Surge protection circuits and electronic equipment

Abstract

The disclosed embodiment provides a surge protection circuit and electronic device. An isolation transformer for transforming alternating current; a thermistor current limiting resistor connected in series with the primary coil of the isolation transformer to limit the surge current; a relay connected in parallel with the thermistor current limiting resistor; a control unit connected to the relay and at least used to control the relay to close to bypass the thermistor current limiting resistor, wherein the switch end of the relay is connected in parallel with the thermistor current limiting resistor and the coil end of the relay is connected to the control unit; a power failure detection unit connected to the secondary coil of the isolation transformer and used to detect power supply changes of the secondary coil, conduct the connection between the relay and the control unit when the secondary coil is powered, and cut off the connection between the relay and the control unit when the secondary coil is powered off to disconnect the relay.

Description

Technical Field

[0001] The utility model relates to the technical field of electronic circuits, in particular to a surge protection circuit and electronic equipment. Background Art

[0002] At present, the electrical boxes of electronic equipment such as surgical robots all have power equipment such as isolation transformers and switching power supplies. These devices have high power and contain energy storage components such as capacitors and inductors. When electronic equipment is powered on, the presence of energy storage components will generate a surge current far greater than the rated current, which can cause the fuse of the machine to be triggered by mistake and blow. Utility Model Content

[0003] In view of this, embodiments of the present disclosure provide a surge protection circuit and an electronic device.

[0004] According to a first aspect of an embodiment of the present disclosure, a surge protection circuit is provided, characterized in that the circuit comprises:

[0005] Isolation transformers for transforming AC power;

[0006] A thermistor current limiting resistor connected in series with the primary coil of the isolation transformer to limit the inrush current;

[0007] a relay connected in parallel with the thermistor current limiting resistor;

[0008] A control unit connected to the relay and at least used to control the relay to close so as to bypass the thermistor current limiting resistor, wherein the switch end of the relay is connected in parallel with the thermistor current limiting resistor, and the coil end of the relay is connected to the control unit;

[0009] A power-off detection unit connected to the secondary coil of the isolation transformer, used to detect power supply changes of the secondary coil, conduct the connection between the relay and the control unit when the secondary coil is energized, and cut off the connection between the relay and the control unit when the secondary coil is powered off to disconnect the relay.

[0010] In combination with some embodiments of the first aspect, in some embodiments, the power failure detection unit includes: a power failure detection module and a controlled switch, wherein:

[0011] The power-off detection module is used to detect the power supply change of the secondary coil and output a switch control signal to control the closing or opening of the controlled switch; wherein, in response to the power-off detection module detecting that the secondary coil is powered off, the switch control signal is used to control the controlled switch to disconnect the connection between the relay and the control unit, or in response to the power-off detection module detecting that the secondary coil is powered on, the switch control signal is used to control the controlled switch to connect the connection between the relay and the control unit.

[0012] In combination with some embodiments of the first aspect, in some embodiments, the power-off detection module includes: a first optocoupler, a second optocoupler and a first resistor, wherein:

[0013] The first control end of the first optical coupler, the second control end of the second optical coupler and the first end of the secondary coil are connected;

[0014] The second control end of the first optical coupler, the first control end of the second optical coupler and the second end of the secondary coil are connected;

[0015] The first controlled end of the first optical coupler, the first controlled end of the second optical coupler and a power ground are connected;

[0016] The second controlled end of the first optocoupler, the second controlled end of the second optocoupler and the first end of the first resistor are connected to output the switch control signal, wherein the second end of the first resistor inputs a first DC voltage generated based on the power supply of the secondary coil.

[0017] In combination with some embodiments of the first aspect, in some embodiments, the power-off detection unit further includes: a first power supply module connected to the secondary coil, configured to generate the first DC voltage based on power supply of the secondary coil.

[0018] In combination with some embodiments of the first aspect, in some embodiments, the controlled switch includes: a third optical coupler, wherein:

[0019] The first control terminal of the third optical coupler is used to input the switch control signal;

[0020] The second control terminal of the third optical coupler is connected to the power ground;

[0021] The controlled end of the third optical coupler is connected in series in the connection between the relay and the control.

[0022] In combination with some embodiments of the first aspect, in some embodiments, the power-off detection unit further includes: a signal filtering module, configured to filter the switch control signal.

[0023] In combination with some embodiments of the first aspect, in some embodiments, the signal filtering module includes: a Schmitt trigger inverter.

[0024] In combination with some embodiments of the first aspect, in some embodiments, the circuit further includes: an uninterruptible power supply, a second power supply module, wherein:

[0025] The uninterruptible power supply is connected to the secondary coil of the isolation transformer, and is used to store the electric energy transmitted by the secondary coil and output the electric energy to the second power supply module at least when the secondary coil loses power;

[0026] The second power supply module is used to provide power to the control unit.

[0027] According to a second aspect of an embodiment of the present disclosure, an electronic device is provided, characterized in that the electronic device comprises the surge protection circuit described in the first aspect.

[0028] The surge protection circuit provided by the embodiment of the present disclosure includes: an isolation transformer for transforming alternating current; a thermistor current limiting resistor connected in series with the primary coil of the isolation transformer to limit the surge current; a relay connected in parallel with the thermistor current limiting resistor; a control unit connected to the relay and at least used to control the relay to close to bypass the thermistor current limiting resistor, wherein the switch end of the relay is connected in parallel with the thermistor current limiting resistor, and the coil end of the relay is connected to the control unit; a power-off detection unit connected to the secondary coil of the isolation transformer and used to detect the power supply change of the secondary coil, conduct the connection between the relay and the control unit when the secondary coil is powered, and cut off the connection between the relay and the control unit when the secondary coil is powered off to disconnect the relay. On the one hand, when the isolation transformer is powered on for the first time, the thermistor current limiting resistor can be used to suppress the surge current and improve the circuit stability. On the other hand, the power failure detection unit recovers the current limiting function of the thermistor current limiting resistor by detecting the power failure of the secondary coil, thereby reducing the time delay of detecting the power failure, improving the response time of recovering the current limiting function of the thermistor current limiting resistor, and improving the surge protection effect. On the other hand, the power failure detection unit is connected to the secondary coil of the isolation transformer to reduce the leakage of the primary coil of the isolation transformer. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a schematic structural diagram of a surge protection circuit according to an exemplary embodiment;

[0030] Figure 2 is a structural schematic diagram of a surge protection circuit according to an exemplary embodiment;

[0031] Figure 3is a structural schematic diagram of a surge protection circuit according to an exemplary embodiment;

[0032] Figure 4 is a structural schematic diagram of a surge protection circuit according to an exemplary embodiment;

[0033] Figure 5 is a structural schematic diagram of a surge protection circuit according to an exemplary embodiment;

[0034] Figure 6 is a structural schematic diagram of a surge protection circuit according to an exemplary embodiment;

[0035] Figure 7 is a structural schematic diagram of a surge protection circuit according to an exemplary embodiment;

[0036] Figure 8 The diagram is a schematic structural diagram of an electronic device according to an exemplary embodiment. DETAILED DESCRIPTION

[0037] In order to make the technical solutions and beneficial effects of the utility model more obvious and easy to understand, the following is a detailed description by listing specific embodiments. The drawings are not necessarily drawn to scale, and local features may be enlarged or reduced to more clearly show the details of the local features; unless otherwise defined, the technical and scientific terms used herein have the same meanings as those in the technical field to which this application belongs.

[0038] The embodiments of the present disclosure are not exhaustive, but are only illustrative of some embodiments, and are not intended to be a specific limitation on the scope of protection of the present disclosure. In the absence of contradiction, each step in a certain embodiment can be implemented as an independent embodiment, and the steps can be arbitrarily combined. For example, a solution after removing some steps in a certain embodiment can also be implemented as an independent embodiment, and the order of the steps in a certain embodiment can be arbitrarily exchanged. In addition, the optional implementation methods in a certain embodiment can be arbitrarily combined; in addition, the embodiments can be arbitrarily combined, for example, some or all of the steps of different embodiments can be arbitrarily combined, and a certain embodiment can be arbitrarily combined with the optional implementation methods of other embodiments.

[0039] In each embodiment of the present disclosure, unless otherwise specified or there is a logical conflict, the terms and / or descriptions between the embodiments are consistent and can be referenced to each other, and the technical features in different embodiments can be combined to form a new embodiment based on their internal logical relationships.

[0040] The terms used in the embodiments of the present disclosure are only for the purpose of describing specific embodiments and are not intended to limit the present disclosure.

[0041] In the embodiments of the present disclosure, unless otherwise specified, elements expressed in the singular form, such as "a", "an", "the", "above", "said", "aforementioned", "this", etc., may mean "one and only one", or "one or more", "at least one", etc. For example, when using articles such as "a", "an", "the" in English in translation, the noun after the article may be understood as a singular expression or a plural expression.

[0042] In the embodiments of the present disclosure, “plurality” refers to two or more.

[0043] In some embodiments, the terms "at least one", "one or more", "a plurality of", "multiple", etc. can be used interchangeably.

[0044] In some embodiments, "at least one of A and B", "A and / or B", "A in one case, B in another case", "A in one case, B in another case", etc., may include the following technical solutions according to the situation: in some embodiments, A (A is executed independently of B); in some embodiments, B (B is executed independently of A); in some embodiments, execution is selected from A and B (A and B are selectively executed); in some embodiments, A and B (both A and B are executed). When there are more branches such as A, B, C, etc., the above is also similar.

[0045] In some embodiments, the recording method of "A or B" may include the following technical solutions according to the situation: in some embodiments, A (A is executed independently of B); in some embodiments, B (B is executed independently of A); in some embodiments, execution is selected from A and B (A and B are selectively executed). When there are more branches such as A, B, C, etc., the above is also similar.

[0046] The prefixes such as "first" and "second" in the embodiments of the present disclosure are only used to distinguish different description objects, and do not constitute restrictions on the position, order, priority, value or content of the description objects. The statement of the description object refers to the description in the context of the claims or embodiments, and should not constitute redundant restrictions due to the use of prefixes. For example, if the description object is a "field", the ordinal number before the "field" in the "first field" and the "second field" does not limit the position or order between the "fields", and the "first" and "second" do not limit whether the "fields" they modify are in the same message, nor do they limit the order of the "first field" and the "second field". For another example, if the description object is a "level", the ordinal number before the "level" in the "first level" and the "second level" does not limit the priority between the "levels". For another example, the numerical value of the description object is not limited by the ordinal number, and can be one or more. Taking the "first device" as an example, the numerical value of the "device" can be one or more. In addition, the objects modified by different prefixes may be the same or different. For example, if the description object is "device", then the "first device" and the "second device" may be the same device or different devices, and their types may be the same or different. For another example, if the description object is "information", then the "first information" and the "second information" may be the same information or different information, and their contents may be the same or different.

[0047] In some embodiments, “including A”, “comprising A”, “used to indicate A”, and “carrying A” can be interpreted as directly carrying A or indirectly indicating A.

[0048] In some embodiments, terms such as “…”, “determine…”, “in the case of…”, “at the time of…”, “when…”, “if…”, “if…”, etc. can be used interchangeably.

[0049] In some embodiments, terms such as "greater than", "greater than or equal to", "not less than", "more than", "more than or equal to", "not less than", "higher than", "higher than or equal to", "not lower than", and "above" can be replaced with each other, and terms such as "less than", "less than or equal to", "not greater than", "less than", "less than or equal to", "no more than", "lower than", "lower than or equal to", "not higher than", and "below" can be replaced with each other.

[0050] In some embodiments, devices, etc. can be interpreted as physical or virtual, and their names are not limited to the names recorded in the embodiments. Terms such as "device", "equipment", "device", "circuit", "network element", "node", "function", "unit", "section", "system", "network", "chip", "chip system", "entity", and "subject" can be used interchangeably.

[0051] In addition, each element, each row, or each column in the table of the embodiments of the present disclosure may be implemented as an independent embodiment, and the combination of any elements, any rows, and any columns may also be implemented as an independent embodiment.

[0052] In some embodiments, the method of reducing the surge circuit is to set a thermistor in series with the fuse, such as a negative temperature coefficient thermistor (NTC) resistor. At the moment of power-on, the surge current is absorbed by the NTC resistor, and after normal operation, the resistance of the NTC resistor decreases as the temperature rises.

[0053] In some embodiments, after normal operation, the NTC resistor can be bypassed by a relay to prevent the resistor from continuing to heat up.

[0054] The above scheme has some disadvantages. The first is that when the machine is powered off and then powered on again, if the time interval between power off and power on is short, the temperature of the NTC resistor is still high, and the surge absorption capacity is greatly reduced. The second is that the power-off release capacity of the time relay is poor (much greater than 10ms), that is, when the power is off, the relay still maintains the NTC resistor bypass state for a period of time, which may cause the machine voltage to drop and then recover and fail to absorb the surge current.

[0055] Therefore, how to effectively absorb the power-on surge current and improve the surge current protection capability of the NTC resistor during a short power-off and power-on interval is an urgent problem to be solved.

[0056] Figure 1 A surge protection circuit 100 is shown according to an embodiment of the present disclosure. The surge protection circuit 100 includes: a thermistor current limiting resistor 110 for limiting surge current, a relay 120, a power failure detection unit 130 and a control unit 140, wherein:

[0057] The thermistor current limiting resistor 110 is connected in series with the primary coil of the isolation transformer T1; the relay 120 is connected in parallel with the thermistor current limiting resistor 110; the control unit 140 is connected with the relay 120, and the control unit 140 is at least used to control the relay 120 to close so as to bypass the thermistor current limiting resistor 110; the power-off detection unit 130 is connected with the secondary coil of the isolation transformer T1; the power-off detection unit 130 is used to: detect the power supply change of the secondary coil, conduct the connection between the relay 120 and the control unit 140 when the secondary coil is energized, and cut off the connection between the relay 120 and the control unit 140 when the secondary coil is powered off, so as to disconnect the relay 120.

[0058] Here, the surge protection circuit 100 can be applied to electronic devices such as surgical robots.

[0059] like Figure 1 As shown, the primary coil of the isolation transformer T1 is used to access AC power such as the mains (hereinafter referred to as input AC power), and the isolation transformer T1 transforms the input AC power and outputs it from the secondary coil of the isolation transformer T1 to the subsequent circuits of the electronic device (such as a rectifier circuit, a DC transformer circuit, etc.). The thermistor current limiting resistor 110 can be connected in series to one end of the primary coil of the isolation transformer T1. When the isolation transformer T1 is powered on for the first time, due to the presence of the thermistor current limiting resistor 110, the current input to the primary coil of the isolation transformer T1 can be limited, thereby suppressing the surge current.

[0060] In one possible implementation, the thermistor 110 may include a negative temperature coefficient resistor (NTC). When the isolation transformer T1 is powered on for the first time, the resistance of the thermistor 110 is relatively high, which can effectively suppress the surge current. After the isolation transformer T1 is powered on, the input current flows through the thermistor 110, causing the temperature of the thermistor 110 to rise, thereby reducing the resistance of the thermistor 110, thereby reducing the influence of the thermistor 110 on the input current.

[0061] In a possible implementation, the relay 120 may also be replaced by a thyristor or the like.

[0062] The control unit 140 may be implemented by hardware. The control unit 140 may also be implemented by combining hardware and software. For example, the control unit 140 may include a microprocessor or the like for implementing control logic.

[0063] The control unit 140 can control the relay 120 to close after detecting that the isolation transformer T1 is powered on, so that the input current flows through the relay 120 and bypasses the thermistor current limiting resistor 110 , thereby reducing the influence of the thermistor current limiting resistor 110 on the input current.

[0064] In a possible implementation, the control unit 140 is further configured to control the relay 120 to be disconnected. When the relay 120 is disconnected, the thermistor current limiting resistor 110 is reconnected to the circuit.

[0065] In some embodiments, Figure 1 As shown, the switch end of the relay 120 is connected in parallel with the thermistor current limiting resistor 110 , and the coil end of the relay 120 is connected with the control unit 140 .

[0066] The relay 120 can be implemented by a single-pole single-throw relay (Relay-SPST). The control unit 140 can control the relay 120 by controlling the power input of the coil end of the relay 120. The controlled switch end of the relay 120 is connected in parallel with the thermistor current limiting resistor 110. The control unit 140 can control the power input of the coil end of the relay 120 to close and open the controlled switch of the relay 120, thereby bypassing the thermistor current limiting resistor 110.

[0067] Electronic devices may experience power failure and power on again in a short time during use. The control unit 140 usually determines whether power is lost based on the voltage condition of the DC terminal; and the control unit 140 needs a certain response time (for example, greater than 100mS) when power is lost, so the relay 120 cannot be disconnected in time. When power is restored, the thermistor current limiting resistor 110 may still be in the bypass state, so that the surge current cannot be suppressed.

[0068] Here, a power failure detection unit 130 can be used to detect the power supply changes of the secondary coil of the isolation transformer T1. The power supply changes may include at least one of the following: power on (power on and / or continuous power supply), power failure. The power failure detection unit 130 detects the power supply changes of the secondary coil of the isolation transformer T1. On the one hand, compared with detecting the power supply changes at the DC end, it is closer to the input end of the input AC power, reducing the delay in detecting the power failure. On the other hand, the power failure detection unit 130 is connected to the secondary coil of the isolation transformer T1 to reduce the leakage of the primary coil of the isolation transformer T1.

[0069] When the power failure detection unit 130 detects that the secondary coil has power, it can connect the connection between the relay 120 and the control unit 140, so that the control unit 140 can control the relay 120. Connecting the connection between the relay 120 and the control unit 140 may include: connecting the electrical connection for the control unit 140 to supply power to the relay 120.

[0070] When the power failure detection unit 130 detects that the secondary coil is powered off, it may cut off the connection between the relay 120 and the control unit 140. Cutting off the connection between the relay 120 and the control unit 140 may include: cutting off the power supply from the control unit 140 to the relay 120.

[0071] In a possible implementation, the connection between the control unit 140 and the relay 120 is a power supply circuit. The control unit 140 controls the relay 120 by supplying power to the relay 120 or cutting off the power supply. When the control unit 140 supplies power to the relay 120, the relay 120 is controlled to close, thereby bypassing the thermistor current limiting resistor. The control unit 140 cuts off the power supply to the relay 120 and controls the relay 120 to open, thereby connecting the thermistor current limiting resistor to the primary coil.

[0072] For example, when the power failure detection unit 130 detects that the secondary coil has a power failure, it can cut off the line through which the control unit 140 supplies power to the relay 120 , thereby disconnecting the switch of the relay 120 and restoring the current limiting capability of the thermistor current limiting resistor 110 .

[0073] In a possible implementation, the surge protection circuit 100 may further include a fuse F1 for disconnecting the input AC power when the input AC power is over-current.

[0074] A thermistor current limiting resistor 110 is set in the primary coil of the isolation transformer T1, and the power-off detection unit 130 detects the power supply change of the secondary coil and disconnects the relay 120 when the power is off to restore the current limiting function of the thermistor current limiting resistor 110. On the one hand, when the isolation transformer T1 is powered on for the first time, the thermistor current limiting resistor 110 can be used to suppress the surge current and improve the circuit stability. On the other hand, the power-off detection unit 130 restores the current limiting function of the thermistor current limiting resistor 110 by detecting the power failure of the secondary coil, reduces the time delay for detecting the power failure, improves the response time for restoring the current limiting function of the thermistor current limiting resistor 110, and improves the surge protection effect. On the other hand, the power-off detection unit 130 is connected to the secondary coil of the isolation transformer T1 to reduce the leakage of the primary coil of the isolation transformer T1.

[0075] Figure 2 A surge protection circuit 100 is shown according to an embodiment of the present disclosure, and the circuit further includes: an uninterruptible power supply 150 and a second power supply module 160, wherein:

[0076] The uninterruptible power supply 150 is connected to the secondary coil of the isolation transformer T1, and is used to store the electric energy transmitted by the secondary coil and output electric energy to the second power supply module 160 at least when the secondary coil loses power; the second power supply module 160 is used to provide power to the control unit 140.

[0077] The uninterruptible power supply 150 has energy storage elements such as batteries. When the input AC power is normal, the uninterruptible power supply 150 obtains and stores electrical energy from the secondary coil of the isolation transformer T1. When the input AC power is cut off, the uninterruptible power supply 150 supplies power to the circuit after the secondary coil of the isolation transformer T1 to keep the electronic equipment working in the case of power failure.

[0078] The second power supply module 160 is used for at least one of the following: AC to DC conversion, voltage conversion, and converting the power output from the secondary coil of the isolation transformer T1 and / or the power output from the uninterruptible power supply 150 to supply power to the internal circuit of the electronic device.

[0079] In a possible implementation, the second power module 160 includes a switching power module.

[0080] The second power module 160 can provide power to the control unit 140 and the like in the electronic device.

[0081] In some embodiments, Figure 3 As shown, the power-off detection unit 130 includes: a power-off detection module 131 and a controlled switch 132, wherein the power-off detection module 131 is used to detect the power supply change of the secondary coil and output a switch control signal to control the closing or opening of the controlled switch 132; wherein, in response to the power-off detection module 131 detecting that the secondary coil is powered off, the switch control signal is used to control the controlled switch 132 to disconnect the connection between the relay 120 and the control unit 140, or in response to the power-off detection module 131 detecting that the secondary coil is powered on, the switch control signal is used to control the controlled switch 132 to connect the connection between the relay 120 and the control unit 140.

[0082] In a possible implementation, the power failure detection module 131 may be implemented by hardware to increase the speed of detecting the power supply change of the secondary coil.

[0083] Exemplarily, the power-off detection module 131 rectifies the secondary coil and detects the rectified voltage to determine whether the secondary coil is powered off.

[0084] In a possible implementation, the controlled switch 132 may be implemented by a thyristor, an optical coupler, or the like to turn on or off the connection between the relay 120 and the control unit 140 .

[0085] Exemplarily, the connection between the control unit 140 and the relay 120 is a power supply circuit. The controlled switch 132 is used to turn on or off the power supply circuit. If the power failure detection module 131 determines that the secondary coil has power, the power failure detection module 131 outputs a switch control signal to control the controlled switch 132 to turn on the power supply circuit, so that the relay 120 is closed and the thermistor current limiting resistor 110 is bypassed. If the power failure detection module 131 determines that the secondary coil is powered off, the power failure detection module 131 outputs a switch control signal to control the controlled switch 132 to disconnect the power supply circuit, so that the relay 120 is disconnected so that the thermistor current limiting resistor 110 is connected to the primary coil to play a current limiting role.

[0086] In some embodiments, Figure 4 As shown, the power-off detection module 131 includes: a first optocoupler 1311, a second optocoupler 1312 and a first resistor, wherein the first control end of the first optocoupler 1311, the second control end of the second optocoupler 1312 and the first end of the secondary coil are connected; the second control end of the first optocoupler 1311, the first control end of the second optocoupler 1312 and the second end of the secondary coil are connected; the first controlled end of the first optocoupler 1311, the first controlled end of the second optocoupler 1312 and the power ground are connected; the second controlled end of the first optocoupler 1311, the second controlled end of the second optocoupler 1312 are connected to the first end of the first resistor 1313, for outputting the switch control signal, wherein the second end of the first resistor 1313 inputs the first DC voltage generated based on the power supply of the secondary coil.

[0087] In a possible implementation, the first optical coupler 1311 and the second optical coupler 1312 are independent electronic components.

[0088] In a possible implementation, the first optical coupler 1311 and the second optical coupler 1312 belong to the same electronic component.

[0089] The first control end of the first optocoupler 1311 may be the positive electrode of the light emitting diode in the first optocoupler 1311. The second control end of the first optocoupler 1311 may be the negative electrode of the light emitting diode in the first optocoupler 1311. The first controlled end of the first optocoupler 1311 and the second controlled end of the first optocoupler 1311 may be the two ends of the photosensitive switch tube controlled by the light emitting diode in the first optocoupler 1311.

[0090] The first control end of the second optocoupler 1312 may be the positive electrode of the light emitting diode in the second optocoupler 1312. The second control end of the second optocoupler 1312 may be the negative electrode of the light emitting diode in the second optocoupler 1312. The first controlled end of the second optocoupler 1312 and the second controlled end of the second optocoupler 1312 may be the two ends of the photosensitive switch tube controlled by the light emitting diode in the second optocoupler 1312.

[0091] The photosensitive switch tube in the optocoupler may include: a photosensitive bipolar transistor, a photosensitive field effect transistor or other photosensitive transistors. The photosensitive switch tube may include one or more photosensitive transistors.

[0092] The first resistor 1313 is used to pull up the switch control signal. The pull-up voltage of the first resistor 1313 is the first DC voltage (VCC) converted from the secondary coil. Figure 4As shown, when the secondary coil is powered (the secondary coil is a positive voltage or a negative voltage), at least one of the photosensitive switch tubes of the first optocoupler 1311 and the second optocoupler 1312 is turned on, so that the second controlled end of the first optocoupler 1311 and the second controlled end of the second optocoupler 1312 are grounded, and the switch control signal is a low level. When the secondary coil is powered off (the secondary coil is 0 voltage), the photosensitive switch tubes in the first optocoupler 1311 and the second optocoupler 1312 are both in the off state, and affected by the pull-up of the first resistor 1313, the switch control signal is a high level. The power-off detection module 131 controls the controlled switch 132 through high and low levels. For example, the power-off detection module 131 controls the controlled switch 132 to be disconnected through a high level, or the power-off detection module 131 controls the controlled switch 132 to be closed through a low level.

[0093] In a possible implementation, a logic gate, such as an inverter, may be provided between the power-off detection module 131 and the controlled switch 132 to implement the switching logic of the controlled switch 132 controlled by the power-off detection module 131 .

[0094] For example, the controlled switch 132 is closed when a high level is input and is opened when a low level is input, while the power-off detection module 131 outputs a high level when the secondary coil is powered off and outputs a low level when the secondary coil is powered on. Therefore, the level output by the power-off detection module 131 can be reversed through a logic gate to meet the control requirements.

[0095] Since the optocoupler has a faster response time (the response time of the optocoupler is in microseconds), when the isolation transformer T1 loses power, the power-off detection module 131 formed by the optocoupler can send a switch control signal to disconnect the controlled switch 132 in a shorter time, thereby improving the response speed to power off.

[0096] In some embodiments, Figure 5 As shown, the power-off detection unit 130 further includes: a first power supply module 133 connected to the secondary coil, for generating the first DC voltage based on the power supply of the secondary coil.

[0097] The first power module 133 can directly draw power from the secondary coil to provide the first DC voltage required for the first resistor 1313 to pull up.

[0098] In a possible implementation, the first power supply module 133 may also supply power to a logic gate between the power-off detection module 131 and the controlled switch 132 , but the present invention is not limited thereto.

[0099] In a possible implementation, the first power module 133 may include a switching power module for converting AC power to DC power.

[0100] The first power supply module 133 usually has energy storage elements such as capacitors and inductors, so it can still maintain the first DC voltage output for a certain period of time after the secondary coil is powered off. The time length of the first power supply module 133 maintaining the output after the secondary coil is powered off is longer than the time length of the power failure detection module 131 controlling the controlled switch 132 to disconnect in response to the power failure of the secondary coil. Therefore, the first power supply module 133 can maintain the normal operation of the power failure detection module 131 and the controlled switch 132.

[0101] In one possible implementation, the controlled switch 132 is disconnected when the switch control signal is at a low level. Therefore, when the secondary coil loses power, the power-off detection module 131 controls the controlled switch 132 to be disconnected by a low level. After the secondary coil loses power and the first power supply module 133 cannot provide the first voltage, the switch control signal remains at a low level due to the power-off, so that the controlled switch 132 remains in the disconnected state.

[0102] In some embodiments, Figure 4 or Figure 5 As shown, the controlled switch 132 includes: a third optocoupler 1321, wherein the first control end of the third optocoupler 1321 is used to input the switch control signal; the second control end of the third optocoupler 1321 is connected to the power ground; and the controlled end of the third optocoupler 1321 is connected in series in the connection between the relay 120 and the control.

[0103] The first control end of the third optocoupler 1321 may be the positive electrode of the light emitting diode in the third optocoupler 1321. The second control end of the third optocoupler 1321 may be the negative electrode of the light emitting diode in the third optocoupler 1321. The controlled ends of the third optocoupler 1321 may be the two ends of the photosensitive switch tube controlled by the light emitting diode in the third optocoupler 1321. The photosensitive switch tube in the optocoupler may include: a photosensitive bipolar transistor, a photosensitive field effect transistor or other photosensitive transistors. The photosensitive switch tube may include one or more photosensitive transistors.

[0104] Since the optocoupler has a fast response time (the response time of the optocoupler is in the microsecond level), in response to power failure of the isolation transformer T1, the power failure detection module 131 composed of the first optocoupler 1311 and the second optocoupler 1312 can send a switch control signal to disconnect the controlled switch 132 in a relatively short time, and the controlled switch 132 composed of the third optocoupler 1321 can disconnect the connection between the relay 120 and the control unit 140 in a relatively short time, thereby restoring the current limiting function of the thermistor current limiting resistor 110. In this way, the response speed of restoring the current limiting function of the thermistor current limiting resistor 110 in response to power failure recovery is improved.

[0105] In some embodiments, Figure 6As shown, the power-off detection unit 130 further includes: a signal filtering module 134, which is used to filter the switch control signal.

[0106] The first optocoupler 1311 and the second optocoupler 1312 included in the power-off detection module 131 are affected by the alternating current on the secondary coil and switch alternately. The optocoupler generates interference signals, such as interference pulses, during the switching process. The interference signal may affect the controlled switch 132, for example, causing the controlled switch 132 to disconnect by mistake. Therefore, a signal filtering module 134 can be set on the transmission path of the switch control signal.

[0107] For example, a ground capacitor may be provided on the transmission path of the switch control signal to filter interference pulses.

[0108] In some embodiments, the signal filtering module 134 includes: a Schmitt trigger inverter.

[0109] The Schmitt trigger inverter can be connected in series between the power-off detection module 131 and the controlled switch 132. On the one hand, the Schmitt trigger inverter can filter the interference signal on the switch control signal based on the hysteresis principle. On the other hand, the Schmitt trigger inverter can invert the switch control signal to meet the control logic requirements of the controlled switch 132.

[0110] Figure 8 An electronic device 10 is shown according to an embodiment of the present disclosure, and the electronic device includes the surge protection circuit 100 described above.

[0111] In some embodiments, the electronic device includes a surgical robot, etc.

[0112] The specific implementation of the surge protection circuit 100 is as follows Figures 1 to 7 Any embodiment described above will not be repeated here.

[0113] The following provides multiple specific examples in combination with any of the above embodiments:

[0114] like Figure 2, the key components of the power supply line of electronic equipment such as surgical robots generally include fuses, isolation transformers, UPS (i.e., uninterruptible power supply 150) and switching power supplies (i.e., second power supply module 160). The fuse and NTC resistor (i.e., thermistor current limiting resistor 110) are connected in series to the primary of the isolation transformer to absorb surges at the moment of powering on the device. When the device is powered on successfully, the control unit (Control Unit) (i.e., control unit 140) inside the device applies the NTC resistor bypass signal, and bypasses the NTC resistor through the single-pole single-throw relay (Relay-SPST) (i.e., relay 120) to ensure that the NTC resistor does not heat up during normal operation. When the device loses power abnormally, the brown-out detector (BOD) unit (i.e., the power-off detection unit 130) in the secondary circuit of the isolation transformer detects the power-off state and immediately cuts off the NTC resistor bypass signal (i.e., the single-pole single-throw relay is disconnected) to ensure the effectiveness of the NTC resistor when it is powered on again. The power-off detection unit needs to be placed in the secondary of the isolation transformer to reduce the impact on the leakage current of the device. At the same time, it is electrically connected in parallel with the UPS. If the equipment loses power abnormally, the UPS switches from AC power to battery power, which has no effect on the power failure detection unit.

[0115] Figure 7 The present example provides a schematic diagram of a power failure detection unit, which includes an AC-DC power supply module (i.e., a first power supply module 133), a power failure detection module (i.e., a power failure detection module 131), a filtering module (i.e., a signal filtering module 134) and a signal switch module (i.e., a controlled switch 130).

[0116] Connector CN1 introduces AC power from the secondary coil, and the AC-DC power supply module U1 provides power for the entire power-off detection unit. The power-off detection module U1 may include two optocouplers (i.e., the first optocoupler and the second optocoupler). After power-on, the AC current passes through the input end of the optocoupler (i.e., the first optocoupler and the second optocoupler), triggering the optocoupler (i.e., the first optocoupler and the second optocoupler) to output a low level, which is inverted by U3, so that the switch of the signal switch module (the third optocoupler) is closed. After power failure, the output end of the optocoupler is pulled up to 5V, and the switch of the signal switch module is triggered to disconnect through U3 inversion. The current output by the control unit to the single-pole single-throw relay flows from connector CN2 to the signal switch module, and flows out from connector CN3 to the single-pole single-throw relay. After the signal switch module is triggered, the switch state changes from the on state to the off state, so that the switch of the single-pole single-throw relay is disconnected, thereby cutting off the bypass of the NTC resistor. To ensure signal reliability, the hysteresis capability of the filter module U3 is used to filter interference pulses to avoid false triggering.

[0117] Figure 7In this example, the circuit can also filter the output signal of the power-off detection module U1 through capacitor C1. The output of the AC-DC power supply module is indicated by LED1, wherein resistor R2 is used to limit current to protect LED1. The inverted signal of the output signal of the power-off detection module U1 is indicated by LED2, wherein resistor R4 is used to limit current to protect LED2 and the light-emitting diode in the signal switch module. Resistor R4 is used to limit current to protect the light-emitting diode in the power-off detection module U1.

[0118] This example uses a control unit, relay, and power-off detection unit to bypass and disconnect the NTC resistor in time to ensure the effectiveness of the surge absorption device when the entire device is powered on, and an isolation transformer is used to ensure electrical safety. The solution in this example: (1) It can effectively absorb the power-on surge current of the device. (2) It supports hot start of the device, that is, the device is directly started without cooling after power failure, and the surge protection device is still effective. (3) The surge protection device has little effect on the leakage current of the device.

[0119] Those skilled in the art will readily conceive of other embodiments of the utility model after considering the specification and practicing the utility model disclosed herein. The present disclosure is intended to cover any variation, use or adaptation of the utility model, which follows the general principles of the utility model and includes common knowledge or customary technical means in the art that are not disclosed in the present disclosure. The specification and examples are to be regarded as exemplary only, and the true scope and spirit of the utility model are indicated by the following claims.

[0120] It should be understood that the present invention is not limited to the precise structure described above and shown in the drawings, and various modifications and changes can be made without departing from the scope thereof. The scope of the present invention is limited only by the appended claims.

Claims

1. A surge protection circuit, characterized in that: The circuit comprises: Isolation transformers for transforming AC power; A thermistor current limiting resistor connected in series with the primary coil of the isolation transformer to limit the inrush current; a relay connected in parallel with the thermistor current limiting resistor; A control unit connected to the relay and at least used to control the relay to close so as to bypass the thermistor current limiting resistor, wherein the switch end of the relay is connected in parallel with the thermistor current limiting resistor, and the coil end of the relay is connected to the control unit; A power-off detection unit connected to the secondary coil of the isolation transformer, used to detect power supply changes of the secondary coil, conduct the connection between the relay and the control unit when the secondary coil is energized, and cut off the connection between the relay and the control unit when the secondary coil is powered off to disconnect the relay.

2. The circuit according to claim 1, characterized in that The power failure detection unit includes: a power failure detection module and a controlled switch, wherein: The power-off detection module is used to detect the power supply change of the secondary coil and output a switch control signal to control the closing or opening of the controlled switch; wherein, in response to the power-off detection module detecting that the secondary coil is powered off, the switch control signal is used to control the controlled switch to disconnect the connection between the relay and the control unit, or in response to the power-off detection module detecting that the secondary coil is powered on, the switch control signal is used to control the controlled switch to connect the connection between the relay and the control unit.

3. The circuit according to claim 2, characterized in that The power-off detection module includes: a first optical coupler, a second optical coupler and a first resistor, wherein: The first control end of the first optical coupler, the second control end of the second optical coupler and the first end of the secondary coil are connected; The second control end of the first optical coupler, the first control end of the second optical coupler and the second end of the secondary coil are connected; The first controlled end of the first optical coupler, the first controlled end of the second optical coupler and a power ground are connected; The second controlled end of the first optocoupler, the second controlled end of the second optocoupler and the first end of the first resistor are connected to output the switch control signal, wherein the second end of the first resistor inputs a first DC voltage generated based on the power supply of the secondary coil.

4. The circuit according to claim 3, characterized in that The power failure detection unit further includes: a first power supply module connected to the secondary coil, configured to generate the first DC voltage based on power supply of the secondary coil.

5. The circuit according to claim 3, characterized in that The controlled switch comprises: a third optical coupler, wherein: The first control terminal of the third optical coupler is used to input the switch control signal; The second control terminal of the third optical coupler is connected to the power ground; The controlled end of the third optical coupler is connected in series in the connection between the relay and the control.

6. The circuit according to any one of claims 2 to 5, characterized in that: The power-off detection unit further includes: a signal filtering module, which is used to filter the switch control signal.

7. The circuit according to claim 6, characterized in that The signal filtering module includes: a Schmitt trigger inverter.

8. The circuit according to any one of claims 1 to 5, characterized in that: The circuit also includes: an uninterruptible power supply and a second power supply module, wherein: The uninterruptible power supply is connected to the secondary coil of the isolation transformer, and is used to store the electric energy transmitted by the secondary coil and output the electric energy to the second power supply module at least when the secondary coil loses power; The second power supply module is used to provide power to the control unit.

9. An electronic device, characterized in that: The electronic device comprises the surge protection circuit according to any one of claims 1 to 8.

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