Voltage-controlled oscillator applied to millimeter wave isolator and digital isolator

Abstract

The utility model provides a voltage-controlled oscillator applied to a millimeter wave isolator and a digital isolator. The voltage-controlled oscillator comprises a pre-charging circuit; the pre-charging circuit comprises a switching tube MS5, a current mirror module and a PCC module; the current mirror image module comprises a switching tube MS1; the switching tube MS5 is connected between a VOP output node and a VON output node of the VOC circuit; the VOP output node or the VON output node is also connected with the grounding end through the current mirror module; and the PCC module is connected with the switching tube MS5 and the switching tube MS1, so that when the VOC circuit receives a high-level input signal, the switching tube MS5 is controlled to be switched off, and meanwhile, the switching tube MS1 is switched on for a preset duration. By additionally arranging the pre-charging circuit in the voltage-controlled oscillator, current for normal operation can be quickly provided for the voltage-controlled oscillator, so that the effect of accelerating oscillation starting of the VCO circuit is achieved.

Description

Technical Field

[0001] The utility model relates to the technical field of oscillators, in particular to a voltage-controlled oscillator and a digital isolator applied to a millimeter wave isolator. Background Art

[0002] Digital isolators are devices that transmit digital signals in an electrically isolated state and are widely used in industrial network environments, especially in harsh environments. Using isolators in the system can eliminate noise caused by ground return on the one hand; on the other hand, it can isolate the manually operated control port from the system execution end where there may be a high-voltage dangerous environment, thereby protecting the devices (people) on the low-voltage side from high-voltage hazards.

[0003] The existing technology adopts antenna coupling and OOK modulation mode to design an isolator, and its structure is as follows: Figure 1 As shown. At the transmitting end, the signal is coupled with the carrier at the voltage-controlled oscillator VCO to form a mixed wave, which is sent to the receiving end on the other side of the isolation through the antenna; after the receiving antenna receives the mixed wave, it amplifies the received signal through the low-noise amplifier LNA, and the demodulator module Demodulator restores the mixed wave to the transmitted signal, which can easily achieve a transmission rate of hundreds of Mbps. Compared with the traditional optocoupler mode, Figure 1 The isolator with the structure shown has a faster transmission speed; compared with the traditional capacitive isolator, Figure 1 The thickness of the isolator in the structure shown can even be as thick as 1 to 2 cm. At this isolation distance, the parasitic capacitance between the two sides of the isolator can be basically ignored, so it can be considered that it will hardly be affected by common-mode transient interference; compared with the on-chip micro-transformer of the magnetic coupling, Figure 1 The structure shown has better isolation and almost no common-mode transient interference.

[0004] However, Figure 1 In the digital isolator structure, every time the system transmits a logic "0", the voltage-controlled oscillator VCO needs to be restarted. If the restart time is too long, the transmission rate will be seriously restricted. Utility Model Content

[0005] The technical problem to be solved by the utility model is to provide a voltage-controlled oscillator and a digital isolator applied to a millimeter wave isolator, which can accelerate the oscillation start-up of the voltage-controlled oscillator and improve the transmission rate to a certain extent.

[0006] In order to solve the above technical problems, the first technical solution adopted by the utility model is:

[0007] A voltage-controlled oscillator applied to a millimeter wave isolator, comprising a VOC circuit and a pre-charging circuit; the pre-charging circuit comprises a switch tube MS5, a current mirror module and a PCC module; the current mirror module comprises a switch tube MS1;

[0008] The switch tube MS5 is connected between the VOP output node and the VON output node of the VOC circuit; the VOP output node or the VON output node is also connected to the ground terminal via the current mirror module; the PCC module is respectively connected to the switch tube MS5 and the switch tube MS1, so as to control the switch tube MS5 to be turned off when the VOC circuit receives a high-level input signal, and the switch tube MS1 is turned on for a preset time.

[0009] Optionally, the switch tube MS5 and the switch tube MS1 are N-channel MOS tubes.

[0010] Optionally, the current mirror module further includes a mirror tube MC1 and a mirror tube MC2; the drain of the switch tube MS1 is connected to the VOP output node or the VON output node; the source of the switch tube MS1 is connected to the drain of the mirror tube MC2; the source of the mirror tube MC2 is connected to the ground terminal, and the gate is respectively connected to the drain and gate of the mirror tube MC1; the source of the mirror tube MC1 is connected to the ground terminal, and the drain is connected to the current source;

[0011] The PCC module is connected to the gate of the switch tube MS1, so as to output a PRE signal to the switch tube MS1 to turn on the switch tube MS1 when the VOC circuit receives a high-level input signal. Optionally, the current mirror module also includes a switch tube MS3; the drain of the switch tube MS1 is also connected to the power supply via the switch tube MS3; the PCC module is connected to the switch tube MS3, so as to output a PREB signal that is inverted from the PRE signal to the switch tube MS1 and turn on the switch tube MS3 synchronously.

[0012] Optionally, the pre-charging circuit further includes a switch tube MS6; the VOC circuit is connected to the power supply via the switch tube MS6; the PCC module is also connected to the switch tube MS6 to control the switch tube MS6 to turn on when the VOC circuit receives a high-level input signal.

[0013] Optionally, the switch tube MS6 is a P-channel MOS tube.

[0014] Optionally, the VOC circuit includes a MOS tube M1, a MOS tube M2, a capacitor C1, a capacitor C2, a capacitor C3, an inductor L1, an inductor L2 and an inductor L3;

[0015] The source of the MOS tube M1 and the source of the MOS tube M2 are connected to the ground terminal; the gate of the MOS tube M1 and the gate of the MOS tube M2 are connected; the drain of the MOS tube M1 is respectively connected to one end of the capacitor C3 and one end of the inductor L1; the drain of the MOS tube M2 is respectively connected to the other end of the capacitor C3 and the other end of the inductor L1; one end of the capacitor C1 is connected to the drain of the MOS tube M1, and the other end is connected to the gate of the MOS tube M2; one end of the capacitor C2 is connected to the drain of the MOS tube M2, and the other end is connected to the gate of the MOS tube M1; one end of the capacitor C3 is used as a VOP output node, and the other end is used as a VON output node;

[0016] The inductor L1 is also connected to a power supply; the inductor L2 is connected in parallel to the capacitor C3; the inductor L3 is coupled to the inductor L2, one end of the inductor L3 is connected to the ground, and the other end is connected to the transmitting antenna.

[0017] Optionally, the VOC circuit includes a MOS tube M1, a MOS tube M2, a capacitor C1, a capacitor C2, a capacitor C3, an inductor L1 and an inductor L2;

[0018] The source of the MOS tube M1 and the source of the MOS tube M2 are grounded; the gate of the MOS tube M1 and the gate of the MOS tube M2 are connected; the drain of the MOS tube M1 is respectively connected to one end of the capacitor C3 and one end of the inductor L1; the drain of the MOS tube M2 is respectively connected to the other end of the capacitor C3 and the other end of the inductor L1; one end of the capacitor C1 is connected to the drain of the MOS tube M1, and the other end is connected to the gate of the MOS tube M2; one end of the capacitor C2 is connected to the drain of the MOS tube M2, and the other end is connected to the gate of the MOS tube M1; one end of the capacitor C3 is used as a VOP output node, and the other end is used as a VON output node;

[0019] The inductor L1 is also connected to a power source; the inductor L2 is coupled to the inductor L1; one end of the inductor L2 is connected to a ground terminal, and the other end is connected to a transmitting antenna.

[0020] Optionally, the VOC circuit also includes a resistor R1 and a resistor R2; the gate of the MOS tube M1 is connected to the gate of the MOS tube M2 via the resistor R1 and the capacitor R2 connected in series; the resistor R1 and the capacitor R2 are also connected to the PCC module to output a VBN signal corresponding to the data to be transmitted when the VOC circuit receives the data to be transmitted.

[0021] The second technical solution adopted by the utility model is:

[0022] A digital isolator comprises the above-mentioned voltage-controlled oscillator applied to a millimeter wave isolator.

[0023] Optionally, a millimeter wave transmitting antenna is also included; the millimeter wave transmitting antenna is connected to the VOC circuit.

[0024] The beneficial effect of the utility model is that by adding a pre-charging circuit in the voltage-controlled oscillator, when the voltage-controlled oscillator needs to start oscillation, the pre-charging circuit can be started, the two output nodes of the VCO circuit are isolated, and the current mirror module charges the capacitor at any output node, so that the voltage-controlled oscillator can quickly enter a normal operating state, thereby achieving the effect of shortening the start-up time of the voltage-controlled oscillator and accelerating the start-up of the VCO circuit, thereby improving the signal quality and improving the transmission rate of the digital isolator to a certain extent. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A schematic diagram of an isolator structure designed by using an antenna coupling method and combining an OOK modulation mode in the prior art;

[0026] Figure 2 A schematic diagram of the structure of a voltage-controlled oscillator applied to a millimeter-wave isolator and key node signals of a PCC module provided in an embodiment of the utility model;

[0027] Figure 3 A schematic diagram of the structure of a voltage-controlled oscillator and key node signals of a PCC module applied to a millimeter-wave isolator provided in a specific embodiment of the utility model;

[0028] Figure 4 A schematic diagram of the structure of a voltage-controlled oscillator and key node signals of a PCC module applied to a millimeter-wave isolator provided in another specific embodiment of the utility model;

[0029] Figure 5 A schematic diagram of the structure of a VCO circuit in a voltage-controlled oscillator provided in an embodiment of the utility model;

[0030] Figure 6 A schematic diagram of the structure of a VCO circuit in a voltage-controlled oscillator provided in another embodiment of the utility model. DETAILED DESCRIPTION

[0031] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in conjunction with the implementation modes and the accompanying drawings.

[0032] The key concept of the utility model is that the pre-charging circuit can isolate the two output nodes of the VCO circuit, and the capacitor at one output node is charged by its current mirror module, so that the voltage-controlled oscillator can quickly enter the normal operation state, thereby achieving the effect of accelerating the oscillation of the VCO circuit.

[0033] In the prior art, since the VCO circuit in the voltage-controlled oscillator needs to restart each time it transmits a logic "1", if the restart time is too long, the transmission efficiency will be seriously restricted. The embodiment of the utility model accelerates the VCO restart by adding a pre-charging circuit, thereby improving the signal quality and increasing the transmission rate of the digital isolator to a certain extent.

[0034] Please refer to Figure 2 , Figure 2 The structure of a voltage-controlled oscillator and a schematic diagram of key node signals of a PCC module for a millimeter wave isolator provided in an embodiment of the utility model. Figure 2 As shown, the voltage-controlled oscillator applied to the millimeter wave isolator provided in this embodiment includes a VOC circuit and a pre-charging circuit; the pre-charging circuit includes a switch tube MS5, a current mirror module and a PCC module; the current mirror module includes a switch tube MS1; the PCC module is a pre-charging circuit control signal modulation module (pre-charge control cell, used to generate a control signal in the pre-charging circuit according to input data;

[0035] The switch tube MS5 is connected between the VOP output node and the VON output node of the VOC circuit; the VOP output node or the VON output node is also connected to the ground terminal via the current mirror module; the PCC module is respectively connected to the switch tube MS5 and the switch tube MS1, so as to control the switch tube MS5 to be turned off when the VOC circuit receives a high-level input signal, and the switch tube MS1 is turned on for a preset time.

[0036] Figure 2 In the key node signal diagram of the PCC module shown, Data is the signal that the voltage-controlled oscillator needs to transmit, that is, the signal to be transmitted; VBP is the signal that controls the shutdown of the switch tube MS5, which corresponds to the start of the pre-charge circuit; PRE is the pre-charge switch signal, when the low level turns to the high level, the pre-charge starts, and when it turns from the high level to the low level, the pre-charge is completed; VBN is the Data characterization signal, that is, the Data input to the PCC module is converted into a VBN signal representation and output to the voltage-controlled oscillator, and the VCO circuit is controlled to start oscillation immediately after the pre-charge is completed, so as to achieve the purpose of transmitting the "Data signal"; VOP / N are the two output node signals of the VCO circuit, which are synchronized with the VBN signal.

[0037] The pre-charge working principle of this embodiment is: when the VCO circuit needs to be started to transmit the signal to be transmitted, that is, when the signal Data to be transmitted is at a high level, the pre-charge circuit is turned on. At this time, the VBP control signal generated by the PCC module will be pulled low, and based on the pulled low VBP control signal, the control switch tube MS5 will be turned off to isolate the VOP output node and the VON output node; at the same time, the PCC module will control the switch tube MS1 in the current mirror module to turn on by pulling up the PRE control signal, so that the current mirror module charges the capacitor at the VOP output node or the VON output node, thereby quickly providing the voltage-controlled oscillator with part of the current Ipre for normal operation. After a short period of pre-charging, the PCC module will control the switch tube MS1 in the current mirror module to turn off by pulling down the PRE control signal, ending the pre-charging. At the same time, the VBN control signal potential will rise, thereby controlling the VCO circuit to start oscillation. The rise in the potential of the VBN control signal will turn on the two MOS tubes M1 and M2 of the VCO circuit, and at this time the power supply current will flow directly into the MOS tubes M1 and M2, and continue to increase until the VCO circuit operates normally.

[0038] It can be seen from the above that the pre-charging circuit provided in this embodiment can significantly improve the startup time of the VCO.

[0039] In some specific implementations of this embodiment, based on the low-level VBP control signal generated by the PCC module, the switch tube MS5 needs to be controlled to be turned off, so the switch tube MS5 uses an N-channel MOS tube (high-level conduction). In addition, the switch tube MS1 is turned on based on the high-level PRE control signal, so a high-level conduction N-channel MOS tube is selected.

[0040] In some specific implementations of this embodiment, Figure 2 As shown, the current mirror module specifically includes a switch tube MS1, a mirror tube MC1 and a mirror tube MC2; the drain of the switch tube MS1 is connected to the VOP output node or the VON output node; the source of the switch tube MS1 is connected to the drain of the mirror tube MC2; the source of the mirror tube MC2 is connected to the ground terminal, and the gate is respectively connected to the drain and gate of the mirror tube MC1; the source of the mirror tube MC1 is connected to the ground terminal, and the drain is connected to the current source;

[0041] The PCC module is connected to the gate of the switch tube MS1 so as to output a PRE signal to the switch tube MS1 to turn on the switch tube MS1 when the VOC circuit receives a high-level input signal.

[0042] In this specific embodiment, when the switch tube MS1 in the current mirror module is turned on due to the high-level PRE control signal, the current mirror formed by the mirror tube MC1 and the mirror tube MC2 will charge all the capacitors at the VOP output node or the VON output node connected thereto, thereby being able to quickly provide the inductor in the VCO circuit with part of the current Ipre when the VCO circuit is operating normally, thereby realizing pre-charging of the VCO circuit.

[0043] See also Figure 3 , Figure 3 The structure of a voltage-controlled oscillator and a schematic diagram of key node signals of a PCC module for a millimeter wave isolator provided in a specific embodiment of the utility model. Figure 3 As shown, in Figure 2 Based on the embodiment, the current mirror module also includes a switch tube MS3; the drain of the switch tube MS1 is also connected to the power supply via the switch tube MS3; the PCC module is connected to the switch tube MS3, so that while outputting a PRE signal to the switch tube MS1, it also outputs a PREB signal that is inverted from the PRE signal to the switch tube MS3 to make the switch tube MS3 synchronously turned on.

[0044] In this specific implementation, when the PRE control signal output port outputs a high level, the PREB control signal output port will synchronously output a low level. That is, when the switch tube MS1 in the current mirror module is turned on due to the high level PRE control signal, the switch tube MS3 will be synchronously turned on due to the low level PREB control signal; the conduction of the switch tubes MS1 and MS3 in the current mirror module will enable the current mirror composed of the mirror tube MC1 and the mirror tube MC2 to charge all the capacitors at the VOP output node or the VON output node connected thereto, so as to quickly provide the inductor in the VCO circuit with a part of the current Ipre when the VCO circuit is operating normally, thereby realizing pre-charging of the VCO circuit.

[0045] In this specific implementation, the switch tube MS3 is a P-channel MOS tube that is turned on at a low level.

[0046] Optionally, the switch tube MS3 may also be a high-level N-channel MOS tube, and directly connected to the PRE control signal output terminal of the PCC module, so as to achieve synchronous conduction with the switch tubes MS1 and MS2.

[0047] In some other specific implementations of this embodiment, Figure 4 As shown, the pre-charging circuit may further include a switch tube MS6; the VOC circuit is connected to the power supply via the switch tube MS6; the PCC module is also connected to the switch tube MS6 to control the switch tube MS6 to turn on when the VOC circuit receives a high-level input signal.

[0048] Here, when the pre-charge circuit is turned on, the VBP control signal generated by the PCC module will be pulled low, thereby controlling the switch tube MS6 to be turned on, so that the VCO circuit is connected to the power supply. This will enable the subsequent current mirror module to charge the capacitor at the VOP output node or the VON output node, combined with the conduction of the switch tube MS6 to form a path to the ground, so as to quickly provide the voltage-controlled oscillator with the normal operating current Ipre.

[0049] The switch tube MS6 can be a P-channel MOS tube (low level conduction).

[0050] See also Figure 5 , Figure 5 The schematic diagram of the structure of a VCO circuit in a voltage controlled oscillator provided in an embodiment of the utility model. Figure 2 On the basis of the embodiment, the VCO circuit therein is further expanded.

[0051] like Figure 5 As shown, the VCO circuit in the voltage-controlled oscillator provided in this embodiment specifically includes a MOS transistor M1, a MOS transistor M2, a capacitor C1, a capacitor C2, a capacitor C3, an inductor L1, an inductor L2 and an inductor L3.

[0052] The source of the MOS tube M1 and the source of the MOS tube M2 are connected to the ground terminal; the gate of the MOS tube M1 and the gate of the MOS tube M2 are connected; the drain of the MOS tube M1 is respectively connected to one end of the capacitor C3 and one end of the inductor L1; the drain of the MOS tube M2 is respectively connected to the other end of the capacitor C3 and the other end of the inductor L1; one end of the capacitor C1 is connected to the drain of the MOS tube M1, and the other end is connected to the gate of the MOS tube M2; one end of the capacitor C2 is connected to the drain of the MOS tube M2, and the other end is connected to the gate of the MOS tube M1; one end of the capacitor C3 is used as a VOP output node, and the other end is used as a VON output node;

[0053] The inductor L1 is also connected to a power supply; the inductor L2 is connected in parallel to the capacitor C3; the inductor L3 is coupled to the inductor L2, one end of the inductor L3 is connected to the ground, and the other end is connected to the transmitting antenna.

[0054] In some specific implementations of this embodiment, a resistor R1 and a resistor R2 are further included; the gate of the MOS tube M1 is connected to the gate of the MOS tube M2 via the resistor R1 and the capacitor R2 connected in series; the resistor R1 and the capacitor R2 are also connected to the PCC module to output a VBN signal corresponding to the signal to be transmitted after the pre-charging circuit completes the pre-charging. Here, the role of the resistor R1 and the resistor R2 is to block the AC signal coupled to the gates of the MOS tubes M1 and M2 through the capacitors C1 and C2 after the VCO starts oscillating, so as to prevent the AC transient signal from causing serious interference to the DC signal at VBN.

[0055] In some specific implementations of this embodiment, the capacitor C3 is a variable capacitor, which can better adjust the LC resonance frequency to make it fall on the expected frequency.

[0056] In this embodiment, the VBN signal provides the MOS transistor M1 and the MOS transistor M2 in the VCO circuit with a DC level required for turning on the VBN signal, which is directly output and controlled by the PCC module.

[0057] The working principle of the VCO circuit described in this embodiment is as follows: after the pre-charging circuit completes the pre-charging, that is, the PCC module controls the switch tube MS1 in the current mirror module to turn off through the control signal, and after the pre-charging stops, the control output is used to represent the VBN signal to be transmitted to the VCO circuit; at this time, the VBN signal potential rises, that is, the VBN signal coupled into the gate of the MOS tube M1 and the MOS tube M2 in the VCO circuit is high level (logic "1"), which provides a DC bias for the gate of the MOS tube M1 and the MOS tube M2, and the MOS tube M1 and the MOS tube M2 are turned on. At this time, the current flowing through the switch tube MS6 directly flows into the MOS tube M1 and the MOS tube M2, and continues to increase until the VCO circuit operates normally. After the VCO starts normally, the inverted signals at the VOP output node and the VON output node of the VCO circuit are coupled to the gates of the MOS tube M1 and the MOS tube M2 through the capacitor C1 and the capacitor C2, respectively, so that the MOS tube M1 and the MOS tube M2 are alternately turned on and off, promoting the LC resonance of the inductor L1 and the inductor L3. At the same time, the signal at the VOP / N output node is coupled to the inductor L3 through the inductor L2, and then sent out through the transmitting antenna, and the receiving end receives the logic "1" signal. When the input VBN signal becomes a low level (logic "0"), the VBN is 0, the MOS tube M1 and the MOS tube M2 are turned off, and the VOP / N output node no longer oscillates. At this time, the transmitting antenna does not transmit a signal, which means that the receiving end receives a logic "0" in the OOK modulation mode.

[0058] See also Figure 6 , Figure 6A schematic diagram of the structure of a VCO circuit in a voltage controlled oscillator provided in another embodiment of the utility model. Figure 5 On the basis of the embodiment, the VCO circuit is further improved by reusing the inductor L1 therein so as to reduce the use of one inductor (L3); thus saving a large chip area and reducing the chip cost.

[0059] like Figure 6 As shown, the VCO circuit in the voltage-controlled oscillator provided in this embodiment specifically includes a MOS transistor M1, a MOS transistor M2, a capacitor C1, a capacitor C2, a capacitor C3, an inductor L1 and an inductor L2.

[0060] The source of the MOS tube M1 and the source of the MOS tube M2 are grounded; the gate of the MOS tube M1 and the gate of the MOS tube M2 are connected; the drain of the MOS tube M1 is respectively connected to one end of the capacitor C3 and one end of the inductor L1; the drain of the MOS tube M2 is respectively connected to the other end of the capacitor C3 and the other end of the inductor L1; one end of the capacitor C1 is connected to the drain of the MOS tube M1, and the other end is connected to the gate of the MOS tube M2; one end of the capacitor C2 is connected to the drain of the MOS tube M2, and the other end is connected to the gate of the MOS tube M1; one end of the capacitor C3 is used as a VOP output node, and the other end is used as a VON output node;

[0061] The inductor L1 is also connected to a power source; the inductor L2 is coupled to the inductor L1; one end of the inductor L2 is connected to a ground terminal, and the other end is connected to a transmitting antenna.

[0062] In some specific implementations of this embodiment, a resistor R1 and a resistor R2 are further included; the gate of the MOS tube M1 is connected to the gate of the MOS tube M2 via the resistor R1 and the capacitor R2 connected in series; the resistor R1 and the capacitor R2 are also connected to the PCC module to output a VBN signal corresponding to the signal to be transmitted after the pre-charging circuit completes the pre-charging. Here, the role of the resistor R1 and the resistor R2 is to block the AC signal coupled to the gates of the MOS tubes M1 and M2 through the capacitors C1 and C2 after the VCO starts oscillating, so as to prevent the AC transient signal from causing serious interference to the DC signal at VBN.

[0063] In some specific implementations of this embodiment, the capacitor C3 is a variable capacitor, which can better adjust the LC resonance frequency to make it fall on the expected frequency.

[0064] In this embodiment, the VBN signal provides the MOS transistor M1 and the MOS transistor M2 in the VCO circuit with a DC level required for turning on the VBN signal, which is directly output and controlled by the PCC module.

[0065] The working principle of the VCO circuit described in this embodiment is as follows: after the pre-charging circuit completes the pre-charging, that is, the PCC module controls the switch tube MS1 in the current mirror module to turn off through the control signal, and after the pre-charging stops, the control output is used to represent the VBN signal to be transmitted to the VCO circuit; at this time, the VBN signal potential rises, that is, the VBN signal coupled into the gate of the MOS tube M1 and the MOS tube M2 in the VCO circuit is high level (logic "1"), which provides a DC bias for the gate of the MOS tube M1 and the MOS tube M2, and the MOS tube M1 and the MOS tube M2 are turned on. At this time, the current flowing through the switch tube MS6 directly flows into the MOS tube M1 and the MOS tube M2, and continues to increase until the VCO circuit operates normally. After the VCO starts oscillating normally, the signals at the VOP output node and the VON output node of the VCO circuit are coupled to the inductor L2 through the inductor L1, and then sent out through the transmitting antenna, and the receiving end receives the logic "1" signal. When the input VBN signal becomes low level (logic "0"), VBN is 0, MOS tube M1 and MOS tube M2 are turned off, and the VOP / N output node no longer oscillates. At this time, the transmitting antenna does not transmit a signal, which means that the receiving end receives logic "0" in the OOK modulation mode.

[0066] It can be seen that the VCO circuit structure of this embodiment is different from that of Figure 5 As for the VCO circuit structure of the embodiment, by reusing the inductor L1, the use of one inductor can be reduced, thereby saving considerable chip area (the on-chip implementation of the inductor requires a relatively large chip area, and reducing one inductor can reduce the area on the chip by about 150um*150um), and at the same time, it can also reduce the chip cost to a certain extent.

[0067] Understandably, whether Figure 5 The VCO circuit described in the embodiment is also Figure 6 The VCO circuits described in the embodiments are both designed by using antenna coupling to transmit signals. Their working principles are that at the transmitting end, the signal to be transmitted is coupled to a mixed wave in the voltage-controlled oscillator by a carrier and then transmitted to the receiving end through a transmitting antenna.

[0068] As a preferred embodiment of the present utility model, Figures 2 to 6The voltage-controlled oscillator described in any embodiment or specific implementation method, and the transmitting antenna coupled to it are all millimeter-wave transmitting antennas. That is to say, in this preferred embodiment, the voltage-controlled oscillator is used in the transmitting end using millimeter-wave wireless transmission, and the receiving end also uses millimeter-wave wireless reception. This design can not only easily achieve a transmission rate of hundreds of Mbps, but also has a faster transmission speed than the traditional optical coupling transmission method; compared with the pure capacitive coupling method, it can eliminate the influence of common-mode transient interference; compared with the magnetic coupling transmission method, it greatly simplifies the process difficulty and cost. Therefore, this preferred embodiment will have a broader and more practical application prospect in the field of wireless transmission.

[0069] The present invention also provides a digital isolator, comprising the voltage-controlled oscillator described in any of the above embodiments and a millimeter wave transmitting antenna connected to the voltage-controlled oscillator. The specific structure of the voltage-controlled oscillator will not be repeated here, please refer to the above embodiments for details.

[0070] The digital isolator provided in this embodiment has all the effects listed in the above preferred embodiments because it adopts millimeter wave wireless transmission technology for isolation transmission; at the same time, the voltage-controlled oscillator in the digital isolator provided in this embodiment has the effect of accelerating the oscillation of the VCO circuit because a pre-charging circuit is added, thereby improving the signal quality and increasing the transmission rate of the digital isolator to a certain extent.

[0071] In some specific implementations of this embodiment, please refer to the specific structure of the digital isolator. Figure 1 In particular, the voltage-controlled oscillator in this embodiment not only includes Figure 1 The VCO circuit shown in FIG. Figures 2 to 6 The pre-charging circuit structure described in any embodiment.

[0072] The above description is only an embodiment of the present invention, and does not limit the patent scope of the present invention. Any equivalent transformations made using the contents of the specification and drawings of the present invention, or directly or indirectly applied in the relevant technical field, are also included in the patent protection scope of the present invention.

Claims

1. A voltage-controlled oscillator for a millimeter wave isolator, comprising a VOC circuit, characterized in that: It also includes a pre-charging circuit; the pre-charging circuit includes a switch tube MS5, a current mirror module and a PCC module; the current mirror module includes a switch tube MS1; The switch tube MS5 is connected between the VOP output node and the VON output node of the VOC circuit; the VOP output node or the VON output node is also connected to the ground terminal via the current mirror module; the PCC module is respectively connected to the switch tube MS5 and the switch tube MS1, so as to control the switch tube MS5 to be turned off when the VOC circuit receives a high-level input signal, and the switch tube MS1 is turned on for a preset time.

2. The voltage controlled oscillator according to claim 1, wherein: The switch tube MS5 and the switch tube MS1 are N-channel MOS tubes.

3. The voltage controlled oscillator according to claim 1, wherein: The current mirror module also includes a mirror tube MC1 and a mirror tube MC2; the drain of the switch tube MS1 is connected to the VOP output node or the VON output node; the source of the switch tube MS1 is connected to the drain of the mirror tube MC2; the source of the mirror tube MC2 is connected to the ground terminal, and the gate is respectively connected to the drain and gate of the mirror tube MC1; the source of the mirror tube MC1 is connected to the ground terminal, and the drain is connected to the current source; The PCC module is connected to the gate of the switch tube MS1 so as to output a PRE signal to the switch tube MS1 to turn on the switch tube MS1 when the VOC circuit receives a high-level input signal.

4. The voltage controlled oscillator according to claim 3, characterized in that: The current mirror module also includes a switch tube MS3; the drain of the switch tube MS1 is also connected to the power supply via the switch tube MS3; the PCC module is connected to the switch tube MS3, so that while outputting a PRE signal to the switch tube MS1, it also outputs a PREB signal that is inverted from the PRE signal to the switch tube MS3 to make the switch tube MS3 synchronously turned on.

5. The voltage controlled oscillator according to claim 1, wherein: The pre-charging circuit also includes a switch tube MS6; the VOC circuit is connected to the power supply via the switch tube MS6; the PCC module is also connected to the switch tube MS6 to control the switch tube MS6 to be turned on when the VOC circuit receives a high-level input signal.

6. The voltage controlled oscillator according to claim 1, wherein: The VOC circuit includes a MOS tube M1, a MOS tube M2, a capacitor C1, a capacitor C2, a capacitor C3, an inductor L1, an inductor L2 and an inductor L3; The source of the MOS tube M1 and the source of the MOS tube M2 are connected to the ground terminal; the gate of the MOS tube M1 and the gate of the MOS tube M2 are connected; the drain of the MOS tube M1 is respectively connected to one end of the capacitor C3 and one end of the inductor L1; the drain of the MOS tube M2 is respectively connected to the other end of the capacitor C3 and the other end of the inductor L1; one end of the capacitor C1 is connected to the drain of the MOS tube M1, and the other end is connected to the gate of the MOS tube M2; one end of the capacitor C2 is connected to the drain of the MOS tube M2, and the other end is connected to the gate of the MOS tube M1; one end of the capacitor C3 is used as a VOP output node, and the other end is used as a VON output node; The inductor L1 is also connected to a power supply; the inductor L2 is connected in parallel to the capacitor C3; the inductor L3 is coupled to the inductor L2, one end of the inductor L3 is connected to the ground, and the other end is connected to the transmitting antenna.

7. The voltage controlled oscillator according to claim 1, wherein: The VOC circuit includes a MOS tube M1, a MOS tube M2, a capacitor C1, a capacitor C2, a capacitor C3, an inductor L1 and an inductor L2; The source of the MOS tube M1 and the source of the MOS tube M2 are grounded; the gate of the MOS tube M1 and the gate of the MOS tube M2 are connected; the drain of the MOS tube M1 is respectively connected to one end of the capacitor C3 and one end of the inductor L1; the drain of the MOS tube M2 is respectively connected to the other end of the capacitor C3 and the other end of the inductor L1; one end of the capacitor C1 is connected to the drain of the MOS tube M1, and the other end is connected to the gate of the MOS tube M2; one end of the capacitor C2 is connected to the drain of the MOS tube M2, and the other end is connected to the gate of the MOS tube M1; one end of the capacitor C3 is used as a VOP output node, and the other end is used as a VON output node; The inductor L1 is also connected to a power source; the inductor L2 is coupled to the inductor L1; one end of the inductor L2 is connected to a ground terminal, and the other end is connected to a transmitting antenna.

8. The voltage controlled oscillator according to claim 6 or 7, characterized in that: The VOC circuit also includes a resistor R1 and a resistor R2; the gate of the MOS tube M1 is connected to the gate of the MOS tube M2 via the resistor R1 and the capacitor R2 connected in series; the resistor R1 and the capacitor R2 are also connected to the PCC module so that when the VOC circuit receives the data to be transmitted, it outputs a VBN signal corresponding to the data to be transmitted.

9. A digital isolator, characterized in that: A voltage-controlled oscillator applied to a millimeter wave isolator comprising the voltage-controlled oscillator as described in any one of claims 1 to 8.

10. The digital isolator according to claim 9, characterized in that It also includes a millimeter wave transmitting antenna; the millimeter wave transmitting antenna is connected to the VOC circuit.

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