A low-power isolated bus-powered MBUS communication interface circuit

Abstract

The invention discloses a low-power isolated bus-powered MBUS communication interface circuit, which belongs to the field of circuit control technology, and includes a rectifier circuit, a constant-current energy storage voltage stabilizing circuit, a buck conversion circuit, a variable-frequency drive push-pull output isolation conversion output circuit, and a device to be powered; the input end of the rectifier circuit is connected to the MBUS bus, the output end of the rectifier circuit is connected to the input end of the constant-current energy storage voltage stabilizing circuit; the output end of the constant-current energy storage voltage stabilizing circuit is connected to the input end of the buck conversion circuit; the output end of the buck conversion circuit is connected to the input end of the variable-frequency drive push-pull output isolation conversion circuit, and the variable-frequency drive push-pull output isolation conversion circuit outputs a voltage signal output by the buck conversion circuit to the device to be powered. The invention can effectively reduce the power consumption of the MBUS communication interface circuit.

Description

Technical Field

[0001] The present invention relates to the technical field of circuit control, and in particular to a low-power consumption isolated bus power supply MBUS communication interface circuit. Background Art

[0002] MBUS is a bus protocol designed specifically for remote data transmission of heat meters. It is an important technology for digital measurement of data transmission and has been widely used in data collection situations for passive contacts (water, electricity, gas, heat meters, buildings, etc.).

[0003] At present, the MBUS bus power supply isolation method used is as follows Figure 1 As shown: The MBUS bus is connected to the TSS721A chip. The STC output pin of the TSS721A chip takes power and inputs it to the voltage regulator. The voltage regulator steps down to 4.4V. The 4.4V voltage is used to power the 4-channel NAND gates. The NAND gates are combined with resistors and capacitors to form an oscillator, and then the output voltage is rectified by a transformer and a diode to provide power to the heat meter.

[0004] However, because the output voltage of the STC pin of the TSS721A chip is only 5.6-6.4V, the conversion loss of the voltage regulator chip and the conversion loss of the isolation transformer will greatly reduce the output efficiency. If 1mA of current is taken from the bus, the power provided to the device will not be greater than 5mW according to the law of conservation of energy. Therefore, the voltage and current provided to the device are low, and the bus loss current is large. In other words, the STC pin also powers the receiving circuit of the TSS721A, thus affecting the stability of the receiving circuit. As a result, the bus power consumption of this circuit is large, the communication stability is poor, and it cannot meet the application of the MBUS bus VMARK (20-42V) range, which limits the application of slave MBUS power supply and reduces the number of slave nodes. Summary of the invention

[0005] The object of the present invention is to provide a low-power consumption isolated bus-powered MBUS communication interface circuit, so as to reduce the bus power consumption of the MBUS communication interface circuit.

[0006] To achieve the above objectives, the present invention adopts a low-power isolated bus power MBUS communication interface circuit, including: a rectifier circuit, a constant current energy storage voltage stabilization circuit, a step-down conversion circuit, a variable frequency drive push-pull output isolation conversion output circuit and a device to be powered;

[0007] The input end of the rectifier circuit is connected to the MBUS bus, and the output end of the rectifier circuit is connected to the input end of the constant current energy storage voltage stabilizing circuit. The constant current energy storage voltage stabilizing circuit converts the voltage signal output by the rectifier circuit into a constant current signal and a stable DC voltage signal.

[0008] The output end of the constant current energy storage voltage stabilizing circuit is connected to the input end of the buck conversion circuit, and the buck conversion circuit converts the DC voltage signal output by the constant current energy storage voltage stabilizing circuit into a 5V voltage;

[0009] The output end of the step-down conversion circuit is connected to the input end of the variable frequency drive push-pull output isolation conversion circuit, and the variable frequency drive push-pull output isolation conversion circuit stabilizes the voltage signal output by the step-down conversion circuit and outputs it to the device to be powered.

[0010] Furthermore, the rectifier circuit is a bridge rectifier composed of diodes, a rectifier bridge composed of triodes, an integrated chip bridge or a rectifier bridge composed of thyristors.

[0011] Furthermore, the constant current energy storage voltage stabilizing circuit is an integrated voltage stabilizing circuit, an operational voltage stabilizing circuit or a transistor voltage stabilizing circuit.

[0012] Furthermore, the transistor-type voltage stabilizing circuit includes a first transistor, a second transistor, an energy storage capacitor and a voltage stabilizing tube, the base of the first transistor is connected to the emitter of the second transistor and then connected to the output end of the rectifier circuit via a resistor R3, and the emitter of the first transistor is connected to the output end of the rectifier circuit;

[0013] The collector of the first transistor is connected to the base of the second transistor, the collector of the first transistor is grounded via resistor R1, the collector of the second transistor is connected to the positive electrode of the energy storage capacitor, the positive electrode of the energy storage capacitor is connected to the negative electrode of the voltage regulator, and the positive electrode of the voltage regulator is connected to the negative electrode of the energy storage capacitor and then grounded.

[0014] Furthermore, the integrated voltage stabilizing circuit includes a constant current source integrated circuit chip, a voltage stabilizing tube and an energy storage capacitor, the input end of the constant current source integrated circuit chip is connected to the output end of the rectifier circuit, the output end of the constant current source integrated circuit chip is connected to the energy storage capacitor, and the energy storage capacitor is connected in parallel with the voltage stabilizing tube.

[0015] Furthermore, the operational voltage stabilizing circuit includes an integrated operational amplifier, a transistor, a resistor, a voltage regulator and an energy storage capacitor; the positive input of the operational amplifier is connected to the reference voltage, the output of the operational amplifier is connected to the base of the transistor, the reverse input of the operational amplifier is connected to the emitter of the transistor and then connected to the resistor R110, the resistor R110 is connected to VCC, the collector of the transistor is connected to the positive electrode of the energy storage capacitor, the negative electrode of the energy storage capacitor is connected to the positive electrode of the voltage regulator and then grounded, and the negative electrode of the voltage regulator is connected to the positive electrode of the energy storage capacitor.

[0016] Furthermore, the step-down conversion circuit includes a voltage stabilizer U2, the input end of the voltage stabilizer U2 is connected to the output end of the constant current energy storage voltage stabilizer circuit, and the voltage stabilizer U2 converts the 20-36V voltage and 1mA current output by the constant current energy storage voltage stabilizer circuit into 5V voltage and 35mW power to provide electrical energy for the device to be powered.

[0017] Furthermore, the voltage regulator U2 is a buck regulator or a linear regulator.

[0018] Furthermore, the variable frequency drive push-pull output isolation conversion circuit includes a driver U4 and a high-frequency transformer, the output end of the driver U4 is connected to the high-frequency transformer to output a switch signal to drive the primary of the high-frequency transformer, and the secondary of the high-frequency transformer pushes the output voltage signal through the intermediate tap;

[0019] The secondary output end of the high-frequency transformer is connected to the positive electrode of the diode D3 and the positive electrode of the diode D5 respectively, the negative electrode of the diode D3 and the negative electrode of the diode D5 are connected and then connected to the filter capacitor C3, and the filter capacitor C3 is connected in parallel with the voltage regulator tube D8 and the resistor R5 in turn;

[0020] The cathode of the voltage regulator tube D8 is connected to the device to be powered as a voltage stabilization output terminal.

[0021] Compared with the prior art, the present invention has the following technical effects: the present invention improves the MBUS slave interface circuit. After the slave device MBUS bus takes power, the voltage signal is reduced by the rectifier circuit, the constant current energy storage voltage regulator circuit and the step-down conversion circuit in sequence, thereby expanding the range of bus power supply and reducing the power consumption of the bus. The frequency conversion drive push-pull output isolation conversion output circuit has the characteristics of high efficiency conversion, electrical isolation, and resistance to external interference, further reducing the power consumption of the bus. At the same time, the voltage signal output by the rectifier circuit is converted into a constant current signal and a stable DC voltage signal through the constant current energy storage voltage regulator circuit, so that the bus current output is stable to effectively ensure the stability of communication, and the slave devices do not affect each other. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings:

[0023] Figure 1 It is a schematic diagram of the existing MBUS bus power supply isolation structure mentioned in the background technology part;

[0024] Figure 2 This is a schematic diagram of the principle of the frequency conversion drive push-pull output isolation conversion output circuit;

[0025] Figure 3 It is a structural schematic diagram of a rectifier circuit, a constant current energy storage voltage stabilization circuit, and a step-down conversion circuit;

[0026] Figure 4 It is a structural diagram of a frequency conversion drive push-pull output isolation conversion output circuit. DETAILED DESCRIPTION

[0027] In order to further illustrate the features of the present invention, please refer to the following detailed description and drawings of the present invention. The drawings are for reference and illustration only and are not intended to limit the scope of protection of the present invention.

[0028] like Figure 2 As shown, this embodiment provides a low-power isolated bus power MBUS communication interface circuit, including a rectifier circuit 1, a constant current energy storage voltage stabilization circuit 2, a buck conversion circuit 3, a variable frequency drive push-pull output isolation conversion output circuit and a device to be powered;

[0029] The input end of the rectifier circuit 1 is connected to the MBUS bus, and the output end of the rectifier circuit 1 is connected to the input end of the constant current energy storage voltage stabilizing circuit 2. The constant current energy storage voltage stabilizing circuit 2 converts the voltage signal output by the rectifier circuit 1 into a constant current signal and a stable DC voltage signal.

[0030] The output end of the constant current energy storage voltage stabilizing circuit 2 is connected to the input end of the buck conversion circuit 3, and the buck conversion circuit 3 converts the DC voltage signal output by the constant current energy storage voltage stabilizing circuit 2 into a 5V voltage signal to provide power drive for the variable frequency drive push-pull output isolation conversion circuit;

[0031] The output end of the step-down conversion circuit 3 is connected to the input end of the variable frequency drive push-pull output isolation conversion circuit, and the variable frequency drive push-pull output isolation conversion circuit stabilizes the voltage signal output by the step-down conversion circuit 3 and outputs it to the device to be powered.

[0032] like Figure 1 , Figure 2 As shown in the figure, this solution can provide power of 27-48.5mW to the load device when the bus consumes 1.5mA current, effectively improving the load capacity. The communication stability is strong, and the abnormality of a single node does not affect the communication of other nodes. It has low power consumption and increases the number of slave nodes;

[0033] It can meet the application range of MBUS bus VMARK (20-42V) and solve the application limitations of slave MBUS power supply.

[0034] Furthermore, the rectifier circuit 1 is a bridge rectifier composed of diodes, a rectifier bridge composed of transistors, an integrated chip bridge or a rectifier bridge composed of thyristors.

[0035] See also Figure 3As shown, the rectifier circuit 1 in this embodiment is composed of four diodes to form a bridge rectifier circuit 1, and the DC voltage output terminal of the rectifier circuit 1 is connected to the input of the constant current energy storage voltage stabilizing circuit 2. MBUS1 is connected to the pin 3 of the diode D2, MBUS2 is connected to the pin 3 of D1, the pin 1 of D2 and the pin 1 of D1 are grounded, and the pin 2 of D2 and the pin 2 of D1 are connected as the output terminal to form a full-wave rectification, so that the non-polarity MBUS bus signal connected to the slave is rectified into a 20-42V DC voltage signal.

[0036] Furthermore, the constant current energy storage voltage stabilizing circuit is an integrated voltage stabilizing circuit, an operational voltage stabilizing circuit or a transistor voltage stabilizing circuit.

[0037] Among them, see Figure 3 As shown, the transistor-type voltage stabilizing circuit includes a first transistor Q1, a second transistor Q2, an energy storage capacitor C19 and a voltage stabilizing tube D9, the base of the second transistor Q2 is connected to the collector of the first transistor Q1 and then connected in series with a resistor R1, the resistor R1 is grounded, the base of the first transistor Q1 is connected to the emitter of the second transistor Q2 and then connected in series with a resistor R3, the resistor R3 is connected to the output end of the rectifier circuit 1, and the emitter of the first transistor Q1 is connected to the output end of the rectifier circuit 1;

[0038] The collector of the second transistor Q2 is connected to the positive electrode of the energy storage capacitor C19, one end of the capacitor C25 and the negative electrode of the voltage regulator D9 in sequence. The negative electrode of the energy storage capacitor C19, the other end of the capacitor C25 and the positive electrode of the voltage regulator D9 are connected and grounded.

[0039] Furthermore, the integrated voltage stabilizing circuit includes a constant current source integrated circuit chip, a voltage stabilizing tube and an energy storage capacitor, wherein the input end of the constant current source integrated circuit chip is connected to the output end of the rectifier circuit, the output end of the constant current source integrated circuit chip is connected to the positive electrode of the energy storage capacitor, the positive electrode of the energy storage capacitor is connected to the negative electrode of the voltage stabilizing tube, and the negative electrode of the energy storage capacitor is connected to the positive electrode of the voltage stabilizing tube and then grounded. Among them, the constant current source integrated circuit chip can be selected as LM334.

[0040] Furthermore, the operational voltage stabilization circuit includes an integrated operational amplifier U13, a transistor Q19, a resistor R110, a resistor R111, a resistor R112, an energy storage capacitor C62 and a voltage regulator tube D23; one end of the resistor R111 is connected to the positive input terminal of the operational amplifier U13, and the other end is connected to the power supply, one end of the resistor R112 is connected to the positive input terminal of the operational amplifier U13, and the other end is grounded; one end of the resistor R111 and one end of the resistor R112 are connected to the positive input terminal of the operational amplifier U13 to provide a reference voltage for the operational amplifier. The reference voltage is (R112 / (R111+R112))×VCC. The reverse input terminal of the operational amplifier U13 is connected to the emitter of the transistor Q19 and then connected in series with the resistor R110. The resistor R110 is connected to VCC to generate an input voltage. The output terminal of the operational amplifier U13 is connected to the base of the transistor Q19. The collector of the transistor Q19 is connected to the positive electrode of the energy storage capacitor C62. The positive electrode of the energy storage capacitor C62 is connected to the negative electrode of the voltage regulator tube D23. The negative electrode of the energy storage capacitor C62 is connected to the positive electrode of the voltage regulator tube D23 and then grounded.

[0041] Among them, the operational amplifier U13 and the transistor Q19 and the resistor R110 form a constant current source circuit. The constant current output value is determined by the virtual short input characteristics of the operational amplifier's in-phase terminal and the reverse terminal. The voltage at the in-phase terminal is equal to the voltage value at the reverse terminal. Therefore, the voltage difference across the resistor R110 is determined, and the current value flowing through the resistor R110 is known. The output of the operational amplifier turns on the transistor Q19, so that the current generated by the resistor R110 is turned on by the transistor Q19 to make the collector output a constant current. The collector outputs a constant current through the energy storage capacitor C62 for current energy storage, and then the energy storage capacitor C62 performs current energy storage and outputs it through the voltage regulator tube D23.

[0042] The constant current energy storage voltage stabilizing circuit in this embodiment can make the output voltage signal of the rectifier circuit output a constant current of 1mA and a stable DC voltage signal of 20-36V through the constant current energy storage voltage stabilizing circuit; the bus current output is stable and effectively ensures the stability of communication and the lack of mutual influence between slave devices, which can meet the bus power supply needs of various devices. Taking the transistor type voltage stabilizing circuit as an example, it should be noted that in the transistor type voltage stabilizing circuit, the rectifier circuit 1 outputs a voltage signal of 20-42V, through the resistor R2, because the Ube voltage difference of the second transistor Q2, that is, the voltage difference between the base and the emitter of the transistor, is 0.7V, and the resistor R2 is connected in parallel at both ends of Ube of the second transistor Q2, it can be concluded that the output current = Ube / R2, the first transistor Q1 is the constant current feedback output by the second transistor Q2, when the load current is large, the voltage difference across R2 becomes larger, and the collector current of the first transistor Q1 The collector voltage of the first transistor Q1 increases, which reduces the Ube voltage of the second transistor Q2 and the collector current. Therefore, the first transistor Q1 has a negative feedback effect, which makes the output current constant. The collector of the second transistor Q2 outputs a constant current and stores current energy through the energy storage capacitor C19. The collector of the second transistor Q2 outputs a constant current and outputs a 20-36V voltage stabilized by the selected voltage regulator D9 to provide a suitable and stable voltage for the step-down circuit. This circuit stabilizes the bus current output and effectively ensures the stability of communication and that the slave devices do not affect each other.

[0043] See also Figure 3 As shown, the buck conversion circuit 3 includes a voltage stabilizer U2 (which can be a buck type voltage stabilizer or a linear voltage stabilizer), the output end of the constant current energy storage voltage stabilizing circuit 2 is connected to the VIN end of the voltage stabilizer U2, the EN end of the voltage stabilizer U2 is connected to one end of the capacitor C24, the other end of the resistor R29 is respectively connected to one end of the capacitor C24 and connected to one end of the resistor R30, the RT end of the voltage stabilizer U2 is connected to one end of the resistor R10, and the other end of the resistor R10, the other end of the capacitor C24 and the other end of the resistor R30 are all grounded;

[0044] The LX end of the voltage regulator U2 is connected in series with the inductor L1 and then connected to one end of the capacitor C10, one end of the resistor R20 and one end of the resistor R22 in sequence. The GND end of the voltage regulator U2 is connected to the other end of the capacitor C10 and then grounded. The other end of the resistor R20 is connected in series with the capacitor C11 and then grounded. The VOUT end of the voltage regulator U2 is connected to the other end of the resistor R22. The other end of the resistor R22 is connected in series with the resistor R15 and then grounded. One end of the resistor R22 is connected to one end of the capacitor C14, and the capacitors C5 and C4 are connected in parallel with the capacitor C14 in sequence and then grounded.

[0045] It should be noted that the buck converter circuit U2 is a current modulation mode buck switching regulator. The constant current energy storage voltage regulator circuit outputs a current of 1.5mA, and a voltage of 20-36V enters the input terminal of the device U2. The voltage is reduced by current modulation of the device U2, and the synchronous switching frequency is set by the resistor R10. The resistor R15 is the feedback resistor of the device U2. The output voltage of U2 is calculated by VDD=(R22 / R15+1)×0.8. The buck converter circuit converts the output current of the constant current energy storage voltage regulator circuit 2 of 1.5mA and the output voltage of 20-36V into a DC voltage signal of 27-48.5mW through the buck converter circuit 3 through the low power buck converter device U2, and the efficiency reaches more than 85%. The micro-ampere level quiescent current effectively reduces the power consumption of the bus.

[0046] See also Figure 4 As shown, the variable frequency drive push-pull output isolation conversion circuit includes a driver U4 and a high-frequency transformer. The GND terminal of the driver U4 is grounded, and the D1 terminal, D2 terminal and VCC terminal of the driver U4 are all connected to the primary coil of the high-frequency transformer. The VCC terminal of the driver U4 is connected in series with the capacitor C16 and then grounded. The secondary output terminal of the high-frequency transformer is respectively connected to the positive electrode of the diode D3 and the positive electrode of the diode D5. The cathode of the diode D3 and the cathode of the diode D5 are connected and then connected to the filter capacitor C3. The filter capacitor C3 is connected in parallel with the voltage regulator D8 and the resistor R5 in turn; the cathode of the voltage regulator D8 is connected to the device to be powered as a voltage-stabilized output terminal.

[0047] The output end of driver U4 is connected to the high-frequency transformer to output a switching signal to drive the primary of the high-frequency transformer. The secondary of the high-frequency transformer pushes the output through the middle tap, rectified by diodes D3 and D5, filtered by capacitor C13, and the voltage-stabilized output of Zener diode D8 is provided to power the equipment.

[0048] It should be noted that the output voltage of the step-down conversion circuit is provided to the driver U4, and the U4 device generates a switching frequency of 360KHZ-410KHZ and outputs it through the D1 and D2 ports of the U4 device. The frequency phase difference between the outputs of the D1 and D2 ports is 180°, and the primary of the high-frequency transformer is pushed-pull driven. The secondary of the high-frequency transformer outputs a pulse signal of the same frequency and amplitude through the middle tap, which is rectified by diodes D3 and D5, filtered by capacitor C13, and the voltage-stabilized output of the Zener diode D8 is provided to power the equipment.

[0049] This circuit makes the push-pull drive high-frequency transformer have high conversion efficiency, electrical isolation and anti-interference. The push-pull circuit has the advantages of complementarity, low loss and high utilization of transformer core, which can improve the conversion efficiency and load capacity of the transformer. When the bus power supply Imark=1.5mA, it can provide 5.4-9.5mA effective current for the device, effectively meeting the use range of MBUS bus VMARK=20.8-42V and Imark<1.5mA, reducing bus power consumption and anti-interference.

[0050] It should be noted that the variable frequency drive push-pull output isolation conversion circuit in this embodiment can replace the primary coil of the oscillator drive transformer composed of a timer device, a resistor network, and a capacitor network, and the secondary coil output is rectified by (a transistor or an integrated chip or a thyristor), a capacitor network, and a voltage regulator diode to form an isolation conversion and voltage stabilization output circuit.

[0051] Alternatively, an oscillator driven transformer primary coil is composed of a resistor network, a capacitor network, and a transistor. The secondary coil output is rectified (by a transistor or an integrated chip or a thyristor) and filtered by a capacitor. A voltage regulator diode is used to stabilize the voltage and form an isolated conversion and voltage stabilization output circuit.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A low-power isolated bus-powered MBUS communication interface circuit, characterized in that: include: Rectification circuit, constant current energy storage voltage stabilization circuit, step-down conversion circuit, variable frequency drive push-pull output isolation conversion output circuit and equipment to be powered; The input end of the rectifier circuit is connected to the MBUS bus, and the output end of the rectifier circuit is connected to the input end of the constant current energy storage voltage stabilizing circuit. The constant current energy storage voltage stabilizing circuit converts the voltage signal output by the rectifier circuit into a constant current signal and a stable DC voltage signal. The output end of the constant current energy storage voltage stabilizing circuit is connected to the input end of the buck conversion circuit, and the buck conversion circuit converts the DC voltage signal output by the constant current energy storage voltage stabilizing circuit into a 5V voltage; The output end of the step-down conversion circuit is connected to the input end of the variable frequency drive push-pull output isolation conversion circuit, and the variable frequency drive push-pull output isolation conversion circuit stabilizes the voltage signal output by the step-down conversion circuit and outputs it to the device to be powered; The constant current energy storage voltage stabilizing circuit adopts an operational voltage stabilizing circuit, which includes an integrated operational amplifier U13, a transistor Q19, a resistor R110, a resistor R111, a resistor R112, an energy storage capacitor C62 and a voltage regulator D23; one end of the resistor R111 is connected to the positive input end of the operational amplifier U13, and the other end is connected to the power supply, one end of the resistor R112 is connected to the positive input end of the operational amplifier U13, and the other end is grounded; one end of the resistor R111 and one end of the resistor R112 are connected to the positive input end of the operational amplifier U13 to form an operational amplifier. The amplifier provides a reference voltage, which is (R112 / (R111+R112))×VCC. The reverse input terminal of the operational amplifier U13 is connected to the emitter of the transistor Q19 and then connected in series with the resistor R110. The resistor R110 is connected to VCC to generate an input voltage. The output terminal of the operational amplifier U13 is connected to the base of the transistor Q19. The collector of the transistor Q19 is connected to the positive electrode of the energy storage capacitor C62. The positive electrode of the energy storage capacitor C62 is connected to the negative electrode of the voltage regulator tube D23. The negative electrode of the energy storage capacitor C62 is connected to the positive electrode of the voltage regulator tube D23 and then grounded. The step-down conversion circuit includes a voltage stabilizer U2, the input end of the voltage stabilizer U2 is connected to the output end of the constant current energy storage voltage stabilizer circuit, and the voltage stabilizer U2 converts the 20-36V voltage and 1mA current output by the constant current energy storage voltage stabilizer circuit into 5V voltage and 35mW power to provide power for the device to be powered; The variable frequency drive push-pull output isolation conversion circuit includes a driver U4 and a high-frequency transformer. The output end of the driver U4 is connected to the high-frequency transformer to output a switch signal to drive the primary of the high-frequency transformer. The secondary of the high-frequency transformer pushes the output voltage signal through the middle tap. The secondary output end of the high-frequency transformer is connected to the positive electrode of the diode D3 and the positive electrode of the diode D5 respectively, the negative electrode of the diode D3 and the negative electrode of the diode D5 are connected and then connected to the filter capacitor C3, and the filter capacitor C3 is connected in parallel with the voltage regulator tube D8 and the resistor R5 in turn; The cathode of the voltage regulator tube D8 is connected to the device to be powered as a voltage stabilization output terminal.

2. The low-power isolated bus-powered MBUS communication interface circuit according to claim 1, characterized in that: The rectifier circuit is a bridge rectifier composed of diodes, a rectifier bridge composed of triodes, an integrated chip bridge or a rectifier bridge composed of thyristors.

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