Signal modulation and demodulation system of digital isolator and millimeter wave isolator

Abstract

The invention provides a signal modulation and demodulation system of a digital isolator. A pulse signal output end and a signal input end of a millimeter wave isolator and a modulation module are respectively connected with a primary modulation node through a first switch; the primary modulation node is connected with the secondary modulation node through the second switch; the RF signal output end is connected with the transmitting unit through the secondary modulation node; the first switch is controlled by a level signal input by the signal input end to be switched on or switched off so as to control whether the pulse signal and the level signal can reach a primary modulation node for primary modulation or not, and a primary modulation signal is obtained; the second switch is controlled by the signal of the primary modulation node to be switched on or switched off so as to control whether the RF signal and the primary modulation signal can reach the secondary modulation node for secondary modulation or not, and a composite modulation signal is obtained. According to the invention, two-stage precise modulation control is realized through the arrangement of the two-stage switch, so that the signal modulation precision of the digital isolator is remarkably improved.

Description

Technical Field

[0001] The present invention relates to signal modulation and demodulation technologies, and particularly to a signal modulation and demodulation system for a digital isolator and a millimeter-wave isolator. Background Art

[0002] In the prior art, the transmission system of a digital isolator usually adopts OOK (On-Off Keying) modulation and demodulation technology. In this technology, the level of an input signal is modulated into high-frequency pulses and then isolated and transmitted to a receiving end; at the receiving end, the received high-frequency pulses are demodulated by a demodulator to restore the original electrical signal.

[0003] In particular, due to the use of millimeter-wave antennas, the frequency modulation and detection of digital isolators based on millimeter-wave transmission, that is, millimeter-wave isolators, have become a major technical difficulty. This is because the input end needs to perform high-frequency modulation on the level of the input signal, so it is necessary to accurately control the level signal; however, the existing switch control method used in OOK modulation technology often cannot meet the accurate control requirements, resulting in waste of system power consumption; moreover, the system design is relatively complex. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a signal modulation and demodulation system for a digital isolator and a millimeter-wave isolator, which can improve the signal modulation accuracy and at the same time has the advantages of low power consumption and simple structure.

[0005] To solve the above technical problem, the first technical solution adopted by the present invention is:

[0006] A signal modulation and demodulation system for a digital isolator, including a modulation module and a signal input end;

[0007] The modulation module includes a pulse signal output end, an RF signal output end, a first switch, a primary modulation node, a second switch, and a secondary modulation node; the pulse signal output end and the signal input end are respectively connected to the primary modulation node through the first switch; the primary modulation node is connected to the secondary modulation node through the second switch; the RF signal output end is connected to the secondary modulation node;

[0008] The first switch is configured to be turned on or off under the control of the level signal input by the signal input end, so as to control whether the pulse signal output by the pulse signal output end and the level signal can both reach the primary modulation node for primary modulation to obtain a primary modulation signal;

[0009] The second switch is configured to be turned on or off under the control of a signal flowing out of the first-stage modulation node, so as to control whether the RF signal output from the RF signal output terminal and the primary modulation signal can both reach the second-stage modulation node for second-stage modulation, and obtain a composite modulation signal.

[0010] Optionally, the pulse signal output terminal is a clock unit inside an OSC unit or a digital isolator; the RF signal output terminal is a VCO unit.

[0011] Optionally, the second-stage modulation node includes an inductor, a MOS transistor, and an output terminal; the gate of the MOS transistor is connected to the RF signal output terminal, its source is connected to the second switch, and its drain is connected to the output terminal via the inductor.

[0012] Optionally, the second-stage modulation node includes an inductor, a MOS transistor, and an output terminal; the gate of the MOS transistor is connected to the RF signal output terminal, its source is grounded, and its drain is connected to the output terminal via the second switch and the inductor in sequence.

[0013] Optionally, the first switch includes a MOS transistor; the gate of the MOS transistor is connected to the signal input terminal, its source is connected to the pulse signal output terminal, and its drain is connected to the first-stage modulation node.

[0014] Optionally, the first switch includes an AND gate circuit; the two input terminals of the AND gate circuit are respectively connected to the signal input terminal and the pulse signal output terminal, and its output terminal is connected to the first-stage modulation node.

[0015] Optionally, the first switch includes a transmission gate composed of an NMOS transistor and a PMOS transistor; the gates of the NMOS transistor and the PMOS transistor are connected in parallel using an inverter and then connected to the signal input terminal; the source of the NMOS transistor is connected to the source of the PMOS transistor and then connected to the first-stage modulation node, and their drains are connected and then connected to the pulse signal output terminal.

[0016] Optionally, it further includes a demodulation module; the demodulation module includes an LNA unit, an ENV unit, an integrator, and a driving unit connected in sequence.

[0017] Another technical solution provided by the present invention is:

[0018] A digital isolator includes a transmitting unit, a receiving unit, and the signal modulation and demodulation system as described above; the modulation module, the transmitting unit, the receiving unit, and the demodulation module are connected in sequence.

[0019] Optionally, the transmitting unit is a millimeter-wave transmitting antenna; the receiving unit is a millimeter-wave receiving antenna.

[0020] The beneficial effects of the present invention are as follows: In the modulation module of the signal modulation and demodulation system of the present invention, two-stage switch settings are used to achieve two-stage precise modulation control, thereby significantly improving the signal modulation accuracy of the modulation module in the digital isolator; at the same time, it can also reduce the power consumption of the signal modulation and demodulation system, and the structural design of the signal modulation and demodulation system also has the advantages of being simple and easy to implement. Brief Description of the Drawings

[0021] Figure 1 It is a schematic structural diagram of the modulation module in the signal modulation and demodulation system of the digital isolator provided in the first embodiment of the present invention;

[0022] Figure 2 It is a schematic structural diagram of the modulation module provided in the specific embodiment of the present invention;

[0023] Figure 3 (a)-(b) are respectively two specific embodiments of the secondary modulation node in the modulation module;

[0024] Figure 4 It is a schematic structural diagram of the demodulation module in the signal modulation and demodulation system of the digital isolator provided in the second embodiment of the present invention;

[0025] Figure 5 It is a signal timing diagram of the signal modulation and demodulation system of the digital isolator provided in the second embodiment of the present invention;

[0026] Figure 6 (a)-(c) are respectively three specific embodiments of the first switch in the modulation module;

[0027] Figure 7 It is a schematic structural diagram of the signal modulation and demodulation system of the digital isolator provided in the fourth embodiment of the present invention;

[0028] Figure 8 It is a schematic structural diagram of the digital isolator provided in the fifth embodiment of the present invention.

[0029] Label Description:

[0030] 1. Modulation module; 2. Signal input terminal; 3. Demodulation module; 4. Transmitting unit; 5. Receiving unit;

[0031] 11. Pulse signal output terminal; 12. RF signal output terminal; S1. First switch; 13. Primary modulation node; S2. Second switch; 14. Secondary modulation node;

[0032] 31. LNA unit; 32. ENV unit; 33. Integrator; 34. Driver unit. Specific Embodiments

[0033] To describe in detail the technical content, achieved objectives and effects of the present invention, the following is described in conjunction with embodiments and with reference to the accompanying drawings.

[0034] Embodiment 1

[0035] Please refer to Figure 1 , this embodiment provides a signal modulation and demodulation system for a digital isolator.

[0036] As Figure 1 shown, the signal modulation and demodulation system includes a modulation module 1 and a signal input terminal 2.

[0037] The signal input terminal 2 is configured to input a high / low level signal TX IN to the modulation module 1.

[0038] The modulation module 1 includes a pulse signal output terminal 11, an RF signal output terminal 12, a first switch S1, a first-level modulation node 13, a second switch S2, and a second-level modulation node 14; the pulse signal output terminal 11 and the signal input terminal 2 are respectively connected to the first-level modulation node 13 through the first switch S1; the first-level modulation node 13 is connected to the second-level modulation node 14 through the second switch S2; the RF signal output terminal 12 is connected to the second-level modulation node 14.

[0039] Among them, the first switch S1 is configured to be controlled by the level signal TX input by the signal input terminal IN to be in a conducting or off state, thereby controlling whether the pulse signal output by the pulse signal output terminal and the level signal TX IN can both reach the first-level modulation node for first-level modulation to obtain a primary modulation signal.

[0040] The second switch S2 is configured to be controlled by the signal flowing out of the first-level modulation node to be in a conducting or off state, thereby controlling whether the RF signal output by the RF signal output terminal and the primary modulation signal obtained through first-level modulation can both reach the second-level modulation node for second-level modulation to obtain a composite modulation signal.

[0041] The first-level modulation node is configured to, when the pulse signal output by the pulse signal output terminal can reach, perform a first signal modulation process on it together with the level signal TX IN output by the signal input terminal, also known as the first-level modulation process, to obtain and output a primary modulation signal.

[0042] The secondary modulation node is configured to operate under the control of the conduction of the second switch S2, to perform a mixing modulation process on the RF signal output from the RF signal output terminal and the primary modulation signal, also known as secondary modulation processing, and then transmit the obtained composite modulation signal.

[0043] The signal modulation and demodulation system described in this embodiment has the following working principle:

[0044] On the transmitting side of the digital isolator, a signal TX with high / low level is input to the modulation module; IN The signal TX IN can control whether the first switch S1 in the modulation module is in the on state or the off state, thereby determining whether the pulse signal output from the pulse signal output terminal can reach the primary modulation node, and further determining whether it can pass through the primary modulation node. According to the pulse signal, the signal TX IN is subjected to primary modulation to obtain an initial modulation signal. Then, the signal of the primary modulation node reaches the second switch S2. If the signal is the signal TX IN , that is, if no primary modulation has been performed, the second switch S2 will remain in the off state, and thus the secondary modulation node will not work, and the RF signal output from the connected RF signal output terminal will not be able to pass through the secondary modulation node and be output to the transmitting unit; if the signal of the primary modulation node is the primary modulation signal, the second switch S2 will switch to the on state, the secondary modulation node will work, the RF signal can reach the secondary modulation node, and at the same time, the primary modulation signal will also reach the secondary modulation node via the second switch S2. The secondary modulation node will perform secondary modulation on it together with the RF signal to obtain a composite modulation signal and output it to the transmitting unit. That is, by the second switch S2, it is determined whether the secondary modulation node works, so as to further modulate the initial modulation signal into a composite modulation signal, and then wirelessly transmit it to the receiving side of the digital isolator.

[0045] In some specific embodiments of this embodiment, as Figure 2 shown, the pulse signal output terminal can be an OSC unit, that is, an oscillator, which is specifically configured to generate a stable pulse signal; it can also be the clock unit inside the digital isolator, that is, directly utilize the existing internal clock signal (which belongs to a kind of pulse signal).

[0046] In some other specific embodiments of this embodiment, as Figure 2 shown, the RF signal output terminal can be a VCO unit, that is, a voltage controlled oscillator. The VCO unit is configured to generate the required RF radio frequency signal (such as a 60G sine wave signal).

[0047] In still some specific embodiments of this embodiment, the second switch S2 is implemented by a MOS transistor, whose gate is connected to the output terminal of the first-stage modulation node, whose source is grounded, and whose drain is connected to the second-stage modulation node. Here, if the signal TX output from the first-stage modulation node to the gate of the second switch S2 is a level signal IN , that is, no first-stage modulation is performed, the second switch S2 will remain in the off state; if the signal output from the first-stage modulation node to the gate of the second switch S2 is a primary modulation signal, that is, not the level signal TX IN , then the second switch S2 will switch to the on state.

[0048] In still some specific embodiments of this embodiment, the second-stage modulation node is essentially a gain mixing circuit that simultaneously has gain and mixing functions. In this embodiment, the second-stage modulation node cooperates with the second switch S2 to perform mixed modulation on the primary modulation signal and the RF signal after gain processing, that is, second-stage modulation, to obtain a composite modulation signal. Next, two specific embodiments of the second-stage modulation node are provided.

[0049] As Figure 3 (a) shows, in a specific embodiment, the second-stage modulation node consists of an inductor, a MOS transistor, and an output terminal; the gate of the MOS transistor is connected to the RF signal output terminal (that is, Figure 2 the VCO unit of Figure 3 (a) shows, the second-stage modulation node specifically includes a pair of magnetically coupled inductor groups, two MOS transistors, and an output terminal; one inductor group consists of two inductors connected in series; both ends of one inductor group are respectively connected to the negative and positive polarities of the second-stage modulation signal output terminal; both ends of the other inductor group are respectively connected to the drain of a MOS transistor; the sources of the two MOS transistors are both connected to the second switch S2 (specifically connected to the drain of the second switch S2), the gate of the MOS transistor corresponding to the "second-stage modulation signal (negative polarity)" in the figure is connected to the positive output of the RF signal output terminal (that is, the "RF signal (positive polarity)" in the figure), and the gate of the other MOS transistor is connected to the negative output of the RF signal output terminal (that is, the "RF signal (negative polarity)" in the figure).

[0050] As Figure 3 (b) shows, in another specific embodiment, the second-stage modulation node consists of an inductor, a MOS transistor, and an output terminal; the gate of the MOS transistor is connected to the RF signal output terminal (that is, Figure 2is connected to the VCO unit), its source is grounded, and its drain is connected to the output terminal (i.e., "second-stage modulation signal (positive polarity)" and "second-stage modulation signal (negative polarity)" in the figure) through an inductor after passing through the second switch S2 (specifically connected to the source of the second switch S2). Preferably, as Figure 3 (b) shows, the second-stage modulation node specifically includes a pair of inductance groups with electromagnetic coupling, two MOS transistors, and a second-stage modulation signal output terminal; one inductance group is composed of two inductors connected in series; both ends of one inductance group are respectively connected to the negative polarity and positive polarity of the output terminal; both ends of the other inductance group are respectively connected to the second switch S2 (specifically connected to the drain of the second switch S2); the sources of the two MOS transistors are both grounded, and the drains are both connected to the second switch S2 (specifically connected to the source of the second switch S2). The gate of the MOS transistor corresponding to "second-stage modulation signal (negative polarity)" in the figure is connected to the positive polarity output of the RF signal output terminal (i.e., "RF signal (positive polarity)" in the figure), and the gate of the other MOS transistor is connected to the negative polarity output of the RF signal output terminal (i.e., "RF signal (negative polarity)" in the figure).

[0051] It can be understood that the second-stage modulation node not only has the function of high-frequency RF signal gain amplification, but also can mix the high-frequency RF signal after gain amplification processing with the local oscillator signal (i.e., the primary modulation signal in this embodiment) to achieve the second-stage mixing modulation function. Specifically, when the second switch S2 is turned off, the circuit of the second-stage modulation node will also be disconnected and cannot work properly, that is, there is no current passing through the second-stage modulation node, and the gain amplification and mixing functions cannot be provided. At this time, there is no signal output or only a very small signal can be output at the output terminal of the second-stage modulation node; when the second switch S2 is turned on, the circuit of the second-stage modulation node will also be turned on and can work properly. At this time, the RF signal can be gain-amplified in the second-stage modulation node and mixed with the first-stage modulation signal output by the second switch S2, and then a stronger signal can be output at the output terminal of the second-stage modulation node, that is, a composite modulation signal is output.

[0052] In the signal modulation and demodulation system of the existing digital isolator, most of them adopt the traditional OOK modulation and demodulation method. The power amplifier PA in the traditional OOK modulation method is directly controlled by the level signal TX input at the signal input terminal IN , when the level signal TX IN is at a high level, the power amplifier PA is always in the working / conducting state and consumes current; when the level signal TX IN is at a low level, the power amplifier PA is turned off, and there is no power consumption or only a low leakage current at this time. It can be seen that the modulation method adopted by the signal modulation and demodulation system of the existing digital isolator only has one-stage modulation, which is difficult to achieve precise modulation, and there is a problem of power consumption waste in the signal modulation and demodulation system.

[0053] The signal modulation and demodulation system of the digital isolator provided in this embodiment, compared with the signal modulation and demodulation system using the traditional OOK modulation and demodulation method, realizes precise two-stage modulation control by setting two-stage switches in the modulation module, thereby significantly improving the signal modulation accuracy of the modulation module in the digital isolator; at the same time, the gain components with a relatively large power consumption are set at the secondary modulation node, which will only work when the primary modulation node is working, and will not work otherwise, without generating power consumption, that is, it can reduce the proportion of the gain components being turned on, thereby reducing the power consumption of the signal modulation and demodulation system; in addition, the structural design of the signal modulation and demodulation system also has the advantages of being simple and easy to implement.

[0054] Embodiment Two

[0055] Please refer to Figure 4 , this embodiment is a further expansion based on Embodiment One, and specifically explains the demodulation module of the signal modulation and demodulation system.

[0056] In this embodiment, the signal modulation and demodulation system of the digital isolator further includes a demodulation module 3 corresponding to the modulation module 1. The modulation module is located on the transmitting side of the digital isolator; the demodulation module is located on the receiving side of the digital isolator.

[0057] The demodulation module 3 is configured to perform two demodulation processes on the composite modulation signal by using a secondary demodulation method corresponding to the secondary modulation method of the modulation module, and finally obtain the original high and low level signals, that is, the level signal TX input at the signal input end IN , and then output it through the signal output end.

[0058] In some specific implementation manners of this embodiment, as Figure 4 shown, the demodulation module 3 specifically includes an LNA unit 31, an ENV unit 32, an integrator 33, and a driver unit 34 connected in sequence.

[0059] Among them, the LNA unit, that is, the low-noise amplifier, is configured to enhance the signal strength, reduce the noise, and perform impedance matching processing on the composite modulation signal, so as to play a role in amplifying the composite modulation signal;

[0060] The ENV unit, that is, the envelope detector, is configured to demodulate the initial modulation signal from the amplified composite modulation signal;

[0061] The integrator is configured to perform low-pass filtering and signal smoothing processing on the initial modulation signal output by the ENV unit, and at the same time perform integral operation on the signal to demodulate the analog original signal;

[0062] The driving unit is configured to convert the analog original signal output by the integrator into the high / low level signal TX input to the signal input terminal. IN .

[0063] In this embodiment, for the demodulation module on the receiving side, a two-stage demodulation method corresponding to the modulation module will be adopted to demodulate the original high / low level signal TX input from the signal input terminal. IN . Specifically, the decoding module of the demodulation module demodulates the initial modulation signal from the received composite modulation signal through the LNA unit and the ENV unit; then, through the integrator and the driving unit, the original high / low level signal TX is demodulated from the initial modulation signal. IN .

[0064] As Figure 5 shown, it shows the signal waveforms of important nodes in the signal modulation and demodulation system of this embodiment. It can be seen from Figure 5 that when a continuous signal is input from the signal input terminal to the modulation module, the signal waveform of the signal input terminal node is shown as "TX input" in the figure; when the continuous signal is at a high level, the signal of the first-stage modulation node is multiple pulses, and the high level on the pulses will turn on the gain mixing circuit of the second-stage modulation node, enabling the second-stage modulation node to work and output an RF signal; when the continuous signal is at a low level, the signal of the first-stage modulation node is constantly at a low level, and the second-stage modulation node does not work and cannot output an RF signal.

[0065] It can be understood that for the signal modulation and demodulation system provided in this embodiment, the decoding module configuration on the receiving side can adopt a two-stage demodulation method corresponding to the modulation module to demodulate the original high / low level signal TX from the received composite modulation signal. IN . This ensures that the signal modulation and demodulation system of the digital isolator can normally carry out signal modulation work in a two-stage modulation and demodulation manner, realize signal isolation transmission of the digital isolator, and improve the accuracy of signal modulation and demodulation at the same time.

[0066] It should be noted that the decoding module in the signal modulation and demodulation system of the digital isolator belongs to a working mode of passively receiving the composite modulation signal and then performing modulation, that is, it cannot be actively turned on or off. Therefore, the power consumption of the decoding module is relatively stable for the entire signal modulation and demodulation system, and there is no waste problem. It can be seen that the decoding module on the receiving side of the signal modulation and demodulation system of the digital isolator provided in this embodiment will not increase the system power consumption, that is, compared with the existing modulation system, its power consumption will not change significantly.

[0067] Embodiment Three

[0068] Please refer to Figure 1 ,Figure 2 and Figure 6 (a)-(c), this embodiment is a further expansion based on any of the above embodiments, and specifically describes in detail the newly added secondary switch control in the modulation module.

[0069] In this embodiment, please refer to Figure 1 and Figure 2 , the first switch S1 in the modulation module 1 of the signal modulation and demodulation system located in the digital isolator is specifically configured such that when the level signal TX input at the signal input terminal 2 IN is a high-level signal, it is controlled to be in the on state; when the level signal TX input at the signal input terminal 2 IN is a low-level signal, it is controlled to be in the off state.

[0070] It can be understood that when the first switch S1 is turned on due to a high-level signal, the pulse signal output from the pulse signal output terminal 11 (corresponding to the OSC unit as shown in Figure 2 ) will be able to reach the primary modulation node 13 via the first switch S1, and the primary modulation node 13 will perform primary modulation on it together with the level signal TX input at the signal input terminal 2 IN to obtain an initial modulation signal and output it; when the first switch S1 is turned off due to a low-level signal, the pulse signal output from the pulse signal output terminal 11 (corresponding to the OSC unit as shown in Figure 2 ) will not be able to pass through the first switch S1 to reach the primary modulation node 13, then the primary modulation node 13 does not perform primary modulation work, and the output is the level signal TX input at the signal input terminal 2 IN , that is, a low-level signal.

[0071] In this embodiment, the first switch S1 can have the following three specific implementation manners:

[0072] As Figure 6 (a) shows, in the first specific implementation manner, the first switch S1 includes a MOS transistor; preferably a PMOS transistor; the gate of the MOS transistor is connected to the signal input terminal (i.e., TXIN in the figure), its source is connected to the pulse signal output terminal (i.e., OSC in the figure), and its drain is connected to the primary modulation node.

[0073] It can be understood that in this specific implementation manner, when the level signal TX input from the signal input terminal to the gate of the MOS transistor IN is a high level, it will cause the MOS transistor to conduct, and the pulse signal flows in from the source of the MOS transistor and is output to the primary modulation node through the drain. At the same time, the high-level signal TX INIt will also be output to the first-stage modulation node through the drain of the MOS transistor; at the same time, the high-level signal TX that reaches the first-stage modulation node IN will be "combined and modulated" with the pulse signal at the first-stage modulation node into a primary modulation signal and then output to the second switch S2. Similarly, when the level signal TX input to the gate of the MOS transistor at the signal input terminal IN is at a low level, it will cause the MOS transistor to turn off, and the pulse signal cannot reach the first-stage modulation node through the MOS transistor. Only the low-level signal TX IN can be output to the first-stage modulation node through the drain of the MOS transistor; at this time, the first-stage modulation node cannot perform "combined and modulated" processing, and only the low-level signal TX output to the second switch S2 IN .

[0074] As Figure 6 (b) shows, in the second specific implementation manner, the first switch includes an AND gate circuit; the two input terminals of the AND gate circuit are respectively connected to the signal input terminal (i.e., TXIN in the figure) and the pulse signal output terminal (i.e., OSC in the figure), and its output terminal is connected to the first-stage modulation node. As a preferred example, the AND gate circuit can be composed of a diode and a resistor, and has the characteristics of simple structure and sensitive response.

[0075] It can be understood that when all the input signals in the AND gate circuit are at a high level, a high level is output; otherwise, a low level is output. In this specific implementation manner, when the level signal TX IN connected to one of the input terminals of the AND gate circuit is at a high level, since the pulse signal connected to the other input terminal of the AND gate circuit is also at a high level, the output terminal of the AND gate circuit outputs a high level to the first-stage modulation node, that is, both the level signal TX IN and the pulse signal can reach the first-stage modulation node, and are "combined and modulated" into a primary modulation signal at the first-stage modulation node and then output to the second switch S2. Similarly, when the level signal TX IN is at a low level, the output terminal of the AND gate circuit will output a low level to the first-stage modulation node, that is, only the level signal TX IN reaches the first-stage modulation node. At this time, the first-stage modulation node cannot perform "combined and modulated" processing, and only the low-level signal TX output to the second switch S2 IN .

[0076] It can be seen that the first switch S1 implemented by the above first and second specific implementation manners has the characteristics of simple structure, easy implementation and sensitive response.

[0077] As Figure 6As shown in (c), in the third specific embodiment, the first switch includes a transmission gate; the transmission gate is composed of an NMOS transistor and a PMOS transistor; an inverter is connected in parallel between the gates of the NMOS transistor and the PMOS transistor to provide two complementary control voltages, and then connected to the signal input terminal (i.e., TXIN in the figure); the sources of the NMOS transistor and the PMOS transistor are connected and then connected to the first-stage modulation node, and their drains are connected and then connected to the pulse signal output terminal (i.e., OSC in the figure).

[0078] It can be understood that when the input control signal of the transmission gate (i.e., the signal input to the gates of the NMOS transistor and the PMOS transistor) is at a low level, both the NMOS transistor and the PMOS transistor are turned off, and the transmission gate is disconnected; when the input control signal is at a high level, both the NMOS transistor and the PMOS transistor are turned on, and the transmission gate is turned on. In this specific embodiment, when the level signal TX IN input from the signal input terminal to the transmission gate is at a high level, it will cause both the NMOS transistor and the PMOS transistor to be turned on, and then the transmission gate is turned on. The pulse signal passes through the transmission gate and is output to the first-stage modulation node. At the same time, the high-level signal TX IN will also be output to the first-stage modulation node through the transmission gate; the high-level signal TX IN arriving at the first-stage modulation node simultaneously will be "combined and modulated" with the pulse signal at the first-stage modulation node to form a primary modulation signal and then output to the second switch S2. Similarly, when the level signal TX IN input from the signal input terminal to the transmission gate is at a low level, it will cause both the NMOS transistor and the PMOS transistor to be turned off, and the pulse signal cannot reach the first-stage modulation node through the transmission gate. Only the low-level signal TX IN can be output to the first-stage modulation node through the transmission gate; at this time, the first-stage modulation node cannot perform the "combined and modulated" processing, and only the low-level signal TX IN output to the second switch S2 is available.

[0079] Compared with the first and second specific embodiments, the above third specific embodiment has higher response sensitivity (i.e., faster response speed) and more flexible controllability.

[0080] In addition, in this embodiment, the second switch S2, which is also located in the modulation module of the signal modulation and demodulation system of the digital isolator, is specifically configured to be in a conducting state when a high-level signal flows in and in a disconnected state when a low-level signal flows in.

[0081] It can be understood that the signal flowing into the second switch S2 is determined by the output signal of the primary modulation node. Combining with the above description of the first switch S1, the output of the primary modulation node is a low-level signal TX IN or the initial modulation signal (appearing as a high level). Therefore, when the output of the primary modulation node is the low-level signal TX IN the second switch S2 will be turned off; when the output of the primary modulation node is the initial modulation signal, the second switch S2 will be turned on. When the second switch S2 is in the off state, the secondary modulation node does not work (it does not work due to the open circuit) and cannot perform secondary modulation processing; when the second switch S2 is in the on state, the secondary modulation node works (it works normally due to the closed circuit and the RF signal can reach the secondary modulation node), and can perform secondary modulation processing to output a composite modulation signal to the transmitting unit.

[0082] In some preferred specific embodiments of this embodiment, the second switch S2 is implemented by a MOS transistor, whose gate is connected to the output terminal of the primary modulation node, whose source is grounded, and whose drain is connected to the secondary modulation node.

[0083] In this embodiment, the first switch S1 serves as a low-speed switch to determine whether primary modulation is necessary; the second switch S2 serves as a high-speed switch to determine whether secondary modulation is necessary. Thus, this embodiment can achieve precise two-stage modulation control through the two-stage switch configuration of the modulation module, thereby significantly improving the signal modulation accuracy of the modulation module in the digital isolator; at the same time, under the control of the second switch S2, only when secondary modulation is performed, the components (such as gain components with a relatively large power consumption) provided at the secondary modulation node will work, so it has the effect of reducing the power consumption of the signal modulation and demodulation system; in addition, the structural design of the signal modulation and demodulation system also has the advantages of being simple and easy to implement.

[0084] Embodiment 4

[0085] Please refer to FIG. 7. Based on any of the above embodiments, this embodiment provides a preferred specific embodiment.

[0086] In this preferred specific embodiment, as Figure 7 shown, the pulse signal output terminal in the modulation module 1 is the OSC unit; the RF signal output terminal is the VCO unit; the secondary modulation node is the gain mixing circuit. The demodulation module 3 includes an LNA unit 31, an ENV unit 32, an integrator 33, and a driving unit 34 connected in sequence.

[0087] The working principle of the signal modulation and demodulation system of the digital isolator provided by this preferred specific embodiment is as follows:

[0088] The signal input terminal 2 inputs a high / low level signal TX IN to the modulation module 1; when the signal TX IN is at a low level, the first switch S1 is in the off state, and the pulse signal output by the OSC unit cannot reach the first-stage modulation node 13 via the first switch S1. Therefore, only the low-level signal TX is output at the first-stage modulation node 13 IN . When the signal TX IN is at a high level, the first switch S1 is in the on state, and the pulse signal output by the OSC unit can reach the first-stage modulation node 13 via the first switch S1. The first-stage modulation node 13 combines it with the level signal TX input from the signal input terminal IN to perform first-stage modulation together, obtaining an initial modulation signal and outputting it. After the signal of the first-stage modulation node 13 reaches the second switch S2, if the signal is the low-level signal TX IN , that is, the low-level signal that has not undergone first-stage modulation 13, the second switch S2 will remain in the off state, and thus the gain mixing circuit of the second-stage modulation node cannot be turned on and operate, and the RF signal output by the connected VCO unit cannot be output through the gain mixing circuit of the second-stage modulation node; if the signal output by the first-stage modulation node 13 is the primary modulation signal, the second switch S2 will switch to the on state, and the gain mixing circuit of the second-stage modulation node can operate normally due to being turned on. The RF signal output by the VCO unit can reach the gain mixing circuit. At the same time, the primary modulation signal will also reach the gain mixing circuit of the second-stage modulation node via the second switch S2. The gain mixing circuit performs second-stage modulation on it together with the gain-processed RF signal, obtains a composite modulation signal and outputs it, and then wirelessly transmits it to the receiving side of the digital isolator, and then transmits it to the demodulation module 3. In the demodulation module 3, the initial modulation signal will be demodulated from the received composite modulation signal successively through the LNA unit 31 and the ENV unit 32; then through the integrator 33 and the drive unit 34, the original high / low level signal TX IN will be demodulated from the initial modulation signal, and then output, completing the wireless isolation transmission of the signal.

[0089] It can be understood that assuming the power consumption when the gain mixing circuit as the second-stage modulation node is always on is P PA , and the power consumption of the OSC unit is P OSC . Taking the power consumption of a pulse signal with a 50% duty cycle in t time as an example. Then the power consumption of the traditional OOK modulation is P 1 =P PA *t / 2, and when using any embodiment of the present invention, especially the signal modulation and demodulation system provided by the above preferred specific embodiment, the power consumption for the transmitting side TX is P 2 =P PA *(t / 2) / 2 + POSC = P PA * t / 4 + P OSC If so, P1 - P2 = P PA * t / 4 - P OSC ; If the OSC unit uses a ring oscillator or an existing internal clock signal, then P PA > 10 * P OSC That is, P1 - P2 > 1.5 * P OSC . It can be seen that the signal modulation and demodulation system of the digital isolator provided by the present invention can significantly reduce the power consumption of the system compared with the traditional OOK modulation system. If the output power of the VCO unit is reduced and the gain of the gain mixing circuit is increased, the power consumption of the entire system can be further reduced when the power given to the transmitting antenna remains unchanged.

[0090] . It can be seen that in this preferred specific embodiment, not only two - stage switches are set in the modulation module to achieve precise two - stage modulation control, and two - stage modulation and demodulation are correspondingly performed in the demodulation module, thereby significantly improving the signal modulation accuracy of the digital isolator; at the same time, it can also significantly reduce the power consumption of the signal modulation and demodulation system; in addition, the structural design of the signal modulation and demodulation system also has the advantages of being simple and easy to implement.

[0091] Embodiment Five

[0092] Please refer to Figure 8 , based on any of the above - mentioned embodiments, this embodiment provides a digital isolator. As shown in Figure 8 , it includes the signal modulation and demodulation system described in any of the above - mentioned embodiments, and also includes a transmitting unit 4 and a receiving unit 5. The modulation module 1, the transmitting unit 4, the receiving unit 5, and the demodulation module 3 in the signal modulation and demodulation system are connected in sequence; among them, an isolation band is formed between the transmitting unit 4 and the receiving unit 5. The specific structure and working principle of the signal modulation and demodulation system will not be repeated here. For details, please refer to the description of the above - mentioned embodiments.

[0093] The transmitting unit 4 is configured to receive the composite modulation signal output by the two - stage modulation node and wirelessly send it to the receiving unit 5 through the isolation band;

[0094] The receiving unit 5 is configured to receive the wirelessly transmitted composite modulation signal and then transmit it to the demodulation module 3.

[0095] In some preferred specific embodiments of this embodiment, the digital isolator is a millimeter - wave isolator. That is, the transmitting unit therein is a millimeter - wave transmitting antenna; the receiving unit is a millimeter - wave receiving antenna.

[0096] Optionally, the operating frequency of the millimeter-wave transmitting antenna and the millimeter-wave receiving antenna is 60 GHz; the operating frequency of the pulse signal output terminal (such as the OSC unit) and / or the RF signal output terminal (such as the VCO unit) in the modulation module is 100 MHz; the operating speed of the first switch S1 and / or the second switch is 10 ns.

[0097] The digital isolator provided in this embodiment, especially the millimeter-wave isolator, sets two-stage switches in the modulation module of its signal modulation and demodulation system to achieve precise two-stage modulation control. After millimeter-wave isolated transmission, secondary modulation and demodulation are performed correspondingly in the demodulation module, thereby significantly improving the signal modulation accuracy in the digital isolator, especially the millimeter-wave isolator; at the same time, it can also significantly reduce the power consumption of the signal modulation and demodulation system and better meet the energy consumption requirements; in addition, the structural design of the signal modulation and demodulation system also has the advantages of simple design and easy implementation.

[0098] The above are only the embodiments of the present invention, and do not limit the patent scope of the present invention accordingly. Any equivalent transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in the related technical fields, shall be equally included in the patent protection scope of the present invention.

Claims

1. A signal modulation and demodulation system of a digital isolator, characterized in that: It includes a modulation module and a signal input terminal; The modulation module includes a pulse signal output terminal, an RF signal output terminal, a first switch, a primary modulation node, a second switch and a secondary modulation node; the pulse signal output terminal and the signal input terminal are respectively connected to the primary modulation node through the first switch; The primary modulation node is connected to the secondary modulation node via the second switch; The RF signal output terminal is connected to the secondary modulation node; The first switch is configured to be turned on or off by the level signal input from the signal input terminal, so as to control whether the pulse signal output from the pulse signal output terminal and the level signal can both reach the primary modulation node for primary modulation, thereby obtaining a primary modulation signal; The second switch is configured to be turned on or off by the signal flowing out of the primary modulation node to control whether the RF signal output by the RF signal output end and the primary modulation signal can both reach the secondary modulation node for secondary modulation to obtain a composite modulation signal.

2. The signal modulation and demodulation system of the digital isolator according to claim 1, characterized in that: The pulse signal output end is an OSC unit or a clock unit inside a digital isolator; the RF signal output end is a VCO unit.

3. The signal modulation and demodulation system of the digital isolator according to claim 1, characterized in that: The secondary modulation node includes an inductor, a MOS tube and an output end; the gate of the MOS tube is connected to the RF signal output end, the source thereof is connected to the second switch, and the drain thereof is connected to the output end via the inductor.

4. The signal modulation and demodulation system of the digital isolator according to claim 1, characterized in that: The secondary modulation node includes an inductor, a MOS tube and an output end; the gate of the MOS tube is connected to the RF signal output end, the source thereof is connected to the ground, and the drain thereof is connected to the output end via the second switch and the inductor in sequence.

5. The signal modulation and demodulation system of the digital isolator according to claim 1, characterized in that: The first switch includes a MOS tube; the gate of the MOS tube is connected to the signal input end, the source of the MOS tube is connected to the pulse signal output end, and the drain of the MOS tube is connected to the primary modulation node.

6. The signal modulation and demodulation system of the digital isolator according to claim 1, characterized in that: The first switch includes an AND gate circuit; two input terminals of the AND gate circuit are respectively connected to the signal input terminal and the pulse signal output terminal, and the output terminal is connected to the primary modulation node.

7. The signal modulation and demodulation system of the digital isolator according to claim 1, characterized in that: The first switch includes a transmission gate composed of an NMOS tube and a PMOS tube; the gate of the NMOS tube and the gate of the PMOS tube are connected in parallel using an inverter and then connected to the signal input end; the source of the NMOS tube is connected to the source of the PMOS tube and then connected to the primary modulation node, and the drains of the two are connected and then connected to the pulse signal output end.

8. The signal modulation and demodulation system of the digital isolator according to claim 1, characterized in that: It also includes a demodulation module; the demodulation module includes an LNA unit, an ENV unit, an integrator and a driving unit connected in sequence.

9. A digital isolator, characterized in that, It comprises a transmitting unit, a receiving unit and the signal modulation and demodulation system as described in any one of claims 1 to 8; the modulation module, the transmitting unit, the receiving unit and the demodulation module are connected in sequence.

10. The digital isolator according to claim 9, characterized in that The transmitting unit is a millimeter wave transmitting antenna; the receiving unit is a millimeter wave receiving antenna.

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