Over-temperature and over-current protection circuit and power adapter system

Abstract

The utility model discloses an over-temperature and over-current protection circuit and a power adapter system, and the over-temperature and over-current protection circuit comprises an over-current monitoring assembly which is used for outputting a first fault signal lasting for a first preset time when the load voltage of a load circuit is greater than a set voltage. And the temperature control unit is used for outputting a second fault signal when the temperature of the load circuit exceeds the preset temperature threshold. And the first logic unit is electrically connected with the overcurrent monitoring assembly, the temperature control unit and the execution unit, and is used for controlling the execution unit to disconnect the load circuit when receiving the first fault signal and / or the second fault signal. And when the first logic unit receives the first recovery signal and / or the second recovery signal, the execution unit is controlled to close the load circuit again. The over-temperature and over-current protection circuit can prevent the load circuit from being disconnected for a long time in the over-temperature and over-current protection process.

Description

TECHNICAL FIELD

[0001] The utility model relates specifically to a kind of over-temperature over-current protection circuit and power adapter system. BACKGROUND

[0002] In modern security, monitoring, dynamic environment monitoring, PON, optical modem and router and other equipment, the key role of power adapter and charger cannot be ignored. However, in recent years, the frequent occurrence of faults caused by over-temperature and over-current of power adapter has become an unstable factor for the operation of equipment. Such accidents are usually caused by poor design, insufficient heat dissipation or load exceeding the rated power of the adapter, resulting in short circuit or overload. Over-temperature may cause circuit aging, shorten the service life, and even cause fire; while over-current may damage internal components and cause complete failure of the equipment. Therefore, it is particularly important to strengthen the quality control and over-temperature and over-current protection design of power adapter to ensure the safe and stable operation of the equipment.

[0003] However, the existing over-temperature and over-current protection circuit will completely disconnect the load circuit when the load circuit appears over-temperature / over-current, until the personnel restart the load circuit, which will cause the load circuit to be disconnected for a long time during the over-temperature and over-current protection process, obviously not conducive to the continuous operation of important systems such as security systems. SUMMARY

[0004] The technical problem to be solved by the utility model is to provide an over-temperature and over-current protection circuit and a power adapter system to avoid the long-time disconnection of the load circuit during the over-temperature and over-current protection process.

[0005] According to the first aspect of the utility model, provide a kind of over-temperature over-current protection circuit, comprising: over-current monitoring component, temperature control unit, first logic unit and execution unit;The over-current monitoring component is electrically connected with the load circuit to be protected, the over-current monitoring component is built-in with set voltage, the over-current monitoring component is used to when the load voltage of the load circuit is greater than set voltage, output first fault signal lasting first preset duration;The temperature control unit is coupled with the load circuit, for detecting the temperature of load circuit, and when the temperature of load circuit exceeds preset temperature threshold, output second fault signal;The execution unit is electrically connected with the load circuit, for controlling the closure / opening of load circuit;The first logic unit, with the over-current monitoring component, the temperature control unit and the execution unit are electrically connected, for when receiving first fault signal, and / or, receiving second fault signal, control the execution unit opens load circuit;The over-current monitoring component is also used to output first recovery signal after first preset duration, the temperature control unit is also used to output second recovery signal when the temperature of load circuit is lower than preset temperature threshold, and the first logic unit receives first recovery signal and / or second recovery signal, control the execution unit re-closes load circuit.

[0006] Preferably, the over-current monitoring component includes a current sampling unit, a comparison unit, and a first delay unit. The current sampling unit is electrically connected with the load circuit for current sampling of the load circuit to obtain a load voltage. The comparison unit is provided with a first voltage input end and a second voltage input end. The first voltage input end is electrically connected with the current sampling unit for accessing the load voltage. The second voltage input end is used for accessing a set voltage. The comparison unit is used for comparing the load voltage with the set voltage and sending a low-level signal when the load voltage is greater than the set voltage. The first delay unit is electrically connected with the comparison unit for timing and outputting a first fault signal when receiving the low-level signal. The first delay unit is used for outputting a first recovery signal after the timing duration reaches the first preset duration.

[0007] Preferably, the temperature control unit comprises a third voltage input end for connecting a temperature regulating voltage and a plurality of temperature sensing contacts, the third voltage input end is electrically connected to the first logic unit through the plurality of temperature sensing contacts, the plurality of temperature sensing contacts are connected in series, the load circuit is provided with a plurality of detection points, the number of the temperature sensing contacts is equal to the number of the detection points, each of the temperature sensing contacts corresponds to one of the detection points, the temperature sensing contacts are normally closed contacts, the temperature sensing contacts are used to sense the temperature of the corresponding detection points and are disconnected when the temperature of the detection points is higher than a preset temperature threshold, when the temperature of one of the detection points of the load circuit is higher than the preset temperature threshold, the corresponding temperature sensing contact is disconnected, so that the temperature control unit outputs a second fault signal, when the temperature of all the detection points of the load circuit is lower than the preset temperature threshold, all the temperature sensing contacts are closed, and the third voltage input end sends a second recovery signal to the first logic unit.

[0008] Preferably, the first logic unit comprises a first NAND gate and a NOR gate, the first NAND gate is provided with a first signal input end, a second signal input end and a signal output end, the first signal input end of the first NAND gate is electrically connected to the first delay unit for receiving the first fault signal / first recovery signal sent by the first delay unit, the second signal input end of the first NAND gate is electrically connected to the temperature control unit for receiving the second fault signal / second recovery signal sent by the temperature control unit, the first NAND gate outputs a recovery execution signal through the signal output end when receiving the first recovery signal and the second recovery signal, the first NAND gate outputs a fault execution signal through the signal output end when receiving the first fault signal and / or the second fault signal, one end of the NOR gate is electrically connected to the signal output end, and the other end is electrically connected to an execution unit, the NOR gate controls the execution unit to disconnect the load circuit when receiving the fault execution signal, or controls the execution unit to restore the conduction of the load circuit when receiving the recovery execution signal.

[0009] Preferably, the over-temperature and over-current protection circuit further comprises a fault reporting unit, the fault reporting unit is electrically connected to the NOR gate of the first logic unit, and the NOR gate is further used to perform fault reporting through the fault reporting unit when receiving the fault execution signal.

[0010] Preferably, the over-temperature and over-current protection circuit further comprises an internal power supply unit, the internal power supply unit comprises a control power supply and an access circuit, the control power supply is electrically connected with the second voltage input end of the comparison unit through the access circuit, the control power supply is used for providing a set voltage to the second voltage input end, the control unit is electrically connected with the third voltage input end of the temperature control unit, the first logic unit and the execution unit in turn through the access circuit, the control power supply is further used for providing a temperature adjustment voltage to the third voltage input end, and the first logic unit and the execution unit are powered.

[0011] Preferably, a power switch is arranged on the access circuit, and the power switch is used for controlling the turn-on / off of the access circuit.

[0012] Preferably, the over-temperature and over-current protection circuit further comprises a second logic unit and a second delay unit, the second delay unit is electrically connected with the signal output end, and is used for outputting a timing electric signal for a second preset time length when receiving the fault execution signal sent by the signal output end; the second logic unit is electrically connected with the second delay unit and the signal output end, and is used for receiving the fault execution signal sent by the signal output end and counting the number of the received fault execution signals to obtain an accumulated fault number; a set number is preset in the second logic unit, and the second logic unit is further electrically connected with the power switch, and is used for controlling the power switch to be turned off when receiving the timing electric signal sent by the second delay unit and the accumulated fault number is greater than or equal to the set number, so that the second voltage input end of the comparison unit, the temperature control unit, the first logic unit and the execution unit are all de-energized, and then the load circuit is disconnected.

[0013] Preferably, the second logic unit comprises a counter and a second NAND gate, the counter comprises a signal receiving end and a counting output end, the signal receiving end is electrically connected with the signal output end, and is used for counting the received fault execution signal sent by the signal output end to obtain an accumulated fault number, a set number is preset in the counter, and the counter is further used for sending a counting excess signal through the counting output end when the accumulated fault number is greater than or equal to the set number, the second NAND gate is electrically connected with the second delay unit, the counting output end and the power switch, and is used for controlling the power switch to be turned off when receiving the timing electric signal sent by the second delay unit and the counting excess signal sent by the counting output end.

[0014] Preferably, the over-temperature and over-current protection circuit further comprises a starting unit, the starting unit is electrically connected with the power switch, and is used for controlling the power switch to be re-closed.

[0015] According to the second aspect of the utility model, provide a kind of power adapter system, including power adapter and above-mentioned over-temperature over-current protection circuit, the over-temperature over-current protection current is electrically connected with the power adapter, for over-temperature over-current protection to the power adapter.

[0016] The over-temperature over-current protection circuit in the utility model monitors the load voltage of the load circuit through the over-current monitoring component, outputs a first fault signal when the load voltage is greater than the set voltage, and the first fault signal lasts for a first preset time length. When receiving the first fault signal, the first logic unit controls the execution unit to disconnect the load circuit. After the timing of the first preset time length ends, the over-current monitoring component also sends a first recovery signal to the first logic unit, and the first logic unit controls the execution unit to re-close the load circuit according to the first recovery signal. The over-temperature over-current protection circuit detects the temperature of the load circuit through the temperature control unit, outputs a second fault signal when the temperature of the load circuit exceeds the preset temperature threshold, and the first logic unit controls the execution unit to disconnect the load circuit when receiving the second fault signal. After the load circuit is powered off, its temperature drops below the preset temperature threshold, and the temperature control unit sends a second recovery signal to the first logic unit when the temperature of the load circuit is lower than the preset temperature threshold, and the first logic unit controls the execution unit to re-close the load circuit according to the first recovery signal.

[0017] In other words, the over-temperature or over-current of the load circuit will trigger the first logic unit, and then disconnect the load circuit through the execution unit, i.e. the over-temperature over-current protection circuit can realize over-temperature and over-current protection of the load circuit. The over-temperature over-current protection circuit has the advantages that after the recovery condition is met, the load circuit is automatically re-closed through the first logic unit without manual operation, which greatly improves the working sustainability of the load circuit under the premise of ensuring the working safety of the load circuit, and avoids long-term interruption of important loads. Therefore, the over-temperature over-current protection circuit is beneficial to the continuous work of the load circuit during over-temperature and over-current protection, and can avoid long-term disconnection of the load circuit during over-temperature and over-current protection. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is a block diagram of the over-temperature over-current protection circuit in some embodiments of the utility model;

[0019] Figure 2 is a circuit structure schematic diagram of the over-temperature over-current protection circuit in some embodiments of the utility model;

[0020] Figure 3 is a circuit wiring schematic diagram of each unit of the over-temperature over-current protection circuit in some embodiments of the utility model.

[0021] In the figure: 1-start unit, 2-inner supply unit, 3-execution unit, 4-current sampling unit, 5-comparison unit, 6-temperature control unit, 7-first logic unit, 8-second logic unit, 9-first delay unit, 10-second delay unit, 11-fault reporting unit. DETAILED DESCRIPTION

[0022] The technical solutions in the utility model will be clearly and completely described below in combination with the drawings in the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of the utility model.

[0023] In the description of the utility model, it should be explained that the terms "upper", "lower" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, and are only for the convenience and simplification of description, and do not indicate or imply that the indicated device or element must be provided with a particular orientation, constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the utility model.

[0024] In the description of the utility model, the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0025] In the description of the utility model, it should be explained that, unless otherwise explicitly specified and limited, the terms "connection", "setting", "installation", "fixing" and the like should be understood in a broad sense, for example, it can be fixedly connected or detachably connected, or integrally connected, it can be directly connected or indirectly connected through an intermediate medium, or it can be the communication between two elements. For those skilled in the art, the specific meaning of the above terms in the utility model can be understood according to the specific circumstances.

[0026] Embodiment 1

[0027] Please refer to Figure 1 , Figure 2 and Figure 3 The utility model discloses a kind of over-temperature over-current protection circuits, comprising: over-current monitoring component, temperature control unit 6, first logic unit 7 and execution unit 3.

[0028] The overcurrent monitoring component is electrically connected with the protected load circuit, and is internally provided with a set voltage. The overcurrent monitoring component is configured to output a first fault signal lasting a first preset time duration when a load voltage of the load circuit is greater than the set voltage. The temperature control unit 6 is coupled with the load circuit and is configured to detect a temperature of the load circuit and output a second fault signal when the temperature of the load circuit exceeds a preset temperature threshold. The execution unit 3 is electrically connected with the load circuit and is configured to control the closing / opening of the load circuit. The first logic unit 7 is electrically connected with the overcurrent monitoring component, the temperature control unit 6 and the execution unit 3, and is configured to control the execution unit 3 to open the load circuit when the first fault signal and / or the second fault signal is received. The overcurrent monitoring component is further configured to output a first recovery signal after the first preset time duration, and the temperature control unit 6 is further configured to output a second recovery signal when the temperature of the load circuit is lower than the preset temperature threshold. The first logic unit 7 controls the execution unit 3 to reclose the load circuit when the first recovery signal and / or the second recovery signal is received.

[0029] It should be noted that the over-temperature and over-current protection circuit monitors the load voltage of the load circuit through the overcurrent monitoring component. When the load voltage is greater than the set voltage, the first fault signal is output, and the first fault signal lasts for a first preset time duration. The first logic unit 7 controls the execution unit 3 to open the load circuit when the first fault signal is received. After the timing of the first preset time duration ends, the overcurrent monitoring component further sends a first recovery signal to the first logic unit 7, and the first logic unit 7 controls the execution unit 3 to reclose the load circuit according to the first recovery signal. The over-temperature and over-current protection circuit detects the temperature of the load circuit through the temperature control unit 6. When the temperature of the load circuit exceeds the preset temperature threshold, the second fault signal is output. The first logic unit 7 controls the execution unit 3 to open the load circuit when the second fault signal is received. After the load circuit is powered off, its temperature drops below the preset temperature threshold. The temperature control unit 6 sends a second recovery signal to the first logic unit 7 when the temperature of the load circuit is lower than the preset temperature threshold, and the first logic unit 7 controls the execution unit 3 to reclose the load circuit according to the first recovery signal.

[0030] In other words, the over-temperature or over-current of the load circuit will trigger the first logic unit 7, and then the load circuit is disconnected by the execution unit 3, that is, the over-temperature and over-current protection circuit can realize the over-temperature and over-current protection of the load circuit. The over-temperature and over-current protection circuit has the advantages that after the recovery condition is met, the load circuit is automatically re-closed by the first logic unit 7 without manual operation of the staff, the working sustainability of the load circuit is greatly improved under the premise of ensuring the working safety of the load circuit, and the long-time interruption of the important load is avoided. Therefore, the over-temperature and over-current protection circuit is beneficial to the continuous work of the load circuit in the process of over-temperature and over-current protection, and can avoid the long-time disconnection of the load circuit in the process of over-temperature and over-current protection.

[0031] Please refer to Figure 1 , Figure 2 and Figure 3 In some embodiments, the over-current monitoring assembly comprises a current sampling unit 4, a comparison unit 5 and a first delay unit 10. The current sampling unit 4 is electrically connected with the load circuit, and is used for sampling the current of the load circuit to obtain a load voltage. The comparison unit 5 is provided with a first voltage input end and a second voltage input end. The first voltage input end is electrically connected with the current sampling unit 4, and is used for accessing the load voltage. The second voltage input end is used for accessing a set voltage. The comparison unit 5 is used for comparing the load voltage with the set voltage, and outputs a low-level signal when the load voltage is greater than the set voltage. The first delay unit 10 is electrically connected with the comparison unit 5, and is used for timing and outputting a first fault signal when the low-level signal is received. The first delay unit 10 is used for inverting to output a first recovery signal after the timing duration reaches a first preset duration.

[0032] Specifically, the current sampling unit 4 comprises a sampling resistor R11, a resistor R12, a resistor R13, a diode D11, a diode D12 and a capacitor C11. The comparison unit 5 comprises a resistor R14, a resistor R15, a voltage stabilizing diode D13 and a comparator U1A. The sampling resistor R11 is connected in series with the second voltage port V3+(i.e., the voltage port for accessing the load current). When the current passes through the current sampling resistor (R11), a voltage drop proportional to the current will be generated at both ends of R11, that is, the load voltage. D11 and D12 are used as rectifier diodes, which can rectify the input alternating current signal into direct current signal. The accessed C11 is used for filtering, stabilizing voltage and smoothing output, and further improves the measurement accuracy. The first input end of the comparator U1A (i.e., the first voltage input end mentioned above, that is, the end "2" of U1A in the attached Figure 2 The second input end of the comparator U1A (i.e., the second voltage input end mentioned above, that is, the end "3" of U1A in the attached Figure 2The end "3" of U1A is connected with the first voltage interface V2+(i.e. the set voltage). When the circuit is powered, VC+ obtains V2+ power through Q1, i.e. the voltage of the first voltage interface is the voltage of the power supply of the design. The comparator is used to compare the load voltage (i.e. the sampling voltage of the power adapter) with the set voltage (i.e. the voltage of the power supply of the circuit), and when the load voltage of the power adapter is greater than the set voltage, i.e. the voltage of the first input end (i.e. end "2") of the comparator U1A is higher than the voltage of the second input end (i.e. end "3"), the output end "1" of the comparator outputs low level.

[0033] In other words, the voltage drop of the protected power adapter load current on R11 (current sampling resistor) is sent to U1A②③ (i.e. end "2", end "3") through R12 and R13, C11, D11 and D12, and U1A② compares with the set voltage of U1A③, and the voltage of U1A③ is the voltage divided by R15, R13 on V2+ through R14 on D13. When the load current rises, the voltage of R11 to ground rises, and when the voltage of U1A② is higher than that of U1A③, U1A① outputs low level, triggering the first delay circuit composed of R21, U2A, C21, R23, U4C, etc.

[0034] Further, the first delay unit 10 comprises: NAND gate U2A, NOR gate U4C, capacitor C21 and resistor R23. The first input end "1" of the NAND gate U2A is electrically connected with the output end "1" of the comparator for receiving the first electrical signal sent by the comparator. The second input end "2" of the NAND gate U2A is electrically connected with the output end "10" of the NOR gate U4C. The output end of the NAND gate U2A is electrically connected with the first input end "8" and the second input end "9" of the NOR gate U4C through the capacitor C21. Specifically, the working principle of the first delay unit 10 is as follows: the first delay unit 10 is a monostable circuit. In the steady state, i.e. without external pulse triggering (low level triggering), the NAND gate U2A is in the conducting state, i.e. both of its input ends are in high level, and the output end is in low level. In the steady state, U4C is in the cut-off state (i.e. both of its input ends are in low level, and the output end is in high level). When the output end "1" of the comparator outputs low level, the NAND gate U2A is triggered, so that its output end flips to high level, and the capacitor C21 is charged. Due to the fact that the voltage of the capacitor end cannot jump, the voltage of the two input ends of U4C rises, and the voltage of the output end falls. The low level of the output end of U4C enables the high level of the output end of U2A to be maintained, and the circuit enters a temporary steady state. In the temporary steady state, the output end of U4C outputs low level (i.e. the first fault signal mentioned above). With the gradual discharge of the capacitor (the discharge time is T1 time), the circuit flips again to the steady state of U2A conducting and U4C cutting off, i.e. the output end of U4C outputs high level (i.e. the first recovery signal mentioned above).

[0035] It can be seen that the monostable circuit is used to realize the timing function, and has the following advantages: the monostable circuit is triggered and kept in a stable state for a specific time, and then automatically returns to the initial state, which is suitable for time delay applications. The structure of the monostable circuit is relatively simple and stable, that is, the monostable circuit can ensure that only one trigger signal is responded, and multiple triggers caused by interference signals are avoided. Moreover, the monostable trigger can accurately set the duration of the high or low level of the output by selecting the capacitor.

[0036] In this embodiment, through the current sampling unit 4, the comparison unit 5 and the first delay unit 10, overcurrent protection can be realized, and the closing of the load circuit can be restored when the recovery condition is met (i.e., the load circuit is disconnected for a first preset time), without manual operation, thereby facilitating the continuous operation of the load circuit during overcurrent protection and avoiding long-term disconnection of the load circuit during overcurrent protection.

[0037] Please refer to Figure 1 , Figure 2 and Figure 3 In some embodiments, the temperature control unit 6 includes a third voltage input end and a plurality of temperature sensing contacts. The third voltage input end is used to access a temperature adjustment voltage, and the third voltage input end is electrically connected to the first logic unit 7 through the plurality of temperature sensing contacts. The plurality of temperature sensing contacts are connected in series. The load circuit has a plurality of detection points, and the number of temperature sensing contacts is equal to the number of detection points. Each temperature sensing contact corresponds to a detection point. The temperature sensing contact is a normally closed contact, and is used to sense the temperature of the corresponding detection point and is disconnected when the temperature of the detection point is higher than a preset temperature threshold. When the temperature of one of the detection points of the load circuit is higher than the preset temperature threshold, the corresponding temperature sensing contact is disconnected, so that the temperature control unit 6 outputs a second fault signal. When the temperature of all detection points of the load circuit is lower than the preset temperature threshold, all temperature sensing contacts are closed, and the third voltage input end sends a second recovery signal to the first logic unit 7.

[0038] In other words, the temperature control unit 6 includes a plurality of temperature sensing contacts, i.e., t1, t2,..., tn in Figure 2 The load circuit of the power adapter has a plurality of detected points, and the number of detected points is the same as the number of temperature sensing contacts. Each temperature sensing contact corresponds to a detected point and is used to sense the temperature of the detected point. The plurality of temperature sensing contacts are connected in series, and the temperature sensing contact is a normally closed contact. The power supply end VC+ of the circuit is electrically connected to the first logic unit 7 through Q1 and the plurality of temperature sensing contacts. When all temperature sensing contacts are closed, the temperature control unit 6 outputs a high level (i.e., the second recovery signal described above). When any one of the temperature sensing contacts is disconnected, the temperature control unit 6 outputs a low level (i.e., the second fault signal described above).

[0039] In this embodiment, over-temperature protection is achieved by multiple temperature sensing contacts, and when the recovery condition is met, i.e. after the load current is disconnected, the temperature gradually decreases until the temperature of all detection points is lower than the preset temperature threshold, all temperature sensing contacts are closed, the third voltage input end sends a high level signal to the first logic unit 7, the closure of the load circuit is restored, manual operation is not required, which is conducive to the continuous work of the load circuit during over-temperature protection, and can avoid long-term disconnection of the load circuit during over-temperature protection.

[0040] Please refer to Figure 1 、 Figure 2 and Figure 3 In some embodiments, the first logic unit 7 includes a first NAND gate and a NOR gate, the first NAND gate is provided with a first signal input end and a second signal input end and a signal output end, the first signal input end of the first NAND gate is electrically connected with the first delay unit 10 for receiving the first fault signal / first recovery signal sent by the first delay unit 10, the second signal input end of the first NAND gate is electrically connected with the temperature control unit 6 for receiving the second fault signal / second recovery signal sent by the temperature control unit 6, the first NAND gate outputs a recovery execution signal through the signal output end when receiving the first recovery signal and the second recovery signal, the first NAND gate outputs a fault execution signal through the signal output end when receiving the first fault signal and / or the second fault signal, one end of the NOR gate is electrically connected with the signal output end, and the other end is electrically connected with the execution unit 3, the NOR gate controls the execution unit 3 to disconnect the load circuit when receiving the fault execution signal. Or, when receiving the recovery execution signal, the execution unit 3 controls the load circuit to be turned on.

[0041] In particular, the first logic unit 7 comprises a NAND gate U2C (i.e. the first NAND gate mentioned above) and a NOR gate U4D. The first input terminal "8" of the NAND gate U2C is electrically connected to the output terminal of the temperature control unit 6, and the second input terminal "8" of the NAND gate U2C is electrically connected to the output terminal "10" of U4C of the first delay unit 10. The two input terminals (terminal "12" and terminal "13") of the NOR gate U4D are both connected to the output terminal "10" of the NAND gate U2C, and the output terminal of the NOR gate U4D is electrically connected to the execution unit 3. The execution unit 3 comprises a switching transistor Q2 and a relay K21, and the relay K21 is connected to the load circuit of the power adapter (i.e. K21A in the figure, and K21 and K21A are synchronous contact points). The working principle of the first logic unit 7 is as follows: in the normal working state, the temperature control unit 6 sends a high level (i.e. all the temperature sensing contacts are closed), and the first delay unit 10 sends a high level (i.e. the load voltage of the load circuit is lower than the set voltage), at this time, the output terminal of the NAND gate U2C is low (i.e. the above-mentioned recovery execution signal), and the input terminal of the NOR gate U4D is low, and the output terminal is high. The high level output by the NOR gate U4D passes through R26 and R27 to make Q2 conductive, and then make K21 / K21A of the relay closed. When the temperature control unit 6 sends a low level (i.e. at least one temperature sensing contact is open), and the first delay unit 10 sends a high level (i.e. the load voltage is lower than the set voltage), the output terminal of the NAND gate U2C is high (i.e. the above-mentioned fault execution signal), and then controls the input terminals "12" and "13" of the NOR gate U4D to flip to high, and the output terminal "11" flips to low. The low level output by the NOR gate U4D passes through R26 and R27 to make Q2 cut off, and then make K21 / K21A open.

[0042] When the temperature control unit 6 sends a high level (i.e. all the temperature sensing contacts are closed), and the first delay unit 10 sends a low level (i.e. the load voltage is higher than the set voltage), the output terminal of the NAND gate U2C is high (i.e. the above-mentioned fault execution signal), and then controls the input terminals "12" and "13" of the NOR gate U4D to flip to high, and the output terminal "11" flips to low. The low level output by the NOR gate U4D passes through R26 and R27 to make Q2 cut off, and then make K21 / K21A open.

[0043] When the temperature control unit 6 sends a low level (i.e. at least one temperature sensing contact is open), and the first delay unit 10 sends a low level (i.e. the load voltage is higher than the set voltage), the output terminal of the NAND gate U2C is high, and then controls the input terminals "12" and "13" of the NOR gate U4D to flip to high, and the output terminal "11" flips to low. The low level output by the NOR gate U4D passes through R26 and R27 to make Q2 cut off, and then make K21 / K21A open.

[0044] In summary, the first logic unit 7 is electrically connected with the temperature control unit 6, the comparison unit 5 and the execution unit 3 respectively, for controlling the execution unit 3 to disconnect the load power supply of the power adapter when receiving the low-level signal output by the first delay unit 10 and / or the low-level signal sent by the temperature switch.

[0045] As shown in Figure 2 In some embodiments, the over-temperature and over-current protection circuit further comprises a fault reporting unit 11, the fault reporting unit 11 is electrically connected with the NOR gate of the first logic unit 7, and the NOR gate is further used for reporting faults through the fault reporting unit 11 when receiving the fault execution signal.

[0046] Specifically, the fault reporting unit 11 comprises a NAND gate U2B, a capacitor C51, a resistor R51, a switching transistor Q5 and an encoder TXK (coding and sending module). The first input end "5" of the NAND gate U2B is electrically connected with the output end (i.e. end "11") of the NOR gate U4D of the first logic unit 7, and the second input end "6" is electrically connected with the output end of the NAND gate U2D of the second logic unit 8. The output end of the NAND gate U2B is electrically connected with the encoder TXK through the C51, R51 and Q5. When the output end of the NAND gate U2C of the first logic unit 7 is high (i.e. the above-mentioned fault execution signal), the output end (i.e. end "11") of the NOR gate U4D outputs a low-level signal, triggering the NAND gate U2B of the fault reporting unit 11 to output a high-level signal, thereby turning on the switching transistor Q5 and triggering the encoder TXK to send a fault coding signal. The TXK encoder of the fault reporting unit 11 can be realized by using an existing encoder.

[0047] In the embodiment, the fault reporting unit 11 is used to report faults, which can remind the staff to check and repair the load circuit with faults, so as to avoid possible safety hazards.

[0048] In some embodiments, the over-temperature and over-current protection circuit further comprises an internal supply unit 2, the internal supply unit 2 comprises a control power supply and an access circuit, the control power supply is electrically connected with the second voltage input end of the comparison unit 5 through the access circuit, the control power supply is used for providing a set voltage to the second voltage input end, the control unit is further electrically connected with the third voltage input end of the temperature control unit 6, the first logic unit 7 and the execution unit 3 in sequence through the access circuit, and the control power supply is further used for providing a temperature adjustment voltage to the third voltage input end, and supplying power to the first logic unit 7 and the execution unit 3.

[0049] Further, a power switch is arranged on the access circuit, and the power switch is used for controlling the turn-on / off of the access circuit.

[0050] In some embodiments, the over-temperature and over-current protection circuit further comprises a second logic unit 8 and a second delay unit, the second delay unit is electrically connected with the signal output end, and is configured to output a timing electric signal for a second preset time length when receiving the fault execution signal sent by the signal output end. The second logic unit 8 is electrically connected with the second delay unit and the signal output end, and is configured to receive the fault execution signal sent by the signal output end, and count the number of the received fault execution signal to obtain an accumulated fault number. The second logic unit 8 is preset with a set number, and the second logic unit 8 is further electrically connected with the power switch, and is configured to control the power switch to be turned off when receiving the timing electric signal sent by the second delay unit and the accumulated fault number is greater than or equal to the set number, so that the second voltage input end of the comparison unit 5, the temperature control unit 6, the first logic unit 7 and the execution unit 3 are all de-energized, and then the load circuit is disconnected.

[0051] Further, the second logic unit 8 comprises a counter and a second NAND gate, the counter comprises a signal receiving end and a counting output end, the signal receiving end is electrically connected with the signal output end, and is configured to count the received fault execution signal sent by the signal output end to obtain an accumulated fault number, the counter is preset with a set number, and the counter is further configured to send a counting excess signal through the counting output end when the accumulated fault number is greater than or equal to the set number, and the second NAND gate is electrically connected with the second delay unit, the counting output end and the power switch, and is configured to control the power switch to be turned off when receiving the timing electric signal sent by the second delay unit and the counting excess signal sent by the counting output end.

[0052] Specifically, the second delay unit comprises a NAND gate U4A, a NAND gate U4B, a capacitor C42, a resistor R42 and the like. Specifically, the first input end “1” of the NAND gate U4A is connected to the output end of the NAND gate U2C, and the second input end “2” of the NAND gate U4A is grounded. Both input ends of the NAND gate U4B are connected with the output end of the NAND gate U4A through the capacitor C42. The second delay unit is a monostable circuit. In a steady state, that is, without external pulse triggering (high level triggering), both input ends of the NAND gate U4A are low, and the output end of the NAND gate U4B is low. When the first output end “10” of the first logic unit 7 outputs a high level, the second delay unit is triggered to output a high level for T2 time, that is, within T2 time, the output end “4” of the NAND gate U4B is high (that is, the above-mentioned timing electric signal).

[0053] The second logic unit 8 comprises a counter U3, a DIP switch S31 and a NAND gate U2D. The counter U3 is provided with a reset port (RST), a pulse input port (CLK) and a plurality of count output ports (1, 2,..., 9). The reset port is connected with the first voltage port V2+, the DIP switch S31 has a plurality of groups of DIP connection ends, each group of DIP connection ends comprises a first port and a second port (for example, port "1" and port "18", port "2" and port "17",..., port "9" and port "10"), and the count output ports numbered "1, 2,..., 9" on the right side of the counter U3 are connected with the plurality of first ports of the DIP switch S31 one by one. The plurality of second ports of the DIP switch S31 are connected in parallel. That is, when the first port of any one of the plurality of groups of DIP connection ends receives a high-level signal sent by the counter U3, the first input "13" of the NAND gate U2D can send a high-level signal (i.e., the above-mentioned count excess signal).

[0054] It should be noted that the first time overcurrent or overtemperature can reset the RST pin of U3 through C41, R41, D32 and R31, that is, the third actual DIP switch is set to be closed between the terminal 2 and the terminal 17 in the T2 window time. When the first time overcurrent or overtemperature protection is performed, the U3 is reset, and when the third time overcurrent or overtemperature protection is performed, the terminal "2" of the U3 is high level, that is, if the 3-time protection is a serious fault in the T2 time, the "2" output of the U3 is high level at this time.

[0055] The working principle of the counter and the DIP switch unit is as follows:

[0056] Each count output port corresponds to a count value, and the numbers of the plurality of count output ports are 1, 2,..., 9 in sequence, and the count value corresponding to each count output port is i+1, wherein i is the number of the count output port. The counter U3 is used for controlling the count output port corresponding to the count value to send a high-level signal according to the number of faults. For example, the first time fault, the pulse input port of the counter U3 receives a one-time pulse signal output by the terminal "10" of the NAND gate U2C, so that the U3 is reset. The second time fault, the pulse input port of the counter U3 receives a two-time pulse signal output by the terminal "10" of the NAND gate U2C, so that the count output port "1" sends a high level. The third time fault, the pulse input port of the counter U3 receives a three-time pulse signal output by the terminal "10" of the NAND gate U2C, so that the count output port "2" sends a high level.

[0057] The process of setting the number of serious faults: the number of key settings can be completed by connecting the dial unit S4 with a pair of connection ports corresponding to the set number. For example, the set number is three, when three over-temperature or over-current faults occur, the "2" output of U3 is high level, that is, it is determined that the circuit of the power adapter has a serious fault. The setting of the number of serious faults can be completed by connecting the end "2" and the end "17" of the dial switch S31. That is, when the end "2" and the end "17" of the dial switch S31 are connected, the counter U3 receives three fault signals, and outputs a high level to the first input end of the NAND gate U2D through the dial connection ends "2" and "17" of the dial switch.

[0058] In summary, in the T2 time, the input end "12" of the NAND gate U2D obtains a high level (i.e. the timing signal described above), and in addition, as long as the number of faults received by the counter U3 exceeds the set number, the input end "13" of the NAND gate U2D also obtains a high level (i.e. the count excess signal described above), at this time, the output end "11" of the NAND gate U2D becomes low level. The NAND gate U2D outputs low level, controls U2B and C51, Q5, TXK (encoding module) to report fault information, in addition, also controls Q3 to be cut off through RQ31, and makes Q1 cut off through R25 and R24, and then makes V2+ become 0, and finally makes the design enter the sleep state. Wait for the RXK near-end switch or the remote fixed telephone coding remote control or the wireless coding remote control module to start.

[0059] In some embodiments, the over-temperature and over-current protection circuit further comprises a starting unit 1, which is electrically connected with the power switch and is used for controlling the power switch to be re-closed.

[0060] In this embodiment, after the staff repairs the load circuit according to the fault information reported by the fault reporting signal, the power switch can be re-closed through the starting unit 1, so that the over-temperature and over-current protection circuit and the load circuit are powered on.

[0061] Specifically, the starting unit 1 comprises an RXK module (i.e. a first switch module), RQ42, RQ41 and Q4. The RXK module can adopt one of a near-end switch, a remote fixed telephone coding remote controller or a wireless coding remote controller. The internal supply unit 2 comprises resistors RQ31 and RQ32, a switching triode Q3 (IN31\IN11 is connected), resistors R25 and R24, a switching triode Q1 and a capacitor C22.

[0062] The RXK module is electrically connected with the switching triode Q4, the switching triode Q4 is electrically connected with the switching triode Q1 through the IN31 port, the IN11 port and the R25. The starting unit 1 RXK is used for sending a high level signal to the switching triode Q4, so that the triode switch Q4 is turned on, and then the Q1 is turned on, and the VC+ obtains the V2+ power supply through the Q1, that is, the power adapter over-temperature and over-current protection circuit is powered on.

[0063] In other words, when the power adapter over-temperature and over-current protection circuit of the design is powered on through the RXK module (i.e. the near-end switch or the remote fixed telephone coding remote control or wireless coding remote control module), the RXK output is high level, the high level signal passes through the RQ42 and the RQ41, so that the Q4 is turned on, the IN31 and the IN11 connected thereto pass through the R25 and the R24, so that the Q1 is turned on, and the power adapter over-temperature and over-current protection circuit obtains the V2+ power supply from the VC+ through the Q1.

[0064] At this time, the U3 is reset through the V2+, the C31 and the R31, so that the output ports of the U3 and the S31 are both low level, and then the first input end "13" of the U2D is low level. The second input end "12" of the NAND gate U2D is grounded, when the first input end "13" is low level, the output end "11" of the NAND gate U2D is high level. The output end "11" of the NAND gate U2D is electrically connected with the switching triode Q3 through the RQ31 and the RQ32. The output end "11" of the NAND gate U2D outputs high level, and then controls the Q1 to be kept on through the RQ31, the RQ32, the Q3, (the IN31\IN11 are connected), the R25, the R24, that is, the power adapter over-temperature and over-current protection circuit is kept powered on.

[0065] The following is the description of the working principle of the over-temperature and over-current protection circuit:

[0066] First of all, it should be pointed out that, Figure 1U1A is a comparator. U2A, U2B, U2C, U2D are NAND gates. U4A, U4B, U4C, U4D are NOR gates. D11, D12, DQ1, DQ2, D21, D31, D32, D51 are diodes, and D13 is a voltage stabilizing diode. Q1, Q2, Q3, Q4, Q5 are switching triodes. K21 is a relay. t1, t2,..., tn are temperature sensitive contacts (specifically, normally closed temperature switches). R11, R12, R13, etc. are resistors. U3 is a counter. S31 is a code switching switch. TXK, RXK are encoders. V1+ is the output voltage of the protected power adapter, VC+ is the power supply of the design, VC+ and V1+ can be the same power supply or independent power supply, V2+ is the first voltage interface, V2+ is electrically connected to VC+ through Q1, VC+ can obtain power on V2+ through Q1, V3+ is the second voltage interface, which is electrically connected to the protected power adapter, that is, the second voltage interface V3+ obtains the output voltage V1+.

[0067] As shown in Figure 1 V1+ output by the monitored power supply is controlled by K21A of the over-temperature and over-current protection circuit, and the output is V3+, which flows through the load and V3- port in turn and then returns to V1- (ground) through current sampling unit 4 of R11. Current sampling unit 4 and comparison unit 5 are composed of R11, R12, R13, R14, R15, C11, D11, D12, D13, U1A, etc. and have the function of converting the load current on R11 into voltage and comparing it with the set voltage of U1A③. When the load current is greater than the set value, the output of comparison unit 5 becomes low level, triggering the delay unit.

[0068] Delay unit: composed of R21, U2A, C21, R23, U4C, etc. Function: when triggered by the low level of comparison unit 5, the delay unit outputs the low level of T1 time (i.e. the first preset time mentioned above) to the first logic unit 7.

[0069] First logic unit 7: composed of U2C, U4D, etc. Function: it discriminates the low level output from the temperature overrun of the monitored area or the low level output triggered by the current overrun of the delay unit, both of which will make U2C control U4D to output from high level to low level.

[0070] (U4D output end is triggered in two ways) one way to control the fault reporting unit 11 TXK sends fault reporting information, fault reporting unit 11: composed of U2B, C51, R51, Q5, TXK (encoding sending module) and so on. The other way to control the execution unit 3 from on to off, cut off the load power supply, play a protective role. Execution unit 3: composed of R26, R27, Q2, K21, D21 and so on. Effect: controlled by the first logic unit 7, the execution of the load power supply on and off, the first logic unit 7 output high level, control K21 (K21A) closed, the first logic unit 7 output low level K21 (K21A) is disconnected (K21 and K21A are synchronous electric control switch).

[0071] Start unit 1: contains RQ42, RQ41, Q4, manual switch or wireless, wired or fixed telephone remote control and other modules or one of them (RXK) and so on. For manual start or wireless, wired or fixed telephone remote control and other modules or one of them (RXK) start instruction (output high level), through RQ42, RQ41, Q4 (IN31\IN11 connected) control the internal power supply unit 2, complete the over-temperature and over-current protection circuit (the design) itself power supply start.

[0072] Internal power supply unit 2: composed of RQ31, RQ32, Q3, (IN31\IN11 connected), R25, R24, Q1, C22 and so on. Effect: controlled by the second logic unit 8, start unit 1 RXK, through Q3 or Q4 control Q1. Complete the over-temperature and over-current protection circuit including comparison unit 5, delay unit, first logic unit 7, second logic unit 8, execution unit 3, fault reporting unit 11 TXK power supply on and off.

[0073] Second logic unit 8: composed of U3, C31, R31, D31, D32, C41, R41, S31, U4A, C42, R42, U4B, U2D and so on. Effect: analysis of the first logic unit 7 output in the set time T2 (i.e. the second preset length above) state, to determine the severity of the fault. If in the set time T2, the first logic unit 7 output exceeds the set number of times (the design example is 3 times), it is judged as a serious fault, at this time, the second logic unit 8 output low level, (the low level output by the second logic unit 8 is controlled in two ways) one way to control the fault reporting unit 11 TXK sends fault reporting information, control internal power supply unit 2 Q3 and Q1 closed, cut off the power adapter over-temperature and over-current protection circuit (the design) and the protected load power supply, enter the hibernation state. Until through RXK start again, restore power supply.

[0074] The circuit principle is as follows:

[0075] When the over-temperature and over-current protection circuit is powered on by the RXK (i.e. the starting unit 1) near-end switch or remote fixed telephone coding remote control or wireless coding remote control module, RXK is high via RQ42, RQ41 to control Q4 to be turned on, so that IN31 and its connected IN11 are turned on, and then Q1 is turned on via R25, R24. The power adapter over-temperature and over-current protection circuit in the design obtains V2+ power supply from VC+ via Q1.

[0076] At this time, U3 is reset by V2+, C31, and R31, so that the output of U3 to U2D⒀ through S31 is low, and then the output of U2D⑾ is triggered to be high, controlling Q1 to be kept on by RQ31, RQ32, Q3, (IN31\IN11 connected), R25, R24. The protected power adapter load current is dropped on R11 (current sampling resistor) via R12, R13, C11, D11, and D12 into U1A②③. U1A② compares the voltage with U1A③. The voltage of U1A③ is the voltage divided by R15, R13 at V2+ via R14 at D13. When the load current rises, the voltage of R11 to ground rises. When the voltage of U1A② is higher than that of U1A③, U1A① outputs low, triggering the delay circuit composed of R21, U2A, C21, R23, and U4C. The low level output by U4C for T1 time (i.e. the first fault signal mentioned above) is sent to U2C⑨, or the state of the temperature sensor connected in series from t1-t2-tn. As long as one temperature sensor temperature exceeds the limit and is disconnected, U2C⑧ will be pulled low by R22 (i.e. receiving the second fault signal mentioned above), so that U2C⑽ outputs high (i.e. the fault execution signal mentioned above), which controls:

[0077] 1. U4D outputs low to control R26, R27 to make Q2 cut off, and then control K21\K21A to disconnect, turning off the protected power adapter to supply power to the load. At the same time, U2B triggers C51, R51, and Q5, and then TXK (coding module) reports the fault information. When the delay circuit output T1 time ends, U2C⑨ input will become high, or the temperature sensor returns to normal temperature and is closed to make U2C⑧ return to high, and then U2C⑽ outputs 0 (i.e. low), so that U4D⑾ outputs 1 (i.e. high), triggering Q2 to be turned on, so that K21 (K21A) is closed to restore power supply to the load.

[0078] 2. Control U3 and S31 to count the number of faults.

[0079] 3. Trigger the high level (i.e. the timing signal mentioned above) of the delay circuit output T2 time (i.e. the second preset time mentioned above) composed of U4A, C42, R42, U4B to U2D and U3 and S31 fault analysis, if the cumulative fault power off exceeds 3 times (can be set) within T2 time, U2D determines as serious fault and outputs 0 level: (1). Control U2B trigger C51, Q5, TXK (encoding module) to report fault information, (2). Control RQ31 trigger Q3 cut-off, and then through R25, R24 trigger Q1 cut-off to make V2+ become 0, so that the design enters the dormant state. Wait for RXK near-end switch or remote fixed-line encoding remote control or wireless encoding remote control module to start.

[0080] V1+ is the output + of the protected power adapter, VC+ is the power supply of the design, and V1+ is the same or independent power supply.

[0081] When VC+ and V1+ use different power supplies, the VA and VB of K21 can control the 220V AC input power supply of the power adapter.

[0082] At present, various types of power adapters almost do not have overcurrent and overtemperature protection, resulting in fire accidents caused by overcurrent or temperature overrun of the power adapter. In order to avoid accidents, the overtemperature and overcurrent protection circuit designed for the power adapter can effectively prevent fire accidents caused by overcurrent and overtemperature of the power adapter for power supply of various safety systems, dynamic environment monitoring, routers, monitoring, security smart home, etc.

[0083] The overtemperature and overcurrent protection circuit is installed between the power adapter and the load when it is used, and it does not need to replace the power adapter to avoid discomfort caused by replacing the power adapter. It has no effect on the original circuit. For power adapters without overcurrent and overtemperature protection or existing ordinary power adapters that use single-chip microcomputer and other program chips for overcurrent and overtemperature protection, since program chips are subject to software constraints, there are disadvantages such as dead machine, failure or ordinary chips that cannot be replaced when a fault occurs. The design uses general-purpose chips to make it stable and reliable with low power consumption.

[0084] The overtemperature and overcurrent protection circuit is designed for the frequent fire accidents of security, monitoring, PON, optical modem, router and its power adapter, battery charger and other devices in recent years. The reason is that the power adapter responsible for power supply of the above-mentioned devices cannot cut off the power supply in time when the load current and temperature overrun, causing fire and other accidents. If the overtemperature and overcurrent protection circuit is installed between the power adapter and the load, it can effectively prevent fire accidents caused by overcurrent and temperature overrun of the power adapter or the load. The overtemperature and overcurrent protection circuit is especially suitable for the following application scenarios: optical modem, router, monitoring, smart home products or various charging or electric bicycle management departments or community property installed and sold.

[0085] Moreover, compared with the existing over-temperature and over-current protection circuit, the over-temperature and over-current protection circuit in the embodiment has the following advantages:

[0086] 1. The over-temperature and over-current protection circuit has the functions of over-current protection, over-temperature protection, automatic closing of the load circuit after meeting the recovery condition, reporting of fault number information, and complete shutdown according to the fault frequency.

[0087] 2. The prior art is mostly designed by combining a single-chip microcomputer with hardware. Once the single-chip microcomputer is damaged, it cannot be replaced, which causes the entire system to be scrapped. The design is restricted by the program of the special single-chip microcomputer, and the safety, maintenance, and updating costs are greatly increased. The design uses a general-purpose chip and does not have a program, so it is not dead and is easy to maintain and replace.

[0088] 3. At present, most of the power adapter, charger and other products of various security, monitoring, dynamic environment monitoring, PON, optical modem, router and the like have faults and accidents caused by the lack of over-temperature and over-current protection or the inability to completely cut off the power supply. If the over-temperature and over-current protection circuit is installed between the power adapter and the load, the fire accidents caused by over-current and temperature overrun can be effectively prevented. The over-temperature and over-current protection circuit can effectively prevent the power adapter of various safety systems, dynamic environment monitoring, routers, monitoring, security smart home and the like from causing fire accidents due to over-current and over-temperature. The circuit can be widely used in various fields to realize low-cost circuit protection and make the system equipment powered by the power adapter safer.

[0089] Embodiment 2

[0090] The utility model discloses a kind of power adapter systems, including power adapter and over-temperature and over-current protection circuit in embodiment 1, over-temperature and over-current protection current is electrically connected with power adapter, for over-temperature and over-current protection to power adapter.

[0091] The power adapter system can realize the following advantages by using the over-temperature and over-current protection circuit in embodiment 1.

[0092] 1. Over-current and over-temperature monitoring of power adapter and load is carried out by using ordinary chip through simple method, and the circuit has the functions of power-off in time and complete power-off for serious faults when current or temperature of monitored area exceeds the limit.

[0093] 2. The circuit is built by using ordinary low-cost chip, which is stable and reliable, and is different from software system using single-chip microcomputer, which is restricted by software chip. Maintenance and replacement are convenient, low-cost and worry-free.

[0094] 3. The unique fault judgment circuit can determine that complete power-off is caused by serious faults when faults of set number occur within set time.

[0095] It can be understood that the above implementation is only an exemplary embodiment for illustrating the principle of the present application, but the present application is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and essence of the present application, and these modifications and improvements are also considered as the protection scope of the present application.

Claims

1. An over-temperature and over-current protection circuit, characterized in that, include: Overcurrent monitoring component, temperature control unit (6), first logic unit (7) and execution unit (3); The overcurrent monitoring component is electrically connected to the protected load circuit. The overcurrent monitoring component has a built-in set voltage. The overcurrent monitoring component is used to output a first fault signal that lasts for a first preset duration when the load voltage of the load circuit is greater than the set voltage. The temperature control unit (6) is coupled to the load circuit and is used to detect the temperature of the load circuit and output a second fault signal when the temperature of the load circuit exceeds a preset temperature threshold. The execution unit (3) is electrically connected to the load circuit and is used to control the closing / opening of the load circuit; The first logic unit (7) is electrically connected to the overcurrent monitoring component, the temperature control unit (6) and the execution unit (3), and is used to control the execution unit (3) to disconnect the load circuit when a first fault signal is received and / or a second fault signal is received. The overcurrent monitoring component is also used to output a first recovery signal after a first preset time period. The temperature control unit (6) is also used to output a second recovery signal when the temperature of the load circuit is lower than a preset temperature threshold. When the first logic unit (7) receives the first recovery signal and / or the second recovery signal, it controls the execution unit (3) to close the load circuit again.

2. The over-temperature and over-current protection circuit according to claim 1, characterized in that, The overcurrent monitoring component includes a current sampling unit (4), a comparison unit (5), and a first delay unit (9). The current sampling unit (4) is electrically connected to the load circuit and is used to sample the current of the load circuit to obtain the load voltage. The comparison unit (5) is provided with a first voltage input terminal and a second voltage input terminal. The first voltage input terminal is electrically connected to the current sampling unit (4) and is used to input the load voltage. The second voltage input terminal is used to input a set voltage. The comparison unit (5) is used to compare the load voltage with the set voltage. When the load voltage is greater than the set voltage, a low-level signal is issued. The first delay unit (9) is electrically connected to the comparison unit (5) and is used to perform timing and output a first fault signal when the low-level signal is received. The first delay unit (9) is used to flip to output a first recovery signal after the timing duration reaches the first preset duration.

3. The over-temperature and over-current protection circuit according to claim 2, characterized in that, The temperature control unit (6) includes a third voltage input terminal and multiple temperature-sensing contacts. The third voltage input terminal is used to connect to a temperature regulation voltage, and the third voltage input terminal is electrically connected to the first logic unit (7) through the multiple temperature-sensing contacts. Multiple temperature-sensing contacts are connected in series. The load circuit has multiple detection points. The number of temperature-sensing contacts is equal to the number of detection points. Each temperature-sensing contact corresponds to one detection point. The temperature-sensing contact is a normally closed contact. The temperature-sensing contact is used to sense the temperature of the corresponding detection point and disconnects when the temperature of the detection point is higher than a preset temperature threshold. When the temperature of one of the detection points of the load circuit is higher than the preset temperature threshold, the corresponding temperature sensing contact is disconnected, causing the temperature control unit (6) to output a second fault signal. When the temperature of all detection points of the load circuit is lower than the preset temperature threshold, all temperature sensing contacts are closed, and the third voltage input terminal sends a second recovery signal to the first logic unit (7).

4. The over-temperature and over-current protection circuit according to claim 3, characterized in that, The first logic unit (7) includes a first NAND gate and a NOR gate. The first NAND gate has a first signal input terminal, a second signal input terminal, and a signal output terminal. The first signal input terminal of the first NAND gate is electrically connected to the first delay unit (9) and is used to receive a first fault signal / first recovery signal issued by the first delay unit (9). The second signal input terminal of the first NAND gate is electrically connected to the temperature control unit (6) and is used to receive a second fault signal / second recovery signal issued by the temperature control unit (6). When the first NAND gate receives the first recovery signal and the second recovery signal, it outputs a recovery execution signal through its signal output terminal. When the first NAND gate receives the first fault signal and / or the second fault signal, it outputs a fault execution signal through its signal output terminal. One end of the NOR gate is electrically connected to the signal output terminal, and the other end is electrically connected to the execution unit (3). When the NOR gate receives a fault execution signal, it controls the execution unit (3) to disconnect the load circuit; or, when it receives a recovery execution signal, it controls the execution unit (3) to restore the conduction of the load circuit.

5. The over-temperature and over-current protection circuit according to claim 4, characterized in that, It also includes a fault reporting unit (11), which is electrically connected to the NOR gate of the first logic unit (7). The NOR gate is also used to report a fault through the fault reporting unit (11) when a fault execution signal is received.

6. The over-temperature and over-current protection circuit according to claim 4, characterized in that, It also includes an internal power supply unit (2), which includes a control power supply and an access circuit. The control power supply is electrically connected to the second voltage input terminal of the comparison unit (5) through the access circuit. The control power supply is used to provide a set voltage to the second voltage input terminal. The control unit is also electrically connected to the third voltage input terminal of the temperature control unit (6), the first logic unit (7) and the execution unit (3) in sequence via an access circuit. The control power supply is also used to provide temperature regulation voltage to the third voltage input terminal and to supply power to the first logic unit (7) and the execution unit (3).

7. The over-temperature and over-current protection circuit according to claim 6, characterized in that, The access circuit is equipped with a power switch, which is used to control the on / off state of the access circuit.

8. The over-temperature and over-current protection circuit according to claim 7, characterized in that, It also includes a second logic unit (8) and a second delay unit (10), the second delay unit (10) being electrically connected to the signal output terminal, and being used to output a timing electrical signal lasting for a second preset duration when a fault execution signal is received from the signal output terminal; The second logic unit (8) is electrically connected to the second delay unit (10) and the signal output terminal, and is used to receive the fault execution signal sent by the signal output terminal, and count the number of received fault execution signals to obtain the cumulative number of faults; The second logic unit (8) has a preset number of times. The second logic unit (8) is also electrically connected to the power switch. When it receives the timing signal sent by the second delay unit (10) and the cumulative number of faults is greater than or equal to the preset number of times, it controls the power switch to turn off, so that the second voltage input terminal of the comparison unit (5), the temperature control unit (6), the first logic unit (7) and the execution unit (3) are all de-energized, and the load circuit is disconnected.

9. The over-temperature and over-current protection circuit according to claim 8, characterized in that, The second logic unit (8) includes a counter and a second NAND gate. The counter includes a signal receiving end and a counting output end. The signal receiving end is electrically connected to the signal output end and is used to count the received fault execution signals emitted by the signal output end to obtain the cumulative number of faults. The counter has a preset number of counts, and it is also used to issue an over-count signal through the counter output terminal when the cumulative number of faults is greater than or equal to the preset number. The second NAND gate is electrically connected to the second delay unit (10), the counting output terminal and the power switch, and is used to control the power switch to turn off when the timing electrical signal issued by the second delay unit (10) and the counting over-limit signal issued by the counting output terminal are received.

10. The over-temperature and over-current protection circuit according to claim 8, characterized in that, It also includes a starting unit (1), which is electrically connected to the power switch and is used to control the power switch to close again.

11. A power adapter system, characterized in that, The device includes a power adapter and an over-temperature and over-current protection circuit as described in any one of claims 1-10, wherein the over-temperature and over-current protection circuit is electrically connected to the power adapter and is used to provide over-temperature and over-current protection for the power adapter.

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