power amplifier, a low - noise amplifier, a switch, and the control circuit according to any one of claims 1 to 5. The power amplifier is separately fabricated on a gallium arsenide HBT wafer and consists of a connected radio - frequency amplification circuit and a bias circuit. The low - noise amplifier, the switch, and the control circuit are integrated on a gallium arsenide HEMT wafer. The voltage VEN of the control signal is input to the control circuit, and the control circuit is connected to the low - noise amplifier, the switch, and the bias circuit. Another control signal C0 and the antenna are both connected to the switch, and the switch is shunt - connected to the low - noise amplifier and the radio - frequency amplification circuit. The low - noise amplifier is connected to the receiver, and the radio - frequency signal is input to the radio - frequency amplification circuit.

[0014] Another technical solution for the present invention to achieve the above - mentioned another object is a radio - frequency front - end chip, which is characterized in that it is composed of a power amplifier, a low - noise amplifier, a switch, and the control circuit according to any one of claims 1 to 5. And the power amplifier, the low - noise amplifier, the switch, and the control circuit are integrally integrated on a gallium arsenide HEMT wafer. The power amplifier consists of a connected radio - frequency amplification circuit and a bias circuit. The voltage VEN of the control signal is input to the control circuit, and the control circuit is connected to the low - noise amplifier, the switch, and the bias circuit. Another control signal C0 and the antenna are both connected to the switch, and the switch is shunt - connected to the low - noise amplifier and the radio - frequency amplification circuit. The low - noise amplifier is connected to the receiver, and the radio - frequency signal is input to the radio - frequency amplification circuit.

[0015] Applying the control circuit with the substrate replaced in the present invention, compared with the control circuit of the existing silicon - based CMOS device, has significant progressiveness: using HEMT transistors and diodes made of gallium arsenide materials to design and construct the control circuit can integrate the control circuit, the low - noise amplifier, and the switch on the same gallium arsenide - based wafer, simplifying the complexity of the R & D design, shortening the R & D time, reducing the chip size, and saving the manufacturing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic structural diagram of a control circuit made of silicon - based materials in the prior art.

[0017] Figure 2 is a schematic diagram of a preferred implementation structure of the control circuit based on gallium arsenide materials in the present invention.

[0018] Figure 3 is Figure 2 a layout design schematic diagram of the shown control circuit under the gallium arsenide chip processing technology.

[0019] Figure 4 is a schematic diagram of the topological structure of the radio - frequency front - end chip to which the control circuit of the present invention is applied. EMBODIMENTS

[0020] The following will further elaborate on the specific implementation manners of the present invention in combination with the accompanying drawings of the embodiments, so that the technical solutions of the present invention can be more easily understood and mastered, thereby making the protection scope of the present invention more clearly defined.

[0021] In view of the above description of the deficiencies of the prior silicon-based control circuit in chip integration, in order to integrate the control circuit onto the wafers of switches and low-noise amplifiers, the control circuit of the radio frequency front end cannot use CMOS transistors made of silicon-based materials as amplification devices, and can only use HEMT transistors made of gallium arsenide materials as amplification devices. For this reason, the control circuit designed by the present invention is powered by VDD, and takes the gallium arsenide HEMT transistor as the main amplification device, and configures gallium arsenide diodes and resistors to construct a drive, amplification, and output circuit for the control signal, that is, a multi-stage amplification circuit including a control signal drive stage, a control signal reverse push stage, and a control signal output stage.

[0022] Although the material of the amplification device has changed, there is still a broad space for the design of the amplification circuit. From a more refined feature perspective, as Figure 2 shown in the preferred embodiment, in this control circuit, the amplification circuit of the control signal drive stage is composed of resistors R1, R2, R3 and HEMT transistor T1, the amplification circuit of the control signal reverse push stage is composed of resistors R4, R5 and HEMT transistor T2, and the amplification circuit of the control signal output stage is composed of HEMT transistors T3, T4 and gallium arsenide diodes D1, D2. From the perspective of device connection, the voltage VEN is connected to one end of resistor R1, the other end of resistor R1 is connected to the gates of resistor R2 and HEMT transistor T1, the other end of resistor R2 is connected to the source of HEMT transistor T1 and grounded together, the drain of HEMT transistor T1 is connected to resistor R3 and resistor R4 at a point, the other end of resistor R3 is connected to the power supply VDD, the other end of resistor R4 is connected to the gate of HEMT transistor T2, the source of HEMT transistor T2 is grounded and the drain is connected to resistor R5 and the gate of HEMT transistor T3, the other end of resistor R5 and the drain of HEMT transistor T3 are both connected to the power supply VDD, the source of HEMT transistor T3 is connected to the drain and gate of HEMT transistor T4 as the output end of the control circuit voltage Vout, and the source of HEMT transistor T4 is grounded through a group of two gallium arsenide diodes D1, D2 connected in series in the forward direction.

[0023] When the RF front-end chip needs to output RF power, the voltage VEN of the control signal is usually at a high potential of 3V. The resistors R1 and R2 are generally in the order of tens of kiloohms and are high-impedance inputs. Therefore, the current drawn from the control signal input terminal is relatively small and can be less than 0.1 mA. The transistor T1 is an enhancement-mode HEMT. According to the ratio of the resistors R1 and R2, the potential of the gate of the transistor T1 is determined. That is, adjusting this ratio can make the amplifier in the first stage in the conducting state. Since the resistor R3 is large enough, about tens of kiloohms, the transistor T1 is in the saturation state, and its drain potential is low enough not to turn on the transistor T2, which is in the cut-off state because the transistor T2 is an enhancement-mode and its drain potential is determined by the resistor R5 and the third stage. The third stage is a source follower circuit. The conduction voltages of the two forward-series diodes D1 and D2, plus the conduction voltage between the gate and source of the transistor T4, determine the level of the output control signal voltage Vout. Usually, the conduction voltage of a gallium arsenide diode is about 1.25V, and the conduction voltage between the gate and source of a HEMT transistor is about 0.5V, and the control signal output is about 3V.

[0024] When the RF front-end chip needs to receive RF signals from the antenna, the voltage VEN of the control signal is usually at a low potential of 0V. Then the first-stage amplifier is in the cut-off state, and the second stage is in the saturation state. The gate of the transistor T3 is at a low potential state, so the output control signal voltage Vout is at a low potential.

[0025] From the processing and manufacturing of this control circuit, a mature gallium arsenide chip processing technology in the integrated circuit industry chain is used. Refer to Figure 3 the layout design schematic diagram shown. The active amplifying devices of this technology are HEMT transistors including enhancement-mode and depletion-mode, and their gate length is 0.5μm. The passive devices include gallium arsenide diodes and high-value resistors. The chip layering of this control circuit includes a substrate with a thickness of 75μm, a bottom Au metal grounding film with a thickness of 4μm, a first Au metal connection line with a thickness of more than 1μm, a second Au metal connection line with a thickness of 4μm, HEMT transistors with a gate length of 0.5μm, gallium arsenide diodes and resistors. And a 0.1μm-thick silicon nitride insulating layer is formed between the two Au metal connection lines and is locally electrically connected through the solid holes in the silicon nitride insulating layer.

[0026] The voltage VEN of the control signal is connected to one end of a resistor R1 through a 2-μm-wide first-layer metal wire. The surface resistivity of this resistor R1 is approximately 5000 ohms per square meter (with a resistance value of approximately twenty kilo-ohms). The other end of this resistor R1 is connected to the gate of a transistor T1 through a second-layer metal wire. The gate width of the transistor T1 is approximately 5 μm, and its gate is connected to one end of a resistor R2 through a first-layer metal wire. The resistor R2 is composed in the same way as the resistor R1. The other end of the resistor R2 is grounded through a first-layer metal wire. The source of the transistor T1 is grounded through a first-layer metal wire, and its drain is connected to one ends of a resistor R3 and a resistor R4 through a first-layer metal wire. The resistor R3 is composed and has the same resistance value as the resistor R1, and its other end is connected to the power supply VDD through a first-layer metal wire. The resistor R4 is also composed and has the same resistance value as the resistor R1, and its other end is connected to the gate of a transistor T2 through a first-layer metal wire. The structure and gate width of the transistor T2 can be the same as those of the transistor T1. Its source is grounded through a first-layer metal wire, and its drain is connected to the gate of a transistor T3 through a first-layer metal wire. The structure of the transistor T3 can be the same as that of the transistor T1, its gate width can be 10 μm, its drain is connected to the power supply VDD through a first-layer metal wire, and its source is connected to the gate and drain of a transistor T4 and the output terminal of the voltage Vout through a first-layer metal wire. Here, the transistor T4 uses a double-finger gate structure with a gate width of 25 μm, and its source is connected to the forward end of a diode D1 through a second-layer metal wire. The conduction area of the diode D1 is 100 μm 2 , and its negative end is connected to the forward end of a diode D2 through a first-layer metal wire. The diode D2 is composed in the same way as the diode D1, and its other end is grounded through a second-layer metal wire.

[0027] Based on the above design and fabrication of the control circuit using gallium arsenide materials, the present invention further optimizes the chip design and fabrication process, and combines it with a power amplifier, a low-noise amplifier, and a switch to form a radio frequency front-end chip. As Figure 4 shown, among which the power amplifier is separately fabricated on a gallium arsenide HBT wafer 12 and consists of a connected radio frequency amplification circuit and a bias circuit; the low-noise amplifier, the switch, and the control circuit are integrated on a gallium arsenide HEMT wafer 11. The voltage VEN of the control signal is input to the control circuit. The control circuit is connected in parallel with the low-noise amplifier, the switch, and the bias circuit. Another control signal C0 and the antenna are both connected to the switch, and the switch is connected in parallel with the low-noise amplifier and the radio frequency amplification circuit. The low-noise amplifier is connected to the receiver, and the radio frequency signal is input to the radio frequency amplification circuit. Thus, the entire radio frequency front-end chip is composed of two wafers of gallium arsenide materials, that is, a power amplifier wafer of gallium arsenide HBT and a wafer integrating the control circuit, the low-noise amplifier, and the switch of gallium arsenide HEMT, and the design and manufacturing process are greatly simplified.

[0028] When transmitting a radio frequency signal, the control circuit with voltage VEN applied will provide a 3V control signal output to the bias circuit of the power amplifier, sufficient to drive the bias circuit and thus control the output of the radio frequency amplification circuit of the power amplifier. At the same time, the voltage Vout output by the control circuit cooperates with another control signal C0 to turn on the transmitting end of the switch and turn off the receiving end of the switch. The radio frequency signal amplified by the power amplifier is sent to the antenna through the switch.

[0029] When receiving a radio frequency signal, the control circuit outputs a low-potential voltage Vout to turn off the bias circuit of the power amplifier and prevent the power amplifier from amplifying the radio frequency signal. At the same time, the low-potential voltage Vout cooperates with another control signal C0 to turn off the transmitting end of the switch and turn on the receiving end of the switch. Meanwhile, the low-noise amplifier is turned on, and the weak radio frequency signal received by the antenna is amplified by the low-noise amplifier and then sent to the receiver.

[0030] In addition to the above-described dual-chip implementation of the radio frequency front-end chip, if the power amplifier is also made of gallium arsenide HEMT, it is optional to integrate the power amplifier, low-noise amplifier, switch, and control circuit as a whole on a gallium arsenide HEMT chip, and the power amplifier consists of a connected radio frequency amplification circuit and a bias circuit (not shown). In terms of chip function design, referring to the foregoing, the voltage VEN of the control signal is input to the control circuit, the control circuit is connected to the low-noise amplifier, switch, and bias circuit, another control signal C0 and the antenna are both connected to the switch, and the switch is shunt-connected to the low-noise amplifier and radio frequency amplification circuit, the low-noise amplifier is connected to the receiver, and the radio frequency signal is input to the radio frequency amplification circuit. Thus, the entire radio frequency front-end chip only needs to be composed of a gallium arsenide material chip, and the circuit design and manufacturing process can be greatly simplified.

[0031] In summary, from the introduction of the solution and detailed description of the embodiments of the radio frequency front-end chip based on the gallium arsenide material control circuit of the present invention, compared with the control circuit of the existing silicon-based material CMOS device, the present invention has prominent substantial features and remarkable progressiveness, manifested as: using HEMT transistors and diodes made of gallium arsenide material to design and construct the control circuit, enabling the integration of the control circuit, low-noise amplifier, and switch on the same gallium arsenide material chip, simplifying the complexity of the R & D design, facilitating shortening the R & D time-consuming, reducing the chip size, and saving the manufacturing cost.

[0032] In addition to the above embodiments, the present invention may also have other implementation manners. All technical solutions formed by equivalent substitution or equivalent transformation fall within the scope of protection required by the present invention.

Claims

1. A control circuit based on gallium arsenide material, which receives the voltage VEN as a control signal and outputs the voltage Vout for controlling the switching of the working state to the power amplifier, is characterized in that: The control circuit is composed of resistors, HEMT transistors made of gallium arsenide materials, and diodes, and is powered by VDD. The control circuit includes a multi-stage amplifier circuit with a control signal driving stage, a control signal reverse driving stage, and a control signal output stage. The amplifier circuit of the control signal driving stage is composed of resistors R1, R2, R3, and HEMT transistor T1. The amplifier circuit of the control signal reverse driving stage is composed of resistors R4, R5, and HEMT transistor T2. The amplifier circuit of the control signal output stage is composed of HEMT transistors T3, T4, and gallium arsenide diodes D1, D2. The voltage VEN is connected to one end of resistor R1. The other end of resistor R1 is connected to the gates of resistor R2 and HEMT transistor T1. The other end of resistor R2 is connected to the source of HEMT transistor T1 and grounded together. The drain of HEMT transistor T1 is connected to resistor R3 and resistor R4 at a point. The other end of resistor R3 is connected to power supply VDD. The other end of resistor R4 is connected to the gate of HEMT transistor T2. The source of HEMT transistor T2 is grounded and the drain is connected to resistor R5 and the gate of HEMT transistor T3. The other end of resistor R5 and the drain of HEMT transistor T3 are both connected to power supply VDD. The source of HEMT transistor T3 is connected to the drain and gate of HEMT transistor T4 and is the output terminal of the control circuit voltage Vout. The source of HEMT transistor T4 is grounded through a group of two gallium arsenide diodes D1 and D2 connected in series forward. The resistors R1, R2, and R3 are all high-impedance resistors of 10KΩ or more. The conduction voltages of the gallium arsenide diodes D1 and D2 are close to 1.25V, and the conduction voltage between the gate and source of the HEMT transistor T4 is close to 0.5V. The control circuit is fabricated by gallium arsenide chip processing technology, including a substrate with a thickness of 75μm, a bottom Au metal grounding film with a thickness of 4μm, a first Au metal connection line with a thickness of 1μm, a second Au metal connection line with a thickness of 4μm, HEMT transistors with a gate length of 0.5μm, gallium arsenide diodes, and resistors. A 0.1μm thick silicon nitride insulating layer is formed between the two Au metal connection lines and is locally electrically connected through the solid holes in the silicon nitride insulating layer.

2. A radio frequency front-end chip, characterized in that: It is composed of a power amplifier, a low-noise amplifier, a switch, and the control circuit described in claim 1. The power amplifier is separately fabricated on a gallium arsenide HBT wafer and is composed of a connected radio frequency amplifier circuit and a bias circuit. The low-noise amplifier, switch, and control circuit are integrated on a gallium arsenide HEMT wafer. The voltage VEN of the control signal is input to the control circuit. The control circuit is connected to the low-noise amplifier, switch, and bias circuit. Another control signal C0 and the antenna are both connected to the switch. The switch is connected in parallel with the low-noise amplifier and the radio frequency amplifier circuit. The low-noise amplifier is connected to the receiver. The radio frequency signal is input to the radio frequency amplifier circuit.

3. A radio frequency front-end chip, characterized in that: It consists of a power amplifier, a low-noise amplifier, a switch, and the control circuit described in claim 1, and the power amplifier, the low-noise amplifier, the switch, and the control circuit are integrally integrated on a gallium arsenide HEMT wafer. The power amplifier consists of a connected radio frequency amplification circuit and a bias circuit; the voltage VEN of the control signal is input to the control circuit, the control circuit is connected to the low-noise amplifier, the switch, and the bias circuit, another control signal C0 and the antenna are both connected to the switch, and the switch is shunt-connected to the low-noise amplifier and the radio frequency amplification circuit, the low-noise amplifier is connected to the receiver, and the radio frequency signal is input to the radio frequency amplification circuit.

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