A power supply protection circuit, high-voltage DC power supply equipment and system

Abstract

This invention discloses a power supply protection circuit, a high-voltage DC power supply device, and a system. The power supply protection circuit includes a short-circuit detection module, a quantity detection module, an overcurrent detection module, and a continuity module. The short-circuit detection module divides the supply voltage and outputs a first output voltage and a second output voltage. The quantity detection module outputs a first enable signal or a first invalid signal to control the output of the second internal voltage based on the first output voltage and a first internal voltage set according to the maximum number of powered devices. The overcurrent detection module outputs a second invalid signal based on the first invalid signal or based on the second internal voltage, the second output voltage, and the voltage receiving terminal current. The continuity module maintains an open circuit based on the second invalid signal. The first output voltage of the short-circuit detection module detects whether a short circuit has occurred in the power supply line, the quantity detection module determines whether the number of connected powered devices exceeds the upper limit, and the overcurrent detection module detects whether an overcurrent exists, thereby improving the safety of the high-voltage DC power supply.

Description

Technical Field

[0001] This invention relates to the field of electronic circuits, and in particular to a power supply protection circuit, a high-voltage DC power supply device and system. Background Technology

[0002] Video intercom systems are widely used in security management services for residential communities, apartments, and villas. The power supply of video intercom equipment is usually either 12V DC power supply or active Ethernet (Power Over Ethernet, PoE) power supply. Among them, 12V DC power supply can support one-to-many power supply, but the cable transmission loss is large; Ethernet is suitable for video intercom systems with network ports.

[0003] Currently, some older residential communities need to upgrade from traditional voice intercom systems to the latest video intercom systems. However, due to factors such as poor quality of existing cables, high impedance, and high cost of rewiring network cables, they cannot use 12V DC power supply or Ethernet power supply. High-voltage DC power supply can be used instead. If high-voltage DC power supply is used, how to ensure power supply safety is an urgent problem to be solved. Summary of the Invention

[0004] This invention provides a power supply protection circuit, a high-voltage DC power supply device and system to solve the problem of how to ensure power supply safety when using high-voltage DC power supply in the prior art.

[0005] In a first aspect, embodiments of the present invention provide a power supply protection circuit applied to high-voltage DC power supply equipment, the power supply protection circuit including a short circuit detection module, a quantity detection module, an overcurrent detection module, and a continuity module;

[0006] The short-circuit detection module is connected to the power supply terminal, the quantity detection module, and the overcurrent detection module, respectively. The quantity detection module is connected to the first internal voltage terminal and the second internal voltage terminal, respectively. The overcurrent detection module is connected to the second internal voltage terminal, the voltage receiving terminal of the powered device, and the switching module, respectively. The switching module is connected to the power supply terminal and the powered device, respectively.

[0007] The short-circuit detection module is used to divide the power supply voltage output from the power supply terminal and output a first output voltage and a second output voltage.

[0008] The quantity detection module is used to output a first enable signal or a first invalid signal based on the first output voltage and the first internal voltage output by the first internal voltage terminal. The first enable signal is used to control the second internal voltage terminal to output a second internal voltage. The first internal voltage is preset based on the maximum number of powered devices.

[0009] The overcurrent detection module is used to output a second invalid signal based on the first invalid signal, or based on the second internal voltage, the second output voltage, and the current of the voltage receiving terminal;

[0010] The on / off module is used to keep the path between the power supply terminal and the power receiving device in an open state according to the second invalid signal.

[0011] In one possible implementation, the overcurrent detection module is further configured to: output a second enable signal based on the second internal voltage, the second output voltage, and the current at the voltage receiving terminal;

[0012] The on / off module is also used to: connect the power supply terminal and the power receiving device according to the second enable signal.

[0013] In one possible implementation, the overcurrent detection module is further configured to:

[0014] After dividing the second internal voltage, when the current formed at the voltage receiving terminal is less than the first preset current value, or when the current formed at the voltage receiving terminal by the second output voltage is less than the first preset current value, the second enable signal is output; otherwise, the second invalid signal is output.

[0015] In one possible implementation, the quantity detection module is further configured to:

[0016] The first internal voltage is divided to obtain a first reference voltage and a second reference voltage. If the first output voltage is greater than or equal to the first reference voltage and less than or equal to the second reference voltage, the first enable signal is output; otherwise, the first invalid signal is output.

[0017] In one possible implementation, the power supply protection circuit further includes a current acquisition module connected to the on / off module;

[0018] The current acquisition module is used to acquire the current in the path when the path between the power supply terminal and the power receiving device is open. When the current acquired by the current acquisition module is greater than a second preset current value, the on / off module is controlled to output a disconnect signal.

[0019] The on / off module is used to disconnect the path between the power supply terminal and the power receiving device based on the disconnection signal.

[0020] In one possible implementation, the short-circuit detection module includes a first resistor, a second resistor, a third resistor, and a first diode;

[0021] The first end of the first resistor is connected to the power supply terminal, the second end of the first resistor is connected to the anode of the first diode and the first end of the second resistor, the second end of the second resistor is connected to the quantity detection module and the first end of the third resistor, the second end of the third resistor is grounded, and the cathode of the first diode is connected to the overcurrent detection module.

[0022] In one possible implementation, the quantity detection module includes a fourth resistor, a fifth resistor, a sixth resistor, a first comparator, a second comparator, and an AND gate;

[0023] The positive input terminal of the first comparator is connected to the short-circuit detection module, the negative input terminal of the first comparator is connected to the first terminal of the fifth resistor and the first terminal of the sixth resistor, respectively, and the output terminal of the first comparator is connected to the first input terminal of the AND gate. The positive input terminal of the second comparator is connected to the short-circuit detection module, the negative input terminal of the second comparator is connected to the second terminal of the fifth resistor and the first terminal of the fourth resistor, the output terminal of the second comparator is connected to the second input terminal of the AND gate, the output terminal of the AND gate is connected to the second internal voltage terminal, the second terminal of the fourth resistor is connected to the first internal voltage terminal, and the second terminal of the sixth resistor is grounded.

[0024] In one possible implementation, the overcurrent detection module includes a first switching transistor, a second switching transistor, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a second diode, and a third diode.

[0025] The anode of the second diode is connected to the second internal voltage terminal. The cathode of the second diode is connected to the first terminal of the seventh resistor and the first terminal of the first switch. The second terminal of the seventh resistor is connected to the short-circuit detection module, the second terminal of the eighth resistor, and the anode of the third diode. The cathode of the third diode is connected to the voltage receiving terminal. The control terminal of the first switch is connected to the first terminal of the eighth resistor. The second terminal of the first switch is connected to the first terminal of the ninth resistor. The second terminal of the ninth resistor is connected to the first terminal of the tenth resistor and the control terminal of the second switch. The second terminal of the tenth resistor is grounded. The first terminal of the second switch is connected to the second terminal of the eleventh resistor, the first terminal of the twelfth resistor, and the switching module. The second terminal of the second switch is connected to the second terminal of the twelfth resistor and grounded. The first terminal of the eleventh resistor is connected to the second internal voltage terminal.

[0026] In one possible implementation, the switching module includes a control unit and a switching unit;

[0027] The input terminal of the control unit is connected to the overcurrent detection module, the control terminal of the control unit is connected to the control terminal of the switching unit, the first terminal of the switching unit is connected to the power supply terminal, and the second terminal of the switching unit is connected to the power receiving device.

[0028] The control unit is configured to output a conduction signal after receiving the second enable signal to control the on / off unit to conduct the first end and the second end of the on / off unit, and not output the control signal after receiving the second invalid signal so that the on / off unit keeps the path between the first end and the second end of the on / off unit in an open state.

[0029] In one possible implementation, the current acquisition module includes a fifteenth resistor and the control unit;

[0030] The first end of the fifteenth resistor is connected to the power supply end, and the second end of the fifteenth resistor is connected to the first end of the switching unit and the current acquisition end of the control unit, respectively.

[0031] The control unit is used to collect the current at the second end of the fifteenth resistor. When the collected current is greater than the second preset current value, it outputs the disconnect signal to the switching unit so that the switching unit disconnects the path between the first end of the switching unit and the second end of the switching unit.

[0032] In one possible implementation, the switching module further includes a power-on unit;

[0033] The power-on unit includes a sixteenth resistor and a first capacitor;

[0034] The first end of the sixteenth resistor is connected to the overcurrent detection module, the second end of the sixteenth resistor is connected to the input terminal of the control unit and the first end of the first capacitor, and the second end of the first capacitor is grounded.

[0035] In one possible implementation, the switching module further includes a power-down unit;

[0036] The power-down unit includes a fourth diode and a seventeenth resistor;

[0037] The anode of the fourth diode is connected to the first end of the seventeenth resistor, the cathode of the fourth diode is connected to the first end of the sixteenth resistor and the overcurrent detection module, and the second end of the seventeenth resistor is connected to the second end of the sixteenth resistor, the first end of the first capacitor and the input end of the control unit.

[0038] In a second aspect, embodiments of the present invention provide a high-voltage DC power supply device, including a power supply protection circuit as described in any of the first aspects.

[0039] Thirdly, embodiments of the present invention provide a high-voltage DC power supply system, including a power receiving device and a high-voltage DC power supply device as described in the second aspect.

[0040] The beneficial effects of this invention are as follows:

[0041] This invention discloses a power supply protection circuit, a high-voltage DC power supply device, and a system. The power supply protection circuit includes a short-circuit detection module, a quantity detection module, an overcurrent detection module, and a continuity module. The short-circuit detection module is connected to the power supply terminal, the quantity detection module, and the overcurrent detection module. The quantity detection module is connected to a first internal voltage terminal and a second internal voltage terminal. The overcurrent detection module is connected to the second internal voltage terminal, the voltage receiving terminal of the powered device, and the continuity module. The continuity module is connected to the power supply terminal and the powered device. The short-circuit detection module is used to divide the power supply voltage output from the power supply terminal, outputting a first output voltage and a second output voltage. The circuit includes a voltage detection module and a quantity detection module, used to output a first enable signal or a first invalid signal based on the first output voltage and the first internal voltage output from the first internal voltage terminal. The first enable signal controls the second internal voltage terminal to output a second internal voltage, which is preset based on the maximum number of powered devices. An overcurrent detection module is used to output a second invalid signal based on the first invalid signal, or based on the second internal voltage, the second output voltage, and the current at the voltage receiving terminal. A continuity module is used to keep the path between the power supply terminal and the powered devices disconnected based on the second invalid signal. Because the short-circuit detection module in the above circuit can detect whether a short circuit has occurred between the power supply terminal and the powered devices, avoiding the risk of line overheating; the quantity detection module can determine whether the number of powered devices connected to the power supply line exceeds the upper limit, avoiding line overload; and the overcurrent detection module can detect whether there is an overcurrent risk in the line, thereby improving the safety of high-voltage DC power supply. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 This is a schematic diagram of the structure of an Ethernet power receiving circuit in related technologies;

[0044] Figure 2A schematic diagram of a power supply protection circuit provided in an embodiment of the present invention;

[0045] Figure 3 This is a schematic diagram of a short-circuit detection module provided in an embodiment of the present invention;

[0046] Figure 4 This is a schematic diagram of a quantity detection module provided in an embodiment of the present invention;

[0047] Figure 5 This is a schematic diagram of the specific structure of an overcurrent detection module provided in an embodiment of the present invention;

[0048] Figure 6 This is a schematic diagram of a low-dropout voltage regulator in related technologies.

[0049] Figure 7 This is a schematic diagram of the specific structure of an integrated acquisition-on / off module provided in an embodiment of the present invention. Detailed Implementation

[0050] 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. Obviously, the described embodiments are merely some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0051] Currently, video intercom equipment typically uses either 12V DC power or Power over Ethernet (PoE). 12V DC power supports one-to-many connections, but cable transmission loss is high; PoE is suitable for video intercom equipment with network ports and is often used for one-to-one power supply, such as... Figure 1 The diagram shows a schematic of an Ethernet power receiving circuit in the related technology. The power receiving device 101 includes a rectifier bridge 1011 and a power receiving device (PD) module 1012. The first end of the rectifier bridge 1011 is connected to the power supply end Vin, and the second end of the rectifier bridge 1011 is connected to the PD module 1012.

[0052] In the process of upgrading from traditional voice intercom systems to the latest video intercom systems, the poor quality and high impedance of the original cables make it impossible to guarantee power supply safety when using high-voltage DC power. In addition, when the power supply equipment is connected to multiple receiving devices, the excessive number of receiving devices also makes it impossible to guarantee power supply safety.

[0053] To address the aforementioned problems, embodiments of the present invention provide a power supply protection circuit, a high-voltage DC power supply device, and a system to solve the problem of how to ensure power supply safety in the context of high-voltage DC power supply in the prior art.

[0054] The power supply protection circuit provided by the exemplary embodiments of this application will be described below with reference to the accompanying drawings and the application scenarios described above. It should be noted that the application scenarios described above are only shown to facilitate understanding of the spirit and principles of this application, and the embodiments of this application are not limited in any way in this respect.

[0055] like Figure 2 The diagram shown is a structural schematic of a power supply protection circuit provided in an embodiment of the present invention, which is applied to a high-voltage DC power supply equipment. The power supply protection circuit includes a short-circuit detection module 201, a quantity detection module 202, an overcurrent detection module 203, and a continuity module 204.

[0056] The short circuit detection module 201 is connected to the power supply terminal Vin, the quantity detection module 202 and the overcurrent detection module 203 respectively. The quantity detection module 202 is connected to the first internal voltage terminal Va and the second internal voltage terminal Vb respectively. The overcurrent detection module 203 is connected to the second internal voltage terminal Vb, the voltage receiving terminal Vc of the powered device 102 and the on / off module 204 respectively. The on / off module 204 is connected to the power supply terminal Vin and the powered device 102 respectively.

[0057] The short-circuit detection module 201 is used to divide the power supply voltage output from the power supply terminal Vin and output a first output voltage VADC_IN and a second output voltage Vout.

[0058] The quantity detection module 202 is used to output a first enable signal V_EN1 or a first invalid signal V_DIS1 based on the first output voltage VADC_IN and the first internal voltage V_AMP output from the first internal voltage terminal Va. The first enable signal V_EN1 is used to control the second internal voltage terminal Vb to output the second internal voltage V_DET. The first internal voltage V_AMP is preset based on the maximum number of powered devices 102.

[0059] The overcurrent detection module 203 is used to output a second invalid signal V_DIS2 based on the first invalid signal V_DIS1, or based on the second internal voltage V_DET, the second output voltage Vout, and the current of the voltage receiving terminal Vc.

[0060] The on / off module 204 is used to keep the path between the power supply terminal Vin and the powered device 102 in an open state according to the second invalid signal V_DIS2.

[0061] This invention discloses a power supply protection circuit, comprising a short-circuit detection module, a quantity detection module, an overcurrent detection module, and a continuity-breaking module. The short-circuit detection module is connected to the power supply terminal, the quantity detection module, and the overcurrent detection module. The quantity detection module is connected to a first internal voltage terminal and a second internal voltage terminal. The overcurrent detection module is connected to the second internal voltage terminal, the voltage receiving terminal of the powered device, and the continuity-breaking module. The continuity-breaking module is connected to the power supply terminal and the powered device. The short-circuit detection module is used to divide the power supply voltage output from the power supply terminal to output a first output voltage and a second output voltage. The quantity detection module is used to output a first enable signal or a first invalid signal based on the first output voltage and the first internal voltage output from the first internal voltage terminal. The first enable signal is used to control the second internal voltage terminal to output a second internal voltage, which is preset based on the maximum number of powered devices. The overcurrent detection module is used to output a second invalid signal based on the first invalid signal, or based on the second internal voltage, the second output voltage, and the current at the voltage receiving terminal. The continuity-breaking module is used to keep the path between the power supply terminal and the powered device disconnected based on the second invalid signal. In this embodiment of the invention, the magnitude of the first output voltage of the short-circuit detection module can detect whether a short circuit has occurred between the power supply end and the powered device, thus avoiding the risk of line overheating. At the same time, the quantity detection module can determine whether the number of powered devices connected to the power supply line exceeds the upper limit, thus avoiding line overload. In addition, the overcurrent detection module can detect whether there is an overcurrent risk in the line, thereby protecting the power supply line. Finally, the continuity module can keep the path between the power supply end and the powered device in an open state when there is a power supply risk, thereby improving the safety of high-voltage DC power supply.

[0062] The function of the power supply protection circuit will be explained in detail below, taking into account its specific structure:

[0063] like Figure 3 The diagram shown is a schematic representation of a short-circuit detection module provided in an embodiment of the present invention. The short-circuit detection module includes a first resistor R1, a second resistor R2, a third resistor R3, and a first diode D1.

[0064] The first end of the first resistor R1 is connected to the power supply terminal Vin. The second end of the first resistor R1 is connected to the anode of the first diode D1 and the first end of the second resistor R2. The second end of the second resistor R2 is connected to the quantity detection module 202 and the first end of the third resistor R3. The second end of the third resistor R3 is grounded. The cathode of the first diode D1 is connected to the overcurrent detection module 203.

[0065] In one possible embodiment, such as Figure 3As shown, the short-circuit detection module also includes a first filter capacitor C301 and a second filter capacitor C302. The first terminal of the first filter capacitor C301 is connected to the first terminal of the second filter capacitor C302, the second terminal of the second resistor R2, the quantity detection module 202, and the first terminal of the third resistor R3, respectively. The second terminal of the first filter capacitor C301 is connected to the second terminal of the second filter capacitor C302 and the second terminal of the third resistor R3, respectively, and is grounded.

[0066] like Figure 3 As shown, if the receiving device 102 is not connected to the high-voltage DC power supply system, the supply voltage U output from the power supply terminal Vin is divided to output the second output voltage Vout. The calculation process is as follows:

[0067] Vout=U*[(R2+R3) / (R1+R2+R3)];

[0068] Where R1 is the resistance of the first resistor R1, R2 is the resistance of the second resistor R2, and R3 is the resistance of the third resistor R3.

[0069] If n power receiving devices 102 are connected to a high-voltage DC power supply system, such as Figure 3 As shown, the internal resistance of each powered device 102 can be equivalent to a resistor R0. Furthermore, the resistance values ​​of the second resistor R2, the third resistor R3, and the n parallel R0s in the short-circuit detection module 201 can be equivalent to a resistor Req. The calculation process is as follows:

[0070] 1 / Req = 1 / (R2+R3)+n / R0;

[0071] At this point, the supply voltage U output from the power supply terminal Vin is divided to produce the second output voltage Vout. The calculation process is as follows:

[0072] Vout = U * [Req / (R1 + Req)];

[0073] In practice, if the second output voltage Vout of the short circuit detection module 201 is detected to be 0V, it can be determined that a short circuit has occurred in the cable between the power supply equipment and the power receiving equipment.

[0074] The second output voltage Vout is further divided to output the first output voltage VADC_IN. The calculation process is shown below:

[0075] VADC_IN=Vout*[R3 / (R2+R3)];

[0076] In specific implementation, R1 can be a resistor with a resistance of 21.5kΩ, R2 can be a resistor with a resistance of 4.7kΩ, and R3 can be a resistor with a resistance of 1.2kΩ. When the input voltage of the powered device 102 is between 1.4V and 10.1V, and the PD module 1012 of the powered device 102 is in the detection state, the internal resistance of the powered device 102 can be equivalent to a resistor R0 with a resistance of 25kΩ.

[0077] For example, if 24 powered devices 102 are connected, i.e., n=24, Req=4.78kΩ, then the power supply voltage U output from the power supply terminal Vin is divided to output a second output voltage Vout of 1.90V. The second output voltage Vout is further divided to output a first output voltage VADC_IN of 0.39V.

[0078] like Figure 4 The diagram shown is a schematic diagram of a quantity detection module provided in an embodiment of the present invention. The quantity detection module may include a fourth resistor R4, a fifth resistor R5, a sixth resistor R6, a first comparator U1, a second comparator U2, and an AND gate AD.

[0079] The positive input terminal of the first comparator U1 is connected to the short-circuit detection module 201. The negative input terminal of the first comparator U1 is connected to the first terminal of the fifth resistor R5 and the first terminal of the sixth resistor R6, respectively. The output terminal of the first comparator U1 is connected to the first input terminal of the AND gate AD. The positive input terminal of the second comparator U2 is connected to the short-circuit detection module 201. The negative input terminal of the second comparator U2 is connected to the second terminal of the fifth resistor R5 and the first terminal of the fourth resistor R4. The output terminal of the second comparator U2 is connected to the second input terminal of the AND gate AD. The output terminal of the AND gate AD is connected to the second internal voltage terminal Vb. The second terminal of the fourth resistor R4 is connected to the first internal voltage terminal Va. The second terminal of the sixth resistor R6 is grounded.

[0080] In one possible embodiment, such as Figure 4 As shown, the quantity detection module 202 may further include a third filter capacitor C401, a fourth filter capacitor C402, a first pull-up resistor R403, a first pull-down resistor R404, a second pull-down resistor R405, and a resistor R406. The third filter capacitor C401 is connected in parallel with the fourth resistor R402, the fourth filter capacitor C402 is connected in parallel with the second pull-down resistor R405, and is grounded. The first end of the resistor R406 is connected to the output terminal of the AND gate AD, and the second end of the resistor R406 is connected to the first end of the fourth filter capacitor C402 and the first end of the second pull-down resistor R405.

[0081] The quantity detection module 202 divides the first internal voltage V_AMP output from the first internal voltage terminal Va to obtain the first reference voltage Vref1 and the second reference voltage Vref2. If the first output voltage VADC_IN is greater than or equal to the first reference voltage Vref1 and less than or equal to the second reference voltage Vref2, the first enable signal V_EN1 is output; otherwise, the first invalid signal V_DIS1 is output. The first enable signal V_EN1 is a high-level signal, and the first invalid signal V_DIS1 is a low-level signal.

[0082] In specific implementation, the first internal voltage terminal Va can provide a first internal voltage V_AMP of 3.3V. The quantity detection module 202 divides the first internal voltage V_AMP output from the first internal voltage terminal Va to obtain a first reference voltage Vref1 of 0.3V and a second reference voltage Vref2 of 3V. If the first output voltage VADC_IN is greater than or equal to 0.3V and less than or equal to 3V, a first enable signal V_EN1 is output so that the overcurrent detection module 203 receives a drive voltage of 10.7V. Otherwise, a first invalid signal V_DIS is output. The correspondence between the voltage value of the first output voltage VADC_IN and the output levels of the first comparator U1, the second comparator U2, and the AND gate AD is shown in the following table:

[0083] VADC_IN U1 U2 AD <0.3V 0 1 0 0.3V~3V 1 1 1 >3V 1 0 0

[0084] For example, in conjunction with the above example, if the high-voltage DC power supply system is connected to 24 power receiving devices 102, the first output voltage VADC_IN of the short-circuit detection module 201 is 0.39V, which is in the range of 0.3V to 3V. Therefore, the quantity detection module 202 outputs the first enable signal V_EN1 so that the overcurrent detection module 203 receives the second internal voltage V_DET of 10.7V.

[0085] like Figure 5 The diagram shown is a schematic diagram of the specific structure of an overcurrent detection module provided in an embodiment of the present invention. The overcurrent detection module 203 includes a first switch M1, a second switch M2, a seventh resistor R7, an eighth resistor R8, a ninth resistor R9, a tenth resistor R10, an eleventh resistor R11, a twelfth resistor R12, a second diode D2, and a third diode D3.

[0086] The anode of the second diode D2 is connected to the second internal voltage terminal Vb. The cathode of the second diode D2 is connected to the first terminal of the seventh resistor R7 and the first terminal of the first switch M1. The second terminal of the seventh resistor R7 is connected to the short-circuit detection module 201, the second terminal of the eighth resistor R8, and the anode of the third diode D3. The cathode of the third diode D3 is connected to the voltage receiving terminal Vc. The control terminal of the first switch M1 is connected to the first terminal of the eighth resistor R8. The second terminal of the first switch M1 is connected to the first terminal of the ninth resistor R9. The second terminal of the ninth resistor R9 is connected to the first terminal of the tenth resistor R10 and the control terminal of the second switch M2. The second terminal of the tenth resistor R10 is grounded. The first terminal of the second switch M2 is connected to the second terminal of the eleventh resistor R11, the first terminal of the twelfth resistor R12, and the switching module 204. The second terminal of the second switch M2 is connected to the second terminal of the twelfth resistor R12 and grounded. The first terminal of the eleventh resistor R11 is connected to the second internal voltage terminal Vb.

[0087] It should be noted that a low-dropout voltage regulator also exists between the quantity detection module 202 and the overcurrent detection module 203, such as... Figure 6 The diagram shows a schematic of a low-dropout regulator in the related technology. The low-dropout regulator circuit is used to output a second internal voltage V_DET according to the first enable signal V_EN1 when the input drive voltage Vcc is received. For example, in conjunction with the above example, the low-dropout regulator receives a 12V drive voltage Vcc. After receiving the first enable signal V_EN1 output by the quantity detection module 202, the bias circuit outputs a second internal voltage V_DET of 10.7V.

[0088] After the overcurrent detection module 203 divides the second internal voltage V_DET, it outputs a second enable signal V_EN2 when the current formed at the voltage receiving terminal Vc is less than the first preset current value, or when the current formed at the voltage receiving terminal Vc of the second output voltage Vout is less than the first preset current value; otherwise, it outputs a second invalid signal V_DIS2. The second enable signal V_EN2 is a high-level signal, and the second invalid signal V_DIS2 is a low-level signal.

[0089] It should be noted that the aforementioned first preset current value is the current value at the first overcurrent point. When the powered device 102 is connected normally, since each powered device 102 includes a PD module 1012, when the PD module 1012 is in the detection state, the characteristic impedance value is relatively large, and the module current flowing through each PD module 1012 is relatively small. The current formed at the voltage receiving terminal Vc is less than the first overcurrent point current value, so the overcurrent detection module 203 will not trigger the power-off protection. Similarly, when the powered device 102 is connected normally, if the current formed at the voltage receiving terminal Vc by the second output voltage Vout is less than the first overcurrent point current value, the overcurrent detection module 203 will also not trigger the power-off protection.

[0090] For example, referring to the above example, if 24 powered devices 102 are connected, the second internal voltage V_DET of 10.7V will be approximately 10.1V after being divided by the second diode D2 and the third diode D3. The resistance of the seventh resistor R7 is 9.4Ω, and the voltage at the first overcurrent point is 0.6V. Therefore, the current value Ilim1 at the first overcurrent point is 64mA. The specific calculation process is as follows:

[0091] Ilim1 = 0.6V / 9.4Ω = 64mA;

[0092] When the PD module 1012 is in detection mode, its characteristic impedance is 25kΩ, and the module current flowing through each Ethernet module is approximately 400uA. Since the overcurrent point current is 64mA, the overcurrent detection module 203 will not trigger its power-off protection. If there is no second internal voltage V_DET input at this time, the second output voltage Vout is 1.90V, and the current formed at the voltage receiving terminal Vc is also less than 64mA, so the overcurrent detection module 203 will not trigger its power-off protection.

[0093] When the power receiving device 102 is connected incorrectly, such as connecting a traditional building video intercom device with a nominal 12V power supply, the device can start. The current formed at the voltage receiving terminal Vc is greater than the first overcurrent point current value, the first switch M1 is turned on, which in turn causes the second switch M2 to turn on. The overcurrent detection module 203 outputs the second invalid signal V_DIS2, thereby ensuring that the video intercom device with a rated 12V power supply will not be burned out when high-voltage DC power supply is used, such as when using a 48V voltage for power supply.

[0094] It should be noted that traditional Ethernet powered devices connect to and receive power from the power supply via a network cable. Although the powered device 102 in this invention includes a PD module 1012, the power supply system of this invention does not use a network cable for power supply, but rather two electrical wires. This greatly simplifies on-site construction, reduces construction costs, and compared to traditional Ethernet power supply methods, the power supply method of this invention has a higher output power and supports the connection of more powered devices 102. Therefore, through the above circuit, it can be ensured that devices mistakenly connected to the high-voltage DC power supply system are not damaged, thereby further ensuring the safety of the entire high-voltage DC power supply system.

[0095] like Figure 7 The diagram shown is a schematic diagram of the specific structure of a data acquisition-on / off integrated module provided in an embodiment of the present invention. The data acquisition-on / off integrated module includes a current acquisition module 701 and an on / off module 204, wherein the on / off module 204 includes a control unit 2041 and an on / off unit 2042.

[0096] Input terminal of control unit 2041 The control terminal GATE of the control unit 2041 is connected to the control terminal of the on / off unit 2042, which is connected to the overcurrent detection module 203. The first terminal of the on / off unit 2042 is connected to the power supply terminal Vin, and the second terminal of the on / off unit 2042 is connected to the power receiving device 102.

[0097] The control unit 2041 in the on / off module 204 is used to output a conduction signal V_THMOS after receiving the second enable signal V_EN2, so as to control the on / off unit 2042 to conduct the first terminal a and the second terminal b of the on / off unit 2042, and not to output a control signal after receiving the second invalid signal V_DIS2, so as to keep the path between the first terminal a and the second terminal b of the on / off unit 2042 in the off state.

[0098] In one possible embodiment, the switching unit 2042 consists of back-to-back driving transistors, specifically including a first driving transistor Q703, a second driving transistor Q704, a switching transistor M702, resistors R705, R706, and R707. The first terminal of resistor R707 is connected to the control terminal GATE of the control unit 2041. The second terminal of resistor R707 is connected to the first terminal of resistor R706 and the control terminal of the second driving transistor Q704, respectively. The second terminal of resistor R706 is connected to the first driving transistor Q705. The control terminal of 703 is connected to the input terminal of the switching transistor M702. The control terminal of the switching transistor M702 is connected to the first terminal of the resistor R705. The second terminal of the resistor R705 is grounded. The output terminal of the switching transistor M702 is connected to the input terminal of the first driving transistor Q703 and serves as the first terminal a of the switching unit 2042. The output terminal of the first driving transistor Q703 is connected to the input terminal of the second driving transistor Q704. The output terminal of the second driving transistor Q704 is connected to the powered device 102 and serves as the second terminal b of the switching unit 2042.

[0099] In specific implementation, the control terminal GATE of the control unit 2041 in the switching module 204 outputs a conduction signal V_THMOS. The switching unit 2042 receives the conduction signal V_THMOS, which drives the second driving transistor Q704 to conduct. Furthermore, the first terminal a of the switching unit 2042 is input with a power supply voltage, which drives the first driving transistor Q703 to conduct. The conduction signal V_THMOS drives the first driving transistor to conduct, thereby controlling the switching unit 2042 to conduct. The path between the first terminal a and the second terminal b of the switching unit 2042 is connected. In addition, the switching transistor M702 can prevent the power supply terminal Vin from being reversed, for example, to prevent the power supply terminal Vin from being grounded and the grounding terminal from being connected to the power supply equipment.

[0100] Furthermore, the on / off module 204 provided in this embodiment of the invention may further include a power-on unit 2043 and a power-off unit 2044. The power-on unit 2043 may include a sixteenth resistor R16 and a first capacitor C1, and the power-off unit 2044 may include a fourth diode D4 and a seventeenth resistor R17. The first end of the sixteenth resistor R16 is connected to the overcurrent detection module 203, and the second end of the sixteenth resistor R16 is connected to the input terminal of the control unit 2041 and the first end of the first capacitor C1, respectively. The second end of the first capacitor C1 is grounded. The anode of the fourth diode D4 is connected to the first end of the seventeenth resistor R17, and the cathode of the fourth diode D4 is connected to the first end of the sixteenth resistor R16 and the overcurrent detection module 203, respectively. The second end of the seventeenth resistor R17 is connected to the second end of the sixteenth resistor R16, the first end of the first capacitor C1, and the input terminal of the control unit 2041, respectively. connect.

[0101] When the system is powered on, the power-on unit 2043 charges through the sixteenth resistor R16 and the first capacitor C1 to achieve slow power-on. When a short circuit occurs during normal operation, the power-off unit 2044 quickly pulls down the second enable signal V_EN2 through the fourth diode D4 and the seventeenth resistor R17, thereby disconnecting the path between the first terminal a and the second terminal b of the on / off unit 2042 controlled by the control unit 2041.

[0102] Furthermore, the on / off module 204 provided in this embodiment of the invention may also include resistors R708, R709, and R710, diodes D711 and D712, capacitors C713, C714, and C715, and switch N716. The first terminal of capacitor C713 is connected to the second terminal of the sixteenth resistor R16, the second terminal of the seventeenth resistor R17, the first terminal of the first capacitor C1, and the input terminal of the control unit 2042. The connection is as follows: the second terminal of capacitor C713 is grounded; the first terminal of resistor R708 is connected to the output terminal VOUT of control unit 2042, the cathode of diode D711, and the first terminal of capacitor 714; the second terminal of resistor R708 is connected to the second terminal b of control unit 2042, the first terminal of resistor R709, the anode of diode D711, the first terminal of capacitor C715, and the cathode of diode D712; the second terminal of resistor R709 is connected to the inductor terminal FB of control element 2042 and the first terminal of resistor R710; the second terminal of resistor R710 is connected to the second terminal of capacitor C715 and the second terminal of switch N716 and grounded; and the anode of diode D712 is connected to the first terminal of switch N716.

[0103] It should be noted that the output voltage of the control terminal GATE of the control unit is greater than the output voltage of the output terminal VOUT.

[0104] In practice, capacitor C714 and resistor R708 can prevent the instantaneous spark voltage generated during hot-plugging from impacting the control unit 2041. In addition, diode D712 can be used to discharge the negative phase voltage, thereby protecting the control unit 2041.

[0105] Furthermore, the current acquisition module 701 may include a fifteenth resistor R15 and a control unit 2041; the first end of the fifteenth resistor R15 is connected to the power supply terminal Vin, and the second end of the fifteenth resistor R15 is connected to the first end of the on / off unit 2042 and the current acquisition terminal SNS of the control unit 2041, respectively.

[0106] When the current acquisition module 701 is in the state of having a conductive path between the power supply terminal Vin and the power receiving device 102, it acquires the current in the path. The current acquisition terminal SNS of the control unit 2041 is used to acquire the current at the second terminal of the fifteenth resistor R15. When the acquired current is greater than the second preset current value, it outputs a disconnect signal to the switching unit 2042 so that the switching unit 2042 disconnects the path between the first terminal a and the second terminal b of the switching unit 2042.

[0107] It should be noted that the above-mentioned second preset current value is the current value Ilim2 of the second overcurrent point. The control unit 2041 is equipped with a reference voltage, and the fifteenth resistor R15 is a sampling resistor. The current value of the second overcurrent point can be determined according to the voltage value of the reference voltage and the resistance value of the sampling resistor, and the current is collected by the current acquisition terminal SNS of the control unit 2041.

[0108] For example, if the control unit 2041 has an internal reference voltage of 50mV and the sampling resistor has a resistance of 0.0115Ω, then the current value Ilim2 at the second overcurrent point is 4.35A. The specific calculation process is as follows:

[0109] Ilim2=50mV / 0.0115Ω=4.35A;

[0110] When the powered device 102 is connected normally, the input terminal of the control unit 2041... The received second enable signal V_EN2 is a high-level signal. The current value collected by the current acquisition terminal SNS of the control unit 2041 is less than the second overcurrent point current value. The control terminal GATEk of the control unit 2041 controls the control terminal of the switching unit 2042 to be turned on. The switching module 204 outputs the on signal V_THMOS, thereby controlling the switching unit 2042 to be turned on. The first terminal a and the second terminal b of the switching unit 2042 are turned on.

[0111] It should be noted that during normal use, if the powered device 102 itself is damaged, causing a short circuit between the power supply terminal Vin and the powered device 102, the PD module 1012 of the powered device 102 will automatically protect itself and will not affect the normal operation of other devices.

[0112] When the power receiving device 102 experiences a connection malfunction, the input terminal of the control unit 2041... The received second invalid signal V_DIS2 is a low-level signal. The on / off module 204 does not output the on signal V_THMOS or the control signal, thereby keeping the path between the first terminal a and the second terminal b of the on / off unit 2042 open.

[0113] When the powered device 102 is connected normally, if a short circuit occurs between the power supply terminal Vin and the powered device 102 during normal use, and the current exceeds the second overcurrent point current value Ilim2, the circuit breaker protection is triggered. The switching module 204 does not output the conduction signal V_THMOS and stops outputting the control signal, thereby disconnecting the path between the first terminal a and the second terminal b of the switching unit 2042.

[0114] It should be noted that at this time, the first output voltage VADC_IN is close to 0V, the first invalid signal V_DIS1 is a low-level signal, and consequently the second invalid signal V_DIS2 is also a low-level signal. At this point, the current in the short-circuited line is in the milliampere range, and there is no risk of cable overheating. After the short-circuit risk is eliminated, the high-voltage DC power supply system resumes normal power supply.

[0115] Based on the same inventive concept, this invention also provides a high-voltage DC power supply device. The implementation of the device can refer to the implementation of the power supply protection circuit described above, and the repeated parts will not be described again.

[0116] Based on the same inventive concept, this invention also provides a high-voltage DC power supply system. The implementation of the device can refer to the implementation of the power supply protection circuit described above, and the repeated parts will not be described again.

[0117] This invention discloses a power supply protection circuit, a high-voltage DC power supply device, and a system. The power supply protection circuit includes a short-circuit detection module, a quantity detection module, an overcurrent detection module, a current acquisition module, and a continuity control module. The short-circuit detection module is connected to the power supply terminal, the quantity detection module, and the overcurrent detection module. The quantity detection module is connected to a first internal voltage terminal and a second internal voltage terminal. The overcurrent detection module is connected to the second internal voltage terminal, the voltage receiving terminal of the powered device, and the continuity control module. The continuity control module is connected to the power supply terminal and the powered device. The current acquisition module is connected to the continuity control module. The short-circuit detection module is used to divide the power supply voltage output from the power supply terminal to output a first output voltage and a second output voltage. The quantity detection module is used to divide the first internal voltage to obtain a first reference voltage and a second reference voltage. If the first output voltage is greater than or equal to the first reference voltage... If the voltage is less than or equal to the second reference voltage, a first enable signal is output; otherwise, a first invalid signal is output. The first enable signal is used to control the output of the second internal voltage terminal, which is preset based on the maximum number of powered devices. The overcurrent detection module is used to divide the second internal voltage and output a second enable signal when the current formed at the voltage receiving terminal is less than the first preset current value, or when the current formed at the voltage receiving terminal by the second output voltage is less than the first preset current value; otherwise, a second invalid signal is output. The current acquisition module is used to acquire the current in the path between the power supply terminal and the powered device when the path is open. When the current acquired by the current acquisition module is greater than the second preset current value, the on / off module is controlled to output a disconnect signal. The on / off module is used to disconnect the path between the power supply terminal and the powered device based on the disconnect signal. The first output voltage of the short-circuit detection module can detect whether a short circuit has occurred between the power supply and the powered device, thus avoiding the risk of line overheating. At the same time, the quantity detection module can determine whether the number of powered devices connected to the power supply line exceeds the capacity limit of the power supply system, thus avoiding line overload. In addition, the overcurrent detection module can detect whether the wrong type of powered device is connected to the line, thereby avoiding the risk of overcurrent. Finally, the continuity module can keep the path between the power supply and the powered device disconnected when there is a power supply risk.

[0118] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A power supply protection circuit applied to a high-voltage direct-current power supply device, characterized in that, The power supply protection circuit comprises a short-circuit detection module, a quantity detection module, an overcurrent detection module and a on-off module; The short-circuit detection module is connected with the power supply end, the quantity detection module and the overcurrent detection module respectively, the quantity detection module is connected with the first internal voltage end and the second internal voltage end respectively, the overcurrent detection module is connected with the second internal voltage end, the voltage receiving end of the powered device and the on-off module respectively, and the on-off module is connected with the power supply end and the powered device respectively; The short-circuit detection module is configured to divide the power supply voltage output by the power supply end to output a first output voltage and a second output voltage; The quantity detection module is configured to output a first enable signal or a first invalid signal according to the first output voltage and a first internal voltage output by the first internal voltage end, wherein the first enable signal is used to control the second internal voltage end to output a second internal voltage, and the first internal voltage is pre-set based on the maximum number of powered devices; The overcurrent detection module is configured to output a second invalid signal based on the first invalid signal, or output the second invalid signal based on the second internal voltage, the second output voltage and a current of the voltage receiving end; The on-off module is configured to keep the passage between the power supply end and the powered device in a disconnected state according to the second invalid signal.

2. The circuit of claim 1, wherein The overcurrent detection module is further configured to output a second enable signal based on the second internal voltage, the second output voltage and the current of the voltage receiving end; The on-off module is further configured to turn on the passage between the power supply end and the powered device according to the second enable signal.

3. The circuit of claim 2, wherein, The overcurrent detection module is further configured to: divide the second internal voltage, and output the second enable signal when the current formed at the voltage receiving end is less than a first preset current value after the division, or when the second output voltage is less than the first preset current value, otherwise output the second invalid signal.

4. The circuit of claim 1, wherein, The quantity detection module is further configured to: divide the first internal voltage to obtain a first reference voltage and a second reference voltage, and output the first enable signal if the first output voltage is greater than or equal to the first reference voltage and less than or equal to the second reference voltage, otherwise output the first invalid signal.

5. The circuit of claim 2, wherein, The power supply protection circuit further comprises a current collection module connected with the on-off module; The current collection module is configured to collect the current on the passage between the power supply end and the powered device when the passage is turned on, and control the on-off module to output a disconnect signal when the current collected by the current collection module is greater than a second preset current value; The on-off module is configured to disconnect the passage between the power supply end and the powered device based on the disconnect signal.

6. The circuit of claim 1, wherein, The short-circuit detection module comprises a first resistor, a second resistor, a third resistor and a first diode; The first end of the first resistor is connected with the power supply end, the second end of the first resistor is connected with the anode of the first diode and the first end of the second resistor respectively, the second end of the second resistor is connected with the quantity detection module and the first end of the third resistor respectively, the second end of the third resistor is grounded, and the cathode of the first diode is connected with the overcurrent detection module.

7. The circuit of claim 1 or 4, wherein The quantity detection module comprises a fourth resistor, a fifth resistor, a sixth resistor, a first comparator, a second comparator and an AND gate. The positive input end of the first comparator is connected with the short circuit detection module, the negative input end of the first comparator is connected with the first end of the fifth resistor and the first end of the sixth resistor respectively, the output end of the first comparator is connected with the first input end of the AND gate, the positive input end of the second comparator is connected with the short circuit detection module, the negative input end of the second comparator is connected with the second end of the fifth resistor and the first end of the fourth resistor, the output end of the second comparator is connected with the second input end of the AND gate, the output end of the AND gate is connected with the second internal voltage end, the second end of the sixth resistor is connected with the first internal voltage end, and the second end of the fourth resistor is grounded.

8. The circuit of any one of claims 1-3, wherein The overcurrent detection module comprises a first switch tube, a second switch tube, a seventh resistor, an eighth resistor, a ninth resistor, a tenth resistor, an eleventh resistor, a twelfth resistor, a second diode and a third diode. The anode of the second diode is connected with the second internal voltage end, the cathode of the second diode is connected with the first end of the seventh resistor and the first end of the first switch tube respectively, the second end of the seventh resistor is connected with the short circuit detection module, the second end of the eighth resistor and the anode of the third diode respectively, the cathode of the third diode is connected with the voltage receiving end, the control end of the first switch tube is connected with the first end of the eighth resistor, the second end of the first switch tube is connected with the first end of the ninth resistor, the second end of the ninth resistor is connected with the first end of the tenth resistor and the control end of the second switch tube respectively, the second end of the tenth resistor is grounded, the first end of the second switch tube is connected with the second end of the eleventh resistor, the first end of the twelfth resistor and the on-off module respectively, the second end of the second switch tube is connected with the second end of the twelfth resistor and grounded, and the first end of the eleventh resistor is connected with the second internal voltage end.

9. The circuit of claim 5, wherein, The on-off module comprises a control unit and an on-off unit. The input end of the control unit is connected with the overcurrent detection module, the control end of the control unit is connected with the control end of the on-off unit, the first end of the on-off unit is connected with the power supply end, and the second end of the on-off unit is connected with the powered device. The control unit is configured to output a conduction signal to control the on-off unit to turn on the first end of the on-off unit and the second end of the on-off unit after receiving the second enable signal, and not output the conduction signal to make the on-off unit keep the passage between the first end of the on-off unit and the second end of the on-off unit in a disconnected state after receiving the second invalid signal.

10. The circuit of claim 9, wherein, The current collection module comprises a fifteenth resistor and the control unit; a first end of the fifteenth resistor is connected with the power supply end, and a second end of the fifteenth resistor is connected with the first end of the on-off unit and a current collection end of the control unit respectively; The control unit is configured to collect the current at the second end of the fifteenth resistor, and output the disconnection signal to the on-off unit to make the on-off unit disconnect the passage between the first end of the on-off unit and the second end of the on-off unit when the collected current is greater than the second preset current value.

11. The circuit of claim 10, wherein, The on-off module further comprises a power-on unit; The power-on unit comprises a sixteenth resistor and a first capacitor; a first end of the sixteenth resistor is connected with the overcurrent detection module, a second end of the sixteenth resistor is connected with an input end of the control unit and a first end of the first capacitor respectively, and a second end of the first capacitor is grounded.

12. The circuit of claim 11, wherein, The on-off module further comprises a power-off unit; The power-off unit comprises a fourth diode and a seventeenth resistor; an anode of the fourth diode is connected with a first end of the seventeenth resistor, a cathode of the fourth diode is connected with the first end of the sixteenth resistor and the overcurrent detection module respectively, a second end of the seventeenth resistor is connected with the second end of the sixteenth resistor, the first end of the first capacitor and the input end of the control unit respectively.

13. A high voltage direct current power supply apparatus, characterized by, The power supply protection circuit comprises any one of the power supply protection circuits according to claims 1-12.

14. A high voltage direct current power supply system characterized by, The power supply protection circuit comprises any one of the power supply protection circuits according to claims 1-12.

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