LNA and VCO current multiplexing fusion structure for BLE radio frequency transceiver

Abstract

The invention discloses a low noise amplifier (LNA) and voltage-controlled oscillator (VCO) current multiplexing fusion structure for a BLE radio frequency transceiver, and relates to the technical field of radio frequency receiver circuits. According to the circuit, a voltage controlled oscillator (VCO) module and a low noise amplifier (LNA) module are vertically integrated through a current multiplexing framework, and the circuit specifically comprises the voltage controlled VCO module forming an oscillator core, a bias sharing module for realizing current multiplexing and the LNA module. According to the design, limitation of a traditional independent framework is broken through, an oscillator and a low-noise amplifier circuit are longitudinally stacked, a bypass capacitor is connected to a common node in parallel to construct an alternating current ground path, and on the premise that it is ensured that the working states of the two modules are mutually independent, sharing and multiplexing of static bias current are achieved. According to the structural design, mutual interference between the oscillator and the low-noise amplifier is avoided, and working current and system power consumption of the whole circuit are effectively reduced through reconstruction of a current path between circuit layers.

Description

Technical Field

[0001] The present invention belongs to the technical field of radio frequency receiving circuits, and specifically relates to an LNA and VCO current multiplexing fusion structure for a BLE radio frequency transceiver. Background Art

[0002] With the advent of the Internet of Things (IoT), the demand for battery life has increased significantly. As a key module in Bluetooth devices, the RF receiver faces the design challenge of using a highly integrated solution to minimize power consumption with sufficient sensitivity in a crowded spectrum while still being compatible with the adopted communication standards. This requires a trade-off between receiver performance and power consumption.

[0003] Based on the work of numerous researchers, current low-power RF receiver technologies are showing the following trends. First, receivers with wake-up functionality significantly reduce power consumption by adopting a fully passive RF front-end design. However, these receivers are sensitive to continuous wave interference and are not suitable for all wireless channels. Furthermore, due to the large capacitance in their structure, the achievable transmission rate is extremely low. Another trend is mixer-first receivers, which advocate replacing traditional active low-noise amplifiers with mixers as the first stage of the receiver. However, because the first stage dominates noise performance, this structure generally suffers from low sensitivity.

[0004] In the IEEE RFIC 2018 paper "A 217μW-82dBm IEEE 802.11Wi-Fi LP-WUR using a3rd-Harmonic Passive Mixer", a receiver structure using a third-harmonic passive mixer was proposed in a 40nm CMOS process to suppress unwanted harmonic components, achieving an operating frequency of 5.8GHz and a bit error rate of 10 -3 At a data rate of 62.5 kb / s, the receiver consumes 217 μW and has a sensitivity of -82 dBm. However, the third-order harmonic mixer increases circuit complexity and requires precise phase and amplitude matching. For applications with higher data rates or lower bit error rates, the receiver's sensitivity may not meet requirements. Summary of the Invention

[0005] Based on this, the present invention proposes a current-reuse fusion structure for the LNA and VCO in a BLE radio frequency transceiver. This current-reuse fusion circuit utilizes current reuse to establish an AC ground path by connecting a bypass capacitor in parallel at the common node between the oscillator and low-noise amplifier circuits. This allows for the sharing of static bias current while ensuring the independent operation of the two modules. This reduces overall circuit power consumption.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] The LNA and VCO current multiplexing fusion structure circuit for the BLE radio frequency transceiver is composed of a voltage-controlled oscillator, a current multiplexing circuit and a low-noise amplifier:

[0008] The voltage-controlled oscillator utilizes a cross-coupled NMOS transistor structure, with its source forming a multiplexing path through an LC component, creating a shared node with the low-noise amplifier (LNA). This LC component path connects the two functional modules, serving as both the current multiplexing module and the low-noise amplifier (LNA), forming a shared path for the DC bias current. At this critical node, a parallel bypass capacitor creates an AC ground path, effectively filtering out high-frequency AC signals and achieving electrical isolation between the oscillator and the low-noise amplifier in the frequency domain. This structure enables the two modules to share the quiescent operating point current while maintaining the independence of their respective circuit operations. This design strategy significantly reduces the overall circuit's static power consumption through the current multiplexing mechanism.

[0009] According to a preferred embodiment of the LNA and VCO current multiplexing fusion structure for a BLE radio frequency transceiver of the present invention, the voltage-controlled oscillator circuit is composed of the following components: a first NMOS transistor (M1), a second NMOS transistor (M2), a first capacitor (C1), a second capacitor (C2), a third capacitor (C3), a first inductor (L1), a first resistor (R1), and a second resistor (R2); the connection relationship thereof is as follows: the positive electrode of the first inductor is connected to the positive electrode of the first capacitor, and the negative electrode of the first inductor is connected to the negative electrode of the first capacitor; the positive electrode of the first capacitor is connected to the positive electrode of the second capacitor, and the negative electrode of the first capacitor is connected to the negative electrode of the second capacitor; the third capacitor is connected to the positive electrode of the first capacitor, and the third capacitor is connected to the negative electrode of the second capacitor; the fourth .... The positive electrode of the second capacitor is connected to the oscillator output signal VCOP, and the negative electrode of the second capacitor is connected to the gate of the second NMOS transistor; the positive electrode of the third capacitor is connected to the gate of the first NMOS transistor, and the negative electrode of the third capacitor is connected to the oscillator output signal VCON; the positive electrode of the first resistor is connected to the gate of the first NMOS transistor, and the negative electrode of the first resistor is connected to the fixed bias voltage VBIAS; the positive electrode of the second resistor is connected to the fixed bias voltage VBIAS, and the negative electrode of the second resistor is connected to the gate of the second NMOS transistor; the source of the first NMOS transistor is connected to the positive electrode of the fourth capacitor, and the drain is connected to the positive electrode of the second capacitor; the source of the second NMOS transistor is connected to the positive electrode of the fourth capacitor, and the drain is connected to the negative electrode of the third capacitor;

[0010] The current multiplexing circuit comprises the following parts: a fourth capacitor (C4), a fifth capacitor (C5), and a second inductor (L2); the connection relationship thereof is as follows: the positive electrode of the fourth capacitor is connected to the positive electrode of the fifth capacitor, and the negative electrode of the fourth capacitor is grounded GND; the positive electrode of the fifth capacitor is connected to the positive electrode of the second inductor, and the negative electrode of the fifth capacitor is connected to the negative electrode of the second inductor; the positive electrode of the second inductor is connected to the source of the second NMOS transistor, and the negative electrode of the second inductor is connected to the positive electrode of the sixth capacitor;

[0011] The low noise amplifier comprises the following parts: a third NMOS transistor (M5), a fourth NMOS transistor (M6), a fifth capacitor (C5), a sixth capacitor (C6), a seventh capacitor (C7), a second inductor (L2), a third inductor (L3), and a fourth inductor (L4); the connection relationship of the parts is as follows: the positive electrode of the fifth capacitor is connected to the positive electrode of the second inductor, and the negative electrode of the fifth capacitor is connected to the negative electrode of the second inductor; the positive electrode of the second inductor is connected to the source of the second NMOS transistor, and the negative electrode of the second inductor is connected to the positive electrode of the sixth capacitor; the negative electrode of the sixth inductor is connected to the positive electrode of the sixth capacitor; the negative electrode of the sixth inductor is connected to the positive electrode of the sixth inductor. The radio frequency signal output terminal RFOUT; the source of the third NMOS transistor is connected to the drain of the fourth NMOS transistor, the gate of the third NMOS transistor is connected to the power supply voltage VDD, and the drain of the third NMOS transistor is connected to the negative electrode of the second inductor; the positive electrode of the third inductor is connected to the radio frequency signal input terminal RFIN, and the negative electrode of the third inductor is connected to the gate of the fourth NMOS transistor; the positive electrode of the seventh capacitor is connected to the gate of the fourth NMOS transistor, and the negative electrode of the seventh capacitor is connected to the positive electrode of the fourth inductor; the source of the fourth NMOS transistor is connected to the positive electrode of the fourth inductor; and the negative electrode of the fourth inductor is grounded GND.

[0012] The core advantages of this invention are reflected in the following three aspects:

[0013] 1. The present invention vertically integrates the oscillator and the low-noise amplifier, connects the two circuit modules in the form of a multiplexing path using LC components, and constructs an AC ground path by connecting a bypass capacitor in parallel at a common node. This ensures that the two modules operate independently of each other, thereby achieving shared multiplexing of the static bias current.

[0014] 2. Compared with the traditional structure, the present invention improves the utilization rate of bias current by reusing the current path, reduces the overall operating current demand of the system, and improves the system energy efficiency in the application scenario.

[0015] 3. Compared with the oscillator and low-noise amplifier circuits with independent structures, the fusion structure circuit of the present invention has significantly reduced the current and power consumption of the overall circuit while achieving the same parameter indicators and functions, while saving circuit area, providing a new technical path for the miniaturization and low-power design of Bluetooth transmission systems. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A circuit diagram of a current multiplexing fusion structure circuit of LNA and VCO in the present invention;

[0017] Figure 2 The phase noise comparison diagram of the voltage controlled oscillator in the independent structure and the fusion structure circuit;

[0018] Figure 3 The curve showing the variation of noise figure with frequency for the low noise amplifier in the LNA and VCO current multiplexing fusion circuit.

[0019] Figure 4 The curve of the input reflection coefficient S11 in the S parameter of the low noise amplifier of the LNA and VCO current multiplexing fusion structure circuit changes with frequency;

[0020] Figure 5 This is the curve of voltage gain changing with frequency in the AC simulation of the low-noise amplifier with LNA and VCO current multiplexing fusion structure circuit. DETAILED DESCRIPTION

[0021] The present invention will be further described below with reference to the accompanying drawings.

[0022] like Figure 1 As shown, the LNA and VCO current multiplexing fusion structure circuit for BLE radio frequency transceiver includes a voltage controlled oscillator, a current multiplexing circuit and a low noise amplifier;

[0023] The voltage-controlled oscillator includes a first NMOS transistor (M1), a second NMOS transistor (M2), a first capacitor (C1), a second capacitor (C2), a third capacitor (C3), a first inductor (L1), a first resistor (R1), and a second resistor (R2);

[0024] The current multiplexing circuit includes a fourth capacitor (C4), a fifth capacitor (C5), and a second inductor (L2);

[0025] The low noise amplifier includes a third NMOS transistor (M5), a fourth NMOS transistor (M6), a fifth capacitor (C5), a sixth capacitor (C6), a seventh capacitor (C7), a second inductor (L2), a third inductor (L3), and a fourth inductor (L4);

[0026] The positive electrode of the first inductor is connected to the positive electrode of the first capacitor, and the negative electrode of the first inductor is connected to the negative electrode of the first capacitor; the positive electrode of the first capacitor is connected to the positive electrode of the second capacitor, and the negative electrode of the first capacitor is connected to the negative electrode of the second capacitor; the positive electrode of the second capacitor is connected to the oscillator output signal VCOP, and the negative electrode of the second capacitor is connected to the gate of the second NMOS transistor; the positive electrode of the third capacitor is connected to the gate of the first NMOS transistor, and the negative electrode of the third capacitor is connected to the oscillator output signal VCON; the positive electrode of the first resistor is connected to the gate of the first NMOS transistor, and the negative electrode of the first resistor is connected to a fixed bias voltage VBIAS; the positive electrode of the second resistor is connected to the fixed bias voltage VBIAS, and the negative electrode of the second resistor is connected to the gate of the second NMOS transistor; the source of the first NMOS transistor is connected to the positive electrode of the fourth capacitor, and the drain is connected to the positive electrode of the second capacitor; the source of the second NMOS transistor is connected to the positive electrode of the fourth capacitor, and the drain is connected to the negative electrode of the third capacitor;

[0027] The positive electrode of the fourth capacitor is connected to the positive electrode of the fifth capacitor, and the negative electrode of the fourth capacitor is grounded GND; the positive electrode of the fifth capacitor is connected to the positive electrode of the second inductor, and the negative electrode of the fifth capacitor is connected to the negative electrode of the second inductor; the positive electrode of the second inductor is connected to the source of the second NMOS transistor, and the negative electrode of the second inductor is connected to the positive electrode of the sixth capacitor;

[0028] The positive electrode of the fifth capacitor is connected to the positive electrode of the second inductor, and the negative electrode of the fifth capacitor is connected to the negative electrode of the second inductor; the positive electrode of the second inductor is connected to the source of the second NMOS tube, and the negative electrode of the second inductor is connected to the positive electrode of the sixth capacitor; the negative electrode of the sixth inductor is connected to the radio frequency signal output terminal RFOUT; the source electrode of the third NMOS tube is connected to the drain electrode of the fourth NMOS tube, the gate electrode of the third NMOS tube is connected to the power supply voltage VDD, and the drain electrode of the third NMOS tube is connected to the negative electrode of the second inductor; the positive electrode of the third inductor is connected to the radio frequency signal input terminal RFIN, and the negative electrode of the third inductor is connected to the gate electrode of the fourth NMOS tube; the positive electrode of the seventh capacitor is connected to the gate electrode of the fourth NMOS tube, and the negative electrode of the seventh capacitor is connected to the positive electrode of the fourth inductor; the source electrode of the fourth NMOS tube is connected to the positive electrode of the fourth inductor; and the negative electrode of the fourth inductor is grounded GND.

[0029] In this circuit, the voltage-controlled oscillator (VCO) utilizes a cross-coupled NMOS transistor structure, with its source forming a shared node with the low-noise amplifier (LNA) via an LC component multiplexing path. This path connects the two functional modules and serves as both the current multiplexing path module and the LNA module, forming a shared path for the DC bias current. At this critical node, a parallel bypass capacitor establishes an AC ground path, effectively filtering out high-frequency AC signals and achieving electrical isolation between the oscillator and the LNA in the frequency domain. This structure enables the two modules to share the quiescent operating point current while maintaining the independence of their respective circuit operations. This design strategy significantly reduces the overall circuit's static power consumption through the current multiplexing mechanism.

[0030] like Figure 2 As shown in the figure, the phase noise of the oscillator in the fusion structure is almost the same as that of the oscillator in the independent structure, which proves that the current multiplexing in the fusion structure has almost no effect on the oscillator phase noise.

[0031] like Figure 3 The figure shows the variation of the noise figure of the low-noise amplifier in the fusion structure circuit with frequency. As can be seen from the figure, the circuit's noise figure NF is less than 1.5dB within the operating frequency band, indicating that the circuit has good noise performance.

[0032] like Figure 4 The figure shows the frequency variation of the input reflection coefficient (S11) of the low-noise amplifier (LNA) in the fusion structure circuit. It can be seen that the input impedance matching coefficient (S11) of the circuit varies within the operating frequency range of -12 to -21 dB, indicating good input impedance matching.

[0033] like Figure 5 The figure shows the voltage gain versus frequency curve for the AC simulation of the low-noise amplifier in the fusion structure circuit. As can be seen, the low-noise amplifier gain ranges from 19dB to 23dB within the circuit's operating frequency band, maintaining a flat gain that ensures effective and uniform signal amplification across the operating frequency band.

[0034] This circuit, based on the principles and basic circuits of an oscillator and a low-noise amplifier, employs the concept of current reuse, breaking through the limitations of traditional independent architectures. By vertically stacking the oscillator and low-noise amplifier circuits and connecting bypass capacitors in parallel at the shared node to create an AC ground path, this allows for shared static bias current reuse while ensuring the two modules operate independently. This structural design not only avoids mutual interference between the oscillator and the low-noise amplifier, but also significantly improves bias current utilization by reconstructing the current path between circuit layers, effectively reducing the overall circuit operating current and system power consumption. While maintaining the key performance indicators of the RF front-end, this fused structure circuit significantly reduces power consumption compared to traditional solutions, and has broad application prospects in low-power Bluetooth devices.

[0035] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A LNA and VCO current multiplexing fusion structure for a BLE radio frequency transceiver, characterized in that: The invention comprises a voltage-controlled oscillator, a current multiplexing circuit and a low-noise amplifier; the voltage-controlled oscillator and the low-noise amplifier are connected via the current multiplexing circuit. The current multiplexing circuit has the characteristics of constructing a DC path and an AC ground, thereby ensuring that static current sharing is achieved under the premise that the working states of the voltage-controlled oscillator and the low-noise amplifier are independent of each other. The voltage-controlled oscillator comprises a first NMOS transistor (M1), a second NMOS transistor (M2), a first capacitor (C1), a second capacitor (C2), a third capacitor (C3), a first inductor (L1), a first resistor (R1), and a second resistor (R2); the positive electrode of the first inductor is connected to the positive electrode of the first capacitor, and the negative electrode of the first inductor is connected to the negative electrode of the first capacitor; the positive electrode of the first capacitor is connected to the positive electrode of the second capacitor, and the negative electrode of the first capacitor is connected to the negative electrode of the second capacitor; the positive electrode of the second capacitor is connected to the oscillator output signal VCOP, and the negative electrode of the second capacitor is connected to the second NMOS transistor (M2). The gate of the MOS tube; the positive electrode of the third capacitor is connected to the gate of the first NMOS tube, and the negative electrode of the third capacitor is connected to the oscillator output signal VCON; the positive electrode of the first resistor is connected to the gate of the first NMOS tube, and the negative electrode of the first resistor is connected to the fixed bias voltage VBIAS; the positive electrode of the second resistor is connected to the fixed bias voltage VBIAS, and the negative electrode of the second resistor is connected to the gate of the second NMOS tube; the source of the first NMOS tube is connected to the positive electrode of the fourth capacitor, and the drain is connected to the positive electrode of the second capacitor; the source of the second NMOS tube is connected to the positive electrode of the fourth capacitor, and the drain is connected to the negative electrode of the third capacitor.

2. The LNA and VCO current multiplexing fusion structure for a BLE radio frequency transceiver according to claim 1, characterized in that: The current multiplexing circuit includes a fourth capacitor (C4), a fifth capacitor (C5), and a second inductor (L2); the positive electrode of the fourth capacitor is connected to the positive electrode of the fifth capacitor, and the negative electrode of the fourth capacitor is grounded GND; the positive electrode of the fifth capacitor is connected to the positive electrode of the second inductor, and the negative electrode of the fifth capacitor is connected to the negative electrode of the second inductor; the positive electrode of the second inductor is connected to the source of the second NMOS tube, and the negative electrode of the second inductor is connected to the positive electrode of the sixth capacitor.

3. The LNA and VCO current multiplexing fusion structure for a BLE radio frequency transceiver according to claim 1, characterized in that: The low-noise amplifier comprises a third NMOS transistor (M5), a fourth NMOS transistor (M6), a fifth capacitor (C5), a sixth capacitor (C6), a seventh capacitor (C7), a second inductor (L2), a third inductor (L3), and a fourth inductor (L4); the positive electrode of the fifth capacitor is connected to the positive electrode of the second inductor, and the negative electrode of the fifth capacitor is connected to the negative electrode of the second inductor; the positive electrode of the second inductor is connected to the source of the second NMOS transistor, and the negative electrode of the second inductor is connected to the positive electrode of the sixth capacitor; and the negative electrode of the sixth inductor is connected to the radio frequency signal output terminal. RFOUT; the source of the third NMOS transistor is connected to the drain of the fourth NMOS transistor, the gate of the third NMOS transistor is connected to the power supply voltage VDD, and the drain of the third NMOS transistor is connected to the negative electrode of the second inductor; the positive electrode of the third inductor is connected to the radio frequency signal input terminal RFIN, and the negative electrode of the third inductor is connected to the gate of the fourth NMOS transistor; the positive electrode of the seventh capacitor is connected to the gate of the fourth NMOS transistor, and the negative electrode of the seventh capacitor is connected to the positive electrode of the fourth inductor; the source of the fourth NMOS transistor is connected to the positive electrode of the fourth inductor; and the negative electrode of the fourth inductor is grounded GND.

4. An electronic device, characterized in that Contains the current multiplexing fusion structure as described in claims 1-3.

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