Control circuit capable of preventing high voltage impact and resisting current surge

Abstract

The utility model relates to the technical field of charging protection, and discloses a high-reliability anti-high-voltage-surge anti-current-surge control circuit, which comprises a charging circuit (100), an AC input voltage monitoring circuit (300) and a master control circuit (400), the AC input voltage monitoring circuit (300) compares an input voltage signal with a reference signal, and when the voltage signal is greater than the reference signal, the master control circuit (400) controls the charging circuit (100) to charge the charging circuit (100). The AC input voltage monitoring circuit (300) outputs a high-level signal and outputs the high-level signal to the main control circuit (400), and the main control circuit (400) outputs a control signal for closing the first switch assembly according to the high-level signal so as to close an output loop of the charging circuit (100).

Description

Technical Field

[0001] The utility model relates to the technical field of charging protection, and more specifically to a high voltage impact and current surge prevention control circuit. Background Art

[0002] Chargers are commonly used charging devices in daily life and usually have an overcharge protection function. Some chargers on the market currently have unreasonable charging circuit designs. When the charger is turned on and connected to the mains, the large current at the instant of startup will cause the contacts of the input relay to spark and stick. During use, the power supply voltage fluctuations increase, causing overvoltage to the components inside the charger and may even damage the charger, which has a significant impact on consumers' experience.

[0003] Therefore, how to improve the charger's ability to withstand voltage and surge current has become a technical problem that technical personnel in this field need to solve urgently. Utility Model Content

[0004] The technical problem to be solved by the utility model is to provide a highly reliable high-voltage shock and current surge protection control circuit in view of the defect of the prior art that the fluctuation of the power supply voltage increases during use, causing overvoltage to the components inside the charger and even possibly damaging the charger.

[0005] The technical solution adopted by the utility model to solve the technical problem is to construct a high voltage impact and current surge control circuit, which has:

[0006] A charging circuit, which is configured in the control circuit, is used to receive a voltage signal input from the AC power supply side, and perform rectification and boost processing on the voltage signal;

[0007] The AC input voltage monitoring circuit has an input terminal connected to the input terminal of the AC power supply side, and is used to receive the voltage signal input from the AC power supply side and perform voltage division processing on the voltage signal; a main control circuit has a signal input terminal coupled to an output terminal of the AC input voltage monitoring circuit,

[0008] The signal output terminal of the main control circuit is connected to the signal terminal of the first switch component of the charging circuit;

[0009] The AC input voltage monitoring circuit compares the input voltage signal with a reference signal. When the voltage signal is greater than the reference signal, the AC input voltage monitoring circuit outputs a high level signal and outputs the high level signal to the main control circuit.

[0010] The main control circuit outputs a control signal for closing the first switch component according to the high level signal, so as to close the output loop of the charging circuit.

[0011] In some embodiments, the normally open contact of the first switch assembly is arranged on the live input line of the charging circuit.

[0012] The coil terminals of the first switch assembly are respectively connected to the signal output ends of the main control circuit.

[0013] In some embodiments, a power supply circuit is further included, whose input end is connected to the output end of the AC power supply side, and is used to receive the voltage signal input from the AC power supply side and perform voltage reduction processing on the voltage signal.

[0014] An output terminal of the power supply circuit is connected to a signal terminal of the AC input voltage monitoring circuit to provide a reference signal for the signal terminal of the AC input voltage monitoring circuit.

[0015] In some embodiments, the AC input voltage monitoring circuit includes at least a first comparator, a second comparator, and a third comparator.

[0016] The non-inverting terminal of the first comparator is connected to the live wire of the AC power supply side,

[0017] The non-inverting terminal of the second comparator is connected to the neutral line of the AC power supply side,

[0018] The inverting terminal of the first comparator is connected to the non-inverting terminal of the second comparator.

[0019] The inverting terminal of the second comparator is connected to the non-inverting terminal of the first comparator.

[0020] The output terminals of the first comparator and the second comparator are connected to the non-inverting terminal of the third comparator.

[0021] The inverting terminal of the third comparator is connected to an output terminal of the power supply circuit for receiving the reference signal.

[0022] The output terminal of the third comparator is connected to a signal input terminal of the main control circuit.

[0023] When the voltage input from the AC power supply side is higher than a preset value, the outputs of the first comparator and the second comparator are high level.

[0024] The potential of the non-inverting terminal of the third comparator is higher than the potential of the inverting terminal, and the output of the third comparator is a high level signal.

[0025] In some implementations, the power supply circuit includes a power adapter controller, a third transformer, and a twelfth MOS transistor.

[0026] One end of the first primary winding of the third transformer is connected to the live wire of the AC power supply side,

[0027] The drain of the twelfth MOS tube is connected to the other end of the first primary winding.

[0028] The gate of the twelfth MOS tube is connected to the output end of the power adapter controller.

[0029] The source of the twelfth MOS tube is connected to the common terminal.

[0030] When the twelfth MOS tube is controlled to be turned on, the first secondary winding side of the third transformer outputs two voltage signals.

[0031] In some implementations, the power supply circuit further includes a thirteenth MOS transistor,

[0032] The drain of the thirteenth MOS tube is connected to one end of the first secondary winding side.

[0033] The gate of the thirteenth MOS tube is connected to a signal output terminal of the main control circuit.

[0034] The source of the thirteenth MOS tube is connected to the common end.

[0035] In some embodiments, one end of the second primary winding of the third transformer is connected to the live wire of the AC power source.

[0036] The other end of the second primary winding is connected to the common end,

[0037] A third voltage signal is outputted on the second secondary winding side of the third transformer.

[0038] In some embodiments, the charging circuit further includes a second switch component and a rectifier bridge.

[0039] The input ends of the rectifier bridge are respectively connected to the secondary winding of the second transformer.

[0040] A normally open contact of the second switch component is connected to an output end of the rectifier bridge,

[0041] Another normally open contact of the second switch component is connected to an input terminal of the power supply circuit.

[0042] A coil terminal of the second switch component is connected to an output end of the power supply circuit.

[0043] In some embodiments, a second resistor is further included, one end of the second resistor is connected to a normally open contact of the second switch component.

[0044] The other end of the second resistor is connected to another normally open contact of the second switch component.

[0045] In the high voltage impact and current surge control circuit described in the utility model, a charging circuit, an AC input voltage monitoring circuit and a main control circuit are included, wherein the AC input voltage monitoring circuit compares the input voltage signal with the reference signal, and when the voltage signal is greater than the reference signal, the AC input voltage monitoring circuit outputs a high level signal, and outputs the high level signal to the main control circuit, and the main control circuit outputs a control signal to close the first switch component according to the high level signal, so as to close the output loop of the charging circuit. Compared with the prior art, the AC input voltage monitoring circuit compares the detected voltage signal with the reference signal, and outputs a control signal to control the on / off state of the first switch component according to the comparison result, thereby shutting down the charging circuit, which can effectively solve the problem that when the machine is turned on and connected to the main power, the large current of the instantaneous start-up will cause the contacts of the input relay to ignite and stick, and the fluctuation of the power supply voltage will increase during use, causing overvoltage to the components inside the charger, and even may cause damage to the charger. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0047] Figure 1 This is a circuit schematic diagram of an embodiment of a charging circuit provided by the utility model;

[0048] Figure 2 This is a circuit schematic diagram of an embodiment of a power supply circuit provided by the utility model;

[0049] Figure 3 This is a circuit schematic diagram of an embodiment of an AC input voltage monitoring circuit provided by the utility model;

[0050] Figure 4 This is a circuit schematic diagram of an embodiment of a main control circuit provided by the utility model;

[0051] Figure 5 This is a circuit schematic diagram of an embodiment of a power supply circuit provided by the utility model;

[0052] Figure 6 The utility model provides a circuit principle diagram of a switch circuit embodiment. DETAILED DESCRIPTION

[0053] In order to have a clearer understanding of the technical features, purposes and effects of the present utility model, the specific implementation methods of the present utility model are now described in detail with reference to the accompanying drawings.

[0054] like Figure 1-Figure 6As shown, in the first embodiment of the high voltage impact and current surge protection control circuit of the utility model, the high voltage impact and current surge protection control circuit includes a charging circuit 100, a power supply circuit 200, an AC input voltage monitoring circuit 300, a main control circuit 400, a power supply circuit 500 and a switching circuit 600.

[0055] The charging circuit 100 is used to receive a voltage signal (such as 220V or greater than 220V) input from the AC power supply side (corresponding to LN), rectify and boost the voltage signal (such as 220V or greater than 220V), and then output it to the power supply circuit 200;

[0056] The power supply circuit 200 is used to receive a voltage signal (such as 220V or greater than 220V) input from the AC power supply side (corresponding to LN), or

[0057] The voltage signal (e.g., 400V) output by the charging circuit 100 is then stepped down to output three voltage signals (e.g., +12V, +14V, and VCC) to provide voltage signals to the first switch component K1 of the charging circuit 100, the AC input voltage monitoring circuit 300, the power supply circuit 500, and the switch circuit 600, respectively;

[0058] An input terminal of the AC input voltage monitoring circuit 300 is connected to the first voltage signal output terminal of the power supply circuit 200 (corresponding to +12V), and the +12V voltage signal is used as a reference signal of the AC input voltage monitoring circuit 300.

[0059] It should be noted that, after the +12V voltage signal is processed by voltage division, the voltage at one input terminal of the AC input voltage monitoring circuit 300 is about 4.5V. That is, the voltage signal of about 4.5V is used as the reference signal of the AC input voltage monitoring circuit 300.

[0060] The AC input voltage monitoring circuit 300 is used for the voltage signal (such as 220V or greater than 220V) input from the AC power supply side (corresponding to LN), and divides the input voltage signal (such as 220V or greater than 220V), and then compares it with the reference signal (such as +12V voltage signal) provided by the power supply circuit 200, and then outputs a high level signal or a low level signal according to the comparison result, and outputs the high level signal or the low level signal to the main control circuit 400;

[0061] The main control circuit 400 has the functions of logic operation, signal reception, processing and outputting multiple control signals, among which,

[0062] The main control circuit 400 is used to receive the level signal output by the AC input voltage monitoring circuit 300, and output a control signal for controlling the charging circuit 100 to be turned on / off according to the state of the level signal;

[0063] The power supply circuit 500 is used to receive the voltage signal (such as +12V) output by the power supply circuit 200, and to step down the input voltage signal (such as +12V) to output +5V and +3.3V voltage signals.

[0064] Then the +3.3V voltage signal is output to the main control circuit 400 to provide working power for the main control circuit 400;

[0065] The switch circuit 600 is used to receive the +14V power signal output by the power supply circuit 200 to control its conduction and provide working power to the second switch component K2 of the charging circuit 100 .

[0066] Specifically, the charging circuit 100 includes a first switch component K1 and a second switch component K2.

[0067] The switch assembly can be selected as a relay or a contactor.

[0068] The charging circuit 100 is configured in the control circuit, and is used to receive a voltage signal (such as 220V or greater than 220V) input from the AC power supply side (corresponding to LN), rectify and boost the voltage signal (such as 220V or greater than 220V), and output a 400V DC signal;

[0069] Furthermore, the input terminals of the AC input voltage monitoring circuit 300 are respectively connected to the output terminals (corresponding to ACL-ACN) of the AC power supply side, and are used to receive the voltage signal (such as 220V or greater than 220V) inputted from the AC power supply side (corresponding to ACL-ACN), and perform voltage division processing on the voltage signal (such as 220V or greater than 220V).

[0070] When the input voltage signal is about 220V, the AC input voltage monitoring circuit 300 divides the 220V voltage signal into a level signal of about 3V.

[0071] When the input voltage signal is about 280V, the AC input voltage monitoring circuit 300 further divides the 280VV voltage signal to a level signal of about 5V;

[0072] Furthermore, a signal input terminal of the main control circuit 400 is coupled to an output terminal of the AC input voltage monitoring circuit 300, and is used to receive a level signal input by the AC input voltage monitoring circuit 300, and output a level state (high level or low level) of the control signal according to the input level signal.

[0073] A signal output terminal of the main control circuit 400 is connected to a signal terminal of the first switch component K1 of the charging circuit 100;

[0074] Specifically, the AC input voltage monitoring circuit 300 compares the input voltage signal with the reference signal (approximately 4.5V). When the voltage signal (approximately 3V) is less than the reference signal (approximately 4.5V), the AC input voltage monitoring circuit 300 outputs a low level signal, and the main control circuit 400 outputs a control signal according to the input low level signal to maintain the first switch component K1 turned on.

[0075] When the voltage signal (about 5V) is greater than the reference signal (about 4.5V), the AC input voltage monitoring circuit 300 outputs a high level signal and outputs the high level signal to the main control circuit 400.

[0076] The main control circuit 400 outputs a control signal for closing the first switch component K1 according to the input high level signal, so as to close the output loop of the charging circuit 100 .

[0077] By using the technical solution, the detected voltage signal is compared with the reference signal through the AC input voltage monitoring circuit 300, and a control signal for controlling the on / off state of the first switch component K1 is output according to the comparison result, thereby shutting down the charging circuit 100. This can effectively solve the problem that when the charger is turned on and connected to the mains, the large current at the instant of startup will cause the contacts of the input relay to spark and stick, and the fluctuation of the power supply voltage will increase during use, causing overvoltage to the components inside the charger, and may even damage the charger.

[0078] In some embodiments, Figure 1 As shown, the normally open contact (corresponding to pins 3 and 4) of the first switch assembly K1 is arranged on the live input line (corresponding to L) of the charging circuit 100, and is used to control the on / off of the live input line (corresponding to L) of the charging circuit 100.

[0079] The coil terminals (corresponding to pin 1 and pin 2) of the first switch component K1 are respectively connected to the signal output terminals of the main control circuit 400 .

[0080] That is, when the main control circuit 400 outputs a control signal to the coil terminal (corresponding to pin 1 and pin 2), the coil of the first switch component K1 is energized, and its normally open contact (corresponding to pin 3 and pin 4) is closed. The voltage signal (such as 220V) input from the AC power supply side (corresponding to ACL-ACN) is output to the boost circuit (composed of the second inductor L2, the fourth MOS tube Q4 and the thirteenth diode D13) via the first transformer LF1, the second transformer LF2 and the rectifier bridge BD1. After the boost circuit boosts the input voltage signal, a DC voltage of about 400V is input to the normally open contact (corresponding to pin 4) of the second switch component K2. When the second switch component K2 is controlled to be turned on, a DC voltage of 400V is output to an input end of the power supply circuit 200.

[0081] In some embodiments, Figure 2 As shown, the power supply circuit 200 is also included, wherein an input end of the power supply circuit 200 is connected to the output end (corresponding to ACL) of the AC power supply side, and is used to receive the voltage signal of the AC input and perform voltage reduction processing on the voltage signal.

[0082] Another input terminal (corresponding to +400V) of the power supply circuit 200 is connected to the output terminal (corresponding to 400V) of the charging circuit 100, and is used to receive the DC voltage signal input by the charging circuit 100 and perform voltage reduction processing on the DC voltage signal;

[0083] An output terminal (corresponding to +12V) of the power supply circuit 200 is connected to a signal terminal (corresponding to +12V) of the AC input voltage monitoring circuit 300 to provide a reference signal for the signal terminal (corresponding to +12V) of the AC input voltage monitoring circuit 300 .

[0084] In some embodiments, Figure 3 As shown, the AC input voltage monitoring circuit 300 includes at least a first comparator U1A, a second comparator U1B and a third comparator U2A.

[0085] The in-phase terminal (corresponding to pin 3) of the first comparator U1A is connected to the live wire (corresponding to ACL) of the AC power supply side through resistors R109-R113 connected in series.

[0086] Among them, the resistance values ​​of resistors R109-R113 are all selected to be 2M.

[0087] The in-phase terminal (corresponding to pin 5) of the second comparator U1B is connected to the neutral line (corresponding to ACN) on the AC power supply side through resistors R149, R150, R154-R156 connected in series.

[0088] Among them, the resistance values ​​of resistors R149, R150, R154-R156 are all selected to be 2M.

[0089] When the input voltage signal is 220V, the 220V voltage signal is divided by resistors R109-R113, R149, R150, R154-R156 to output a level signal of about 3V.

[0090] When the input voltage signal is about 280V, the 280V voltage signal is divided by resistors R109-R113, resistors R149, R150, and R154-R156 to output a level signal of about 5V.

[0091] It can be understood that: the voltage of the in-phase terminal (corresponding to pin 3) of the first comparator U1A and the in-phase terminal (corresponding to pin 5) of the second comparator U1B is a level signal of about 3V or about 5V;

[0092] The inverting terminal (corresponding to pin 2) of the first comparator U1A is connected to the non-inverting terminal (corresponding to pin 5) of the second comparator U1B through a resistor R124, wherein one end of the resistor R124 is also connected to one end of the resistor R150.

[0093] The inverting terminal (corresponding to pin 6) of the second comparator U1A is connected to the non-inverting terminal (corresponding to pin 3) of the first comparator U1B through a resistor R137, wherein one end of the resistor R137 is also connected to one end of the resistor R113.

[0094] That is, it can be understood that when the input voltage signal is about 280V, the potential of the non-inverting end (corresponding to pin 3) of the first comparator U1A and the non-inverting end (corresponding to pin 5) of the second comparator U1B is higher than the potential of the inverting end (corresponding to pin 2) of the first comparator U1A and the inverting end (corresponding to pin 6) of the second comparator U1A, and the output end (corresponding to pin 1) of the first comparator U1A and the output end (corresponding to pin 6) of the second comparator U1B output a high level signal (about 5V).

[0095] The output terminal (corresponding to pin 1) of the first comparator U1A is connected to the in-phase terminal (corresponding to pin 3) of the third comparator U2A through a resistor R120.

[0096] The output terminal (corresponding to pin 6) of the second comparator U1B is connected to the in-phase terminal (corresponding to pin 3) of the third comparator U2A through a resistor R140.

[0097] The inverting terminal (corresponding to pin 2) of the third comparator U2A is connected to an output terminal (corresponding to +12V) of the power supply circuit 200 through resistors R101 and R105 to receive the reference signal.

[0098] The +12V voltage signal is divided by resistors R101 and R105 to output a voltage signal of about 4.5V, that is, the voltage value of the reference signal is 4.5V.

[0099] The output terminal (corresponding to pin 1) of the third comparator U2A is connected to a signal input terminal (corresponding to pin 31) of the main control circuit 400 through a resistor R103 and a diode D23.

[0100] When the voltage input from the AC power supply side (corresponding to LN) is higher than the preset value (such as higher than 280V), the outputs of the first comparator U1A and the second comparator U1B are high level.

[0101] The potential of the in-phase terminal (corresponding to pin 3) of the third comparator U2A (approximately 5V) is higher than the potential of the inverting terminal (corresponding to pin 2) of the third comparator U2A (approximately 4.5V). Therefore, the output terminal (corresponding to pin 1) of the third comparator U2A outputs a high level signal.

[0102] The high level signal is output to a signal input terminal (corresponding to pin 31) of the main control circuit 400 via the resistor 103 and the diode D23.

[0103] In some embodiments, Figure 4 As shown, the main control circuit 400 includes a main controller U5, which has the functions of logic operation, signal reception, processing and outputting multiple control signals;

[0104] Among them, a signal input terminal (corresponding to pin 31) of the main controller U5 is connected to the output terminal (corresponding to pin 1) of the third comparator U2A, and is used to receive the level signal input by the third comparator U2A.

[0105] When the input level signal is high, pins 39 and 40 of the main controller U5 output a control signal to close the first switch component K1, so that the normally open contact of the first switch component K1 is disconnected to close the output loop of the charging circuit 100.

[0106] In some embodiments, Figure 2 As shown, the power supply circuit 200 includes a power adapter controller U20, a third transformer T2 and a twelfth MOS transistor Q12.

[0107] Among them, one end of the first primary winding of the third transformer T2 (corresponding to pin 5) is connected to the live wire (corresponding to ACL) on the AC power side through the resistor 189.

[0108] The drain of the twelfth MOS tube Q12 is connected to the other end of the first primary winding (corresponding to pin 6).

[0109] The gate of the twelfth MOS tube Q12 is connected to the output end (corresponding to pin 6) of the power adapter controller U20.

[0110] The source of the twelfth MOS tube Q12 is connected to the common terminal.

[0111] When the twelfth MOS tube Q12 is controlled to be turned on, the first primary winding of the third transformer T2 (corresponding to pins 5 and 6) forms a loop, the current signal is coupled to the first secondary winding side (corresponding to pins 9 and 10), and the first voltage signal (corresponding to +12V) is output, and

[0112] The second voltage signal (corresponding to VCC) is output on the first secondary winding side (corresponding to pins 7 and 8).

[0113] In some embodiments, Figure 2 As shown, the power supply circuit 200 further includes a thirteenth MOS transistor Q13, wherein the thirteenth MOS transistor Q13 is selected as an N-channel MOS transistor, which has a switch function.

[0114] The drain of the thirteenth MOS tube Q13 is connected to one end of the first secondary winding side (corresponding to pin 10).

[0115] The gate of the thirteenth MOS transistor Q13 is connected to a signal output terminal (corresponding to pin 27) of the main controller U5 (belonging to the main control circuit 400) to receive the control signal output by the main controller U5.

[0116] The source of the thirteenth MOS tube Q13 is connected to the common terminal.

[0117] When the control signal output by the main controller U5 is at a high level, the thirteenth MOS tube Q13 is controlled to be turned on, and outputs a first voltage signal (corresponding to +12V).

[0118] In some embodiments, Figure 2 As shown, one end of the second primary winding of the third transformer T2 (corresponding to pin 4) is connected to the live wire (corresponding to ACL) on the AC power side.

[0119] The other end of the second primary winding (corresponding to pin 3) is connected to the common terminal.

[0120] When one end of the second primary winding of the third transformer T2 (corresponding to pin 4) is connected to the live wire (corresponding to ACL), a current loop is formed on the second primary winding side of the third transformer T2 (corresponding to pins 3 and 4), and the current signal is coupled to the second secondary winding side of the third transformer T2 (corresponding to pins 1 and 2), so that a third voltage signal (corresponding to +14V) is output on the second secondary winding side of the third transformer T2 (corresponding to pins 1 and 2).

[0121] In some embodiments, Figure 6 As shown, the switch circuit 600 includes a sixth transistor Q6, a seventh MOS transistor Q7 and an eighth MOS transistor Q8.

[0122] The collector of the sixth transistor Q6 is connected to the gate of the thirteenth MOS transistor Q13.

[0123] The gate of the thirteenth MOS tube Q13 is also connected to the input end of the photocoupler U17A.

[0124] The base of the sixth transistor Q6 is connected to the output end of the photocoupler U17A.

[0125] The emitter of the sixth transistor Q6 is connected to the source of the seventh MOS transistor Q7.

[0126] The gate of the seventh MOS tube Q7 is connected to the drain of the eighth MOS tube Q8.

[0127] The drain of the seventh MOS tube Q7 is connected to a coil terminal (corresponding to pin 1) of the second switch component K2.

[0128] When the photocoupler U17A is controlled to be turned on, the base of the sixth transistor Q6 is at a high level and is controlled to be turned on, thereby controlling the seventh MOS transistor Q7 to be turned on, so that the +14V power supply is output to a coil terminal (corresponding to pin 1) of the second switch component K2 through the seventh MOS transistor, forming a current loop in the coil of the second switch component K2, so that a normally open contact of the second switch component K2 is closed.

[0129] In some embodiments, Figure 1 As shown, the charging circuit 100 further includes a second switch component K2 and a rectifier bridge BD1.

[0130] The input ends of the rectifier bridge BD1 are respectively connected to the secondary windings (corresponding to pins 2 and 3) of the second transformer LF2, for receiving the voltage signal input by the second transformer LF2 and rectifying the input voltage signal;

[0131] A normally open contact (corresponding to pin 4) of the second switch assembly K2 is connected to an output terminal of the rectifier bridge BD1.

[0132] Another normally open contact (corresponding to pin 3) of the second switch assembly K2 is connected to an input terminal (corresponding to +400V) of the power supply circuit 200.

[0133] A coil terminal (corresponding to pin 1) of the second switch component K2 is connected to an output end (corresponding to pin 2) of the second secondary winding side of the third transformer T2 (belonging to the power supply circuit 200) for receiving a third voltage signal (corresponding to +14V).

[0134] When a +14V voltage signal flows through a coil terminal (corresponding to pin 1) of the second switch component K2, the normally open contact (corresponding to pins 3 and 4) of the second switch component K2 is closed, and a +400V DC voltage signal is output to the first primary winding (corresponding to pin 5) of the third transformer T2.

[0135] In some embodiments, Figure 1 As shown, the second resistor R2 is also included, wherein the second resistor R2 is an NTC resistor.

[0136] Specifically, one end of the second resistor R2 is connected to a normally open contact (corresponding to pin 4) of the second switch component K2.

[0137] The other end of the second resistor R2 is connected to another normally open contact (corresponding to pin 3) of the second switch component K2.

[0138] In some embodiments, Figure 5As shown, the power supply circuit 500 is also included, wherein the power supply circuit 500 is used to receive the voltage signal (such as +12V) output by the power supply circuit 200, and to step down the input voltage signal (such as +12V) to output +5V and +3.3V voltage signals.

[0139] Then, the +3.3V voltage signal is output to the power input terminal of the main controller U5 (belonging to the main control circuit 400 ) to provide working power for the main controller U5 .

[0140] Its working principle is:

[0141] When AC voltage is input, the AC input voltage is limited by resistor R198, rectified by diode D35, and filtered by capacitors EC4 and EC5, and provides voltage to the power adapter controller U20, the twelfth MOS tube Q12, and the third transformer T2. After the flyback circuit works, the output is converted into the required DC voltage, and 3.3VDC is provided to the main controller U5, and 12VDC is provided to the first switch component K1, the second switch component K2, and the comparators U1A, U1B, U2A, and U3A.

[0142] When the power adapter controller U20 is working, it outputs a 400V DC voltage, and the flyback voltage is powered by the +400V voltage through the diode D2;

[0143] When the AC input voltage is connected, the AC-L and AC-N input voltage signals are divided by resistors R109 to R113 and R150 to R156, and then sent to the 2nd, 3rd, 5th and 6th pins of the first comparator U1A and the second comparator U1B. After being amplified, they are sent to the in-phase terminal (corresponding to the 3rd pin) of the third comparator U2A through resistors R120 and R140.

[0144] When the input AC voltage is less than 280VAC, the potential of the in-phase terminal (corresponding to pin 3) of the third comparator U2A is less than the potential of the inverting terminal (corresponding to pin 2), and the output of the third comparator U2A is a low level, which is output to pin 31 of the main controller U5. When the low level is low, the main controller U5 is judged to be normal, and the main controller U5 sends a signal to control the first switch component K1 to be attracted;

[0145] When the input voltage is higher than 280VAC, the voltage of the in-phase terminal (corresponding to pin 3) of the third comparator U2A increases, and the potential of the in-phase terminal (corresponding to pin 3) of the third comparator U2A is higher than the potential of the inverting terminal (corresponding to pin 2). The output of the third comparator U2A is a high level, which is output to pin 31 of the main controller U5. When the high level is high, the main controller U5 determines that the mains power has suddenly changed, and the main controller U5 sends a signal to turn off the first switch component K1 and turn off the power supply of the subsequent stage, so as to protect the subsequent stage circuit from being damaged by overvoltage caused by the high input voltage;

[0146] When the AC input voltage is less than 280VAC, the first switch component K1 will be closed. At this time, the voltage of the PFC and related electrolytic capacitors in the subsequent stage is 0VDC. If the first switch component K1 is directly closed, the DC voltage rectified by the rectifier bridge BD1 charges the electrolytic capacitor with 0 voltage. The instantaneous surge current may damage the contacts of the first switch component K1. The NTC resistor R2 is connected in series at the front end of the PFC electrolytic capacitor. The input current is limited by the NTC resistor R2 to prevent excessive surge current from being generated at the moment when the first switch component K1 is closed, which may damage the related components in the circuit.

[0147] After the current becomes stable, the main controller U5 turns on the second switch component K2 at both ends of the current-limiting NTC resistor R2 to short-circuit the NTC resistor R2 to reduce the loss of the NTC resistor R2 when loaded.

[0148] The embodiments of the utility model are described above in conjunction with the accompanying drawings, but the utility model is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the enlightenment of the utility model, ordinary technicians in this field can also make many forms without departing from the scope of protection of the utility model and the claims, which all fall within the protection of the utility model.

Claims

1. A high voltage impact and current surge control circuit, characterized in that: have: A charging circuit, which is configured in the control circuit, is used to receive a voltage signal input from the AC power supply side, and perform rectification and boost processing on the voltage signal; An AC input voltage monitoring circuit, whose input terminals are respectively connected to the input terminals of the AC power supply side, for receiving the voltage signal input from the AC power supply side and performing voltage division processing on the voltage signal; A main control circuit, a signal input terminal of which is coupled to an output terminal of the AC input voltage monitoring circuit, The signal output terminal of the main control circuit is connected to the signal terminal of the first switch component of the charging circuit; The AC input voltage monitoring circuit compares the input voltage signal with a reference signal. When the voltage signal is greater than the reference signal, the AC input voltage monitoring circuit outputs a high level signal and outputs the high level signal to the main control circuit. The main control circuit outputs a control signal for closing the first switch component according to the high level signal, so as to close the output loop of the charging circuit.

2. The high voltage impact and current surge control circuit according to claim 1, characterized in that: The normally open contact of the first switch assembly is arranged on the live input line of the charging circuit. The coil terminals of the first switch assembly are respectively connected to the signal output ends of the main control circuit.

3. The high voltage impact and current surge control circuit according to claim 1 or 2, characterized in that: It also includes a power supply circuit, whose input end is connected to the output end of the AC power supply side, and is used to receive the voltage signal input from the AC power supply side and perform voltage reduction processing on the voltage signal. An output terminal of the power supply circuit is connected to a signal terminal of the AC input voltage monitoring circuit to provide a reference signal for the signal terminal of the AC input voltage monitoring circuit.

4. The high voltage impact and current surge control circuit according to claim 3, characterized in that: The AC input voltage monitoring circuit includes at least a first comparator, a second comparator and a third comparator. The non-inverting terminal of the first comparator is connected to the live wire of the AC power supply side, The non-inverting terminal of the second comparator is connected to the neutral line of the AC power supply side, The inverting terminal of the first comparator is connected to the non-inverting terminal of the second comparator. The inverting terminal of the second comparator is connected to the non-inverting terminal of the first comparator. The output terminals of the first comparator and the second comparator are connected to the non-inverting terminal of the third comparator. The inverting terminal of the third comparator is connected to an output terminal of the power supply circuit for receiving the reference signal. The output terminal of the third comparator is connected to a signal input terminal of the main control circuit. When the voltage input from the AC power supply side is higher than a preset value, the outputs of the first comparator and the second comparator are high level. The potential of the non-inverting terminal of the third comparator is higher than the potential of the inverting terminal, and the output of the third comparator is a high level signal.

5. The high voltage impact and current surge control circuit according to claim 3, characterized in that: The power supply circuit includes a power adapter controller, a third transformer and a twelfth MOS tube. One end of the first primary winding of the third transformer is connected to the live wire of the AC power supply side, The drain of the twelfth MOS tube is connected to the other end of the first primary winding. The gate of the twelfth MOS tube is connected to the output end of the power adapter controller. The source of the twelfth MOS tube is connected to the common terminal. When the twelfth MOS tube is controlled to be turned on, the first secondary winding side of the third transformer outputs two voltage signals.

6. The high voltage impact and current surge control circuit according to claim 5, characterized in that: The power supply circuit further includes a thirteenth MOS tube, The drain of the thirteenth MOS tube is connected to one end of the first secondary winding side. The gate of the thirteenth MOS tube is connected to a signal output terminal of the main control circuit. The source of the thirteenth MOS tube is connected to the common end.

7. The high voltage impact and current surge control circuit according to claim 5, characterized in that: One end of the second primary winding of the third transformer is connected to the live wire of the AC power supply side, The other end of the second primary winding is connected to the common end, A third voltage signal is outputted on the second secondary winding side of the third transformer.

8. The high voltage impact and current surge control circuit according to claim 3, characterized in that: The charging circuit also includes a second switch component and a rectifier bridge. The input ends of the rectifier bridge are respectively connected to the secondary winding of the second transformer. A normally open contact of the second switch component is connected to an output end of the rectifier bridge, Another normally open contact of the second switch component is connected to an input terminal of the power supply circuit. A coil terminal of the second switch component is connected to an output end of the power supply circuit.

9. The high voltage impact and current surge control circuit according to claim 8, characterized in that: It also includes a second resistor, one end of which is connected to a normally open contact of the second switch component. The other end of the second resistor is connected to another normally open contact of the second switch component.

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