A protection circuit for a power adapter

Abstract

The present invention discloses a protection circuit for a power adapter, which relates to the technical field of power adapters and includes a power control module for current sampling and high-frequency voltage regulation; a first output module for rectification, power transmission and filtering processing; a second output module for rectification and filtering; an abnormality detection module for performing overvoltage detection on the power control module; a voltage processing module for subtracting a voltage threshold from the voltage provided by the second output module; a fault judgment module for controlling a signal transmission module to switch a transmission path when the power control module is not overvoltage and the first output module is overvoltage; a signal transmission module for transmitting the voltage output by the first output module or the voltage processing module to a feedback module; and a feedback module for voltage and current feedback. The protection circuit of the power adapter of the present invention can perform overvoltage power-off protection, improve the safety of the power adapter, and ensure the power supply status of the remaining normal output branches, thereby improving power supply efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of power adapters, in particular to a protection circuit for a power adapter. Background Art

[0002] A power adapter, also known as a power converter or power supply, is a small electronic device that is mainly used to convert alternating current (AC) into direct current (DC) to meet the usage requirements of electronic devices. Power adapters in the prior art generally adopt a switching power supply method, which maintains a stable output voltage by controlling the time ratio of the switch tube to be turned on and off, and detects the output voltage and determines overvoltage. When overvoltage occurs, power-off protection is performed. However, when the power adapter is multi-channel power supply, since the switching power supply only samples the output voltage of one output branch, when the electronic device connected to the output branch is overvoltage, the power adapter as a whole will be powered off. This will cause the remaining output branches to be unable to perform power supply control normally, reducing the power supply efficiency of the power adapter, and therefore needs to be improved. Summary of the Invention

[0003] An embodiment of the present invention provides a protection circuit for a power adapter to solve the problems raised in the above background technology.

[0004] According to an embodiment of the present invention, a protection circuit for a power adapter is provided, comprising: a power control module, a first output module, a second output module, an abnormality detection module, a voltage processing module, a signal transmission module, a fault judgment module, and a feedback module;

[0005] a power control module, connected to the feedback module, configured to receive AC power, filter, reduce voltage, and rectify the AC power to output a first electric energy, sample current from the switch tube and output a current signal, and upon receiving a feedback signal output by the feedback module, perform high-frequency voltage conversion on the first electric energy and output a second electric energy by controlling the on-time ratio of the switch tube;

[0006] a first output module, connected to the power control module and the fault judgment module, configured to rectify the second electric energy, transmit and filter the processed electric energy, and output third electric energy, and stop the electric energy transmission operation upon receiving the second control signal output by the fault judgment module;

[0007] a second output module, connected to the power control module, for rectifying and filtering the second electric energy and outputting fourth electric energy;

[0008] an abnormality detection module, connected to the power control module, configured to convert the current signal into a voltage signal and amplify and filter the voltage signal, and output a first control signal when the processed signal is less than a set first overvoltage threshold;

[0009] a voltage processing module connected to the second output module, configured to set a voltage threshold and perform subtraction processing on the fourth electric energy and the voltage threshold to output fifth electric energy;

[0010] a fault judgment module, connected to the abnormality detection module and the feedback module, configured to output a second control signal when the first control signal is received and the first sampling signal output by the feedback module is greater than a set second overvoltage threshold;

[0011] a signal transmission module connected to the first output module, the voltage processing module of the feedback module, and the abnormality judgment module, and configured to transmit the third electric energy to the feedback module and transmit the fifth electric energy to the feedback module upon receiving the second control signal;

[0012] The feedback module is configured to perform voltage sampling on the third electric energy or the fifth electric energy transmitted by the signal transmission module and output a first sampling signal, perform voltage and current detection on the first sampling signal and output a feedback signal.

[0013] As a further solution of the present invention: the power control module includes a power interface, a voltage conversion device, a first capacitor, a first resistor, a first diode, a first power tube, a second resistor, a first transformer and a switch driver;

[0014] Preferably, the first end and the second end of the power interface are respectively connected to the first end and the second end of the voltage conversion device, the third end of the voltage conversion device is connected to the first end of the primary side of the first transformer and one end of the first capacitor and is connected to the other end of the first capacitor and the cathode of the first diode through the first resistor, the anode of the first diode is connected to the second end of the primary side of the first transformer and the drain of the first power tube, the source of the first power tube is connected to the current end of the switch driver and the first end of the second resistor, the gate of the first power tube is connected to the drive end of the switch driver, the feedback end of the switch driver is connected to the feedback module, the ground end of the switch drive device is connected to the second end of the second resistor, the fourth end of the voltage conversion device and the ground end, the first end and the second end of the first secondary side of the first transformer are connected to the first output module, and the first end and the second end of the second secondary side of the first transformer are connected to the second output module.

[0015] As a further solution of the present invention: the first output module includes a second diode, a third resistor, a second power tube, a first switch tube, a fifth resistor, a third capacitor, a first inductor and a first output port;

[0016] Preferably, the anode of the second diode is connected to the first end of the first secondary side of the first transformer, the cathode of the second diode is connected to the drain of the second power tube and is connected to the gate of the second power tube and the collector of the first switching tube through the third resistor, the source of the second power tube is connected to one end of the third capacitor and is connected to the first end of the first output port through the first inductor, the emitter of the first switching tube is connected to the second end of the first secondary side of the first transformer, the other end of the third capacitor, the second end of the first output port and the ground, the base of the first switching tube is connected to the first end of the fifth resistor, and the second end of the fifth resistor is connected to the fault judgment module.

[0017] As a further solution of the present invention: the second output module includes a third diode, a fourth capacitor, a second inductor and a second output port;

[0018] Preferably, the anode of the third diode is connected to the first end of the second secondary side of the first transformer, the cathode of the third diode is connected to one end of the fourth capacitor and connected to the first end of the second output port through the second inductor, and the other end of the fourth capacitor is connected to the second end of the second output port, the second end of the second secondary side of the first transformer and the ground.

[0019] As a further solution of the present invention: the signal transmission module includes a first thyristor, a second thyristor and a fourth resistor;

[0020] Preferably, the anode of the first thyristor is connected to the source of the second power tube, the anode of the second thyristor is connected to the voltage processing module, the cathode of the first thyristor is connected to the cathode of the second thyristor and the feedback module, the control end of the first thyristor is connected to the gate of the second power tube through the fourth resistor, and the control end of the second thyristor is connected to the fault judgment module.

[0021] As a further solution of the present invention: the voltage processing module includes a sixth resistor, a seventh resistor, a first operational amplifier, a ninth resistor, a tenth resistor and a voltage threshold device;

[0022] Preferably, the in-phase terminal of the first operational amplifier is connected to one end of the sixth resistor and is grounded through the seventh resistor, the other end of the sixth resistor is connected to the cathode of the third diode, the inverting terminal of the first operational amplifier is connected to one end of the ninth resistor and is connected to the voltage threshold device through the tenth resistor, and the output terminal of the first operational amplifier is connected to the other end of the ninth resistor and the anode of the second thyristor.

[0023] As a further solution of the present invention: the fault judgment module includes a sixth diode, a fifth diode, a fourth diode, an eighth resistor and a first logic chip;

[0024] Preferably, the anode of the sixth diode is connected to the Y end of the first logic chip, the control end of the second thyristor and the second end of the fifth resistor, the A end of the first logic chip is connected to the cathode of the sixth diode and the cathode of the fifth diode, the anode of the fifth diode is connected to the anode of the fourth diode, the cathode of the fourth diode is connected to the first end of the eighth resistor, the second end of the eighth resistor is connected to the feedback module, and the B end of the first logic chip is connected to the abnormality detection module.

[0025] As a further solution of the present invention: the abnormality detection module includes a signal processing device, an eleventh resistor, a seventh diode and a first inverter;

[0026] Preferably, the first input terminal and the second input terminal of the signal processing device are respectively connected to the first end and the second end of the second resistor, the output terminal of the signal processing device is connected to the cathode of the seventh diode through the eleventh resistor, the anode of the seventh diode is connected to the input terminal of the first inverter, and the output terminal of the first inverter is connected to the B terminal of the first logic chip.

[0027] As a further solution of the present invention: the feedback module includes a twelfth resistor, a thirteenth resistor, a first optocoupler, a fourteenth resistor, a fifth capacitor, a fifteenth resistor and a first voltage stabilization source;

[0028] Preferably, one end of the twelfth resistor is connected to the cathode of the first thyristor and the cathode of the second thyristor and is connected to the second end of the eighth resistor, one end of the fifth capacitor, the reference end of the first voltage regulator and one end of the fifteenth resistor through the thirteenth resistor, the anode of the first voltage regulator is connected to the other end of the fifteenth resistor and the ground end, the cathode of the first voltage regulator is connected to the other end of the fifth capacitor and the second end of the first optocoupler, the first end of the first optocoupler is connected to the other end of the twelfth resistor, the third end of the first optocoupler is connected to the feedback end of the switch driver, and the fourth end of the first optocoupler is grounded through the fourteenth resistor.

[0029] Compared with the prior art, the beneficial effects of the present invention are as follows: the protection circuit of the power adapter of the present invention can perform voltage conversion and high-frequency voltage regulation on the connected AC power through the power control module, the feedback module and the first output module. At the same time, the abnormality detection module performs overvoltage detection on the power control module, and the fault judgment module performs overvoltage detection on the first output module. When the power control module is overvoltage, the power supply will be stopped directly. When the first output module is overvoltage and the power control module is not overvoltage, the fault judgment module will control the signal transmission module to transmit the signal provided by the voltage processing module to the feedback module, so that the power control module can perform voltage regulation control according to the output status of the second output module, and disconnect the power supply of the first output module, thereby improving the safety of the power adapter and ensuring the power supply status of the remaining normal output branches, thereby improving the power supply efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in describing the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0031] Figure 1 A schematic block diagram of a protection circuit for a power adapter provided by an embodiment of the present invention.

[0032] Figure 2 A circuit diagram of a protection circuit for a power adapter provided by an embodiment of the present invention.

[0033] Figure 3 This is a circuit diagram of an anomaly detection module provided in an embodiment of the present invention.

[0034] Figure 4 This is a circuit diagram of a feedback module provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0035] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0036] In one embodiment, see Figure 1 , a protection circuit for a power adapter, comprising: a power control module 1, a first output module 2, a second output module 3, an abnormality detection module 4, a voltage processing module 5, a signal transmission module 6, a fault judgment module 7 and a feedback module 8;

[0037] Specifically, the power control module 1 is connected to the feedback module 8 and is used to receive AC power, filter, reduce voltage and rectify the AC power and output the first power, sample the current of the switch tube and output the current signal, and upon receiving the feedback signal output by the feedback module 8, perform high-frequency voltage regulation on the first power by controlling the on-time ratio of the switch tube and output the second power;

[0038] a first output module 2 connected to the power control module 1 and the fault judgment module 7, configured to rectify the second electric energy, transmit and filter the processed electric energy, and output third electric energy, and stop the electric energy transmission operation upon receiving the second control signal output by the fault judgment module 7;

[0039] a second output module 3, connected to the power control module 1, for rectifying and filtering the second electric energy and outputting fourth electric energy;

[0040] an abnormality detection module 4 connected to the power control module 1, configured to convert the current signal into a voltage signal and amplify and filter the voltage signal, and output a first control signal when the processed signal is less than a set first overvoltage threshold;

[0041] a voltage processing module 5 connected to the second output module 3, configured to set a voltage threshold and perform subtraction processing on the fourth electric energy and the voltage threshold to output fifth electric energy;

[0042] a fault judgment module 7 connected to the abnormality detection module 4 and the feedback module 8, and configured to output a second control signal when the first control signal is received and the first sampling signal output by the feedback module 8 is greater than a set second overvoltage threshold;

[0043] a signal transmission module 6 connected to the first output module 2, the feedback module 8, the voltage processing module 5, and the abnormality judgment module, and configured to transmit the third electrical energy to the feedback module 8 and, upon receiving the second control signal, transmit the fifth electrical energy to the feedback module 8;

[0044] The feedback module 8 is configured to perform voltage sampling on the third electric energy or the fifth electric energy transmitted by the signal transmission module 6 and output a first sampling signal, perform voltage and current detection on the first sampling signal and output a feedback signal.

[0045] In a specific embodiment, the power control module 1 may adopt a power control circuit composed of a power interface, a voltage conversion device, a field effect transistor, a transformer, etc., which may be connected to AC power and perform EMI filtering, voltage reduction and rectification on the AC power, and perform high-frequency voltage regulation on the power by cooperating with the transformer by controlling the time ratio of the switch tube to be turned on and off, and perform current sampling on the switch tube; the first output module 2 may adopt a first output circuit composed of a diode, a field effect transistor, a triode, an inductor, an output port, etc., which may perform rectification, energy storage transmission and filtering and transmit the power to the connected electronic device; the second output module 3 may adopt a second output circuit composed of a diode, a resistor, an inductor, an output port, etc., which may perform rectification and filtering and transmit the power to the connected electronic device; the abnormality detection module 4 may adopt an abnormality detection circuit composed of an inverter, a signal processing device, a diode, etc., which may convert the current signal into a voltage signal and perform signal amplification and filtering, and compare the processed signal with the set first overvoltage threshold. , the first overvoltage threshold is the overvoltage limit of the power control module 1; the above-mentioned voltage processing module 5 can adopt a voltage processing circuit composed of an operational amplifier, a resistor and a voltage threshold device, and can perform subtraction processing on the voltage output by the second output module 3 and the voltage threshold device, and the voltage threshold device is obtained by subtracting the voltage provided by the first output module 2 from the voltage provided by the second output module 3; the above-mentioned signal transmission module 6 can adopt a signal transmission circuit composed of a thyristor and a resistor to control the connection state of the first output module 2 or the voltage processing module 5 and the feedback module 8; the above-mentioned fault judgment module 7 can adopt a fault judgment circuit composed of a resistor, a diode and a logic chip to set the second overvoltage threshold and perform overvoltage detection on the signal sampled by the feedback module 8, and control the operation of the signal transmission module 6 when the abnormality detection module 4 is not overvoltage and the feedback module 8 is overvoltage; the above-mentioned feedback module 8 can adopt a feedback circuit composed of a logic chip, a capacitor, a controllable voltage regulator, etc., to perform current and voltage detection on the input electric energy and provide a feedback signal to the power control module 1.

[0046] In another embodiment, see Figure 1 、 Figure 2 、 Figure 3 and Figure 4 The power control module 1 includes a power interface, a voltage conversion device, a first capacitor C1, a first resistor R1, a first diode D1, a first power tube Q1, a second resistor R2, a first transformer B1 and a switch driver;

[0047] Specifically, the first end and the second end of the power interface are respectively connected to the first end and the second end of the voltage conversion device, the third end of the voltage conversion device is connected to the first end of the primary side of the first transformer B1 and one end of the first capacitor C1 and is connected to the other end of the first capacitor C1 and the cathode of the first diode D1 through the first resistor R1, the anode of the first diode D1 is connected to the second end of the primary side of the first transformer B1 and the drain of the first power tube Q1, the source of the first power tube Q1 is connected to the current end of the switch driver and the first end of the second resistor R2, the gate of the first power tube Q1 is connected to the driving end of the switch driver, the feedback end of the switch driver is connected to the feedback module 8, the ground end of the switch driving device is connected to the second end of the second resistor R2, the fourth end of the voltage conversion device and the ground end, the first end and the second end of the first secondary side of the first transformer B1 are connected to the first output module 2, and the first end and the second end of the second secondary side of the first transformer B1 are connected to the second output module 3.

[0048] In a specific embodiment, the voltage conversion device may be composed of an EMI filter, a transformer, and a rectifier; the first power tube Q1 may be an N-channel field-effect tube, and an RCD protection circuit composed of a first resistor R1, a first diode D1, and a first capacitor C1 may be used for switch protection; the first transformer B1 may be a high-frequency transformer; the second resistor R2 may be used for current sampling; and the switch driver may be a UC3844 high-performance fixed-frequency current mode controller.

[0049] Furthermore, the first output module 2 includes a second diode D2, a third resistor R3, a second power tube Q2, a first switch tube V1, a fifth resistor R5, a third capacitor C3, a first inductor L1 and a first output port;

[0050] Specifically, the anode of the second diode D2 is connected to the first end of the first secondary side of the first transformer B1, the cathode of the second diode D2 is connected to the drain of the second power tube Q2 and is connected to the gate of the second power tube Q2 and the collector of the first switching tube V1 through the third resistor R3, the source of the second power tube Q2 is connected to one end of the third capacitor C3 and is connected to the first end of the first output port through the first inductor L1, the emitter of the first switching tube V1 is connected to the second end of the first secondary side of the first transformer B1, the other end of the third capacitor C3, the second end of the first output port and the ground, the base of the first switching tube V1 is connected to the first end of the fifth resistor R5, and the second end of the fifth resistor R5 is connected to the fault judgment module 7.

[0051] In a specific embodiment, the second power tube Q2 can be an N-channel field effect tube; the first switch tube V1 can be an NPN transistor; and the first inductor L1 and the third capacitor C3 perform filtering.

[0052] Furthermore, the second output module 3 includes a third diode D3, a fourth capacitor C4, a second inductor L2 and a second output port;

[0053] Specifically, the anode of the third diode D3 is connected to the first end of the second secondary side of the first transformer B1, the cathode of the third diode D3 is connected to one end of the fourth capacitor C4 and is connected to the first end of the second output port through the second inductor L2, and the other end of the fourth capacitor C4 is connected to the second end of the second output port, the second end of the second secondary side of the first transformer B1, and the ground.

[0054] In a specific embodiment, the third diode D3 performs rectification, and the fourth capacitor C4 and the second inductor L2 perform filtering.

[0055] Furthermore, the signal transmission module 6 includes a first thyristor S1, a second thyristor S2 and a fourth resistor R4;

[0056] Specifically, the anode of the first thyristor S1 is connected to the source of the second power tube Q2, the anode of the second thyristor S2 is connected to the voltage processing module 5, the cathode of the first thyristor S1 is connected to the cathode of the second thyristor S2 and the feedback module 8, the control end of the first thyristor S1 is connected to the gate of the second power tube Q2 through the fourth resistor R4, and the control end of the second thyristor S2 is connected to the fault judgment module 7.

[0057] In a specific embodiment, both the first thyristor S1 and the second thyristor S2 can be unidirectional thyristors.

[0058] Furthermore, the voltage processing module 5 includes a sixth resistor R6, a seventh resistor R7, a first operational amplifier OP1, a ninth resistor R9, a tenth resistor R10 and a voltage threshold device;

[0059] Specifically, the non-inverting terminal of the first operational amplifier OP1 is connected to one end of the sixth resistor R6 and is grounded through the seventh resistor R7, the other end of the sixth resistor R6 is connected to the cathode of the third diode D3, the inverting terminal of the first operational amplifier OP1 is connected to one end of the ninth resistor R9 and is connected to the voltage threshold device through the tenth resistor R10, and the output terminal of the first operational amplifier OP1 is connected to the other end of the ninth resistor R9 and the anode of the second thyristor S2.

[0060] In a specific embodiment, the first operational amplifier OP1 can be an LM158 operational amplifier, which cooperates with the sixth resistor R6, the seventh resistor R7, the ninth resistor R9 and the tenth resistor R10 to perform subtraction processing; the voltage threshold device can be composed of a reference power supply and resistors.

[0061] Furthermore, the fault judgment module 7 includes a sixth diode D6, a fifth diode D5, a fourth diode D4, an eighth resistor R8 and a first logic chip J1;

[0062] Specifically, the anode of the sixth diode D6 is connected to the Y end of the first logic chip J1, the control end of the second thyristor S2 and the second end of the fifth resistor R5, the A end of the first logic chip J1 is connected to the cathode of the sixth diode D6 and the cathode of the fifth diode D5, the anode of the fifth diode D5 is connected to the anode of the fourth diode D4, the cathode of the fourth diode D4 is connected to the first end of the eighth resistor R8, the second end of the eighth resistor R8 is connected to the feedback module 8, and the B end of the first logic chip J1 is connected to the abnormality detection module 4.

[0063] In a specific embodiment, the eighth resistor R8 and the fourth diode D4 set the second overvoltage threshold; the first logic chip J1 can be an AND gate chip, which cooperates with the fifth diode D5 and the sixth diode D6 to perform high-level self-locking.

[0064] Furthermore, the abnormality detection module 4 includes a signal processing device, an eleventh resistor R11, a seventh diode D7 and a first inverter INV1;

[0065] Specifically, the first input terminal and the second input terminal of the signal processing device are respectively connected to the first terminal and the second terminal of the second resistor R2, the output terminal of the signal processing device is connected to the cathode of the seventh diode D7 through the eleventh resistor R11, the anode of the seventh diode D7 is connected to the input terminal of the first inverter INV1, and the output terminal of the first inverter INV1 is connected to the B terminal of the first logic chip J1.

[0066] In a specific embodiment, the above-mentioned signal processing device can be composed of an operational amplifier, a resistor and a capacitor to perform current-voltage conversion and signal amplification and filtering processing; the above-mentioned first inverter INV1 can use a NOT gate chip; the above-mentioned eleventh resistor R11 and the seventh diode D7 set the first overvoltage threshold.

[0067] Furthermore, the feedback module 8 includes a twelfth resistor R12, a thirteenth resistor R13, a first optocoupler U1, a fourteenth resistor R14, a fifth capacitor C5, a fifteenth resistor R15 and a first voltage stabilizing source U2;

[0068] Specifically, one end of the twelfth resistor R12 is connected to the cathode of the first thyristor S1 and the cathode of the second thyristor S2 and is connected to the second end of the eighth resistor R8, one end of the fifth capacitor C5, the reference end of the first voltage regulator U2 and one end of the fifteenth resistor R15 through the thirteenth resistor R13, the anode of the first voltage regulator U2 is connected to the other end of the fifteenth resistor R15 and the ground end, the cathode of the first voltage regulator U2 is connected to the other end of the fifth capacitor C5 and the second end of the first optocoupler U1, the first end of the first optocoupler U1 is connected to the other end of the twelfth resistor R12, the third end of the first optocoupler U1 is connected to the feedback end of the switch driver, and the fourth end of the first optocoupler U1 is grounded through the fourteenth resistor R14.

[0069] In a specific embodiment, the first optical coupler U1 may be a PC817 photoelectric coupler; and the first voltage regulator U2 may be a TL431 voltage regulator.

[0070] In a protection circuit of a power adapter of this embodiment, AC power is connected to the power interface, the voltage conversion device performs EMI filtering, voltage reduction and rectification processing, and outputs the first power. The switch driver controls the conduction of the first power tube Q1, and cooperates with the current signal sampled by the second resistor R2 and the feedback signal provided by the first optocoupler U1. Specifically, the first optocoupler U1 cooperates with the twelfth resistor R12, the thirteenth resistor R13, the fifteenth resistor R15, the fourteenth resistor R14, the fifth capacitor C5, the fifteenth resistor R15 and the first voltage regulator U2 to sample the voltage and current of the power output by the first output module 2 transmitted by the first thyristor S1, so as to Provides a feedback signal to the switch driver, which then controls the on-off time ratio of the first power tube Q1, cooperates with the first transformer B1 to perform high-frequency and voltage transformation on the first electric energy and outputs the second electric energy. The second electric energy is rectified by the second diode D2, transmitted by the second power tube Q2, filtered by the first inductor L1 and the third capacitor C3, and then transmitted to the electronic device connected to the first output port. After rectification and filtering by the third diode D3, the fourth capacitor C4 and the second inductor L2, it is transmitted to the electronic device connected to the second output port. At the same time, the signal processing device converts the current signal sampled by the second resistor R2 into a voltage signal. The voltage signal is amplified and filtered. When the processed signal is less than the first overvoltage threshold set by the eleventh resistor R11 and the seventh diode D7, the first inverter INV1 will output a high-level signal, i.e., the first control signal. At this time, when the first sampling signal sampled by the thirteenth resistor R13 and the fifteenth resistor R15 is greater than the second overvoltage threshold set by the eighth resistor R8 and the fourth diode D4, the first logic chip J1 will cooperate with the fifth diode D5 and the sixth diode D6 to perform high-level self-locking and output the second control signal, indicating that the first output module 2 is partially faulty at this time, which may be due to the electronic device connected to the first output port being faulty. Due to capacitor leakage, the second control signal will control the first switch tube V1 and the second thyristor S2 to be turned on, the second power tube Q2 and the first thyristor S1 to be turned off, and the first output module 2 to perform power-off protection. Since the voltage of the electric energy output by the second output module 3 is fixed, the first operational amplifier OP1 cooperates with the sixth resistor R6, the seventh resistor R7, the ninth resistor R9 and the tenth resistor R10 to subtract the electric energy output by the second output module 3 from the voltage threshold set by the voltage threshold device, and transmits the result to the feedback module 8 through the second thyristor S2, thereby maintaining the feedback module 8 to provide a feedback signal to the switch driver and maintain the power supply state of the second output module 3.

[0071] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and all variations within the meaning and range of equivalents of the claims are intended to be included therein. Any reference sign in a claim should not be construed as limiting the claim to which it relates.

[0072] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A protection circuit for a power adapter, characterized in that: The protection circuit of the power adapter includes: a power control module, a first output module, a second output module, an abnormality detection module, a voltage processing module, a signal transmission module, a fault judgment module and a feedback module; The power control module is connected to the feedback module and is used to receive AC power, filter, reduce voltage and rectify the AC power and output first power, sample current of the switch tube and output current signal, and upon receiving the feedback signal output by the feedback module, perform high-frequency voltage transformation on the first power and output second power by controlling the on-time ratio of the switch tube. The first output module is connected to the power control module and the fault judgment module, and is used to rectify the second electric energy, transmit and filter the processed electric energy and output the third electric energy, and stop the electric energy transmission when receiving the second control signal output by the fault judgment module; The second output module is connected to the power control module and is used to rectify and filter the second electric energy and output fourth electric energy; The abnormality detection module is connected to the power control module and is used to convert the current signal into a voltage signal and amplify and filter the voltage signal, and output a first control signal when the processed signal is less than a set first overvoltage threshold; The voltage processing module is connected to the second output module, and is used to set a voltage threshold and perform subtraction processing on the fourth electric energy and the voltage threshold to output the fifth electric energy; The fault judgment module is connected to the abnormality detection module and the feedback module, and is configured to output a second control signal when the first control signal is received and the first sampling signal output by the feedback module is greater than a set second overvoltage threshold; The signal transmission module is connected to the first output module, the feedback module voltage processing module and the abnormality judgment module, and is used to transmit the third electric energy to the feedback module, and transmit the fifth electric energy to the feedback module when receiving the second control signal; The feedback module is used to perform voltage sampling on the third electric energy or the fifth electric energy transmitted by the signal transmission module and output a first sampling signal, perform voltage and current detection on the first sampling signal and output a feedback signal.

2. The protection circuit of a power adapter according to claim 1, characterized in that: The power control module includes a power interface, a voltage conversion device, a first capacitor, a first resistor, a first diode, a first power tube, a second resistor, a first transformer and a switch driver; The first end and the second end of the power interface are respectively connected to the first end and the second end of the voltage conversion device, the third end of the voltage conversion device is connected to the first end of the primary side of the first transformer and one end of the first capacitor and is connected to the other end of the first capacitor and the cathode of the first diode through the first resistor, the anode of the first diode is connected to the second end of the primary side of the first transformer and the drain of the first power tube, the source of the first power tube is connected to the current end of the switch driver and the first end of the second resistor, the gate of the first power tube is connected to the driving end of the switch driver, the feedback end of the switch driver is connected to the feedback module, the ground end of the switch driving device is connected to the second end of the second resistor, the fourth end of the voltage conversion device and the ground end, the first end and the second end of the first secondary side of the first transformer are connected to the first output module, and the first end and the second end of the second secondary side of the first transformer are connected to the second output module.

3. The protection circuit of a power adapter according to claim 2, characterized in that: The first output module includes a second diode, a third resistor, a second power tube, a first switch tube, a fifth resistor, a third capacitor, a first inductor and a first output port; The anode of the second diode is connected to the first end of the first secondary side of the first transformer, the cathode of the second diode is connected to the drain of the second power tube and is connected to the gate of the second power tube and the collector of the first switching tube through the third resistor, the source of the second power tube is connected to one end of the third capacitor and is connected to the first end of the first output port through the first inductor, the emitter of the first switching tube is connected to the second end of the first secondary side of the first transformer, the other end of the third capacitor, the second end of the first output port and the ground, the base of the first switching tube is connected to the first end of the fifth resistor, and the second end of the fifth resistor is connected to the fault judgment module.

4. The protection circuit of a power adapter according to claim 3, characterized in that: The second output module includes a third diode, a fourth capacitor, a second inductor and a second output port; The anode of the third diode is connected to the first end of the second secondary side of the first transformer, the cathode of the third diode is connected to one end of the fourth capacitor and connected to the first end of the second output port through the second inductor, and the other end of the fourth capacitor is connected to the second end of the second output port, the second end of the second secondary side of the first transformer and the ground.

5. The protection circuit of a power adapter according to claim 4, characterized in that: The signal transmission module includes a first thyristor, a second thyristor and a fourth resistor; The anode of the first thyristor is connected to the source of the second power tube, the anode of the second thyristor is connected to the voltage processing module, the cathode of the first thyristor is connected to the cathode of the second thyristor and the feedback module, the control end of the first thyristor is connected to the gate of the second power tube through the fourth resistor, and the control end of the second thyristor is connected to the fault judgment module.

6. The protection circuit of a power adapter according to claim 5, characterized in that: The voltage processing module includes a sixth resistor, a seventh resistor, a first operational amplifier, a ninth resistor, a tenth resistor and a voltage threshold device; The non-inverting terminal of the first operational amplifier is connected to one end of the sixth resistor and is grounded through the seventh resistor, the other end of the sixth resistor is connected to the cathode of the third diode, the inverting terminal of the first operational amplifier is connected to one end of the ninth resistor and is connected to the voltage threshold device through the tenth resistor, and the output terminal of the first operational amplifier is connected to the other end of the ninth resistor and the anode of the second thyristor.

7. The protection circuit of a power adapter according to claim 5, characterized in that: The fault judgment module includes a sixth diode, a fifth diode, a fourth diode, an eighth resistor and a first logic chip; The anode of the sixth diode is connected to the Y end of the first logic chip, the control end of the second thyristor and the second end of the fifth resistor, the A end of the first logic chip is connected to the cathode of the sixth diode and the cathode of the fifth diode, the anode of the fifth diode is connected to the anode of the fourth diode, the cathode of the fourth diode is connected to the first end of the eighth resistor, the second end of the eighth resistor is connected to the feedback module, and the B end of the first logic chip is connected to the abnormality detection module.

8. The protection circuit of a power adapter according to claim 7, characterized in that: The abnormality detection module includes a signal processing device, an eleventh resistor, a seventh diode and a first inverter; The first input terminal and the second input terminal of the signal processing device are respectively connected to the first terminal and the second terminal of the second resistor, the output terminal of the signal processing device is connected to the cathode of the seventh diode through the eleventh resistor, the anode of the seventh diode is connected to the input terminal of the first inverter, and the output terminal of the first inverter is connected to the B terminal of the first logic chip.

9. The protection circuit of a power adapter according to claim 7, characterized in that: The feedback module includes a twelfth resistor, a thirteenth resistor, a first optocoupler, a fourteenth resistor, a fifth capacitor, a fifteenth resistor and a first voltage stabilization source; One end of the twelfth resistor is connected to the cathode of the first thyristor and the cathode of the second thyristor and is connected to the second end of the eighth resistor, one end of the fifth capacitor, the reference end of the first voltage-stabilizing source and one end of the fifteenth resistor through the thirteenth resistor, the anode of the first voltage-stabilizing source is connected to the other end of the fifteenth resistor and the ground end, the cathode of the first voltage-stabilizing source is connected to the other end of the fifth capacitor and the second end of the first optocoupler, the first end of the first optocoupler is connected to the other end of the twelfth resistor, the third end of the first optocoupler is connected to the feedback end of the switch driver, and the fourth end of the first optocoupler is grounded through the fourteenth resistor.

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