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 first-stage modulation node is connected with the input end of the second-stage modulation node through the phase inverter; the RF signal output end is also connected with the input end of 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 secondary modulation node is controlled by the signal flowing out of the primary modulation node to be switched on or switched off so as to control whether the RF signal output by the RF signal output end and the signal flowing out of the primary modulation node can be subjected to 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] The utility model relates to signal modulation and demodulation technology, concretely relates to digital isolator's signal modulation and demodulation system, digital isolator. BACKGROUND

[0002] In prior art, the transmission system of digital isolator usually adopts OOK (On-Off Keying) modulation and demodulation technology. In this technology, the level of input signal will be modulated into high frequency pulse, and then be isolated and transmitted to receiving end; in receiving end, the received high frequency pulse will be demodulated by demodulator, so as to restore original electric signal.

[0003] Especially, due to the use of millimeter wave antenna, the frequency modulation and detection of digital isolator based on millimeter wave transmission, namely millimeter wave isolator, become a big technical difficulty. This is because the input end needs to modulate the level of input signal into high frequency, so it is necessary to accurately control the level signal; and the switch control mode used in existing OOK modulation technology often cannot meet the requirement of accurate control, so that the power consumption of system is wasted; and the system design is relatively complex. SUMMARY

[0004] The utility model wants to solve the technical problem that provides digital isolator's signal modulation and demodulation system, digital isolator, can promote signal modulation precision, and has the advantages that the structure is simple.

[0005] In order to solve the above technical problem, the first technical scheme adopted by the utility model is:

[0006] A kind of digital isolator's signal modulation and demodulation system, including modulation module and signal input end;The modulation module includes pulse signal output end, RF signal output end, first switch, first modulation node, second switch, inverter and second modulation node;The second modulation node includes coupling inductance, second MOS tube and output end;The second switch is a MOS switch tube;

[0007] The pulse signal output end and the signal input end are connected with the first modulation node respectively by the first switch;The first modulation node is connected with the gate of the second switch by the inverter;The source of the second switch is connected with the primary side of the coupling inductance and the drain of the second MOS tube respectively;The drain of the second switch is connected with the primary side of the coupling inductance and the drain of the second MOS tube respectively;The gate of the second MOS tube is connected with the RF signal output end;The secondary side of the coupling inductance is connected with the output end.

[0008] The first switch is configured to be turned on or turned 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 primary modulation node to perform primary modulation and obtain a 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 primary modulation node, so as to control whether the RF signal output by the RF signal output end and the signal flowing out of the primary modulation node can perform secondary modulation at the secondary modulation node to obtain a composite modulation signal.

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

[0011] Optionally, the number of the coupling inductors is two groups, and the number of the second MOS transistors is two; the two groups of coupling inductors are connected in series, the two terminals of the secondary sides of the two groups of coupling inductors are connected with the output end respectively, the two terminals of the primary sides of the two groups of coupling inductors are connected with the source and the drain of the second switch respectively; the sources of the two second MOS transistors are connected with the ground respectively, the gates of the two second MOS transistors are connected with the RF signal output end, and the drains of the two second MOS transistors are connected with the drain and the source of the second switch respectively.

[0012] Optionally, the second MOS transistor and the second switch are PMOS transistors.

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

[0014] Optionally, the first switch comprises an AND gate circuit; the 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 of the AND gate circuit is connected with the primary modulation node.

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

[0016] Optionally, 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 is:

[0018] The digital isolator comprises a transmitting unit, a receiving unit and the signal modulation and demodulation system, and the modulation module, the transmitting unit, the receiving unit and the demodulation module are sequentially connected.

[0019] Optionally, the transmitting unit comprises a millimeter wave transmitting antenna, and the receiving unit comprises a millimeter wave receiving antenna.

[0020] The signal modulation and demodulation system of the digital isolator provided in the utility model has the advantages that two-stage precise modulation control is realized by adding two-stage switches and two-stage modulation nodes in the modulation module of the signal modulation and demodulation system, so that the signal modulation precision of the modulation module in the digital isolator is significantly improved, and the structure design of the signal modulation and demodulation system has the advantages of simplicity and easy realization. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 Fig. 1 is a schematic structural diagram of a modulation module in a signal modulation and demodulation system of a digital isolator according to an embodiment of the utility model;

[0022] Figure 2 Fig. 1 is a schematic structural diagram of a modulation module in a signal modulation and demodulation system of a digital isolator according to an embodiment of the utility model;

[0023] Figure 3 Fig. 1 is a schematic structural diagram of a modulation module in a signal modulation and demodulation system of a digital isolator according to an embodiment of the utility model;

[0024] Figure 4 Fig. 1 is a schematic structural diagram of a modulation module in a signal modulation and demodulation system of a digital isolator according to an embodiment of the utility model;

[0025] Figure 5 Fig. 1 is a schematic structural diagram of a modulation module in a signal modulation and demodulation system of a digital isolator according to an embodiment of the utility model;

[0026] Figure 6 Fig. 1 is a schematic structural diagram of a modulation module in a signal modulation and demodulation system of a digital isolator according to an embodiment of the utility model;

[0027] Figure 7 Fig. 1 is a schematic structural diagram of a modulation module in a signal modulation and demodulation system of a digital isolator according to an embodiment of the utility model;

[0028] Figure 8 Fig. 1 is a schematic structural diagram of a modulation module in a signal modulation and demodulation system of a digital isolator according to an embodiment of the utility model;

[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, first modulation node; 14, second modulation node; S2, second switch;

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

[0033] To make the technical content of the utility model, the purpose and effect realized are clear, the following will be explained in combination with the embodiment and the drawings.

[0034] Embodiment one

[0035] Please refer to Figure 1 and Figure 2 , the embodiment provides a kind of signal modulation and demodulation system of digital isolator.

[0036] As Figure 1 Shown, the signal modulation and demodulation 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, second switch S2, first modulation node 13, inverter and second modulation node 14;As Figure 2 Shown, the second modulation node 14 includes coupling inductance, second MOS tube and output end;The second switch S2 is a MOS switch tube, preferably the second MOS tube and the second switch are P-channel MOS tube.

[0039] The pulse signal output end 11 and the signal input end 2 are connected with the first modulation node 13 respectively by the first switch S1;The output end of the first modulation node 13 is connected with the gate of the second switch S2 by inverter, the source of the second switch S2 is connected with the primary side of the coupling inductance and the drain of the second MOS tube respectively;The drain of the second switch S2 is also connected with the primary side of the coupling inductance and the drain of the second MOS tube respectively;The gate of the second MOS tube is connected with the RF signal output end;The secondary side of the coupling inductance is connected with the output end.

[0040] In the embodiment, 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 INwhether the primary modulation signal can be obtained by the primary modulation at the primary modulation node.

[0041] The second switch S2 is configured to be in the on or off state controlled by the signal flowing out of the primary modulation node, so as to control whether the RF signal output by the RF signal output end and the signal flowing out of the primary modulation node can be secondarily modulated at the secondary modulation node to obtain the composite modulation signal. Specifically, if the signal output by the primary modulation node is a low-level signal TX IN , which is not subjected to primary modulation, the signal is inverted to a high-level signal by the inverter and then reaches the gate of the second switch S2, so that the second switch S2 is turned on. At this time, the second switch S2 is equivalent to a resistor, and the AC signals at the two nodes of the drain and the source of the second switch S2 are short-circuited, so that the RF signal is difficult to reach the coupling inductor and cannot be secondarily modulated; if the signal output by the primary modulation node to the gate of the second switch S2 is a primary modulation signal obtained by primary modulation, that is, a non-level signal TX IN , the level of the signal is inverted by the inverter and then reaches the gate of the second switch S2, so that the second switch S2 is switched to the off state, and the RF signal can reach the coupling inductor to be secondarily modulated with the primary modulation signal.

[0042] The primary modulation node is configured to, when the pulse signal output by the pulse signal output end can reach, perform a first signal modulation process, that is, a primary modulation process, together with the level signal TX IN output by the signal input end, to obtain a primary modulation signal and output the primary modulation signal.

[0043] The secondary modulation node is configured to work controlled by the off state of the second switch S2 to perform a mixing modulation process, that is, a secondary modulation process, on the RF signal output by the RF signal output end together with the primary modulation signal, to obtain a composite modulation signal and then transmit the composite modulation signal.

[0044] Specifically, the secondary modulation node is essentially a gain mixing circuit having both gain and mixing functions. The secondary modulation node cooperates with the second switch S2 to realize mixed modulation, that is, secondary modulation, on the primary modulation signal and the RF signal subjected to gain processing, to obtain a composite modulation signal.

[0045] In some specific embodiments of the embodiment, as Figure 2As shown, the secondary modulation node specifically comprises two groups of coupled inductors, two second MOS tubes and an output end; one group of coupled inductors is composed of two inductors which are oppositely arranged and can generate electromagnetic coupling reaction; the two groups of coupled inductors are connected in series; after the two groups of coupled inductors are connected in series, the two terminals located at the secondary side are respectively connected with the output end to respectively output "secondary modulation signal (negative polarity)" and "secondary modulation signal (positive polarity)"; the two terminals located at the primary side are respectively connected with the source and the drain of the second switch S2; specifically, the primary side terminal corresponding to the terminal outputting "secondary modulation signal (negative polarity)" is connected with the source of the second switch S2, and the primary side terminal corresponding to the terminal outputting "secondary modulation signal (positive polarity)" is connected with the drain of the second switch S2. Figure 2 the primary side terminal corresponding to the terminal outputting "secondary modulation signal (negative polarity)", is connected with the source of the second switch S2, and Figure 2 the primary side terminal corresponding to the terminal outputting "secondary modulation signal (positive polarity)", is connected with the drain of the second switch S2; the source of the second switch S2 is also connected with the drain of one of the second MOS tubes in the secondary modulation node, the gate of the second MOS tube is connected with the positive polarity output of the RF signal output end (i.e. "RF signal (positive polarity)" in the figure), and the source of the second MOS tube is grounded; the drain of the second switch S2 is also connected with the drain of another second MOS tube in the secondary modulation node, the gate of the M second MOS tube is connected with the negative polarity output of the RF signal output end (i.e. "RF signal (negative polarity)" in the figure), and the source of the second MOS tube is grounded. It can be seen that the structure of the secondary modulation node has the characteristics of simple structure and easy implementation.

[0046] It can be understood that the secondary modulation node described in the embodiment not only has the function of gain amplification of high frequency RF signal, but also can mix the high frequency RF signal after gain amplification processing with the local oscillation signal (i.e. the primary modulation signal of the embodiment) to realize the function of secondary mixing modulation. Specifically, when the second switch S2 is turned on because the signal flowing out of the primary modulation node is a low level signal TX IN (i.e. without primary modulation), the circuit of the secondary modulation node will be disconnected due to the short circuit effect of the second switch S2, and cannot provide the function of gain amplification, at this time, the output end of the secondary modulation node has no signal output or can only output a very small signal; when the second switch S2 is turned off because the signal flowing out of the primary modulation node is a high level primary modulation signal (i.e. after primary modulation), the circuit of the secondary modulation node will be turned on (the drain of the second MOS tube to the coupled inductor is turned 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, then the output end of the secondary modulation node can output a stronger signal, i.e. output a composite modulation signal.

[0047] The working principle of the signal modulation and demodulation system described in the embodiment is as follows:

[0048] At the transmitting side of the digital isolator, a signal input end inputs a high / low level signal TX IN to a modulation module; the signal TX IN The first switch S1 in the modulation module can be controlled to be in an on state or an off state, so as to determine whether the pulse signal output end outputs a pulse signal to the first modulation node, and further determine whether the signal TX IN is modulated by the first modulation node to obtain an initial modulation signal. Then, the signal of the first modulation node reaches the gate of the second switch S2 through an inverter; if the signal is a low level signal TX IN , i.e., not modulated by the first modulation node, the second switch S2 is in an on state after the high level signal is inverted by the inverter, the second switch S2 in the on state is equivalent to a resistance, and the node connected by the drain and the source of the second switch S2 is short-circuited, so that the RF signal output by the RF signal output end cannot reach the primary side of the coupling inductor in the second modulation node, i.e., the second modulation cannot be performed; if the signal of the first modulation node is a high level initial modulation signal, the second switch S2 is switched to an off state after the low level signal is inverted by the inverter, the nodes connected by the drain and the source of the second switch S2 are all in an on state, the RF signal can reach the primary side of the coupling inductor from the drain of the second MOS tube, at the same time, the primary modulation signal also reaches the primary side of the coupling inductor in the second modulation node through the second switch S2, and the two are modulated by the second modulation node to obtain a composite modulation signal, which is output to the transmitting unit through the output end of the second modulation node, and then is wirelessly transmitted to the receiving side of the digital isolator.

[0049] In some specific embodiments of the present embodiment, as shown in Figure 3 , the pulse signal output end can be an OSC unit, i.e., an oscillator, which is specifically configured to generate a stable pulse signal; or can be a clock unit inside the digital isolator, i.e., directly using an internal existing clock signal (which belongs to a kind of pulse signal).

[0050] In still some specific embodiments of the present embodiment, as shown in Figure 3 , the RF signal output end can be a VCO unit, i.e., a voltage controlled oscillator. The VCO unit is configured to generate a required RF signal (such as a 60G sine wave signal).

[0051] Compared with the signal modulation and demodulation system using the traditional OOK modulation and demodulation mode, the signal modulation and demodulation system of the digital isolator provided by the present embodiment realizes precise two-stage modulation control by setting two-stage switches in the modulation module, so as to significantly improve the signal modulation precision of the modulation module in the digital isolator; at the same time, the structural design of the signal modulation and demodulation system also has the advantages of simplicity and easy implementation.

[0052] Embodiment Two

[0053] For reference Figure 4 , this embodiment is based on Embodiment One or Embodiment Two and further extends the signal modulation and demodulation system.

[0054] 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 at the sending side of the digital isolator, and the demodulation module is located at the receiving side of the digital isolator.

[0055] 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, and 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.

[0056] In some specific embodiments of this embodiment, as shown in Figure 4 , 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.

[0057] The LNA unit, i.e., a low noise amplifier, is configured to perform signal strength enhancement, noise reduction, and impedance matching processing on the composite modulation signal to amplify the composite modulation signal.

[0058] The ENV unit, i.e., an envelope detector, is configured to demodulate the initial modulation signal from the composite modulation signal after amplification processing.

[0059] 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 integration operation on the signal to demodulate the analog original signal.

[0060] The driving unit is configured to convert the analog original signal output by the integrator into the high / low level signal TX IN input by the signal input end.

[0061] In this embodiment, for the demodulation module at the receiving side, a two-stage demodulation mode corresponding to the modulation module is adopted to demodulate the original high / low level signal TX IN input by the signal input end. 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 then demodulates the original high / low level signal TXIN .

[0062] As shown in Figure 5 , which shows the signal waveforms of important nodes in the signal modulation and demodulation system of the embodiment. As can be seen from Figure 5 , 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 in the figure as "TX input"; when the continuous signal is high level, the signal of the first modulation node is a plurality of pulses, and the high level on the pulse will turn on the gain mixing circuit of the second modulation node, so that the second modulation node works and can output RF signal; when the continuous signal is low level, the signal of the first modulation node is always low level, and the second modulation node does not work and cannot output RF signal.

[0063] It can be understood that the decoding module of the receiving side of the signal modulation and demodulation system provided by the embodiment is configured to adopt the second 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, it is ensured that the signal modulation and demodulation system of the digital isolator can normally carry out signal modulation work in the second modulation and demodulation mode, realize signal isolation transmission of the digital isolator, and at the same time improve the precision of signal modulation and demodulation.

[0064] It should be noted that the decoding module in the signal modulation and demodulation system of the digital isolator belongs to the working mode of passively accepting composite modulation signal and then modulating, that is, it 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 of the signal modulation and demodulation system of the digital isolator provided by the embodiment will not increase the system power consumption, that is, compared with the existing modulation system, the power consumption will not change greatly.

[0065] Embodiment Three

[0066] Please refer to Figure 1 , Figure 2 , Figure 3 and Figure 6 (a)-(c), which are further extended based on any of the above embodiments, and specifically describe the newly added second switch control in the modulation module.

[0067] In this embodiment, please refer to Figure 1 and Figure 2 , the first switch S1 located in the modulation module in the signal modulation and demodulation system of the digital isolator is specifically configured to be in the on state when the level signal TX IN input by the signal input end 2 is a high level signal; when the level signal TXIN If the signal input end 2 inputs a high level signal, the first switch S1 is turned on.

[0068] It can be understood that when the first switch S1 is turned on due to a high level signal, the pulse signal output by the pulse signal output end 11 (corresponding to the OSC unit as shown in Figure 3 ) 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 the pulse signal together with the level signal TX IN input by the signal input end 2 to obtain an initial modulation signal and output; when the first switch S1 is turned off due to a low level signal, the pulse signal output by the pulse signal output end 11 (corresponding to the OSC unit as shown in Figure 3 ) will not be able to reach the primary modulation node 13 via the first switch S1, and the primary modulation node 13 will not perform primary modulation and output the level signal TX IN input by the signal input end 2, i.e., a low level signal.

[0069] In the embodiment, the first switch S1 can have the following three specific implementations:

[0070] As shown in Figure 6 (a), in the first specific implementation, the first switch S1 includes a first MOS tube; preferably a PMOS tube; the gate of the first MOS tube is connected to the signal input end (i.e., TXIN in the figure), the source thereof is connected to the pulse signal output end (i.e., OSC in the figure), and the drain thereof is connected to the primary modulation node.

[0071] It can be understood that in this specific implementation, when the level signal TX IN input by the signal input end to the gate of the first MOS tube is a high level, the first MOS tube will be turned on, the pulse signal will flow in from the source of the first MOS tube and be output to the primary modulation node through the drain, at the same time, the high level signal TX IN will also be output to the primary modulation node through the drain of the first MOS tube; the high level signal TX IN and the pulse signal will be "combined and modulated" into a primary modulation signal after reaching the primary modulation node and then output to the secondary modulation node. Similarly, when the level signal TX IN input by the signal input end to the gate of the first MOS tube is a low level, the first MOS tube will be turned off, the pulse signal will not be able to reach the primary modulation node through the first MOS tube, and only the low level signal TX INThe signal can be output to the first-level modulation node through the drain of the first MOS transistor; at this time, the first-level modulation node cannot perform "combined modulation" processing, and its output to the second-level modulation node is only a low-level signal TX. IN .

[0072] 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.

[0073] 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 "merged and modulated" into a primary modulation signal before being output to the second-level modulation node. 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-level modulation node is only a low-level signal TX. IN .

[0074] 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.

[0075] like Figure 6 As 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; the gate of the NMOS transistor and the gate of the PMOS transistor are connected in parallel using an inverter to provide two complementary control voltages, which are then connected to the signal input terminal (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-level modulation node, and the drains of the two are connected to the pulse signal output terminal (i.e., OSC in the figure).

[0076] It is understood that when the input control signal of the transmission gate (i.e., the signal input to the gates of the NMOS and PMOS transistors) is low, both the NMOS and PMOS transistors are cut off, and the transmission gate is open; when the input control signal is high, both the NMOS and PMOS transistors are turned on, and the transmission gate is turned on. In this specific embodiment, when the level signal TX is input to the transmission gate at the signal input terminal... IN When the signal is high, both the NMOS and PMOS transistors will be turned on, thus turning on the transmission gate. The pulse signal is then output to the first-stage modulation node through the transmission gate. Simultaneously, the high-level signal TX... IN It will also be output to the first-level modulation node through the transmission gate; at the same time, the high-level signal TX arriving at the first-level modulation node will also be 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-level modulation node. Similarly, when the level signal TX is input to the transmission gate at the signal input terminal... IN When the signal is low, both the NMOS and PMOS transistors will be turned off, preventing the pulse signal from reaching the first-level modulation node through the transmission gate. Only the low-level signal TX will be present. IN The signal can be output to the first-level modulation node through the transmission gate; at this time, the first-level modulation node cannot perform "combined modulation" processing, and its output to the second-level modulation node is only a low-level signal TX. IN .

[0077] Compared with the first and second specific embodiments, the third specific embodiment described above has higher response sensitivity (i.e., faster response speed) and greater flexibility and controllability.

[0078] In addition, in this embodiment, the combination of an inverter and a second switch S2 in the modulation module of the signal modulation and demodulation system of the digital isolator is specifically configured such that when the output of the first-level modulation node is a low-level signal, the second switch S2 is controlled to be in the conducting state; when the output of the first-level modulation node is a high-level signal, the second switch S2 is controlled to be in the disconnected state.

[0079] It can be understood that the second switch S2 is controlled by the output signal of the first-level modulation node. Combined with the above description of the first switch S1, it can be known that the output of the first-level modulation node is a low-level signal TX. IN Or it could be the initial modulation signal (manifested as a high level). When the output of the first-level modulation node is a low-level signal TX... IN When the output of the first-stage modulation node is a high-level initial modulation signal, it is inverted by the inverter to a low-level signal and reaches the gate of the second switch S2, turning the second switch S2 on. When the output of the first-stage modulation node is a high-level initial modulation signal, it is inverted by the inverter to a low-level signal and reaches the gate of the second switch S2, turning the second switch S2 off.Figure 2 It can be seen that when the second switch S2 is in the on state, the second switch S2 is equivalent to a resistor, which will short-circuit the AC signal of the nodes at both ends of it. Therefore, the RF signal is difficult to reach the coupling inductor, that is, the line of the secondary modulation node is open and the secondary modulation processing cannot be performed. When the second switch S2 is in the off state, the node of its source and drain is equivalent to an open circuit. Therefore, the RF signal can reach the primary side of the coupling inductor from the drain of the second MOS transistor. That is, the line of the secondary modulation node is on, and the RF signal can reach the secondary modulation node for secondary modulation processing, and output the composite modulation signal to the transmitting unit.

[0080] 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, thereby significantly improving the signal modulation accuracy of the modulation module in the digital isolator; simultaneously, the structural design of the signal modulation and demodulation system also has the advantages of being simple and easy to implement.

[0081] Example 4

[0082] Please refer to 7. This embodiment is based on any of the above embodiments and provides a preferred specific implementation method.

[0083] 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.

[0084] The working principle of the signal modulation and demodulation system of the digital isolator provided in this preferred embodiment is as follows:

[0085] Input high / low level signal TX at signal input terminal 2 IN To modulation module 1; when signal TX IN When the signal is low, the first switch S1 is off, and the pulse signal output by the OSC unit cannot reach the first-level modulation node 13 via the first switch S1. Therefore, the first-level modulation node 13 only outputs the low-level signal TX. IN When signal TX IN When the signal is high, the first switch S1 is in the ON state, and the pulse signal output by the OSC unit can reach the first-level modulation node 13 via the first switch S1. The first-level modulation node 13 then modulates it with the level signal TX input to the signal input terminal. INThe first level modulation is performed together to obtain the initial modulation signal and output. The signal of the first level modulation node 13 reaches the second switch S2 through the inverter. If the signal is a low level signal TX IN , that is, the low level signal without first level modulation 13, the second switch S2 will be turned on, and then the gain mixing circuit of the second level modulation node cannot be turned on and works normally. The RF signal output by the VCO unit cannot be output through the gain mixing circuit. If the signal output by the first level modulation node 13 is the primary modulation signal, the second switch S2 will be switched to the off state after passing through the inverter, and then the gain mixing circuit of the second level modulation node can work normally. 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 through the second switch S2. The gain mixing circuit will perform secondary modulation on the RF signal processed by the gain and the primary modulation signal to obtain the composite modulation signal and output. Then the composite modulation signal is transmitted wirelessly 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.

[0086] It can be seen that the preferred embodiment can realize accurate two-stage modulation control by arranging two-stage switches in the modulation module, and can realize secondary modulation and demodulation in the demodulation module, thereby significantly improving the signal modulation accuracy of the digital isolator. At the same time, the structure design of the signal modulation and demodulation system also has the advantages of simplicity and easy implementation.

[0087] Embodiment five

[0088] 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 connected in sequence. The 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, and details can be referred to the description of the above embodiments.

[0089] The transmitting unit 4 is configured to receive the composite modulation signal output by the second level modulation node and send it to the millimeter wave receiving unit 5 through the isolation band in a wireless manner.

[0090] The receiving unit 5 is configured to receive the composite modulated signal transmitted wirelessly and then transmit to the demodulation module 3.

[0091] In some preferred embodiments of the present embodiment, the digital isolator is a millimeter wave isolator, wherein the transmitting unit comprises a millimeter wave transmitting antenna; and the receiving unit comprises a millimeter wave receiving antenna.

[0092] Optionally, the millimeter wave transmitting antenna and the millimeter wave receiving antenna have a working frequency of 60GHz; the pulse signal output end (such as the OSC unit) and / or the RF signal output end (such as the VCO unit) in the modulation module have a working frequency of 100MHz; and the first switch S1 and / or the second switch have a working speed of 10ns.

[0093] The digital isolator, particularly the millimeter wave isolator, provided by the present embodiment has two-stage switches in the modulation module of the signal modulation and demodulation system to achieve precise two-stage modulation control, and the transmission through the millimeter wave isolation is correspondingly subjected to two-stage modulation and demodulation in the demodulation module, so that the precision of signal modulation in the digital isolator, particularly the millimeter wave isolator, is significantly improved; at the same time, the power consumption of the signal modulation and demodulation system can be obviously reduced, and the energy consumption requirement can be better met; in addition, the structural design of the signal modulation and demodulation system also has the advantages of simple design and easy implementation.

[0094] The above only 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 modem system for a digital isolator, characterized by, The signal modulation system comprises a modulation module and a signal input end; the modulation module comprises a pulse signal output end, an RF signal output end, a first switch, a first-order modulation node, a second switch, an inverter and a second-order modulation node; the second-order modulation node comprises a coupling inductor, a second MOS tube and an output end; the second switch is a MOS switch tube; 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 gate of the second switch through the inverter; the source of the second switch is connected with the primary side of the coupling inductor and the drain of the second MOS tube respectively; the drain of the second switch is connected with the primary side of the coupling inductor and the drain of the second MOS tube respectively; the gate of the second MOS tube is connected with the RF signal output end; the secondary side of the coupling inductor is connected with the output end.

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 in 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 number of the coupling inductors is two groups, and the number of the second MOS tubes is two; two groups of coupling inductors connected in series, the two terminals of the secondary side of the coupling inductors are connected with the output end respectively, and the two terminals of the primary side of the coupling inductors are connected with the source and the drain of the second switch respectively; the sources of the two second MOS tubes are connected with the ground respectively, the gates are connected with the RF signal output end respectively, and the drains are connected with the drain and the source of the second switch respectively.

4. The digital isolator based signal modem system of claim 3, wherein, The second MOS tube and the second switch are both PMOS tubes.

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

6. The digital isolator based signal modem system of claim 1, wherein, The first switch comprises an AND gate circuit; the 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 is connected with the first-order modulation node.

7. The digital isolator based signal modem system of claim 1, wherein, The first switch comprises 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 through an inverter and then connected with the signal input end; the source of the NMOS tube and the source of the PMOS tube are connected and then connected with the first-order modulation node, and the drains are connected and then connected with the pulse signal output end.

8. The digital isolator based signal modem system of claim 1, wherein, The signal modulation 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.

9. A digital isolator characterized by, The signal modulation system comprises a transmitting unit, a receiving unit and the signal modulation system according to any one of claims 1 to 8; 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 comprises a millimeter wave transmitting antenna; the receiving unit comprises a millimeter wave receiving antenna.

Images