Signal modulation and demodulation system of digital isolator and digital isolator

Abstract

The utility model provides a signal modulation and demodulation system of a digital isolator. The digital isolator and a pulse signal output end and a signal input end of 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 utility model, 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] This utility model relates to signal modulation and demodulation technology, specifically to a signal modulation and demodulation system for digital isolators and a digital wave isolator. Background Technology

[0002] In existing technologies, digital isolators typically employ OOK (On-Off Keying) modulation and demodulation techniques in their transmission systems. In this technique, the input signal level is modulated into high-frequency pulses, which are then isolated and transmitted to the receiving end. At the receiving end, the received high-frequency pulses are demodulated by a demodulator to recover the original electrical signal.

[0003] In particular, the use of millimeter-wave antennas makes frequency modulation and detection of millimeter-wave-based digital isolators a major technical challenge. This is because the input terminal needs to perform high-frequency modulation on the input signal level, which requires precise control of the level signal; however, the switching control method used in existing OOK modulation technology often cannot meet the requirements of precise control, resulting in wasted power consumption in the system; moreover, the system design is more complex. Utility Model Content

[0004] The technical problem to be solved by this utility model is to provide a signal modulation and demodulation system and a digital wave isolator that can improve signal modulation accuracy, while having the advantages of low power consumption and simple structure.

[0005] To solve the above-mentioned technical problems, the first technical solution adopted by this utility model is as follows:

[0006] The signal modulation and demodulation system of a digital isolator includes a modulation module and a signal input terminal;

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

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

[0009] The second switch is configured to be turned on or turned off under the control of the signal flowing out of the first modulation node, so as to control whether the RF signal output by the RF signal output end and the primary modulation signal can reach the secondary modulation node to be secondarily modulated to obtain a composite modulation signal.

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

[0011] Optionally, the secondary modulation node comprises an inductor, a MOS tube and an output end; the gate of the MOS tube is connected with the RF signal output end, the source thereof is connected with the second switch, and the drain thereof is connected with the output end via the inductor.

[0012] Optionally, the secondary modulation node comprises an inductor, a MOS tube and an output end; the gate of the MOS tube is connected with the RF signal output end, the source thereof is connected with the second switch, and the drain thereof is connected with the output end via the inductor.

[0013] Optionally, the first switch comprises a MOS tube; the gate of the MOS tube is connected with the signal input end, the source thereof is connected with the pulse signal output end, and the drain thereof is connected with the first modulation node.

[0014] Optionally, the first switch comprises an AND gate; two input ends of the AND gate are connected with the signal input end and the pulse signal output end respectively, and the output end thereof is connected with the first modulation node.

[0015] Optionally, the first switch comprises a transmission gate composed of an NMOS tube and a PMOS tube; an inverter is connected in parallel between the gate of the NMOS tube and the gate of the PMOS tube, and then the inverter is connected with the signal input end; the source of the NMOS tube is connected with the source of the PMOS tube, and then the source is connected with the first modulation node; the drain of the NMOS tube is connected with the drain of the PMOS tube, and then the drain is connected with the pulse signal output end.

[0016] Optionally, the signal modulation and demodulation system further comprises a demodulation module; the demodulation module comprises an LNA unit, an ENV unit, an integrator and a driving unit connected in sequence.

[0017] Another technical scheme provided by the utility model provides:

[0018] The digital isolator comprises a transmitting unit, a receiving unit and the signal modulation and demodulation system; 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, and the receiving unit is a millimeter wave receiving antenna.

[0020] The utility model discloses beneficial effect lies in: the utility model discloses in the modulation module of signal modulation system through two stage switch setting to realize two stage accurate modulation control, to this remarkable promotion digital isolator in modulation module's signal modulation precision, can also reduce signal modulation system's power consumption simultaneously, and signal modulation system's structure design still has simple and easy to realize's advantage. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The structure diagram of modulation module in signal modulation system of digital isolator is provided for the utility model embodiment one;

[0022] Figure 2 The structure diagram of modulation module is provided for the utility model specific embodiment;

[0023] Fig. 3 (a) - (b) are two kinds of specific embodiments of two stage modulation node in modulation module respectively;

[0024] Figure 4 The structure diagram of demodulation module in signal modulation system of digital isolator is provided for the utility model embodiment two;

[0025] Figure 5 The signal timing diagram of signal modulation system of digital isolator is provided for the utility model embodiment two;

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

[0027] Figure 7 The structure diagram of signal modulation system of digital isolator is provided for the utility model embodiment four;

[0028] Figure 8 The structure diagram of digital isolator is provided for the utility model embodiment five.

[0029] Label explanation:

[0030] 1, modulation module;2, signal input end;3, demodulation module;4, transmitting unit;5, receiving unit;

[0031] 11, pulse signal output end;12, RF signal output end;S1, first switch;13, primary modulation node;S2, second switch;14, two stage modulation node;

[0032] 31, LNA unit;32, ENV unit;33, integrator;34, drive unit. DETAILED DESCRIPTION

[0033] In order to explain the technical content, the purposes and effects of the present application, the following embodiments are described in conjunction with the accompanying drawings.

[0034] Embodiment one

[0035] Please refer to Figure 1 , the embodiment provides a kind of signal modulation system of digital isolator.

[0036] As Figure 1 Shown, the signal modulation system includes modulation module 1 and signal input end 2.

[0037] The signal input end 2 is configured as input high / low level signal TX IN To modulation module 1.

[0038] The modulation module 1 includes pulse signal output end 11, RF signal output end 12, first switch S1, first-order modulation node 13, second switch S2 and second-order modulation node 14;The pulse signal output end 11 and the signal input end 2 are connected with the first-order modulation node 13 by the first switch S1 respectively;The first-order modulation node 13 is connected with the second-order modulation node 14 by the second switch S2;The RF signal output end 12 is connected with the second-order modulation node 14.

[0039] Wherein, the first switch S1 is configured as the level signal TX IN Input by the signal input end is in on or off state, to control the pulse signal output by the pulse signal output end and the level signal TX IN Whether can reach the first-order modulation node and carry out first-order modulation, obtain primary modulation signal.

[0040] The second switch S2 is configured as the signal flowing out of the first-order modulation node is in on or off state, to control the RF signal output by the RF signal output end and the primary modulation signal obtained by first-order modulation whether can reach the second-order modulation node and carry out second-order modulation, obtain composite modulation signal.

[0041] The first-order modulation node is configured as when the pulse signal output by the pulse signal output end can reach, then it carries out first signal modulation processing together with the level signal TX IN Outputted by the signal input end, also known as first-order modulation processing, obtains primary modulation signal.

[0042] The secondary modulation node is configured to operate under the control of the second switch S2 to perform a mixing modulation process, also known as secondary modulation processing, on the RF signal output from the RF signal output terminal together with the primary modulation signal to obtain a composite modulation signal for transmission.

[0043] The working principle of the signal modulation and demodulation system described in this embodiment is as follows:

[0044] On the transmitting side of the digital isolator, a high / low level signal TX is input to the signal input terminal. IN To the modulation module; signal TX IN The system can control whether the first switch S1 in the modulation module is in an on or off state, thereby determining whether the pulse signal output from the pulse signal output terminal can reach the first-level modulation node, and further determining whether to pass through the first-level modulation node. Based on the pulse signal, the signal TX is... IN First-stage modulation is performed to obtain the initial modulation signal. Then, the signal from the first-stage modulation node reaches the second switch S2. If this signal is signal TX... IN If no primary modulation is performed, the second switch S2 will remain open, and the secondary modulation node will not operate. The RF signal output from the connected RF signal output terminal will not be able to reach the transmitting unit via the secondary modulation node. If the signal from the primary modulation node is a primary modulation signal, the second switch S2 will switch to the on state, the secondary modulation node will operate, and the RF signal will reach the secondary modulation node. Simultaneously, the primary modulation signal will also reach the secondary modulation node via the second switch S2. The secondary modulation node will then perform secondary modulation on the primary modulation signal and the RF signal together to obtain a composite modulation signal, which will be output to the transmitting unit. In other words, the second switch S2 determines whether the secondary modulation node operates, thereby further modulating the initial modulation signal into a composite modulation signal before wireless transmission to the receiving side of the digital isolator.

[0045] In some specific implementations of this embodiment, such as Figure 2 As shown, the pulse signal output terminal can be an OSC unit, i.e. an oscillator, specifically configured to generate a stable pulse signal; or it can be the clock unit inside the digital isolator, i.e., directly using the existing internal clock signal (which is a type of pulse signal).

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

[0047] In some specific embodiments of this example, the second switch S2 is implemented by a MOS transistor, whose gate is connected to the output terminal of the first-level modulation node, whose source is grounded, and whose drain is connected to the second-level modulation node. Here, if the output of the first-level modulation node to the gate of the second switch S2 is a level signal TX... IN If no first-stage modulation is performed, the second switch S2 will remain open; if the first-stage modulation node outputs a primary modulation signal, i.e., a non-level signal TX, to the gate of the second switch S2. IN Then the second switch S2 will switch to the on state.

[0048] In some specific embodiments of this example, the secondary modulation node is essentially a gain mixer circuit that simultaneously possesses gain and mixing functions. In this embodiment, the secondary modulation node, in conjunction with the second switch S2, performs mixed modulation of the primary modulation signal and the gain-processed RF signal, i.e., secondary modulation, to obtain a composite modulation signal. Below, two specific implementations of the secondary modulation node are provided.

[0049] As shown in Figure 3(a), in one specific embodiment, the secondary modulation node consists of an inductor, a MOSFET, and an output terminal; the gate of the MOSFET is connected to the RF signal output terminal (i.e., Figure 2 The VCO unit is connected, and its source is connected to the second switch S2 (specifically, connected to the drain of the second switch S2). Its drain is connected to the output terminal (i.e., the "secondary modulation signal (negative polarity)" and "secondary modulation signal (positive polarity)" in the figure) via the inductor. Preferably, as shown in Figure 3(a), the secondary modulation node specifically includes a pair of electromagnetically coupled inductor groups, two MOS transistors, and an output terminal; one inductor group consists of two inductors connected in series; the two ends of one inductor group are respectively connected to the negative and positive polarities of the secondary modulation signal output terminal; the two ends of the other inductor group are connected to the drain of a MOS transistor; the sources of both MOS transistors are 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 "secondary modulation signal (negative polarity)" in the figure is connected to the positive polarity output of the RF signal output terminal (i.e., the "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., the "RF signal (negative polarity)" in the figure).

[0050] As shown in Figure 3(b), in another specific embodiment, the secondary 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 (i.e., Figure 2The VCO unit is connected with the source connected to the ground, the drain connected to the output (i.e. "secondary modulation signal (positive polarity)" and "secondary modulation signal (negative polarity)" in the figure) via the second switch S2 (specifically connected to the source of the second switch S2) and then via the inductor. Preferably, as shown in Figure 3 (b), the secondary modulation node specifically comprises a pair of electromagnetically coupled inductor groups, two MOS tubes and secondary modulation signal output terminals; an inductor group is composed of two inductors connected in series; the two ends of one inductor group are connected to the negative polarity and the positive polarity of the output terminal respectively; the two ends of the other inductor group are connected to the second switch S2 (specifically connected to the drain of the second switch S2); the sources of the two MOS tubes are both connected to the ground, 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 tube corresponding to "secondary 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 tube 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 secondary 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 of the present embodiment) to realize the function of secondary mixing modulation. Specifically, when the second switch S2 is off, the circuit of the secondary modulation node will also be off and cannot work normally, i.e. no current passes through the secondary modulation node, and the secondary modulation node cannot provide the functions of gain amplification and mixing. At this time, the output terminal of the secondary modulation node has no signal output or can only output a very small signal; when the second switch S2 is on, the circuit of the secondary modulation node will also be on and can work normally. At this time, the RF signal can be gain amplified in the secondary modulation node, and mixed with the primary modulation signal output by the second switch S2, so that the output terminal of the secondary modulation node can output a relatively strong signal, i.e. output a composite modulation signal.

[0052] The signal modulation and demodulation system in the prior art digital isolator mostly adopts the traditional OOK modulation and demodulation mode. The power amplifier PA in the traditional OOK modulation mode is directly controlled by the level signal TX IN input from the signal input terminal. When the level signal TX IN is high, the power amplifier PA is always in the working / conducting state and consumes current; when the level signal TX IN is low, the power amplifier PA is turned off, at which time there is no power consumption or only a low leakage exists. It can be seen that the modulation mode adopted by the signal modulation and demodulation system of the prior art digital isolator only has one level of modulation, it is difficult to achieve accurate modulation, and there is a problem of power consumption waste in the signal modulation and demodulation system.

[0053] Compared with the signal modulation and demodulation system adopting the traditional OOK modulation and demodulation mode, the signal modulation and demodulation system of the digital isolator provided by the embodiment realizes accurate two-stage modulation control by arranging two-stage switches in the modulation module, so as to significantly improve the signal modulation accuracy of the modulation module in the digital isolator; meanwhile, the gain component with a large power consumption ratio is arranged at the two-stage modulation node, which only works when the one-stage modulation node works, and does not work otherwise, so as to 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 simplicity and easy implementation.

[0054] Embodiment two

[0055] Please refer to Figure 4 , the embodiment is further extended based on embodiment one, and the demodulation module of the signal modulation and demodulation system is specifically described.

[0056] In the 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 at the sending side of the digital isolator; and the demodulation module is located at the receiving side of the digital isolator.

[0057] The demodulation module 3 is configured to adopt a two-stage demodulation mode corresponding to the two-stage modulation mode of the modulation module to perform two-stage demodulation processing on the composite modulation signal, so as to finally obtain the original high-low level signal, i.e. the level signal TX IN input by the signal input end, and then output through the signal output end.

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

[0059] The LNA unit, i.e. the low noise amplifier, is configured to perform signal strength enhancement, noise reduction and impedance matching processing on the composite modulation signal, so as to amplify the composite modulation signal;

[0060] The ENV unit, i.e. the envelope detector, is configured to demodulate the initial modulation signal from the composite modulation signal after the amplification processing;

[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 simultaneously performs 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 a high / low level signal TX input by the signal input end IN .

[0063] In the embodiment, for the demodulation module of the receiving side, a two-stage demodulation mode corresponding to the modulation module is adopted to demodulate the original high / low level signal TX input by the signal input end 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, and demodulates the original high / low level signal TX from the initial modulation signal through the integrator and the driving unit IN .

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

[0065] It can be understood that the signal modulation and demodulation system provided by the embodiment can adopt a two-stage demodulation mode corresponding to the modulation module to demodulate the original high / low level signal TX IN from the received composite modulation signal. In this way, the signal modulation and demodulation system of the digital isolator can normally carry out signal modulation in a two-stage modulation and demodulation mode, realize signal isolation transmission of the digital isolator, and improve the precision of signal modulation and demodulation.

[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 accepting the composite modulation signal and then modulating, i.e., cannot be actively turned on or turned 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 of the receiving side in the signal modulation and demodulation system of the digital isolator provided by the embodiment does not increase the system power consumption, i.e., the power consumption does not change greatly compared with the existing modulation system.

[0067] Embodiment Three

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

[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, specifically configured to when the level signal TX IN input by the signal input end 2 is high level signal, then control is in the on state; when the level signal TX IN input by the signal input end 2 is low level signal, then control is in the off state.

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

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

[0072] As shown in Figure 6 (a), in the first specific implementation, the first switch S1 includes a MOS tube; preferably a PMOS tube; the gate of the MOS tube is connected with the signal input end (i.e. TXIN in the figure), the source thereof is connected with the pulse signal output end (i.e. OSC in the figure), and the drain thereof is connected with the primary modulation node.

[0073] It can be understood that in this specific implementation, when the level signal TX IN input by the signal input end into the gate of the MOS tube is high level, the MOS tube will be turned on, the pulse signal will flow in from the source of the MOS tube, and will be output to the primary modulation node through the drain, at the same time, the high level signal TX INThe signal TX, which is also output through the drain of the MOS transistor, is sent to the first-level modulation node; simultaneously, the high-level signal TX reaching the first-level modulation node is also output. IN The pulse signal is "combined and modulated" into a primary modulated signal at the first-level modulation node and then output to the second switch S2. Similarly, when the signal input terminal receives the level signal TX at the gate of the MOS transistor... IN When the signal is low, the MOSFET will be turned off, and the pulse signal cannot reach the first-level modulation node through the MOSFET. Only the low-level signal TX will be received. IN The signal can be output to the first-level modulation node through the drain of the MOS transistor; at this time, the first-level modulation node cannot perform "combined modulation" processing, and its output to the second switch S2 is only a low-level signal TX. IN .

[0074] like Figure 6 As shown in (b), in the second specific embodiment, 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-level modulation node. As a preferred example, the AND gate circuit can be composed of a diode and a resistor, which has the characteristics of simple structure and sensitive response.

[0075] It can be understood that an AND gate outputs a high level when all input signals are simultaneously high; otherwise, it outputs a low level. In this specific embodiment, when the level signal TX connected to one of the input terminals of the AND gate is high... IN When the signal is high, since the pulse signal connected to the other input of the AND gate is also high, the output of the AND gate outputs a high level to the first-level modulation node, i.e., the level signal TX. IN Both the pulse signal and the signal can reach the first-level modulation node, where they are "combined and modulated" into a primary modulation signal before being output to the second switch S2. Similarly, when the level signal TX... IN When the signal is low, the output of the AND gate will output a low level to the first-level modulation node, meaning only the level signal TX will be output. IN Upon reaching the first-level modulation node, it is unable to perform "combined modulation" processing, and its output to the second switch S2 is only a low-level signal TX. IN .

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

[0077] like Figure 6(c) As shown, in the third embodiment, the first switch comprises a transmission gate; the transmission gate is composed of an NMOS transistor and a PMOS transistor; an inverter is connected in parallel between the gate of the NMOS transistor and the gate of the PMOS transistor to provide two complementary control voltages, which are then connected to the signal input end (i.e. TXIN in the figure); the source of the NMOS transistor is connected to the source of the PMOS transistor, and then connected to the first modulation node; the drain of the NMOS transistor is connected to the drain of the PMOS transistor, and then connected to the pulse signal output end (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 cut off, and the transmission gate is turned off; 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 embodiment, when the level signal TX IN input to the transmission gate from the signal input end is at a high level, both the NMOS transistor and the PMOS transistor are turned on, and the transmission gate is turned on, so that the pulse signal is output to the first modulation node through the transmission gate, and at the same time, the signal TX IN at a high level is also output to the first modulation node through the transmission gate; the signal TX IN at a high level and the pulse signal at the first modulation node are "combined and modulated" into a primary modulation signal, which is then output to the second switch S2. Similarly, when the level signal TX IN input to the transmission gate from the signal input end is at a low level, both the NMOS transistor and the PMOS transistor are cut off, and the pulse signal cannot reach the first modulation node through the transmission gate, only the signal TX IN at a low level can be output to the first modulation node through the transmission gate; at this time, the first modulation node cannot perform "combined and modulated" processing, and the signal TX IN at a low level is the only signal output to the second switch S2.

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

[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 control the on state when a high-level signal flows in, and control the off 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 first-stage modulation node. Combined with the above description of the first switch S1, it is known that the output of the first-stage modulation node is a low-level signal TX. IN Or it could be the initial modulation signal (manifested as a high level). Therefore, when the output of the first-level modulation node is a low-level signal TX... IN 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 will not work (because the line is disconnected), and secondary modulation processing cannot be performed; when the second switch S2 is in the on state, the secondary modulation node will work (because the line is connected and it works normally, the RF signal can reach the secondary modulation node), and secondary modulation processing can be performed, outputting a composite modulation signal to the transmitting unit.

[0082] In some preferred embodiments of this example, the second switch S2 is implemented by a MOS transistor, whose gate is connected to the output terminal of the first-level modulation node, whose source is connected to ground, and whose drain is connected to the second-level modulation node.

[0083] In this embodiment, the first switch S1 serves as a low-speed switch, used to determine whether primary modulation is necessary; the second switch S2 serves as a high-speed switch, used to determine whether secondary modulation is necessary. Thus, this embodiment, through the two-stage switch configuration of the modulation module, achieves precise two-stage modulation control, significantly improving the signal modulation accuracy of the modulation module in the digital isolator. Simultaneously, under the control of the second switch S2, components located at the secondary modulation nodes (such as gain components with high power consumption) only operate during secondary modulation, thereby reducing the power consumption of the signal modulation and demodulation system. Furthermore, the structural design of the signal modulation and demodulation system is simple and easy to implement.

[0084] Example 4

[0085] Please refer to 7. This embodiment is based on any of the above embodiments and provides a preferred specific implementation method.

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

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

[0088] The signal input end 2 inputs high / low level signal TX IN to the modulation module 1; when the signal TX IN is low, the first switch S1 is in the off state, and the pulse signal output by the OSC unit cannot reach the primary modulation node 13 via the first switch S1, so the primary modulation node 13 only outputs the low-level signal TX IN . When the signal TX IN is high, the first switch S1 is in the on state, and the pulse signal output by the OSC unit can reach the primary modulation node 13 via the first switch S1, which is modulated together with the level signal TX IN input by the signal input end to obtain the initial modulation signal and output. After the signal of the primary modulation node 13 reaches the second switch S2, if the signal is the low-level signal TX IN that has not been modulated by the primary modulation node 13, the second switch S2 will remain in the off state, so that the gain mixing circuit of the secondary modulation node cannot be turned on and work, and the RF signal output by the VCO unit cannot be output through the gain mixing circuit of the secondary modulation node; if the signal output by the primary modulation node 13 is the primary modulation signal, the second switch S2 will switch to the on state, the gain mixing circuit of the secondary modulation node can work normally due to the on state, the RF signal output by the VCO unit can reach the gain mixing circuit, at the same time, the primary modulation signal also reaches the gain mixing circuit of the secondary modulation node via the second switch S2, and the gain mixing circuit modulates the primary modulation signal together with the RF signal processed by the gain to obtain the composite modulation signal and output, which is then wirelessly transmitted to the receiving side of the digital isolator and then transmitted to the demodulation module 3. In the demodulation module 3, the initial modulation signal is demodulated from the received composite modulation signal through the LNA unit 31 and the ENV unit 32 in sequence; then the original high / low level signal TX IN is demodulated from the initial modulation signal through the integrator 33 and the driving unit 34, and then output, completing the wireless isolation transmission of the signal.

[0089] It can be understood that, assuming that the power consumption of the gain mixing circuit as the secondary modulation node is always on is P PA , the power consumption of the OSC unit is P OSC , and the power consumption of a pulse signal with a 50% duty cycle at time t is taken as an example. The power consumption of the traditional OOK modulation is P1=P PA *t / 2, while the power consumption of the signal modulation and demodulation system provided by any one of the embodiments of the present application, in particular the preferred specific embodiment, is P2= P PA * (t / 2) / 2 + P OSC = PPA t / 4+P OSC , then P1-P2= P PA t / 4-P OSC ; if the OSC unit uses a ring oscillator or an internal clock signal already exists, then P PA >10*P OSC , i.e. P1-P2>1.5*P OSC It can be seen that the signal modulation system of the digital isolator provided by the utility model can obviously 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 under the condition that the power supplied to the transmitting antenna is unchanged.

[0090] It can be seen that the preferred specific embodiment not only sets two-stage switches in the modulation module to achieve precise two-stage modulation control, and correspondingly performs two-stage modulation and demodulation in the demodulation module, thereby significantly improving the signal modulation precision of the digital isolator, but also can obviously reduce the power consumption of the signal modulation and demodulation system. In addition, the structure design of the signal modulation and demodulation system also has the advantages of simplicity and easy implementation.

[0091] Embodiment five

[0092] Please refer to Figure 8 , the embodiment based on any of the above embodiments provides a digital isolator, as shown in Figure 8 , which comprises the signal modulation and demodulation system described in any of the above embodiments, and further comprises a transmitting unit 4 and a receiving unit 5. The modulation module 1 in the signal modulation and demodulation system, the transmitting unit 4, the receiving unit 5 and the demodulation module 3 in the signal modulation and demodulation system are sequentially connected; wherein the transmitting unit 4 and the receiving unit 5 constitute an isolation band. The specific structure and working principle of the signal modulation and demodulation system will not be repeated here, and details can be referred to the description of the above embodiments.

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

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

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

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

[0097] The digital isolator, particularly the millimeter wave isolator, provided by the embodiment can realize precise two-stage modulation control by setting two-stage switches in the modulation module in the signal modulation and demodulation system thereof, can significantly improve the precision of signal modulation in the digital isolator, particularly the millimeter wave isolator, and can obviously reduce the power consumption of the signal modulation and demodulation system, thereby better meeting the energy consumption requirement.

[0098] The above merely describes the embodiments of the present application, and does not limit the patent range of the present application, and any equivalent transformation or direct or indirect application in the related technical field based on the content of the present application specification and drawings is also included in the patent protection range of the present application.

Claims

1. A signal modulation system for a digital isolator, characterized by, The modulation module and the signal input end are included. The modulation module includes a pulse signal output end, an RF signal output end, a first switch, a first-order modulation node, a second switch, and a second-order modulation node; the pulse signal output end and the signal input end are connected with the first-order modulation node through the first switch respectively. The first-order modulation node is connected with the second-order modulation node through the second switch. The RF signal output end is connected with the second-order modulation node. 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 reach the first-order modulation node to perform first-order modulation and obtain a primary modulation signal. The second switch is configured to be turned on or off under the control of the signal flowing out of the first-order modulation node, so as to control whether the RF signal output by the RF signal output end and the primary modulation signal can reach the second-order modulation node to perform second-order modulation and obtain a composite modulation signal.

2. The digital isolator based signal modem system of claim 1, wherein, 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 digital isolator based signal modem system of claim 1, wherein, The second-order modulation node includes an inductor, a MOS tube, and an output end; the gate of the MOS tube is connected with the RF signal output end, the source thereof is connected with the second switch, and the drain thereof is connected with the output end through the inductor.

4. The digital isolator based signal modem system of claim 1, wherein, The second-order modulation node includes an inductor, a MOS tube, and an output end; the gate of the MOS tube is connected with the RF signal output end, the source thereof is grounded, and the drain thereof is connected with the output end through the second switch and the inductor in sequence.

5. The digital isolator based signal modem system of claim 1, wherein, The first switch includes a MOS tube; the gate of the MOS tube is connected with the signal input end, the source thereof is connected with the pulse signal output end, and the drain thereof is connected with the first-order modulation node.

6. The digital isolator based signal modem system of claim 1, wherein, The first switch includes an AND gate circuit; two input ends of the AND gate circuit are connected with the signal input end and the pulse signal output end respectively, and the output end thereof is connected with the first-order modulation node.

7. The digital isolator based signal modem system of claim 1, wherein, The first switch includes a transmission gate composed of an NMOS tube and a PMOS tube; an inverter is connected in parallel between the gate of the NMOS tube and the gate of the PMOS tube, and then connected with the signal input end; the source of the NMOS tube is connected with the source of the PMOS tube, and then connected with the first-order modulation node; the drain of the NMOS tube is connected with the drain of the PMOS tube, and then connected with the pulse signal output end.

8. The digital isolator based signal modem system of claim 1, wherein, The demodulation module is further included; the demodulation module includes an LNA unit, an ENV unit, an integrator, and a driving unit connected in sequence.

9. A digital isolator characterized by, The signal modulation and demodulation system of any one of claims 1 to 8 is included; the modulation module, the transmitting unit, and the receiving unit are connected in sequence.

10. The digital isolator of claim 9, wherein, The transmitting unit is a millimeter wave transmitting antenna; and the receiving unit is a millimeter wave receiving antenna.

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