Rectifier bridge power supply circuit of power supply system and Ethernet rectifier bridge power supply system

Abstract

The invention provides a rectifier bridge power supply circuit of a power supply system. The rectifier bridge power supply circuit comprises a pre-stage protection circuit electrically connected with a first power supply and a second power supply of an active Ethernet power supply system respectively; the first power supply path is electrically connected with the first power supply; the second power supply path is electrically connected with the second power supply; wherein when the first power supply encounters a surge, the first power supply access triggers a first bidirectional transient voltage suppression diode in the pre-stage protection circuit to be conducted and work, and the surge is discharged; and / or, when the second power supply encounters a surge, the second power supply path triggers a second bidirectional transient voltage suppression diode of the pre-stage protection circuit to be conducted and work, and the surge is discharged. According to the scheme, the on resistance of the rectifier bridge power supply circuit of the power supply system can be reduced, and the switching speed, the thermal stability and the surge protection capability are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of rectifier bridge power supply, and particularly to a rectifier bridge power supply circuit for a power supply system and an Ethernet rectifier bridge power supply system. Background Art

[0002] With the development of modern power electronic devices towards higher power density, smaller volume and lower energy consumption. In the field of power electronics, especially in the application of full-bridge rectifier circuits, traditional silicon-based diode full-bridge rectifiers have gradually revealed some limitations. These challenges mainly include a relatively high forward voltage drop, a long reverse recovery time, poor temperature characteristics, and a lack of effective surge protection. The relatively high forward voltage drop: ordinary silicon diodes have a relatively high forward voltage drop (usually about 0.7V), which leads to a large conduction loss, especially under high-current conditions. The long reverse recovery time: when the current switches from one direction to another, the silicon diode needs a certain time to turn off, and this process is called reverse recovery. The long reverse recovery time not only increases the switching loss but may also cause electromagnetic interference (EMI) problems. Poor temperature sensitivity: the performance parameters of silicon diodes such as the forward voltage drop increase with the increase of temperature, and the on-resistance increases, affecting the stability and reliability of the system. Lack of surge protection: traditional rectifier bridges are vulnerable to voltage mutations or surges, and are prone to component damage, especially in harsh working environments. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to provide a rectifier bridge power supply circuit for a power supply system and an Ethernet rectifier bridge power supply system, which can reduce the on-resistance of the rectifier bridge power supply circuit of the power supply system, improve the switching speed, thermal stability and surge protection ability.

[0004] To solve the above technical problems, the technical solution of the present invention is as follows:

[0005] A rectifier bridge power supply circuit for a power supply system, comprising:

[0006] A pre-stage protection circuit electrically connected to the first power supply and the second power supply of the active Ethernet power supply system respectively:

[0007] A first power supply path electrically connected to the first power supply;

[0008] A second power supply path electrically connected to the second power supply;

[0009] Wherein, when a surge occurs in the first power supply, the first power supply path triggers the first bidirectional transient voltage suppression diode in the pre-stage protection circuit to conduct and work, discharging the surge; and / or, when a surge occurs in the second power supply, the second power supply path triggers the second bidirectional transient voltage suppression diode in the pre-stage protection circuit to conduct and work, discharging the surge.

[0010] Optionally, the pre-stage protection circuit includes:

[0011] A first variable resistor electrically connected to the first pole of the first power supply;

[0012] A second variable resistor electrically connected to the second pole of the first power supply;

[0013] A first bidirectional transient voltage suppression diode, one end of which is electrically connected to the first pole of the first power supply, and the other end of which is electrically connected to the second pole of the first power supply;

[0014] A third variable resistor electrically connected to the first pole of the second power supply;

[0015] A fourth variable resistor electrically connected to the second pole of the second power supply;

[0016] A second bidirectional transient voltage suppression diode, one end of which is electrically connected to the first pole of the second power supply, and the other end of which is electrically connected to the second pole of the second power supply;

[0017] Wherein, when a surge occurs in the first power supply, the first bidirectional transient voltage suppression diode conducts to stop the first power supply from supplying power to the first power supply path; when a surge occurs in the second power supply, the second bidirectional transient voltage suppression diode conducts to stop the second power supply from supplying power to the second power supply path.

[0018] Optionally, the pre-stage protection circuit further includes:

[0019] A self-resetting fuse electrically connected to the first variable resistor, the second variable resistor, the third variable resistor, and the fourth variable resistor; the self-resetting fuse is connected to the ground;

[0020] Wherein, by setting the first variable resistor, the second variable resistor, the third variable resistor, and the fourth variable resistor, the current in the pre-stage protection circuit is controlled, and the self-resetting fuse is used to increase the resistance in the pre-stage protection circuit when the current reaches a preset value.

[0021] Optionally, the first power supply path includes:

[0022] A first Schottky diode electrically connected to the first pole of the first power supply;

[0023] A first forward power supply loop electrically connected to the first Schottky diode;

[0024] A second Schottky diode electrically connected to the second pole of the first power supply;

[0025] A first reverse power supply loop electrically connected to the second Schottky diode;

[0026] Wherein, when the first pole of the first power supply is the positive electrode and the second pole is the negative electrode, the first power supply path is powered through the first forward power supply loop, and the first reverse power supply loop is a protection circuit; when the second pole of the first power supply is the positive electrode and the first pole is the negative electrode, the first power supply path is powered through the first reverse power supply loop, and the first forward power supply loop is a protection circuit.

[0027] Optionally, the first forward power supply loop includes:

[0028] A first MOS transistor electrically connected to the first Schottky diode, and the source electrode of the first MOS transistor is electrically connected to the first Schottky diode;

[0029] A first resistor electrically connected to the gate electrode of the first MOS transistor, and the other end of the first resistor is electrically connected to the first pole of the first power supply;

[0030] A second resistor electrically connected to the gate electrode of the first MOS transistor, and the other end of the second resistor is electrically connected to the source electrode of the first MOS transistor;

[0031] A first capacitor electrically connected to the gate electrode of the first MOS transistor, and the other end of the first capacitor is electrically connected to the source electrode of the first MOS transistor;

[0032] A first diode electrically connected to the gate electrode of the first MOS transistor, and the other end of the first diode is electrically connected to the first pole of the first power supply;

[0033] Wherein, the drain electrode of the first MOS transistor is electrically connected to the second pole of the first power supply. When the gate voltage of the first MOS transistor is higher than a preset threshold of the source voltage, the first MOS transistor conducts and works to supply power to the powered device.

[0034] Optionally, the first reverse power supply loop includes:

[0035] A second MOS transistor electrically connected to the second Schottky diode, and the source electrode of the second MOS transistor is electrically connected to the second Schottky diode;

[0036] A third resistor electrically connected to the gate electrode of the second MOS transistor, and the other end of the third resistor is electrically connected to the second pole of the first power supply;

[0037] A fourth resistor electrically connected to the gate electrode of the second MOS transistor, and the other end of the fourth resistor is electrically connected to the source electrode of the second MOS transistor;

[0038] A second capacitor electrically connected to the gate electrode of the second MOS transistor, and the other end of the second capacitor is electrically connected to the source electrode of the second MOS transistor;

[0039] A second diode electrically connected to the gate of the second MOS transistor, with the other end of the second diode electrically connected to the second pole of the first power supply;

[0040] Wherein, the drain of the second MOS transistor is electrically connected to the first pole of the first power supply. When the gate voltage of the second MOS transistor is higher than a preset threshold of the source voltage, the second MOS transistor conducts to supply power to the powered device.

[0041] Optionally, the second power supply path includes:

[0042] A third Schottky diode electrically connected to the first pole of the second power supply;

[0043] A second forward power supply loop electrically connected to the third Schottky diode;

[0044] A fourth Schottky diode electrically connected to the second pole of the second power supply;

[0045] A second reverse power supply loop electrically connected to the fourth Schottky diode;

[0046] Wherein, when the first pole of the second power supply is the positive pole and the second pole is the negative pole, the second power supply path supplies power through the second forward power supply loop, and the second reverse power supply loop is a protection circuit; when the second pole of the second power supply is the positive pole and the first pole is the negative pole, the second power supply path supplies power through the second reverse power supply loop, and the second forward power supply loop is a protection circuit.

[0047] Optionally, the second forward power supply loop includes:

[0048] A third MOS transistor electrically connected to the third Schottky diode, with the source of the third MOS transistor electrically connected to the third Schottky diode;

[0049] A fifth resistor electrically connected to the gate of the third MOS transistor, with the other end of the fifth resistor electrically connected to the first pole of the second power supply;

[0050] A sixth resistor electrically connected to the gate of the third MOS transistor, with the other end of the sixth resistor electrically connected to the source of the third MOS transistor;

[0051] A third capacitor electrically connected to the gate of the third MOS transistor, with the other end of the third capacitor electrically connected to the source of the third MOS transistor;

[0052] A third diode electrically connected to the gate of the third MOS transistor, with the other end of the third diode electrically connected to the first pole of the second power supply;

[0053] Wherein, the drain of the third MOS transistor is electrically connected to the second pole of the second power supply. When the gate voltage of the third MOS transistor is higher than a preset threshold of the source voltage, the third MOS transistor conducts and operates to supply power to the power-receiving device.

[0054] Optionally, the second reverse power supply loop includes:

[0055] A fourth MOS transistor electrically connected to the fourth Schottky diode, the source of the fourth MOS transistor being electrically connected to the second Schottky diode;

[0056] A seventh resistor electrically connected to the gate of the fourth MOS transistor, the other end of the seventh resistor being electrically connected to the second pole of the second power supply;

[0057] An eighth resistor electrically connected to the gate of the fourth MOS transistor, the other end of the eighth resistor being electrically connected to the source of the fourth MOS transistor;

[0058] A fourth capacitor electrically connected to the gate of the fourth MOS transistor, the other end of the fourth capacitor being electrically connected to the source of the fourth MOS transistor;

[0059] A fourth diode electrically connected to the gate of the fourth MOS transistor, the other end of the fourth diode being electrically connected to the second pole of the second power supply;

[0060] Wherein, the drain of the fourth MOS transistor is electrically connected to the first pole of the second power supply. When the gate voltage of the fourth MOS transistor is higher than a preset threshold of the source voltage, the fourth MOS transistor conducts and operates to supply power to the power-receiving device.

[0061] An embodiment of the present invention further provides an Ethernet rectifier bridge power supply system, including: a rectifier bridge power supply circuit electrically connected to a power-receiving device, the rectifier bridge power supply circuit being the rectifier bridge power supply circuit described in the above solution.

[0062] The above technical solution of the present invention has at least the following technical effects:

[0063] The rectifier bridge power supply circuit of the above power supply system of the present invention includes a pre-stage protection circuit electrically connected to the first power supply and the second power supply of the active Ethernet power supply system respectively; a first power supply path electrically connected to the first power supply; a second power supply path electrically connected to the second power supply; wherein, when the first power supply encounters a surge, the first power supply path triggers the first bidirectional transient voltage suppression diode in the pre-stage protection circuit to conduct and discharge the surge; and / or, when the second power supply encounters a surge, the second power supply path triggers the second bidirectional transient voltage suppression diode in the pre-stage protection circuit to conduct and discharge the surge. It can reduce the on-resistance of the rectifier bridge power supply circuit of the power supply system, improve the switching speed, thermal stability and surge protection ability. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 is a schematic diagram of the first power supply path and the second power supply path of the rectifier bridge power supply circuit of the present invention;

[0065] Figure 2 is a schematic diagram of the pre-stage protection circuit of the rectifier bridge power supply circuit of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0066] Hereinafter, exemplary embodiments of the present invention will be described in more detail with reference to the accompanying drawings. Although the exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided so that the present invention can be more thoroughly understood and the scope of the present invention can be completely conveyed to those skilled in the art.

[0067] As Figure 1 shown, an embodiment of the present invention provides a rectifier bridge power supply circuit for a power supply system, including:

[0068] A pre-stage protection circuit electrically connected to the first power supply U1 and the second power supply U2 of the active Ethernet power supply system respectively;

[0069] A first power supply path electrically connected to the first power supply U1;

[0070] A second power supply path electrically connected to the second power supply U2;

[0071] Wherein, when the first power supply U1 encounters a surge, the first power supply path triggers the first bidirectional transient voltage suppression diode TVS1 in the pre-stage protection circuit to conduct and discharge the surge; and / or, when the second power supply U2 encounters a surge, the second power supply path triggers the second bidirectional transient voltage suppression diode TVS2 in the pre-stage protection circuit to conduct and discharge the surge.

[0072] In this embodiment, asFigure 1 As shown, the rectifier bridge power supply circuit of the power supply system includes two power supplies, a first power supply U1 and a second power supply U2. The first power supply U1 and the second power supply U2 are electrically connected to a pre-stage protection circuit. The pre-stage protection circuit is used to quickly discharge the surge at the front end of the rectifier bridge power supply circuit when a negative pressure surge occurs, so as to protect the rectifier bridge power supply circuit from damage. The first power supply path is electrically connected to the first power supply U1, and the second power supply path is electrically connected to the second power supply U2. Both the first power supply path and the second power supply path are electrically connected to the power receiving device, and jointly provide power for the power receiving device. Connectors can also be installed on the first power supply path and the second power supply path for connecting external devices or other circuit modules, facilitating the expansion and connection of the circuit. When the first power supply U1 and / or the second power supply U2 encounters a negative pressure surge, the first power supply path and / or the second power supply path can instantaneously trigger the pre-stage protection circuit to work. When the first power supply U1 encounters a negative pressure surge, the first power supply path triggers the first bidirectional transient voltage suppressor diode TVS1 in the pre-stage protection circuit to conduct and work, discharging the negative pressure surge; and / or, when the second power supply U2 encounters a negative pressure surge, the second power supply path triggers the second bidirectional transient voltage suppressor diode (TVS2) in the pre-stage protection circuit to conduct and work, discharging the negative pressure surge. Discharging the negative pressure surge through the pre-stage protection circuit achieves the purpose of protecting the safety of each device in the circuit and enables the entire circuit to operate stably and reliably.

[0073] As Figure 1 shown, in an optional embodiment of the present invention, the pre-stage protection circuit includes:

[0074] A first variable resistor MOV1 electrically connected to the first pole of the first power supply U1;

[0075] A second variable resistor MOV2 electrically connected to the second pole of the first power supply U1;

[0076] A first bidirectional transient voltage suppressor diode TVS1, one end of which is electrically connected to the first pole of the first power supply U1, and the other end of which is electrically connected to the second pole of the first power supply U1;

[0077] A third variable resistor MOV3 electrically connected to the first pole of the second power supply U2;

[0078] A fourth variable resistor MOV4 electrically connected to the second pole of the second power supply U2;

[0079] A second bidirectional transient voltage suppressor diode TVS2, one end of which is electrically connected to the first pole of the second power supply U2, and the other end of which is electrically connected to the second pole of the second power supply U2;

[0080] Wherein, when the first power supply U1 encounters a surge, the first bidirectional transient voltage suppression diode TVS1 conducts to stop the first power supply U1 from supplying power to the first power supply path; when the second power supply U2 encounters a surge, the second bidirectional transient voltage suppression diode TVS2 conducts to stop the second power supply U2 from supplying power to the second power supply path.

[0081] In this embodiment, as Figure 1 shown, in the pre-stage protection circuit, the first pole of the first power supply U1 is electrically connected to the first variable resistor MOV1; the second pole of the first power supply U1 is electrically connected to the second variable resistor MOV2; a first bidirectional transient voltage suppression diode TVS1 is electrically connected between the first pole and the second pole of the first power supply U1; the first pole of the second power supply U2 is electrically connected to the third variable resistor MOV3; the fourth variable resistor MOV4 is electrically connected to the second pole of the second power supply U2; a second bidirectional transient voltage suppression diode TVS2 is electrically connected between the first pole and the second pole of the second power supply U2; the variable resistor can gradually change the current in the electrical appliance connected in series with it, can also gradually change the voltage of the electrical appliance connected in series with it, and can also play a role in protecting the electrical appliance. The bidirectional transient voltage suppression diode (TVS) is a high-performance protection device used to protect electronic circuits from transient voltage impacts. It can quickly reduce the impedance and absorb a large current when the circuit is subjected to an instantaneous high-energy impact, clamp the voltage at a predetermined value, thereby protecting the subsequent circuit components from damage. TVS can be applied to various AC and DC power supply circuits to suppress instantaneous overvoltage. When a surge pulse voltage appears instantaneously in the protected circuit, the bidirectional breakdown diode can quickly break down in a Zener manner, change from a high-resistance state to a low-resistance state, shunt and clamp the surge voltage, thereby protecting the components in the circuit from being damaged by the instantaneous surge pulse voltage.

[0082] As Figure 1 shown, in an optional embodiment of the present invention, the pre-stage protection circuit further includes:

[0083] A self-resetting fuse PTC electrically connected to the first variable resistor MOV1, the second variable resistor MOV2, the third variable resistor MOV3, and the fourth variable resistor MOV4; the self-resetting fuse PTC is connected to the ground;

[0084] Wherein, by setting the first variable resistor MOV1, the second variable resistor MOV2, the third variable resistor MOV3, and the fourth variable resistor MOV4, the current in the pre-stage protection circuit is controlled, and the self-resetting fuse PTC is used to increase the resistance in the pre-stage protection circuit when the current reaches a preset value.

[0085] In this embodiment, as Figure 1As shown, the pre-stage protection circuit further includes a self-resetting fuse PTC electrically connected to the first varistor MOV1, the second varistor MOV2, the third varistor MOV3, and the fourth varistor MOV4; the varistors can adjust and control the current in the pre-stage protection circuit; when the circuit current exceeds the rated value, the resistance of the resettable fuse PTC will rapidly increase to limit the current passing through, playing an overcurrent protection role. When the fault is eliminated, its resistance will return to the low-resistance state, and there is no need to replace it like a traditional fuse.

[0086] As Figure 1 shown, in an optional embodiment of the present invention, the first power supply path includes:

[0087] a first Schottky diode X1 electrically connected to the first pole of the first power supply U1;

[0088] a first forward power supply loop electrically connected to the first Schottky diode X1;

[0089] a second Schottky diode X2 electrically connected to the second pole of the first power supply U1;

[0090] a first reverse power supply loop electrically connected to the second Schottky diode X2;

[0091] Wherein, when the first pole of the first power supply U1 is the positive pole and the second pole is the negative pole, the first power supply path is powered through the first forward power supply loop, and the first reverse power supply loop is a protection circuit; when the second pole of the first power supply U1 is the positive pole and the first pole is the negative pole, the first power supply path is powered through the first reverse power supply loop, and the first forward power supply loop is a protection circuit.

[0092] In this embodiment, as Figure 1 shown, in the first power supply path, the first pole of the first power supply U1 is electrically connected to the first Schottky diode X1, the other end of the first Schottky diode X1 is electrically connected to the first forward power supply loop, the second pole of the first power supply U1 is electrically connected to the second Schottky diode X2, the other end of the second Schottky diode X2 is electrically connected to the first reverse power supply loop, the first forward power supply loop and the first reverse power supply loop are electrically connected to the power-receiving device, and the first power supply U1 supplies power to the power-receiving device through the first forward power supply loop or the first reverse power supply loop; the Schottky diode is a hot-carrier diode with an extremely short reverse recovery time that can be as small as a few nanoseconds, a forward conduction voltage drop of only about 0.4V, and a rectifying current that can reach several amperes. It can be used as a switching diode and a low-voltage high-current rectifying diode. The biggest feature of the Schottky diode is that its forward voltage drop (VF) is relatively small. Under the same current condition, its forward voltage drop is much smaller, and its recovery time is short, which is used to handle the current flow in the freewheeling path to ensure that the entire circuit can operate normally under any circumstances.

[0093] When the first pole of the first power supply U1 is positive and the second pole is negative, the first power supply U1 supplies power to the powered device through the first forward power supply circuit. At this time, the first reverse circuit acts as a surge protection circuit. When the first power supply U1 is subjected to a reverse surge, it interacts with the first forward power supply circuit to make the first bidirectional transient voltage suppression diode TVS1 in the front-stage protection circuit connected, and the negative voltage surge is discharged in time to prevent the components in the circuit from being damaged, thereby ensuring the stable and reliable operation of the circuit.

[0094] When the first pole of the first power supply U1 is negative and the second pole is positive, the first power supply U1 supplies power to the powered device through the first reverse power supply circuit. At this time, the first forward circuit acts as a surge protection circuit. When the first power supply U1 is subjected to a reverse surge, it interacts with the first reverse power supply circuit to allow the first bidirectional transient voltage suppression diode TVS1 in the front-stage protection circuit to be connected, so that the negative voltage surge is discharged in time to prevent the components in the circuit from being damaged, thereby ensuring stable and reliable operation of the circuit. When the negative voltage surge exceeds the tolerance threshold of the first bidirectional transient voltage suppression diode TVS1, the power supply is disconnected through the self-recovery fuse PTC to prevent the components in the circuit from being damaged.

[0095] like Figure 1 As shown, in an optional embodiment of the present invention, the first forward power supply circuit includes:

[0096] a first MOS transistor Q1 electrically connected to the first Schottky diode X1, wherein a source of the first MOS transistor Q1 is electrically connected to the first Schottky diode X1;

[0097] A first resistor R1 electrically connected to the gate of the first MOS transistor Q1, wherein the other end of the first resistor R1 is electrically connected to the first electrode of the first power source U1;

[0098] a second resistor R2 electrically connected to the gate of the first MOS transistor Q1, wherein the other end of the second resistor R2 is electrically connected to the source of the first MOS transistor Q1;

[0099] a first capacitor C1 electrically connected to the gate of the first MOS transistor Q1, wherein the other end of the first capacitor C1 is electrically connected to the source of the first MOS transistor Q1;

[0100] A first diode D1 electrically connected to the gate of the first MOS transistor Q1, wherein the other end of the first diode D1 is electrically connected to the first electrode of the first power source U1;

[0101] Wherein, the drain of the first MOS transistor Q1 is electrically connected to the second pole of the first power supply U1. When the gate voltage of the first MOS transistor Q1 is higher than a preset threshold of the source voltage, the first MOS transistor Q1 conducts to supply power to the powered device.

[0102] In this embodiment, as Figure 1 shown, in the first positive power supply loop, the source of the first MOS transistor Q1 is electrically connected to the first Schottky diode X1, the gate of the first MOS transistor Q1 is electrically connected to one ends of a first resistor R1 and a second resistor R2, the drain of the first MOS transistor Q1 is electrically connected to the second pole of the first power supply U1, the other end of the first resistor R1 is electrically connected to the first pole of the first power supply U1, the other end of the second resistor R2 is electrically connected to the source of the first MOS transistor Q1, one end of a first capacitor C1 is electrically connected to the gate of the first MOS transistor Q1, the other end of the first capacitor C1 is electrically connected to the source of the first MOS transistor Q1, one end of a first diode D1 is electrically connected to the gate of the first MOS transistor Q1, and the other end of the first diode D1 is electrically connected to the first pole of the first power supply U1;

[0103] Resistors are used for current limiting, voltage division, etc. in a circuit. The resistor connected to the gate of a MOS transistor can limit the current flowing into the gate to ensure that the MOS transistor operates in a suitable state. Capacitors can remove high-frequency noise in a signal to make the DC voltage smoother. In a power supply circuit, capacitors can filter out the ripple of the power supply output and provide a stable and pure power supply for other components.

[0104] The conduction condition of a MOS transistor is that the gate voltage (Vg) is higher than the source voltage (Vs), and the voltage difference (Vgs) between the two is greater than the threshold voltage Vgs(th) of the MOS transistor, that is: Vg - Vs > Vgs(th). When Vgs is greater than the threshold voltage, an inversion layer (N-type channel) will be formed under the gate of the MOS transistor, making the source and drain conduct.

[0105] When the first pole of the first power supply U1 is the positive pole and the second pole is the negative pole, for example, the voltage of the first pole is +48V. At this time, the gate voltage of the first MOS transistor Q1 is 4.3V, and the first MOS transistor Q1 turns on, and the first positive power supply loop forms a return current to supply power to the powered device;

[0106] When the first pole of the first power supply U1 is the negative pole and the second pole is the positive pole, at this time, the first forward power supply circuit exists as the protection circuit of the first reverse circuit. When the first power supply U1 encounters a negative voltage surge, the second pole of the first power supply U1 instantly becomes a negative high voltage. Since the second pole of the first power supply U1 is electrically connected to the gate of the second MOS transistor Q2 through the second diode D2, the gate of the second MOS transistor Q2 can also instantly become a negative voltage, so that the second MOS transistor Q2 is instantly turned off; at this time, since the source of the first MOS transistor Q1 is connected to the second pole of the first power supply U1, it will also instantly become a negative voltage, which is lower than the gate voltage of the first MOS transistor Q1, and the first MOS transistor Q1 is turned on and conducts, so as to form a protection circuit with the resistor in the circuit, making the first bidirectional transient voltage suppression diode TVS1 in the pre-stage protection circuit conduct, discharging the negative voltage surge in time, preventing the components in the circuit from being damaged, and ensuring the stable and reliable operation of the circuit.

[0107] As Figure 1 shown, in an optional embodiment of the present invention, the first reverse power supply circuit includes:

[0108] A second MOS transistor Q2 electrically connected to the second Schottky diode X2, and the source of the second MOS transistor Q2 is electrically connected to the second Schottky diode X2;

[0109] A third resistor R3 electrically connected to the gate of the second MOS transistor Q2, and the other end of the third resistor R3 is electrically connected to the second pole of the first power supply U1;

[0110] A fourth resistor R4 electrically connected to the gate of the second MOS transistor Q2, and the other end of the fourth resistor R4 is electrically connected to the source of the second MOS transistor Q2;

[0111] A second capacitor C2 electrically connected to the gate of the second MOS transistor Q2, and the other end of the second capacitor C2 is electrically connected to the source of the second MOS transistor Q2;

[0112] A second diode D2 electrically connected to the gate of the second MOS transistor Q2, and the other end of the second diode D2 is electrically connected to the second pole of the first power supply U1;

[0113] Wherein, the drain of the second MOS transistor Q2 is electrically connected to the first pole of the first power supply U1. When the gate voltage of the second MOS transistor Q2 is higher than the preset threshold of the source voltage, the second MOS transistor Q2 conducts and supplies power to the powered device.

[0114] In this embodiment, as Figure 1As shown, in the first reverse power supply loop, the source of the second MOS transistor Q2 is electrically connected to the second Schottky diode X2. The gate of the second MOS transistor Q2 is electrically connected to one end of the third resistor R3 and the fourth resistor R4. The drain of the second MOS transistor Q2 is electrically connected to the first pole of the first power supply U1. The other end of the third resistor R3 is electrically connected to the second pole of the first power supply U1. The other end of the fourth resistor R4 is electrically connected to the source of the second MOS transistor Q2. One end of the second capacitor C2 is electrically connected to the gate of the second MOS transistor Q2, and the other end of the second capacitor C2 is electrically connected to the source of the second MOS transistor Q2. One end of the second diode D2 is electrically connected to the gate of the second MOS transistor Q2, and the other end of the second diode D2 is electrically connected to the second pole of the first power supply U1;

[0115] When the first pole of the first power supply U1 is the negative pole and the second pole is the positive pole, for example, the voltage of the second pole is +48V. At this time, the gate voltage of the second MOS transistor Q2 is 4.3V, and the second MOS transistor Q2 is turned on. The first reverse power supply loop forms a reflux to supply power to the power receiving device.

[0116] When the first pole of the first power supply U1 is the positive pole and the second pole is the negative pole, at this time, the first reverse power supply loop exists as a protection circuit for the first forward circuit. When a negative voltage surge occurs in the first power supply U1, the first pole of the first power supply U1 instantaneously becomes a negative high voltage. Since the first pole of the first power supply U1 is electrically connected to the gate of the first MOS transistor Q1 through the first diode D1, the gate of the first MOS transistor Q1 can also instantaneously become a negative voltage, so that the first MOS transistor Q1 is instantaneously turned off; at this time, since the source of the second MOS transistor Q2 is connected to the first pole of the first power supply U1, it will also instantaneously become a negative voltage, which is lower than the gate voltage of the second MOS transistor Q2, and the second MOS transistor Q2 is turned on and conducts, so as to form a protection loop with the resistors in the circuit, making the first bidirectional transient voltage suppression diode TVS1 in the front-stage protection circuit conduct through, discharging the negative voltage surge in time, preventing the components in the circuit from being damaged, and ensuring the stable and reliable operation of the circuit.

[0117] As Figure 1 shown, in an optional embodiment of the present invention, the second power supply path includes:

[0118] A third Schottky diode X3 electrically connected to the first pole of the second power supply U2;

[0119] A second forward power supply loop electrically connected to the third Schottky diode X3;

[0120] A fourth Schottky diode X4 electrically connected to the second pole of the second power supply U2;

[0121] A second reverse power supply loop electrically connected to the fourth Schottky diode X4;

[0122] Among them, when the first pole of the second power supply U2 is positive and the second pole is negative, the second power supply path is powered by the second forward power supply circuit, and the second reverse power supply circuit is a protection circuit; when the second pole of the second power supply U2 is positive and the first pole is negative, the second power supply path is powered by the second reverse power supply circuit, and the second forward power supply circuit is a protection circuit.

[0123] In this embodiment, Figure 1 As shown, in the second power supply path, the first pole of the second power supply U2 is electrically connected to the third Schottky diode X3, the other end of the third Schottky diode X3 is electrically connected to the second forward power supply circuit, the second pole of the second power supply U2 is electrically connected to the fourth Schottky diode X4, the other end of the fourth Schottky diode X4 is electrically connected to the second reverse power supply circuit, the second forward power supply circuit and the second reverse power supply circuit are electrically connected to the powered device, and the second power supply U2 supplies power to the powered device through the second forward power supply circuit or the second reverse power supply circuit;

[0124] When the first pole of the second power supply U2 is positive and the second pole is negative, the second power supply U2 supplies power to the powered device through the second forward power supply circuit. At this time, the second reverse circuit acts as a surge protection circuit. When the second power supply U2 is subjected to a reverse surge, it interacts with the second forward power supply circuit to connect the second bidirectional transient voltage suppression diode TVS2 in the front-stage protection circuit, thereby discharging the negative voltage surge in time to prevent the components in the circuit from being damaged and ensure stable and reliable operation of the circuit. The Schottky diode is a hot carrier diode with an extremely short reverse recovery time of as little as a few nanoseconds, a forward conduction voltage drop of only about 0.4V, and a rectifier current of several amperes. It can be used as a switching diode and a low-voltage, high-current rectifier diode. The biggest feature of the Schottky diode is that the forward voltage drop VF is relatively small. Under the same current, its forward voltage drop is much smaller, and its recovery time is short. It is used to handle the current flow in the freewheeling path to ensure that the entire circuit can operate normally under any circumstances.

[0125] When the first pole of the second power supply U2 is negative and the second pole is positive, the second power supply U2 supplies power to the powered device through the second reverse power supply circuit. At this time, the second forward circuit acts as a surge protection circuit. When the second power supply U2 is subjected to a reverse surge, it interacts with the second reverse power supply circuit to allow the second bidirectional transient voltage suppression diode TVS2 in the front-stage protection circuit to be connected, thereby discharging the negative voltage surge in time to prevent the components in the circuit from being damaged and ensure stable and reliable operation of the circuit. When the negative voltage surge exceeds the tolerance threshold of the second bidirectional transient voltage suppression diode TVS2, the power supply is disconnected by the self-recovery fuse PTC to prevent the components in the circuit from being damaged.

[0126] like Figure 1As shown in the figure, in an alternative embodiment of the present invention, the second positive power supply loop includes:

[0127] A third MOS transistor Q3 electrically connected to the third Schottky diode X3, the source electrode of the third MOS transistor Q3 being electrically connected to the third Schottky diode X3;

[0128] A fifth resistor R5 electrically connected to the gate electrode of the third MOS transistor Q3, the other end of the fifth resistor R5 being electrically connected to the first pole of the second power supply U2;

[0129] A sixth resistor R6 electrically connected to the gate electrode of the third MOS transistor Q3, the other end of the sixth resistor R6 being electrically connected to the source electrode of the third MOS transistor Q3;

[0130] A third capacitor C3 electrically connected to the gate electrode of the third MOS transistor Q3, the other end of the third capacitor C3 being electrically connected to the source electrode of the third MOS transistor Q3;

[0131] A third diode D3 electrically connected to the gate electrode of the third MOS transistor Q3, the other end of the third diode D3 being electrically connected to the first pole of the second power supply U2;

[0132] Wherein, the drain electrode of the third MOS transistor Q3 is electrically connected to the second pole of the second power supply U2. When the gate voltage of the third MOS transistor Q3 is higher than a preset threshold of the source voltage, the third MOS transistor Q3 conducts to supply power to the powered device.

[0133] In this embodiment, as Figure 1 shown, in the second positive power supply loop, the source electrode of the third MOS transistor Q3 is electrically connected to the third Schottky diode X3, the gate electrode of the third MOS transistor Q3 is electrically connected to one ends of the fifth resistor R5 and the sixth resistor R6, the drain electrode of the third MOS transistor Q3 is electrically connected to the second pole of the second power supply U2, the other end of the fifth resistor R5 is electrically connected to the first pole of the second power supply U2, the other end of the sixth resistor R6 is electrically connected to the source electrode of the third MOS transistor Q3, one end of the third capacitor C3 is electrically connected to the gate electrode of the third MOS transistor Q3, the other end of the third capacitor C3 is electrically connected to the source electrode of the third MOS transistor Q3, one end of the third diode D3 is electrically connected to the gate electrode of the third MOS transistor Q3, and the other end of the third diode D3 is electrically connected to the first pole of the second power supply U2;

[0134] Resistors are used for current limiting, voltage dividing, etc. in a circuit. The resistor connected to the gate electrode of a MOS transistor can limit the current flowing into the gate electrode to ensure that the MOS transistor operates in a proper state. Capacitors can remove high-frequency noise in a signal to make the DC voltage smoother. In a power supply circuit, capacitors can filter out the ripple of the power supply output to provide a stable and pure power supply for other components.

[0135] The conduction condition of the MOS transistor is that the gate voltage (Vg) is higher than the source voltage (Vs), and the voltage difference (Vgs) between the two is greater than the threshold voltage Vgs(th) of the MOS transistor, that is: Vg - Vs > Vgs(th). When Vgs is greater than the threshold voltage, an inversion layer N-channel is formed under the gate of the MOS transistor, making the conduction between the source and the drain.

[0136] When the first pole of the second power supply U2 is the positive pole and the second pole is the negative pole, for example, the voltage of the first pole is +48V. At this time, the gate voltage of the third MOS transistor Q3 is 4.3V, and the third MOS transistor Q3 is turned on, and the second forward power supply loop forms a return current to supply power to the powered device;

[0137] When the first pole of the second power supply U2 is the negative pole and the second pole is the positive pole, at this time, the second forward power supply loop exists as the protection circuit of the second reverse circuit. When the second power supply U2 encounters a negative voltage surge, the first pole of the second power supply U2 instantly becomes a negative high voltage. Since the second pole of the second power supply U2 is electrically connected to the gate of the fourth MOS transistor Q4 through the fourth diode D4, the gate of the fourth MOS transistor Q4 can also instantly become a negative voltage, so that the fourth MOS transistor Q4 is instantly turned off; at this time, since the source of the third MOS transistor Q3 is connected to the second pole of the second power supply U2, it will also instantly become a negative voltage, lower than the gate voltage of the third MOS transistor Q3, and the third MOS transistor Q3 is turned on and conducts, so as to form a protection loop with the resistor in the circuit, making the second bidirectional transient voltage suppression diode TVS2 in the front-stage protection circuit conduct, discharging the negative voltage surge in time, preventing the components in the circuit from being damaged, and ensuring the stable and reliable operation of the circuit.

[0138] As Figure 1 shown, in an optional embodiment of the present invention, the second reverse power supply loop includes:

[0139] A fourth MOS transistor Q4 electrically connected to the fourth Schottky diode X4, and the source of the fourth MOS transistor Q4 is electrically connected to the second Schottky diode X2;

[0140] A seventh resistor R7 electrically connected to the gate of the fourth MOS transistor Q4, and the other end of the seventh resistor R7 is electrically connected to the second pole of the second power supply U2;

[0141] An eighth resistor R8 electrically connected to the gate of the fourth MOS transistor Q4, and the other end of the eighth resistor R8 is electrically connected to the source of the fourth MOS transistor Q4;

[0142] A fourth capacitor C4 electrically connected to the gate of the fourth MOS transistor Q4, and the other end of the fourth capacitor C4 is electrically connected to the source of the fourth MOS transistor Q4;

[0143] A fourth diode D4 electrically connected to the gate of the fourth MOS transistor Q4, with the other end of the fourth diode D4 electrically connected to the second pole of the second power supply U2;

[0144] Wherein, the drain of the fourth MOS transistor Q4 is electrically connected to the first pole of the second power supply U2. When the gate voltage of the fourth MOS transistor Q4 is higher than a preset threshold of the source voltage, the fourth MOS transistor Q4 conducts to supply power to the powered device.

[0145] In this embodiment, as Figure 1 shown, in the second reverse power supply loop, the source of the fourth MOS transistor Q4 is electrically connected to the fourth Schottky diode X4, the gate of the fourth MOS transistor Q4 is electrically connected to one ends of a seventh resistor R7 and an eighth resistor R8, the drain of the fourth MOS transistor Q4 is electrically connected to the first pole of the second power supply U2, the other end of the seventh resistor R7 is electrically connected to the second pole of the second power supply U2, the other end of the eighth resistor R8 is electrically connected to the source of the fourth MOS transistor Q4, one end of a fourth capacitor C4 is electrically connected to the gate of the fourth MOS transistor Q4, the other end of the fourth capacitor C4 is electrically connected to the source of the fourth MOS transistor Q4, one end of the fourth diode D4 is electrically connected to the gate of the fourth MOS transistor Q4, and the other end of the fourth diode D4 is electrically connected to the second pole of the second power supply U2;

[0146] When the first pole of the second power supply U2 is the negative pole and the second pole is the positive pole, for example, the voltage of the second pole is +48V. At this time, the gate voltage of the fourth MOS transistor Q4 is 4.3V, the fourth MOS transistor Q4 turns on, and the second reverse power supply loop forms a return current to supply power to the powered device.

[0147] When the first pole of the second power supply U2 is the positive pole and the second pole is the negative pole, at this time, the second reverse power supply loop exists as a protection circuit for the second forward circuit. When the second power supply U2 encounters a negative voltage surge,

[0148] The first pole of the second power supply U2 instantaneously becomes a negative high voltage. Since the first pole of the second power supply U2 is electrically connected to the gate of the third MOS transistor Q3 through the third diode D3, the gate of the third MOS transistor Q3 can also instantaneously become a negative voltage, thereby instantaneously turning off the third MOS transistor Q3; At this time, since the source of the fourth MOS transistor Q4 is connected to the first pole of the second power supply U1, it will also instantaneously become a negative voltage, which is lower than the gate voltage of the fourth MOS transistor Q4. The fourth MOS transistor Q4 turns on and conducts, thereby forming a protection loop with the resistors in the circuit, enabling the second bidirectional transient voltage suppression diode TVS2 in the front-stage protection circuit to conduct, discharging the negative voltage surge in time, preventing the components in the circuit from being damaged, and ensuring the stable and reliable operation of the circuit.

[0149] Taking the first pole of the first power supply U1 as the positive pole and the second pole as the negative pole as an example, the working steps of the first forward power supply loop and the first reverse power supply loop in the first power supply path are described as follows; when the first power supply U1 supplies power normally, for example, the voltage of the first pole of the first power supply U1 is +48V. At this time, the gate voltage of the first MOS transistor Q1 is 4.3V, and the first MOS transistor Q1 is turned on, and the first forward power supply loop forms a return current to supply power to the power receiving device; when a negative voltage surge occurs, the voltage of the cathode of the first diode D1 will be quickly pulled from +48V to a negative voltage. When the voltage across the first diode D1 reaches 0.7V, the first diode D1 will be turned on and connected. At this time, when the voltage reaches 4.3 - 0.7 = 3.6V, the first diode D1 will always conduct; at this time, the second MOS transistor Q2 still remains cut off; the current-carrying path remains unchanged. Then, as the surge negative voltage drops below 0V, at this time, the gate voltage of the first MOS transistor Q1 always remains equal to the negative voltage, so the first MOS transistor Q1 is turned off and will not conduct. The source voltage of the second MOS transistor Q2 is at a negative voltage, so the second MOS transistor Q2 is turned on and conducts, and the current-carrying path is reversed, thereby achieving the protection of the MOS transistor and enabling the entire circuit to operate stably and reliably.

[0150] The resistance values of the first resistor R1 to the eighth resistor R8 are as Figure 1 shown. The first diode D1 to the fourth diode D4 use IN4148WS, the first Schottky diode X1 to the fourth Schottky diode X4 use US 1D, the first MOS transistor Q1 to the fourth MOS transistor Q4 use CJ2324, the first capacitor C1 to the fourth capacitor C4 use 220PF, the first variable resistor MOV1 to the fourth variable resistor MOV4 use SDVL321 6SD650PTHS501, the first bidirectional transient voltage suppression diode TVS 1 and the second bidirectional transient voltage suppression diode TVS2 use WS58P20SMB, and the self-resetting fuse PTC uses WES1006S.

[0151] It should be noted that although the circuit description in this document uses 48V as the power supply voltage, when the power supply voltage is adjusted to different values such as 30V and 57V, the circuit still works effectively and should not affect the validity of this patent.

[0152] An embodiment of the present invention further provides an Ethernet rectifier bridge power supply system, including: a rectifier bridge power supply circuit electrically connected to a power receiving device, and the rectifier bridge power supply circuit is the rectifier bridge power supply circuit described in the above embodiment.

[0153] The present invention provides a novel full-bridge rectifier structure based on MOS transistors and Schottky diodes, which significantly enhances its surge protection ability by introducing additional diodes. This design not only improves the efficiency and stability of the rectifier bridge circuit, adapts to various complex surge impacts, has high stability and reliability, but also reduces the volume and cost, and has broad application prospects in the field of power electronics technology. The specific beneficial effects are mainly as follows:

[0154] 1. High efficiency: Since MOS transistors have a low on-resistance, the rectifier bridge circuit has a high efficiency.

[0155] 2. Low distortion: MOS transistors have good linear characteristics, resulting in less voltage distortion (low on-voltage drop) in the rectifier bridge circuit during operation.

[0156] 3. Good temperature stability: The on-current of MOS transistors has little relation with temperature, enabling the rectifier bridge circuit to maintain stable operating performance at different temperatures.

[0157] 4. Stronger surge protection ability. The overall surge protection level of the circuit for differential mode and common mode test standards is as follows:

[0158] Differential mode: 8 / 20 combined wave, 12 ohm, 2 KV;

[0159] Common mode: 8 / 20 combined wave, 12 ohm, 6 KV.

[0160] 5. Smaller volume: Since the MOS transistor has a simple structure and high integration, the rectifier bridge circuit composed of this MOS transistor and diodes has a smaller volume.

[0161] 6. Stable and reliable operation, reducing the failure rate and maintenance cost.

[0162] The above is the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art of this technology, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A rectifier bridge power supply circuit of a power supply system, characterized in that: include: A front-stage protection circuit electrically connected to a first power source (U1) and a second power source (U2) of an active Ethernet power supply system respectively; a first power supply path electrically connected to the first power source (U1); a second power supply path electrically connected to the second power source (U2); When the first power supply (U1) encounters a surge, the first power supply path triggers the first bidirectional transient voltage suppression diode (TVS1) in the front-stage protection circuit to turn on and discharge the surge; and / or when the second power supply (U2) encounters a surge, the second power supply path triggers the second bidirectional transient voltage suppression diode (TVS2) in the front-stage protection circuit to turn on and discharge the surge.

2. The rectifier bridge power supply circuit of the power supply system according to claim 1, characterized in that: The front-stage protection circuit comprises: a first variable resistor (MOV1) electrically connected to a first pole of the first power source (U1); a second variable resistor (M0V2) electrically connected to a second pole of the first power supply (U1); a first bidirectional transient voltage suppression diode (TVS1), one end of which is electrically connected to a first pole of the first power supply (U1), and the other end of which is electrically connected to a second pole of the first power supply (U1); a third variable resistor (MOV3) electrically connected to a first electrode of the second power supply (U2); a fourth variable resistor (M0V4) electrically connected to the second electrode of the second power supply (U2); a second bidirectional transient voltage suppression diode (TVS2), one end of which is electrically connected to the first electrode of the second power supply (U2), and the other end of which is electrically connected to the second electrode of the second power supply (U2); When the first power supply (U1) encounters a surge, the first bidirectional transient voltage suppression diode (TVS1) is turned on to stop the first power supply (U1) from supplying power to the first power supply path; when the second power supply (U2) encounters a surge, the second bidirectional transient voltage suppression diode (TVS2) is turned on to stop the second power supply (U2) from supplying power to the second power supply path.

3. The rectifier bridge power supply circuit of the power supply system according to claim 2, characterized in that: The front-stage protection circuit further includes: a resettable fuse (PTC) electrically connected to the first variable resistor (MOV1), the second variable resistor (MOV2), the third variable resistor (MOV3), and the fourth variable resistor (MOV4); the resettable fuse (PTC) is connected to the ground; Among them, by setting the first variable resistor (MOV1), the second variable resistor (MOV2), the third variable resistor (MOV3), and the fourth variable resistor (MOV4), the current in the front-stage protection circuit is controlled, and the resettable fuse (PTC) is used to increase the resistance in the front-stage protection circuit when the current reaches a preset value.

4. The rectifier bridge power supply circuit of the power supply system according to claim 3, characterized in that: The first power supply path comprises: a first Schottky diode (X1) electrically connected to a first electrode of the first power supply (U1); a first forward power supply loop electrically connected to the first Schottky diode (X1); a second Schottky diode (X2) electrically connected to a second electrode of the first power supply (U1); a first reverse power supply loop electrically connected to the second Schottky diode (X2); Among them, when the first pole of the first power supply (U1) is positive and the second pole is negative, the first power supply path is powered by the first forward power supply circuit, and the first reverse power supply circuit is a protection circuit; when the second pole of the first power supply (U1) is positive and the first pole is negative, the first power supply path is powered by the first reverse power supply circuit, and the first forward power supply circuit is a protection circuit.

5. The rectifier bridge power supply circuit of the power supply system according to claim 4, characterized in that: The first forward power supply circuit comprises: a first MOS transistor (Q1) electrically connected to the first Schottky diode (X1), wherein a source of the first MOS transistor (Q1) is electrically connected to the first Schottky diode (X1); a first resistor (R1) electrically connected to the gate of the first MOS tube (Q1), the other end of the first resistor (R1) being electrically connected to a first electrode of the first power source (U1); a second resistor (R2) electrically connected to the gate of the first MOS transistor (Q1), the other end of the second resistor (R2) being electrically connected to the source of the first MOS transistor (Q1); a first capacitor (C1) electrically connected to the gate of the first MOS transistor (Q1), the other end of the first capacitor (C1) being electrically connected to the source of the first MOS transistor (Q1); a first diode (D1) electrically connected to the gate of the first MOS transistor (Q1), the other end of the first diode (D1) being electrically connected to the first electrode of the first power source (U1); The drain of the first MOS tube (Q1) is electrically connected to the second electrode of the first power supply (U1); when the gate voltage of the first MOS tube (Q1) is higher than a preset threshold value of the source voltage, the first MOS tube (Q1) is turned on to supply power to the powered device.

6. The rectifier bridge power supply circuit of the power supply system according to claim 4 or 5, characterized in that: The first reverse power supply circuit includes: a second MOS transistor (Q2) electrically connected to the second Schottky diode (X2), wherein a source of the second MOS transistor (Q2) is electrically connected to the second Schottky diode (X2); a third resistor (R3) electrically connected to the gate of the second MOS tube (Q2), the other end of the third resistor (R3) being electrically connected to the second electrode of the first power supply (U1); a fourth resistor (R4) electrically connected to the gate of the second MOS transistor (Q2), the other end of the fourth resistor (R4) being electrically connected to the source of the second MOS transistor (Q2); a second capacitor (C2) electrically connected to the gate of the second MOS transistor (Q2), the other end of the second capacitor (C2) being electrically connected to the source of the second MOS transistor (Q2); a second diode (D2) electrically connected to the gate of the second MOS transistor (Q2), the other end of the second diode (D2) being electrically connected to the second electrode of the first power supply (U1); The drain of the second MOS tube (Q2) is electrically connected to the first electrode of the first power supply (U1); when the gate voltage of the second MOS tube (Q2) is higher than a preset threshold value of the source voltage, the second MOS tube (Q2) is turned on to supply power to the powered device.

7. The rectifier bridge power supply circuit of the power supply system according to claim 3, characterized in that: The second power supply path comprises: a third Schottky diode (X3) electrically connected to a first electrode of the second power supply (U2); a second forward power supply loop electrically connected to the third Schottky diode (X3); a fourth Schottky diode (X4) electrically connected to a second electrode of the second power supply (U2); a second reverse power supply loop electrically connected to the fourth Schottky diode (X4); Among them, when the first pole of the second power supply (U2) is positive and the second pole is negative, the second power supply path is powered by the second forward power supply circuit, and the second reverse power supply circuit is a protection circuit; when the second pole of the second power supply (U2) is positive and the first pole is negative, the second power supply path is powered by the second reverse power supply circuit, and the second forward power supply circuit is a protection circuit.

8. The rectifier bridge power supply circuit of the power supply system according to claim 7, characterized in that: The second forward power supply circuit comprises: a third MOS transistor (Q3) electrically connected to the third Schottky diode (X3), wherein a source of the third MOS transistor (Q3) is electrically connected to the third Schottky diode (X3); a fifth resistor (R5) electrically connected to the gate of the third MOS tube (Q3), the other end of the fifth resistor (R5) being electrically connected to the first electrode of the second power supply (U2); a sixth resistor (R6) electrically connected to the gate of the third MOS transistor (Q3), the other end of the sixth resistor (R6) being electrically connected to the source of the third MOS transistor (Q3); a third capacitor (C3) electrically connected to the gate of the third MOS tube (Q3), the other end of the third capacitor (C3) being electrically connected to the source of the third MOS tube (Q3); a third diode (D3) electrically connected to the gate of the third MOS tube (Q3), the other end of the third diode (D3) being electrically connected to the first electrode of the second power supply (U2); The drain of the third MOS tube (Q3) is electrically connected to the second electrode of the second power supply (U2); when the gate voltage of the third MOS tube (Q3) is higher than a preset threshold value of the source voltage, the third MOS tube (Q3) is turned on to supply power to the powered device.

9. The rectifier bridge power supply circuit of the power supply system according to claim 7 or 8, characterized in that: The second reverse power supply circuit includes: a fourth MOS transistor (Q4) electrically connected to the fourth Schottky diode (X4), wherein a source of the fourth MOS transistor (Q4) is electrically connected to the second Schottky diode (X2); a seventh resistor (R7) electrically connected to the gate of the fourth MOS tube (Q4), the other end of the seventh resistor (R7) being electrically connected to the second electrode of the second power supply (U2); an eighth resistor (R8) electrically connected to the gate of the fourth MOS transistor (Q4), the other end of the eighth resistor (R8) being electrically connected to the source of the fourth MOS transistor (Q4); a fourth capacitor (C4) electrically connected to the gate of the fourth MOS transistor (Q4), the other end of the fourth capacitor (C4) being electrically connected to the source of the fourth MOS transistor (Q4); a fourth diode (D4) electrically connected to the gate of the fourth MOS tube (Q4), the other end of the fourth diode (D4) being electrically connected to the second electrode of the second power supply (U2); The drain of the fourth MOS tube (Q4) is electrically connected to the first electrode of the second power supply (U2); when the gate voltage of the fourth MOS tube (Q4) is higher than a preset threshold value of the source voltage, the fourth MOS tube (Q4) is turned on to supply power to the powered device.

10. An Ethernet rectifier bridge power supply system, characterized in that: include: A rectifier bridge power supply circuit electrically connected to a powered device, wherein the rectifier bridge power supply circuit is the rectifier bridge power supply circuit according to any one of claims 1 to 9.

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