A direct current power port protection circuit and power supply device

Abstract

The present application relates to a kind of direct current power port protection circuit and power supply equipment, the circuit includes anti-reverse switch unit, switch protection unit and driving unit, wherein, when input power polarity is reversed, anti-reverse switch unit disconnects input power loop, to carry out protection to power output port, further to carry out protection to load and its subsequent circuit, the disconnection of anti-reverse switch unit will cause its first end to produce sharp end high voltage signal, i.e. sharp end high voltage signal is generated at input power negative pole, further make driving unit drive switch protection unit work, absorb the sharp end high voltage signal, prevent anti-reverse switch unit from overvoltage damage due to sharp end high voltage signal, to carry out protection, therefore, relative to traditional direct current power port protection circuit, the direct current power port protection circuit increases the protection of anti-reverse switch unit, i.e. increase the protection of protection circuit itself, further improve the protection effect of circuit and the reliability of system.

Description

Technical Field

[0001] This invention relates to the field of power supplies, and in particular to a DC power supply port protection circuit and power supply device. Background Technology

[0002] During application, power supply equipment is frequently affected by various factors such as abnormal power supply voltage, complex electromagnetic environment, unauthorized operation by construction personnel, and lightning weather. Issues such as overvoltage, undervoltage, overcurrent, reverse polarity connection, or signal interference often occur at the DC power supply port, leading to power supply damage and impacting subsequent circuits, thus reducing system reliability. Therefore, reliable protection for the DC power supply port is necessary. Current DC power supply port protection circuits provide protection for the DC power supply port through various protective circuits, but lack protection for the protection circuits themselves, reducing the effectiveness of the protection and the reliability of system operation. Summary of the Invention

[0003] The present invention aims to provide a DC power port protection circuit and power supply device, which can not only protect the DC power port, but also protect the protection circuit itself, thereby improving the protection effect of the circuit and the reliability of the system.

[0004] To solve the above-mentioned technical problems, the present invention provides the following technical solutions: In a first aspect, the present invention provides a DC power port protection circuit, the DC power port protection circuit comprising: an anti-reverse switch unit, a switch protection unit, and a drive unit;

[0005] The first end of the anti-reverse switch unit is electrically connected to the negative terminal of the input power supply, and the second end of the anti-reverse switch unit is electrically connected to the negative terminal of the power output port, which is used to protect the power output port when the polarity of the input power supply is reversed.

[0006] The first terminal of the switch protection unit is electrically connected to the positive terminal of the input power supply; the second terminal of the switch protection unit is electrically connected to both the negative terminal of the input power supply and the first terminal of the reverse polarity protection switch unit; and the third terminal of the switch protection unit is electrically connected to the output terminal of the drive unit. This is used to protect the reverse polarity protection switch unit when the input power supply polarity is reversed.

[0007] The first input terminal of the driving unit is electrically connected to the negative terminal of the input power supply, and the second input terminal of the driving unit is electrically connected to the positive terminal of the input power supply. This is used to drive the switch protection unit when the polarity of the input power supply is reversed, so as to control the working state of the switch protection unit.

[0008] In some embodiments, the driving unit includes an optocoupler module, the first primary side of the optocoupler module is electrically connected to the negative terminal of the input power supply, the second primary side of the optocoupler module is electrically connected to the positive terminal of the input power supply, and the output terminal of the optocoupler module is electrically connected to the third terminal of the switch protection unit.

[0009] In some embodiments, the driving unit further includes a voltage regulator module, the negative terminal of which is electrically connected to the second primary side of the optocoupler module, and the positive terminal of which is electrically connected to the positive terminal of the input power supply, for setting the voltage threshold for the primary circuit of the optocoupler module to conduct.

[0010] In some embodiments, a soft-start switch unit is further included, which is electrically connected to the second terminal of the anti-reverse switch unit and the negative terminal of the power output port, respectively, for protecting the power output port when the input power supply is turned on to provide power.

[0011] In some embodiments, the system further includes a first-stage surge protection unit and a first-stage EMC filtering unit, which are connected in parallel. One end of the first-stage surge protection unit is electrically connected to the positive terminal of the input power supply, and the other end of the first-stage surge protection unit is electrically connected to the negative terminal of the input power supply, the first terminal of the reverse protection switch unit, and the second terminal of the switch protection unit, respectively, for discharging differential-mode surge energy between the positive and negative terminals of the power input port. The first-stage EMC filtering unit is used to suppress differential-mode surge energy between the positive and negative terminals of the power input port.

[0012] In some embodiments, a decoupling unit is further included. One end of the decoupling unit is electrically connected to the negative terminal of the input power supply, the first-stage surge protection unit, and the first-stage EMC filter unit, respectively. The other end of the decoupling unit is electrically connected to the first terminal of the anti-reverse switch unit and the second terminal of the switch protection unit, respectively, for suppressing surge energy.

[0013] In some embodiments, the system further includes a second-stage surge protection unit and a second-stage EMC filter unit, which are connected in parallel. One end of the second-stage surge protection unit is electrically connected to the positive terminal of the input power supply, and the other end of the second-stage surge protection unit is electrically connected to the decoupling unit, the first terminal of the reverse protection switch unit, and the second terminal of the switch protection unit, respectively, for discharging common-mode surge energy from the positive and negative terminals of the power input port to ground. The second-stage EMC filter unit is used to suppress common-mode surge energy from the positive and negative terminals of the power input port to ground.

[0014] In some embodiments, the system further includes a third-level surge protection unit and a third-level EMC filter unit. One end of the third-level surge protection unit is electrically connected to the positive terminal of the input power supply, and the other end of the third-level surge protection unit is electrically connected to the decoupling unit, the second-level surge protection unit, the second-level EMC filter unit, the first terminal of the reverse-bias switch unit, and the second terminal of the switch protection unit. The third-level surge protection unit is used to absorb residual surge energy at the power input port. One end of the third-level EMC filter unit is electrically connected to the positive terminal of the input power supply, and the other end of the third-level EMC filter unit is electrically connected to the second terminal of the reverse-bias switch unit. The third-level EMC filter unit is used to suppress residual surge energy at the power input port.

[0015] In some embodiments, the switch protection unit includes a first thyristor, a first gate resistor, and a second gate resistor. The cathode of the first thyristor is electrically connected to the positive terminal of the input power supply. The anode of the first thyristor is electrically connected to the negative terminal of the input power supply and the first terminal of the reverse protection switch unit. The control terminal of the first thyristor is connected to one end of the first gate resistor and one end of the second gate resistor. The other end of the first gate resistor is electrically connected to the positive terminal of the input power supply, and the other end of the second gate resistor is electrically connected to the output terminal of the drive unit.

[0016] In some embodiments, the reverse protection switch unit includes a first MOSFET, a first Zener diode, and a second Zener diode. The gate of the first MOSFET is connected to the cathode of the second Zener diode and is used to receive the drive signal of the first MOSFET. The drain of the first MOSFET is electrically connected to the cathode of the first Zener diode, the negative terminal of the input power supply, and the second terminal of the switch protection unit, respectively. The source of the first MOSFET is electrically connected to the anode of the first Zener diode, the anode of the second Zener diode, and the negative terminal of the power output port, respectively.

[0017] In some embodiments, the optocoupler module includes a first optocoupler, the voltage regulator module includes a third Zener diode, the anode of the primary-side light-emitting diode of the first optocoupler is electrically connected to the negative terminal of the input power supply, the cathode of the primary-side light-emitting diode of the first optocoupler is connected to the cathode of the third Zener diode, the output terminal of the first optocoupler is electrically connected to the third terminal of the switch protection unit, and the anode of the third Zener diode is electrically connected to the positive terminal of the input power supply.

[0018] In some embodiments, the soft-start switch unit includes a second MOSFET, a fourth Zener diode, a fifth Zener diode, and a first variable resistor. The gate of the second MOSFET is connected to the cathode of the fifth Zener diode and is used to receive a drive signal from the second MOSFET. The drain of the second MOSFET is electrically connected to the cathode of the fourth Zener diode, one end of the first variable resistor, and the negative terminal of the power output port. The source of the second MOSFET is electrically connected to the anode of the fourth Zener diode, the anode of the fifth Zener diode, the other end of the first variable resistor, and the second terminal of the reverse protection switch unit.

[0019] In a second aspect, embodiments of the present invention provide a power supply device, the power supply device comprising: a DC power port protection circuit as described above.

[0020] In various embodiments of the present invention, the DC power port protection circuit includes a reverse-bias switch unit, a switch protection unit, and a drive unit. When the polarity of the input power supply is reversed, the reverse-bias switch unit disconnects the input power supply circuit to protect the power output port, thereby protecting the load and its subsequent circuits. The disconnection of the reverse-bias switch unit will cause a high-voltage signal to be generated at its first terminal, i.e., a high-voltage signal is generated at the negative terminal of the input power supply. This causes the drive unit to drive the switch protection unit to work, absorb the high-voltage signal, and prevent the reverse-bias switch unit from being damaged by overvoltage due to the high-voltage signal, thus protecting it. Therefore, compared with the traditional DC power port protection circuit, this DC power port protection circuit increases the protection of the reverse-bias switch unit, i.e., increases the protection of the protection circuit itself, further improving the protection effect of the circuit and the reliability of the system. Attached Figure Description

[0021] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0022] Figure 1 This is a schematic diagram of one type of power supply device structure provided in an embodiment of the present invention;

[0023] Figure 2 This is a schematic diagram of the structure of one of the DC power supply port protection circuits provided in an embodiment of the present invention;

[0024] Figure 3 This is a schematic diagram of the structure of one of the DC power supply port protection circuits provided in an embodiment of the present invention;

[0025] Figure 4This is a schematic diagram of the circuit structure of one of the DC power port protection circuits provided in an embodiment of the present invention. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0027] Please see Figure 1 , Figure 1 This is a schematic diagram of the structure of a power supply device provided in an embodiment of the present invention. Figure 1 As shown, the power supply device includes a DC power port protection circuit 100, a power supply 200, and a load 300.

[0028] Power supply 200 is connected to DC power port protection circuit 100. Power supply 200 provides power to load 300 through power output port. DC power port protection circuit 100 protects the power port, subsequent circuits, and load 300. Power supply 200 can be a DC power supply or an AC power supply. When power supply 200 is an AC power supply, after rectification and filtering, it provides DC power to load 300 through DC power port protection circuit 100. Furthermore, power supply 200 can be a power circuit composed of any suitable discrete components. For example, in some embodiments, power supply 200 is a power circuit composed of filter circuit, rectifier circuit, and voltage regulator circuit. In other embodiments, power supply 200 is an integrated power chip.

[0029] The DC power port protection circuit 100 protects the downstream circuits and load 300 of the power port, providing protection such as EMC protection, lightning surge protection, reverse connection protection, and fault isolation protection. This prevents damage to the power supply of the system to which the power port belongs and avoids impacting the downstream circuits and load 300. However, the traditional DC power port protection circuit 100 lacks protection for the protection circuit itself. If the protection circuit is damaged by a high-voltage signal during operation—for example, if the protection circuit loses its protective function when cutting off an input surge and protecting the downstream circuits—the protection effect of the circuit and the reliability of the system will be reduced.

[0030] Please see Figure 2 , Figure 2 This invention provides a DC power supply port protection circuit, such as... Figure 2As shown, the DC power supply port protection circuit 100 includes a reverse polarity switch unit 101, a switch protection unit 102, and a drive unit 103. The first terminal of the reverse polarity switch unit 101 is electrically connected to the negative terminal Vin of the input power supply, and the second terminal of the reverse polarity switch unit 101 is electrically connected to the negative terminal Vbus of the power output port. The reverse polarity switch unit 101 is connected in series on the negative line of the input power supply. When the polarity of the input power supply is reversed, the reverse polarity switch unit 101 activates, cutting off the input power supply circuit, thereby cutting off the power supply circuit to subsequent circuits and the load 300, thus protecting the power output port, subsequent circuits, and the load 300.

[0031] When the polarity of the input power supply is reversed, the reverse polarity protection switch unit 101 is in the open state, cutting off the input power supply circuit. However, due to the opening of the reverse polarity protection switch unit 101, a high-voltage signal is generated at its first terminal, that is, the negative terminal Vin- of the input power supply is a high-voltage signal at the tip, which can damage the reverse polarity protection switch unit 101.

[0032] The first terminal of the switch protection unit 102 is electrically connected to the positive terminal Vin+ of the input power supply. The second terminal of the switch protection unit 102 is electrically connected to the negative terminal Vin- of the input power supply and the first terminal of the reverse protection switch unit 101. The third terminal of the switch protection unit 102 is electrically connected to the output terminal of the drive unit 103. The first input terminal of the drive unit 103 is electrically connected to the negative terminal Vin- of the input power supply, and the second input terminal of the drive unit 103 is electrically connected to the positive terminal Vin+ of the input power supply.

[0033] When the input power polarity is reversed, the first input terminal of the drive unit 103 is connected to a high-voltage signal, and the second input terminal of the drive unit 103 is connected to the positive terminal of the input power. The voltage value of the high-voltage signal is much greater than the voltage of the positive terminal of the input power. The drive unit 103 is automatically triggered to output a drive signal through its output terminal to drive the switch protection unit 102 to work, thereby controlling the working state of the switch protection unit 102. This allows the switch protection unit 102 to absorb the high-voltage signal, thereby preventing the high-voltage signal from damaging the reverse switch unit 101 and protecting it.

[0034] Therefore, when the input power polarity is reversed, this DC power port protection circuit can protect the load and its subsequent circuits. At the same time, the drive unit drives the switch protection unit to work, preventing the reverse switch unit from being damaged by overvoltage due to the high voltage signal at the tip, thus protecting the switch protection unit. Therefore, compared with the traditional DC power port protection circuit, this DC power port protection circuit adds protection for the reverse switch unit, that is, it adds protection for the protection circuit itself, further improving the protection effect of the circuit and the reliability of the system.

[0035] Please see Figure 3 , Figure 3 This is a schematic diagram of the circuit structure of a DC power supply port protection circuit provided in an embodiment of the present invention, as shown below. Figure 3 As shown, the driving unit 103 includes an optocoupler module 1031. The first primary side of the optocoupler module 1031 is electrically connected to the negative terminal Vin- of the input power supply, the second primary side of the optocoupler module 1031 is electrically connected to the positive terminal Vin+ of the input power supply, and the output terminal of the optocoupler module 1031 is electrically connected to the third terminal of the switch protection unit 102.

[0036] The optocoupler module 1031 can isolate the input signal from the output signal, that is, isolate the input power signal from the output drive signal. When the polarity of the input power is reversed, the negative terminal Vin- of the input power is a high-voltage signal. The first primary input terminal of the optocoupler module 1031 is connected to this high-voltage signal, and the second primary input terminal of the optocoupler module 1031 is connected to the positive terminal signal of the input power. The voltage of this high-voltage signal is much greater than the positive terminal voltage of the input power, and the primary circuit of the optocoupler module 1031 is turned on, thereby causing the output terminal of the optocoupler module 1031 to output a high-level signal. This high-level signal is used to drive the switch protection unit 102 to operate.

[0037] In some embodiments, the driving unit 103 further includes a voltage regulator module 1032, the negative terminal of which is electrically connected to the second primary side of the optocoupler module 1031, and the positive terminal of which is electrically connected to the positive terminal Vin+ of the input power supply, for the purpose of protecting the primary side of the optocoupler module 1031.

[0038] The voltage regulator module 1032 sets a voltage threshold for the primary circuit of the optocoupler module 1031 to conduct. Only when the difference between the voltage of the high voltage signal at the tip and the positive voltage of the input power supply is greater than the voltage regulation value of the voltage regulator module 1032 will the primary circuit of the optocoupler module 1031 conduct, preventing the primary circuit of the optocoupler module 1031 from conducting arbitrarily, that is, preventing the drive unit 103 from arbitrarily outputting drive signals and driving the switch protection unit 102 to operate.

[0039] In some embodiments, the drive unit 103 further includes a controller that can perform data processing and logic operations, and output drive signals for the anti-reverse switch unit 101 and other switch units.

[0040] The controller can be a general-purpose processor, digital signal processor (DSP), application-specific integrated circuit (ASIC), field-programmable gate array (FPGA), microcontroller, ARM (Acorn RISC Machine) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination of these components. Furthermore, the controller can also be any conventional processor, controller, microcontroller, or state machine. The controller can also be implemented as a combination of computing devices, such as a combination of DSP and microprocessor, multiple microprocessors, one or more microprocessors combined with DSP and / or any other such configuration. The specific model and composition of the controller can be configured as needed.

[0041] In some embodiments, please continue reading Figure 3 The DC power port protection circuit 100 also includes a soft-start switch unit 104, which is electrically connected to the second terminal of the anti-reverse switch unit 101 and the negative terminal Vbus- of the power output port.

[0042] When the input power supply is turned on, the soft-start switch unit 104 first supplies power to the subsequent circuit or load 300 through the power output port. Then, the soft-start switch unit 104 activates, forming a circuit with the input power supply, and then supplies power to the subsequent circuit or load 300, thereby protecting the power output port from the impact of the input power supply and achieving power-on buffering. In some embodiments, the on / off state of the soft-start switch unit 104 is controlled according to the magnitude of the input voltage and the output voltage of the input power supply. That is, the soft-start switch unit 104 is turned on only when the output voltage is close to the input voltage and both are within the rated operating range. If the voltage difference across the soft-start switch unit is greater than 10V or the input voltage is overvoltage, the soft-start switch unit 104 is turned off.

[0043] In some embodiments, the DC power port protection circuit 100 further includes a first-stage surge protection unit 105 and a first-stage EMC filter unit 106. The first-stage surge protection unit 105 and the first-stage EMC filter unit 106 are connected in parallel. One end of the first-stage surge protection unit 105 is electrically connected to the positive terminal Vin+ of the input power supply, and the other end of the first-stage surge protection unit 105 is electrically connected to the negative terminal Vin- of the input power supply, the first terminal of the reverse switch unit 101, and the second terminal of the switch protection unit 102.

[0044] When a lightning surge signal occurs at the input power terminal, the first-stage surge protection unit 105 discharges the differential-mode surge energy between the positive and negative terminals of the power input port, providing surge protection for the subsequent circuits and load 300 at the power output port. The first-stage EMC filtering unit 106 then suppresses the differential-mode surge energy between the positive and negative terminals of the power input port, further providing surge protection for the subsequent circuits and load 300 at the power output port.

[0045] In some embodiments, the DC power port protection circuit 100 further includes a decoupling unit 107, one end of which is electrically connected to the negative terminal Vin- of the input power supply, the first-stage surge protection unit 105, and the first-stage EMC filter unit 106, respectively, and the other end of which is electrically connected to the first end of the anti-reverse switch unit 101 and the second end of the switch protection unit 102, respectively.

[0046] The decoupling unit 107 is connected in series on the negative terminal of the input power supply and is located after the first-stage surge protection unit 105 and the first-stage EMC filter unit 106. The decoupling unit 107 contains inductors and other devices. The current of the inductor will not surge. Therefore, when a surge occurs, it can block or block the surge, suppress the surge energy, suppress the current change, and thus prevent the surge from impacting the subsequent circuits.

[0047] In some embodiments, the DC power port protection circuit 100 further includes a second-stage surge protection unit 108 and a second-stage EMC filter unit 109. The second-stage surge protection unit 108 and the second-stage EMC filter unit 109 are connected in parallel. One end of the second-stage surge protection unit 108 is electrically connected to the positive terminal Vin+ of the input power supply, and the other end of the second-stage surge protection unit 108 is electrically connected to the decoupling unit 107, the first end of the anti-reverse switch unit 101, and the second end of the switch protection unit 102, respectively.

[0048] The second-stage surge protection unit 108 and the second-stage EMC filter unit 109 are located after the decoupling unit 107. When a surge signal occurs at the input power terminal, the second-stage surge protection unit 108 discharges the common-mode surge energy of the positive and negative terminals of the power input port to ground, providing surge protection for the subsequent circuits and load 300 at the power output port. The second-stage EMC filter unit 109 further suppresses the common-mode surge energy of the positive and negative terminals of the power input port to ground, providing further surge protection for the subsequent circuits and load 300 at the power output port.

[0049] In some embodiments, the DC power port protection circuit 100 further includes a third-stage surge protection unit 110 and a third-stage EMC filter unit 111. One end of the third-stage surge protection unit 110 is electrically connected to the positive terminal Vin+ of the input power supply. The other end of the third-stage surge protection unit 110 is electrically connected to the decoupling unit 107, the second-stage surge protection unit 108, the second-stage EMC filter unit 109, the first terminal of the reverse protection switch unit 101, and the second terminal of the switch protection unit 102. One end of the third-stage EMC filter unit 111 is electrically connected to the positive terminal Vin+ of the input power supply. The other end of the third-stage EMC filter unit 111 is electrically connected to the second terminal of the reverse protection switch unit 101.

[0050] The third-stage surge protection unit 110 is positioned before the reverse-bias switch unit 101 and the switch protection unit 102, while the third-stage EMC filter unit 111 is positioned after the reverse-bias switch unit 101 and the switch protection unit 102. When a surge signal occurs at the power input terminal, the third-stage surge protection unit 110 absorbs the residual surge energy at the power input port and provides surge protection for the subsequent circuits and load 300 at the power output port. The third-stage EMC filter unit 111 suppresses the residual surge energy at the power input port and further provides surge protection for the subsequent circuits and load 300 at the power output port.

[0051] The multi-stage surge protection unit can effectively absorb lightning surge energy and protect downstream circuits. The multi-stage EMC filtering unit has superior EMC characteristics.

[0052] In some embodiments, the DC power port protection circuit 100 further includes an input fuse unit 112, which can be multiple and connected in series on the positive line and the negative line of the input power supply, respectively.

[0053] In some embodiments, the DC power port protection circuit 100 further includes a signal acquisition unit 113. The signal acquisition unit 113 can acquire the voltage and current signals at the input terminal and the voltage and current signals at the output terminal. It can also transmit the acquired voltage or current signals to the controller in the drive unit 103, whereby the controller processes the voltage or current signals accordingly and outputs the corresponding drive signals.

[0054] Please see Figure 4 , Figure 4 This is a schematic diagram of the circuit structure of a DC power supply port protection circuit provided in an embodiment of the present invention, as shown below. Figure 4As shown, the switch protection unit 102 includes a first thyristor SCR1, a first gate resistor R1, and a second gate resistor R2. The cathode of the first thyristor SCR1 is electrically connected to the positive terminal Vin+ of the input power supply. The anode of the first thyristor SCR1 is electrically connected to the negative terminal Vin- of the input power supply and the first terminal of the anti-reverse switch unit 101. The control terminal of the first thyristor SCR1 is connected to one end of the first gate resistor R1 and one end of the second gate resistor R2. The other end of the first gate resistor R1 is electrically connected to the positive terminal Vin+ of the input power supply. The other end of the second gate resistor R2 is electrically connected to the output terminal of the drive unit 103.

[0055] The anti-reverse switch unit 101 includes a first MOSFET Q1, a first Zener diode D1, and a second Zener diode D2. The gate of the first MOSFET Q1 is connected to the cathode of the second Zener diode D2 and is used to receive the drive signal of the first MOSFET Q1. The drain of the first MOSFET Q1 is electrically connected to the cathode of the first Zener diode D1, the negative terminal Vin- of the input power supply, and the second terminal of the switch protection unit 102. Specifically, the drain of the first MOSFET Q1 is connected to the anode of the first thyristor SCR1, and the source of the first MOSFET Q1 is electrically connected to the anode of the first Zener diode D1, the anode of the second Zener diode D2, and the negative terminal Vbus- of the power output port.

[0056] The reverse protection switch unit 101 also includes a first resistor R3 and a second resistor R4. One end of the first resistor R3 is used to connect to the drive signal of the first MOSFET Q1. The other end of the first resistor R3 is connected to one end of the second resistor R4, the gate of the first MOSFET Q1, and the cathode of the second Zener diode D2. The other end of the second resistor R4 is connected to the source of the first MOSFET Q1 and the anode of the second Zener diode D2. The first MOSFET Q1 is selected as a MOSFET with low on-resistance to reduce conduction losses. The first Zener diode D1 provides voltage clamping protection when the first MOSFET Q1 is turned off. The first Zener diode D1 is connected in parallel with the gate drive of the first MOSFET Q1 to provide gate clamping protection.

[0057] The optocoupler module 1031 includes a first optocoupler U1, and the voltage regulator module 1032 includes a third Zener diode D3. The anode of the primary-side LED of the first optocoupler U1 is electrically connected to the negative terminal Vin- of the input power supply, and the cathode of the primary-side LED of the first optocoupler U1 is connected to the cathode of the third Zener diode D3. The output terminal of the first optocoupler U1 is connected to the second gate resistor R2, and the anode of the third Zener diode D3 is electrically connected to the positive terminal Vin+ of the input power supply. The anode of the primary-side LED of the first optocoupler U1 is pin 1, the cathode of the primary-side LED of the first optocoupler U1 is pin 3, the output terminal of the first optocoupler U1 is pin 5, pin 4 of the first optocoupler U1 is grounded, and pin 6 of the first optocoupler U1 is connected to the power supply VCC.

[0058] The driving unit 103 also includes a third resistor R5 and a first diode D4. The third resistor R5 is connected in series between the negative terminal Vin- of the input power supply and the anode of the primary-side LED of the first optocoupler U1. The cathode of the first diode D4 is connected to the anode of the primary-side LED of the first optocoupler U1, and the anode of the first diode D4 is connected to the cathode of the primary-side LED of the first optocoupler U1. The third resistor R5 is a current-limiting resistor, and the first diode D4 protects the primary-side LED of the optocoupler. When the input power supply voltage is large, the first diode D4 clamps the voltage across the primary-side LED of the first optocoupler U1 to the diode's forward voltage, preventing it from being damaged by a large voltage.

[0059] The soft-start switch unit 104 includes a second MOSFET Q2, a fourth Zener diode D5, a fifth Zener diode D6, and a first variable resistor RT1. The gate of the second MOSFET Q2 is connected to the cathode of the fifth Zener diode D6 and is used to receive the drive signal of the second MOSFET Q2. The drain of the second MOSFET Q2 is electrically connected to the cathode of the fourth Zener diode D5, one end of the first variable resistor RT1, and the negative terminal Vbus- of the power output port. The source of the second MOSFET Q2 is electrically connected to the anode of the fourth Zener diode D5, the anode of the fifth Zener diode D6, the other end of the first variable resistor RT1, and the second terminal of the anti-reverse switch unit 101. Specifically, the source of the second MOSFET Q2 is connected to the anode of the fourth Zener diode D5, the anode of the fifth Zener diode D6, the other end of the first variable resistor RT1, and the source of the first MOSFET Q1. The second MOSFET Q2 is selected as a MOSFET with low on-resistance to reduce conduction losses. The fourth Zener diode D5 plays a voltage clamping protection role when the second MOSFET Q2 is turned off. The fifth Zener diode D6 is connected in parallel with the gate drive of the second MOSFET Q2 to clamp the gate.

[0060] In this embodiment of the invention, both the first MOSFET Q1 and the second MOSFET Q2 are NMOS transistors. The drive signals for the first MOSFET Q1 and the second MOSFET Q2 can be generated by separate drive circuits or output by the controller, and no limitation is made here.

[0061] The soft-start switch unit 104 also includes a fourth resistor R6 and a fifth resistor R7. One end of the fourth resistor R6 is used to connect to the drive signal of the second MOSFET Q2. The other end of the fourth resistor R6 is connected to one end of the fifth resistor R7, the gate of the second MOSFET Q2, and the cathode of the fifth Zener diode D6. The other end of the fifth resistor R7 is connected to the source of the second MOSFET Q2 and the anode of the fifth Zener diode D6.

[0062] Before the first-stage surge protection unit 105, the DC power port protection circuit 100 also includes an input fuse unit 112, which includes a fuse F1 connected in series with the positive terminal of the input power supply and a fuse F2 connected in series with the negative terminal of the input power supply.

[0063] The first-stage surge protection unit 105 includes a multi-section ceramic gas discharge tube DG1 connected in parallel between the positive and negative terminals of the input power supply, and a first ceramic capacitor C1, a second ceramic capacitor C2, a third ceramic capacitor C3, and a fourth ceramic capacitor C4 respectively connected across each section of the ceramic gas discharge tube DG1 and the negative terminal of the input power supply line. This multi-section gas discharge tube configuration can increase the arc voltage, thereby improving the follow current interruption capability. Furthermore, by adding a capacitor network, each section of the multi-section gas discharge tube can be broken down sequentially, thereby reducing the overall breakdown voltage and improving the overall breakdown voltage response time. The first-stage surge protection unit 105 is mainly used to discharge differential-mode surge energy between the positive and negative terminals of the input port.

[0064] The first-stage EMC filter unit 106 includes a first differential-mode filter capacitor CX1 connected in parallel between the positive and negative terminals of the input power supply, a first common-mode filter capacitor CY1 connected in parallel between the positive terminal of the input power supply and ground, and a second common-mode filter capacitor CY2 connected in parallel between the negative terminal of the input power supply and ground. It also includes a sixth resistor R8 and a seventh resistor R9. The sixth resistor R8 and the seventh resistor R9 are connected in series and then in parallel across the two ends of the differential-mode filter capacitor CX1 as a discharge dummy load 300.

[0065] The decoupling unit 107 includes an air-core inductor L1, which is connected in series on the negative line of the input power supply and placed after the first-stage surge protection unit 105 and the first-stage EMC filter unit 106. The air-core inductor L1 has strong anti-saturation capability. When a surge occurs, it isolates or blocks the surge to prevent it from impacting the subsequent circuits and plays a role in suppressing current changes.

[0066] The second-stage surge protection unit 108 includes a gas discharge tube DG2 connected in parallel between the positive terminal of the input power supply and the ground, and a varistor RV1 connected in parallel between the negative terminal of the input power supply and the ground. The second-stage surge protection unit 108 is mainly used to discharge and consume common-mode surge energy between the positive and negative terminals of the input power supply and the ground.

[0067] The second-stage EMC filter unit 109 includes a second differential-mode filter capacitor CX2, a first common-mode inductor L2, a third common-mode filter capacitor CY3 between the positive terminal and ground, a fourth common-mode filter capacitor CY4 between the negative terminal and ground, a third differential-mode filter capacitor CX3, and a second common-mode inductor L3. The second differential-mode filter capacitor CX2 is connected in parallel between pins 1 and 2 of the first common-mode inductor L2. The third common-mode filter capacitor CY3 and the fourth common-mode filter capacitor CY4 are connected in series and then in parallel between pins 3 and 4 of the first common-mode inductor L2, and simultaneously in parallel between pins 1 and 4 of the second common-mode inductor L3. The third common-mode filter capacitor CY3 and the fourth common-mode filter capacitor CY4 are positioned between the first common-mode inductor L2 and the second common-mode inductor L3. Pin 2 of the third common-mode filter capacitor CY3 is connected to the positive terminal Vin+ of the input power supply, and pin 3 of the third common-mode filter capacitor CY3 is connected to the negative terminal Vin- of the input power supply.

[0068] The third-level surge protection unit 110 includes a bidirectional TVS diode D7 connected in parallel between the positive and negative terminals; the TVS diode clamps and absorbs residual surge voltage.

[0069] The third-stage EMC filter unit 111 includes a fifth common-mode filter capacitor CY5 between the positive terminal and the ground, a sixth common-mode filter capacitor CY6 between the negative terminal and the ground, a capacitor EC1 for differential-mode filtering and energy storage, and a first dummy load resistor R10 and a second dummy load resistor R11 connected in series and in parallel with the capacitor EC1.

[0070] In some embodiments, the DC power port protection circuit 100 further includes a signal acquisition unit, which can acquire voltage and current signals at the power input terminal and voltage and current signals at the power output terminal, and then transmit the acquired signals to the drive unit 103. The drive unit 103 performs logical processing on the electrical signals at the input and output terminals and outputs drive signals to control the on / off state of the anti-reverse switch unit 101, the switch protection unit 102, and the soft-start switch unit 104.

[0071] Combination Figure 4 The working principle of the DC power port protection circuit 100 can be described as follows:

[0072] In the event of a lightning surge, a multi-stage surge protection circuit is employed. The first-stage surge protection unit 105, the second-stage surge protection unit 108, and the third-stage surge protection unit 110 effectively absorb lightning surge energy, protecting downstream circuits. Furthermore, the DC power port protection circuit 100 utilizes a multi-stage differential-mode and common-mode filter circuit, exhibiting superior EMC characteristics. The soft-start switch unit 104 also provides power-on buffering, preventing sudden input power supply from impacting subsequent circuits.

[0073] When the input power polarity is reversed, the first MOSFET Q1 is driven to turn off, cutting off the input power circuit and protecting the subsequent circuit, output power port, and load 300. Simultaneously, because the first MOSFET Q1 is turned off, a high-voltage signal is generated at its drain. This high-voltage signal, which is the negative voltage of the input power supply, is much greater than the positive voltage. This causes the primary-side LED of optocoupler U1 to conduct, resulting in a high-level signal output from pin 5 of optocoupler U1. This high-level signal acts on the control electrode of the first thyristor SCR1, turning it on to absorb the high-voltage signal at the drain of the first MOSFET Q1, reliably protecting Q1 from overvoltage damage during circuit disconnection. This further improves the circuit's protection effect and the system's reliability.

[0074] In summary, when the input power polarity is reversed, this DC power port protection circuit can protect the load and its downstream circuits. At the same time, the drive unit drives the switch protection unit to work, preventing the reverse switch unit from being damaged by overvoltage due to the high voltage signal at the tip, thus protecting the switch protection unit. Therefore, compared with the traditional DC power port protection circuit, this DC power port protection circuit adds protection for the reverse switch unit, that is, it adds protection for the protection circuit itself, further improving the protection effect of the circuit and the reliability of the system.

[0075] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; under the concept of the present invention, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of the present invention as described above, which are not provided in detail for the sake of brevity; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A DC power supply port protection circuit, characterized in that, The DC power port protection circuit includes: an anti-reverse switch unit, a switch protection unit, and a drive unit; The first end of the anti-reverse switch unit is electrically connected to the negative terminal of the input power supply, and the second end of the anti-reverse switch unit is electrically connected to the negative terminal of the power output port, which is used to protect the power output port when the polarity of the input power supply is reversed. The first terminal of the switch protection unit is electrically connected to the positive terminal of the input power supply; the second terminal of the switch protection unit is electrically connected to both the negative terminal of the input power supply and the first terminal of the reverse polarity protection switch unit; and the third terminal of the switch protection unit is electrically connected to the output terminal of the drive unit. This is used to protect the reverse polarity protection switch unit when the input power supply polarity is reversed. The first input terminal of the driving unit is electrically connected to the negative terminal of the input power supply, and the second input terminal of the driving unit is electrically connected to the positive terminal of the input power supply. This is used to drive the switch protection unit when the polarity of the input power supply is reversed, so as to control the working state of the switch protection unit. The driving unit includes an optocoupler module. The first primary side of the optocoupler module is electrically connected to the negative terminal of the input power supply, the second primary side of the optocoupler module is electrically connected to the positive terminal of the input power supply, and the output terminal of the optocoupler module is electrically connected to the third terminal of the switch protection unit.

2. The DC power port protection circuit according to claim 1, characterized in that, The driving unit further includes a voltage regulator module, the negative terminal of which is electrically connected to the second primary side of the optocoupler module, and the positive terminal of which is electrically connected to the positive terminal of the input power supply, for setting the voltage threshold for the primary side circuit of the optocoupler module to conduct.

3. The DC power port protection circuit according to claim 1, characterized in that, It also includes a soft-start switch unit, which is electrically connected to the second terminal of the reverse protection switch unit and the negative terminal of the power output port, respectively, and is used to protect the power output port when the input power supply is turned on to provide power.

4. The DC power port protection circuit according to claim 1, characterized in that, It also includes a first-stage surge protection unit and a first-stage EMC filter unit, which are connected in parallel. One end of the first-stage surge protection unit is electrically connected to the positive terminal of the input power supply, and the other end of the first-stage surge protection unit is electrically connected to the negative terminal of the input power supply, the first terminal of the reverse protection switch unit, and the second terminal of the switch protection unit, respectively, for discharging differential-mode surge energy between the positive and negative terminals of the power input port. The first-stage EMC filter unit is used to suppress differential-mode surge energy between the positive and negative terminals of the power input port.

5. The DC power port protection circuit according to claim 4, characterized in that, It also includes a decoupling unit, one end of which is electrically connected to the negative terminal of the input power supply, the first-stage surge protection unit, and the first-stage EMC filter unit, respectively, and the other end of which is electrically connected to the first terminal of the anti-reverse switch unit and the second terminal of the switch protection unit, respectively, for suppressing surge energy.

6. The DC power port protection circuit according to claim 5, characterized in that, It also includes a second-stage surge protection unit and a second-stage EMC filter unit, which are connected in parallel. One end of the second-stage surge protection unit is electrically connected to the positive terminal of the input power supply, and the other end of the second-stage surge protection unit is electrically connected to the decoupling unit, the first terminal of the reverse switch unit, and the second terminal of the switch protection unit, respectively, for discharging the common-mode surge energy of the positive and negative terminals of the power input port to ground. The second-stage EMC filter unit is used to suppress the common-mode surge energy of the positive and negative terminals of the power input port to ground.

7. The DC power port protection circuit according to claim 6, characterized in that, It also includes a third-level surge protection unit and a third-level EMC filter unit. One end of the third-level surge protection unit is electrically connected to the positive terminal of the input power supply, and the other end of the third-level surge protection unit is electrically connected to the decoupling unit, the second-level surge protection unit, the second-level EMC filter unit, the first terminal of the reverse protection switch unit, and the second terminal of the switch protection unit. The third-level surge protection unit is used to absorb residual surge energy at the power input port. One end of the third-level EMC filter unit is electrically connected to the positive terminal of the input power supply, and the other end of the third-level EMC filter unit is electrically connected to the second terminal of the reverse protection switch unit. The third-level EMC filter unit is used to suppress residual surge energy at the power input port.

8. The DC power supply port protection circuit according to any one of claims 1-7, characterized in that, The switch protection unit includes a first thyristor, a first gate resistor, and a second gate resistor. The cathode of the first thyristor is electrically connected to the positive terminal of the input power supply. The anode of the first thyristor is electrically connected to the negative terminal of the input power supply and the first terminal of the reverse protection switch unit. The control terminal of the first thyristor is connected to one end of the first gate resistor and one end of the second gate resistor. The other end of the first gate resistor is electrically connected to the positive terminal of the input power supply, and the other end of the second gate resistor is electrically connected to the output terminal of the drive unit.

9. The DC power supply port protection circuit according to any one of claims 1-7, characterized in that, The reverse protection switch unit includes a first MOSFET, a first Zener diode, and a second Zener diode. The gate of the first MOSFET is connected to the cathode of the second Zener diode and is used to receive the drive signal of the first MOSFET. The drain of the first MOSFET is electrically connected to the cathode of the first Zener diode, the negative terminal of the input power supply, and the second terminal of the switch protection unit. The source of the first MOSFET is electrically connected to the anode of the first Zener diode, the anode of the second Zener diode, and the negative terminal of the power output port.

10. The DC power port protection circuit according to claim 2, characterized in that, The optocoupler module includes a first optocoupler, and the voltage regulator module includes a third Zener diode. The anode of the primary-side light-emitting diode of the first optocoupler is electrically connected to the negative terminal of the input power supply, and the cathode of the primary-side light-emitting diode of the first optocoupler is connected to the cathode of the third Zener diode. The output terminal of the first optocoupler is electrically connected to the third terminal of the switch protection unit, and the anode of the third Zener diode is electrically connected to the positive terminal of the input power supply.

11. The DC power port protection circuit according to claim 3, characterized in that, The soft-start switch unit includes a second MOSFET, a fourth Zener diode, a fifth Zener diode, and a first variable resistor. The gate of the second MOSFET is connected to the cathode of the fifth Zener diode and is used to receive the drive signal of the second MOSFET. The drain of the second MOSFET is electrically connected to the cathode of the fourth Zener diode, one end of the first variable resistor, and the negative terminal of the power output port. The source of the second MOSFET is electrically connected to the anode of the fourth Zener diode, the anode of the fifth Zener diode, the other end of the first variable resistor, and the second terminal of the reverse protection switch unit.

12. A power supply device, characterized in that, The power supply device includes: a DC power port protection circuit as described in any one of claims 1-11.

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