Intelligent fast charging circuit

Abstract

The utility model relates to the technical field of lithium battery charging, and discloses an intelligent fast charging circuit which is high in charging efficiency and reliable, the intelligent fast charging circuit comprises a deexcitation constant current circuit (100) and an auxiliary power supply circuit (200), the deexcitation constant current circuit (100) at least comprises an output module (160), and the auxiliary power supply circuit (200) at least comprises a signal output module (220). A signal input end of the output module (160) is connected with a signal output end of the main controller (MCU) and is used for receiving a pulse signal, a power signal input end of the output module (160) is connected with an output end of the signal output module (220) and is used for receiving a 12V voltage signal, and when the pulse signal is in a high level and the 12V voltage signal is applied at the same time, the output module (160) is controlled to be switched on, and the output module (160) is controlled to be switched off. And the output module (160) outputs the charging current in a constant current manner.

Description

TECHNICAL FIELD

[0001] The utility model relates to lithium battery charging technical field more specifically, relate to an intelligent fast charging circuit. BACKGROUND

[0002] Lithium battery fast charging technology has developed rapidly in the past two years, the traditional lithium battery charging technology charging current is below 2A, the traditional lithium battery charging technology charging scheme, the charging current of lithium battery Is is rectified through diode, because the rectifier diode has a voltage drop Vd (Vd = 0.4V ~ 0.6V) when forward conducting, there is power loss Pw on the rectifier diode, Pw = Is * Vd, when the charging current increases to 3 ~ 5A, the power loss will be very large, and will cause the line board to heat, affect the service life of the product, and the line board layout of the existing charging circuit is relatively complex, so that its cost price is higher, and the performance is single, leading to the low efficiency of the whole machine.

[0003] Therefore, how to optimize the circuit structure to improve its charging efficiency becomes a technical problem that the technical personnel in the field need to solve. CONTENT OF THE UTILITY MODEL

[0004] The utility model solves the technical problem that the line board layout of the existing charging circuit in prior art is relatively complex, so that its cost price is higher, and the performance is single, leading to the low efficiency of the whole machine, and provides an intelligent fast charging circuit with higher charging efficiency and reliability.

[0005] The utility model adopts the technical scheme in the solution to the technical problem thereof: construct an intelligent fast charging circuit, have:

[0006] The flyback constant current circuit is configured in the fast charging circuit, is used to receive the voltage signal input from the commercial power side, and carries out voltage reduction, rectification and voltage stabilization to the voltage signal, to output the current signal for charging;

[0007] The auxiliary power supply circuit is connected with the output end of the flyback constant current circuit at the power input end, is used to obtain the voltage signal,

[0008] The output end of the auxiliary power supply circuit is connected with the signal input end of the flyback constant current circuit, is used to control the on / off state of the flyback constant current circuit; Wherein,

[0009] The flyback constant current circuit at least includes output module,

[0010] The auxiliary power supply circuit at least includes signal output module,

[0011] The signal input end of the output module is connected with the signal output end of the host computer, is used to receive the pulse signal,

[0012] A power signal input terminal of the output module is connected to the output terminal of the signal output module for receiving a 12V voltage signal.

[0013] When the pulse signal is at a high level and the 12V voltage signal is applied at the same time, the output module is controlled to be turned on, and the output module outputs a constant current charging current.

[0014] In some embodiments, the anti-excitation constant current circuit further includes an input module, a control module and a coupling module.

[0015] The input module is used to receive the voltage signal input from the mains side and perform voltage reduction processing on the voltage signal.

[0016] The input end of the control module and the input end of the coupling module are respectively connected to the output end of the input module.

[0017] The output end of the control module is connected to one end of the coupling module, and is used to control the on / off state of the coupling module.

[0018] When the coupling module is controlled to be turned off, the coupling module couples the input voltage signal to the output module.

[0019] In some embodiments, the anti-excitation constant current circuit further includes a filtering module, a current detection module and a comparison module.

[0020] The input end of the filtering module is connected to the output end of the coupling module for receiving the voltage signal.

[0021] The input end of the current detection module is coupled to the output end of the filter module, and is used to obtain the current signal output by the filter module.

[0022] An output terminal of the current detection module is connected to an input terminal of the output module.

[0023] An input terminal of the comparison module and another output terminal of the current detection module are used to receive the current signal.

[0024] The other input terminal of the comparison module is connected to the other signal output terminal of the main controller for receiving a reference signal.

[0025] The comparison module compares the current signal with the reference signal.

[0026] When the current signal is greater than the reference signal, the output is a low level signal.

[0027] When the current signal is less than the reference signal, the output is a high level signal.

[0028] The output terminal of the comparison module is connected to the feedback terminal of the control module.

[0029] In some embodiments, an output terminal of the signal output module is connected to the electrical signal input terminal of the comparison module.

[0030] In some embodiments, the output module includes at least a relay and a first transistor.

[0031] One end of the normally open switch of the relay is connected to the output end of the current detection module,

[0032] One end of the coil of the relay is connected to an output end of the signal output module.

[0033] The base of the first transistor is coupled to the signal output terminal 1 of the main controller for receiving the pulse signal.

[0034] The collector of the first transistor is connected to the other end of the coil of the relay.

[0035] The emitter of the first transistor is connected to the common end.

[0036] In some embodiments, the current detection module includes a current detector.

[0037] The input end of the current detector is coupled to the output end of the filter module.

[0038] An output terminal of the current detector is connected to one end of the normally open switch of the relay,

[0039] The other output terminal of the current detector is connected to an input terminal of the comparison module.

[0040] In some embodiments, the comparison module includes at least a comparator, a first photocoupler, and a second transistor.

[0041] The non-inverting terminal of the comparator is connected to the other signal output terminal of the main controller, and is used to receive the reference signal.

[0042] The inverting terminal of the comparator is coupled to the other output terminal of the current detector,

[0043] An input terminal of the first photoelectric coupler is connected to an output terminal of the signal output module for receiving a 5V voltage signal.

[0044] The first output terminal of the first photoelectric coupler is connected to the output terminal of the comparator,

[0045] The second output terminal of the first photoelectric coupler is connected to the feedback terminal of the control module,

[0046] The base of the second transistor and the output end of the filter module,

[0047] The collector of the second transistor is connected to an output end of the first photocoupler.

[0048] The emitter of the second transistor is connected to the common terminal.

[0049] In some embodiments, the control module includes at least a controller,

[0050] The feedback terminal of the controller is coupled to the second output terminal of the first photoelectric coupler.

[0051] The control end of the controller is connected to an output end of the coupling module.

[0052] In some embodiments, the coupling module includes at least a second transformer,

[0053] One end of the primary winding of the second transformer is connected to the output end of the input module,

[0054] The other end of the primary winding of the second transformer is connected to the control end of the controller U2.

[0055] One end of the secondary winding of the second transformer is connected to the input end of the filter module 140 .

[0056] The intelligent fast-charging circuit described in the present invention includes an anti-excitation constant current circuit and an auxiliary power supply circuit. When the pulse signal is at a high level and a 12V voltage signal is applied simultaneously, the output module is controlled to conduct, and the output module outputs a constant current charging current. Compared with the prior art, the auxiliary power supply circuit provides a stable voltage for the primary and secondary of the anti-excitation constant current circuit. Since the "VCC of the auxiliary power supply circuit" is always present and provides power for the anti-excitation constant current circuit, the anti-excitation constant current circuit will not be undervoltage protected due to excessively low output voltage, and can meet the charging requirements of 0-20V battery packs, thereby meeting customer needs. In addition, the circuit board layout of this solution is relatively simple, and the output voltage width is relatively large, which can effectively improve the charging efficiency of the entire device. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] The present invention will be further described below with reference to the accompanying drawings and embodiments, in which:

[0058] Figure 1 This is a circuit schematic diagram of an embodiment of a reverse excitation constant current circuit provided by the present utility model;

[0059] Figure 2 This is a circuit principle diagram of an embodiment of an auxiliary power supply circuit provided by the utility model. DETAILED DESCRIPTION

[0060] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, the specific implementation methods of the present invention are now described in detail with reference to the accompanying drawings.

[0061] like Figure 1-Figure 2 As shown, in the first embodiment of the intelligent fast charging circuit of the present utility model, the intelligent fast charging circuit (100, 200) includes a reverse excitation constant current circuit 100 and an auxiliary power supply circuit 200,

[0062] The input end of the anti-excitation constant current circuit 100 is used to receive a voltage signal input from the mains side (100-240VAC), and to step down, rectify and stabilize the voltage signal to output a current signal that can be used for charging.

[0063] The auxiliary power supply circuit 200 provides the VCC, 5V and 12V voltage signals to the anti-excitation constant current circuit 100 to trigger or control the operation of the subsequent circuit of the anti-excitation constant current circuit 100;

[0064] The anti-excitation constant current circuit 100 includes an input module 110, a control module 120, a coupling module 130, a filtering module 140, a current detection module 150, an output module 160 and a comparison module 170.

[0065] The input module 110 is used to receive the voltage signal input from the mains side (100-240VAC).

[0066] The control module 120 is used to receive the feedback electrical signal (voltage signal or current signal) and adjust the duty cycle of the control signal according to the feedback electrical signal to control the on / off state of the coupling module 130;

[0067] The coupling module 130 is used to couple the voltage signal input by the input module 110 to the filtering module 140;

[0068] The filtering module 140 is used to filter the input voltage signal;

[0069] The current detection module 150 is used to detect and output the input charging signal;

[0070] The output module 160 is used to receive the charging signal output by the current detection module 150 and charge the battery pack to be charged;

[0071] The comparison module 170 is used to receive the charging current signal input by the current detection module 150 and the reference signal input by the main controller MCU, and compare the current signal with the reference signal, and then output a high level / low level signal according to the comparison result;

[0072] The auxiliary power supply circuit 200 includes a VCC power supply module 210 and a signal output module 220.

[0073] The input side of the VCC power module 210 is used to receive the voltage signal output by the coupling module 130, and perform rectification and filtering on the voltage signal to output a VCC voltage signal.

[0074] The signal output module 220 is used to receive the voltage signal output by the input module 110 and step down the voltage signal to 12V and 5V voltage signals;

[0075] Specifically, the anti-excitation constant current circuit 100 is configured in the fast charging circuit to receive the voltage signal input from the mains side (100-240VAC), and to step down, rectify and stabilize the voltage signal to output a current signal that can be used to charge the battery pack (corresponding to B+ / B-);

[0076] Furthermore, the power input terminal of the auxiliary power supply circuit 200 is connected to an output terminal (corresponding to the HV terminal) of the anti-excitation constant current circuit 100, for obtaining a voltage signal, and performing a voltage reduction process on the voltage signal to output 12V and 5V voltage signals;

[0077] The output terminal (corresponding to 12V) of the auxiliary power supply circuit 200 is connected to a signal input terminal of the anti-excitation constant current circuit 100 to control the on / off state of the anti-excitation constant current circuit 100; wherein,

[0078] The anti-excitation constant current circuit 100 at least includes an output module 160.

[0079] The auxiliary power supply circuit 200 at least includes a signal output module 220,

[0080] Specifically, a signal input terminal of the output module 160 is connected to a signal output terminal (MCU_RELAY) of the main controller MCU for receiving a pulse signal.

[0081] A power signal input terminal (corresponding to 12V) of the output module 160 is connected to the output terminal (corresponding to 12V) of the signal output module 160 for receiving a 12V voltage signal.

[0082] When the pulse signal is at a high level and a 12V voltage signal is applied at the same time, the output module 160 is controlled to be turned on, and the output module 160 outputs a constant current charging current to charge the battery pack (corresponding to B+ / B-).

[0083] The auxiliary power supply circuit 200 provides stable voltage for the primary and secondary of the flyback constant current circuit 100, and the VCC of the auxiliary power supply circuit 200 always exists, so that the flyback constant current circuit 100 is not protected by under-voltage due to too low output voltage, and can meet the requirements of 0-20V battery pack charging, thereby meeting the customer requirements, and the circuit board layout of the present scheme is relatively simple, the output voltage width is relatively large, and the charging efficiency of the whole machine can be effectively improved.

[0084] In some embodiments, as shown in FIG. 1, in order to improve the reliability of the charging current, an input module 110, a control module 120 and a coupling module 130 can be arranged in the flyback constant current circuit 100, Figure 1

[0085] The input module 110 is configured to receive a voltage signal input from a commercial power supply (100-240VAC), and perform voltage reduction processing on the voltage signal, and then output the voltage signal to the control module 120 and the coupling module 130.

[0086] Further, the input end of the control module 120 is connected with the output end of the input module 110, and is configured to receive the voltage signal.

[0087] The input end of the coupling module 130 is connected with the output end of the input module 110, and is configured to receive the voltage signal.

[0088] The output end of the control module 120 is connected with one end of the coupling module 130, and is configured to control the on / off state of the coupling module 130.

[0089] When the coupling module 130 is controlled to be turned off, the coupling module 130 couples the input voltage signal to the output module 160.

[0090] Specifically, the input 100-240VAC is transformed by a first transformer LF1, rectified by a rectifier bridge BD1, and filtered by a capacitor EC1, and then output to a controller U2 (belonging to the control module 120) and one end of a primary winding of a second transformer T1A (belonging to the coupling module 130).

[0091] In some embodiments, as shown in FIG. 1, in order to improve the reliability of the charging current, a filter module 140, a current detection module 150 and a comparison module 170 can be arranged in the flyback constant current circuit 100, Figure 1 The input end of the filter module 140 is connected with the output end of the coupling module 130, and is configured to receive the voltage signal and perform filtering processing on the input voltage signal, and then output the voltage signal to the current detection module 150.

[0092]

[0093] ​​The input end of the current detection module 150 is coupled to the output end of the filter module 140 and is used to obtain the current signal output by the filter module 140 after filtering, and divide the current signal into two outputs;

[0094] An output terminal of the current detection module 150 is connected to an input terminal of the output module 160, and a current signal is output to the output module 160.

[0095] An input terminal of the comparison module 170 is connected to another output terminal of the current detection module 150, and the comparison module 170 is used to receive another current signal.

[0096] The other input terminal of the comparison module 170 is connected to the other signal output terminal (MCU_PWM) of the main controller MCU, and is used to receive the reference signal.

[0097] The comparison module 170 compares the current signal with the reference signal and outputs a level signal according to the comparison result.

[0098] When the current signal is greater than the reference signal, the output is a low level signal.

[0099] When the current signal is less than the reference signal, the output is a high level signal.

[0100] An output terminal of the comparison module 170 is connected to a feedback terminal of the control module 120 .

[0101] In some embodiments, as Figure 2 As shown, in order to ensure the reliability of the comparison module 170, an output terminal (corresponding to 5V) of the signal output module 220 can be connected to the electrical signal input terminal (corresponding to 5V) of the comparison module 170.

[0102] In some embodiments, as Figure 1 As shown, in order to improve the stability of the charging signal output, a relay K1 and a first transistor Q1 may be provided in the output module 160 , wherein the first transistor Q1 is selected as an NPN transistor, which functions as a switch.

[0103] Specifically, one end of the normally open switch of the relay K1 is connected to the output end of the current detection module 150.

[0104] One end of the coil of relay K1 (corresponding to 12V) is connected to an output end of the signal output module 220 (corresponding to 12V) for receiving a 12V voltage signal.

[0105] The base of the first transistor Q1 is connected to the signal output terminal (MCU_RELAY) of the main controller MCU through the tenth resistor R10, and is used to receive the pulse signal.

[0106] The collector of the first transistor Q1 is connected to the other end of the coil of the relay K1.

[0107] The emitter of the first transistor Q1 is connected to the common terminal.

[0108] When the pulse signal is at a high level and a 12V voltage signal is applied at the same time, the coil of relay K1 is energized, the first transistor Q1 is controlled to be turned on, the normally open switch of relay K1 is closed, and a constant current charging current is output to charge the battery pack (corresponding to B+ / B-).

[0109] In some embodiments, as Figure 1 As shown, the current detection module 150 includes a current detector U1, which is used to detect the current signal passing through and output the current signal;

[0110] Specifically, the input terminal (corresponding to pin 1) of the current detector U1 is coupled to the output terminal of the filter module 140.

[0111] One output terminal of the current detector U1 (corresponding to pins 3 and 4) is connected to one end of the normally open switch of relay K1.

[0112] The other output terminal of the current detector U1 (corresponding to pin 7) is connected to an input terminal of the comparison module 170 through the seventh resistor R7, dividing the current signal into two outputs, one output to one side of the relay K1 and the other output to the comparison module 170.

[0113] In some embodiments, as Figure 1 As shown, the comparison module 170 includes at least a comparator U3B, a first photocoupler (PC1A-PC1B), and a second transistor Q2. The comparator U3B has a signal comparison function, the first photocoupler (PC1A-PC1B) has an isolation and signal transmission function, and the second transistor Q2 is selected as an NPN transistor, which has a switch function.

[0114] Specifically, the in-phase terminal of the comparator U3B (corresponding to pin 5) is connected to the other signal output terminal (MCU_PWM) of the main controller MCU to receive the reference signal.

[0115] The inverting terminal of the comparator U3B (corresponding to pin 5) is connected to the other output terminal of the current detector U1 (corresponding to pin 7) through the seventh resistor R7.

[0116] An input terminal of the first photocoupler (PC1A-PC1B) is connected to an output terminal of the signal output module 220 through the twelfth resistor R12 for receiving a 5V voltage signal.

[0117] The first output end of the first photoelectric coupler (PC1A-PC1B) is connected with the output end (corresponding to pin 7) of the comparator U3B through the fourth diode D4,

[0118] The second output end (corresponding to point C) of the first photoelectric coupler (PC1A-PC1B) is connected with the feedback end of the control module 120,

[0119] The base of the second triode Q2 is connected with the output end (corresponding to the V+ end) of the filter module 140 through the series connection of the fourteenth resistor R14 and the voltage stabilizing tube ZD1,

[0120] The collector of the second triode Q2 is connected with an output end of the first photoelectric coupler (PC1A-PC1B),

[0121] The emitter of the second triode Q2 is connected with the common end.

[0122] When the output of the comparator U3B is high and the second triode Q2 is controlled to be turned on, the 5V voltage signal is pulled to low, indicating that the charging current signal is in constant current output state;

[0123] When the output of the comparator U3B is low and the second triode Q2 is controlled to be turned on, the 5V voltage signal is fed back to the control module 120 by the first photoelectric coupler (PC1A-PC1B), and the control module 120 controls the on / off frequency of the coupling module 130 according to the feedback signal to control the output charging current signal.

[0124] In some embodiments, as shown in Figure 1 The control module 120 at least includes a controller U2, which has the functions of signal receiving and adjusting the duty cycle of the control signal;

[0125] Specifically, the feedback end (corresponding to pin 2) of the controller U2 is connected with the second output end (corresponding to point C) of the first photoelectric coupler (PC1A-PC1B),

[0126] The control end (corresponding to pin 6) of the controller U2 is connected with an output end of the coupling module 130.

[0127] In some embodiments, as shown in Figure 1 The coupling module 130 at least includes a second transformer T1A,

[0128] Wherein, one end (corresponding to pin 5) of the primary winding of the second transformer T1A is connected with the output end of the input module 110,

[0129] The other end (corresponding to pin 3) of the primary winding of the second transformer T1A is connected with the control end (corresponding to pin 6) of the controller U2,

[0130] One end of the secondary winding of the second transformer T1A is connected to the input end of the filter module 140 .

[0131] When the controller U2 controls the primary winding of the second transformer T1A to be turned on, the voltage is positive at the top and negative at the bottom. When the controller U2 controls the primary winding of the second transformer T1A to be turned off, the voltage is positive at the bottom and negative at the top. The primary winding of the second transformer T1A couples the current signal to the secondary winding. The above actions are repeated to output the current signal to the filtering module 140.

[0132] In some embodiments, as Figure 2 As shown, an input side of the VCC power module 210 is coupled to the secondary winding of the second transformer T1A to obtain a voltage signal, which is then limited by the twenty-ninth resistor R29 and rectified by the seventh diode D7 to output a VCC voltage signal.

[0133] In some embodiments, as Figure 2 As shown, the signal output module 220 at least includes a second photocoupler (PC3A-PC2B) and a voltage regulator U4.

[0134] Among them, one end of the primary winding of the third transformer T3A (corresponding to pin 3) is connected to the positive pole (corresponding to HV) of the rectifier bridge BD1 to receive the voltage signal.

[0135] The other end of the primary winding of the third transformer T3A (corresponding to pin 4) is connected to the control end (corresponding to pin 4) of the control chip U6. The on / off state of the third transformer T3A is controlled by the control chip U6.

[0136] After the primary winding of the third transformer T3A forms a loop and is controlled to be turned off, the primary winding couples the current signal to the secondary winding. The current signal is input to one end (corresponding to A) of the second photocoupler (PC3A-PC2B) and the input end (corresponding to Vin) of the voltage regulator U4 through the fifth diode D5.

[0137] Among them, the 12V voltage signal is output at the cathode of the fifth diode D5, providing a 12V voltage signal for the coil of the relay K1;

[0138] The output terminal (corresponding to the Out terminal) of the 5V voltage signal regulator U4 provides a 5V voltage signal to the first photocoupler (PC1A-PC1B) and the second transistor Q2.

[0139] This technical solution uses a nitride-gathered sealed chip as the energy conversion control core, and combines it with a secondary synchronous rectification chip to improve efficiency. It also uses ultra-low internal resistance devices to improve product efficiency. The circuit is simple and intelligent charging is available. It is an extremely cost-effective product that can meet customers' charging needs.

[0140] The embodiments of the present application are described above with reference to the drawings; however, the present application is not limited to the specific embodiments described above, but the specific embodiments described above are merely illustrative rather than restrictive, and a person of ordinary skill in the art can make many forms under the inspiration of the present application without departing from the purpose of the present application and the scope protected by the claims, and these all belong to the protection of the present application.

Claims

1. An intelligent fast charging circuit, characterized in that: have: The reverse excitation constant current circuit is configured in the fast charging circuit, and is used to receive the voltage signal input from the mains side, and perform voltage reduction, rectification and voltage stabilization on the voltage signal to output a current signal for charging; An auxiliary power supply circuit, whose power input terminal is connected to an output terminal of the anti-excitation constant current circuit, is used to obtain a voltage signal. The output end of the auxiliary power supply circuit is connected to a signal input end of the anti-excitation constant current circuit, and is used to control the on / off state of the anti-excitation constant current circuit; wherein, The anti-excitation constant current circuit at least includes an output module, The auxiliary power supply circuit at least includes a signal output module, A signal input terminal of the output module is connected to a signal output terminal of the main controller for receiving a pulse signal. A power signal input terminal of the output module is connected to the output terminal of the signal output module for receiving a 12V voltage signal. When the pulse signal is at a high level and the 12V voltage signal is applied at the same time, the output module is controlled to be turned on, and the output module outputs a constant current charging current.

2. The intelligent fast charging circuit according to claim 1, characterized in that: The anti-excitation constant current circuit also includes an input module, a control module and a coupling module. The input module is used to receive the voltage signal input from the mains side and perform voltage reduction processing on the voltage signal. The input end of the control module and the input end of the coupling module are respectively connected to the output end of the input module. The output end of the control module is connected to one end of the coupling module, and is used to control the on / off state of the coupling module. When the coupling module is controlled to be turned off, the coupling module couples the input voltage signal to the output module.

3. The intelligent fast charging circuit according to claim 2, characterized in that: The anti-excitation constant current circuit also includes a filtering module, a current detection module and a comparison module. The input end of the filtering module is connected to the output end of the coupling module for receiving the voltage signal. The input end of the current detection module is coupled to the output end of the filter module, and is used to obtain the current signal output by the filter module. An output terminal of the current detection module is connected to an input terminal of the output module. An input terminal of the comparison module and another output terminal of the current detection module are used to receive the current signal. The other input terminal of the comparison module is connected to the other signal output terminal of the main controller for receiving a reference signal. The comparison module compares the current signal with the reference signal. When the current signal is greater than the reference signal, the output is a low level signal. When the current signal is less than the reference signal, the output is a high level signal. The output terminal of the comparison module is connected to the feedback terminal of the control module.

4. The intelligent fast charging circuit according to claim 3, characterized in that: An output terminal of the signal output module is connected to the electrical signal input terminal of the comparison module.

5. The intelligent fast charging circuit according to claim 3, characterized in that: The output module at least includes a relay and a first transistor, One end of the normally open switch of the relay is connected to the output end of the current detection module, One end of the coil of the relay is connected to an output end of the signal output module. The base of the first transistor is coupled to the signal output terminal 1 of the main controller for receiving the pulse signal. The collector of the first transistor is connected to the other end of the coil of the relay. The emitter of the first transistor is connected to the common end.

6. The intelligent fast charging circuit according to claim 5, characterized in that: The current detection module includes a current detector, The input end of the current detector is coupled to the output end of the filter module. An output terminal of the current detector is connected to one end of the normally open switch of the relay, The other output terminal of the current detector is connected to an input terminal of the comparison module.

7. The intelligent fast charging circuit according to claim 6, characterized in that: The comparison module at least includes a comparator, a first photocoupler and a second transistor. The non-inverting terminal of the comparator is connected to the other signal output terminal of the main controller, and is used to receive the reference signal. The inverting terminal of the comparator is coupled to the other output terminal of the current detector, An input terminal of the first photoelectric coupler is connected to an output terminal of the signal output module for receiving a 5V voltage signal. The first output terminal of the first photoelectric coupler is connected to the output terminal of the comparator, The second output terminal of the first photoelectric coupler is connected to the feedback terminal of the control module, The base of the second transistor and the output end of the filter module, The collector of the second transistor is connected to an output end of the first photocoupler. The emitter of the second transistor is connected to the common terminal.

8. The intelligent fast charging circuit according to claim 7, characterized in that: The control module at least includes a controller, The feedback terminal of the controller is coupled to the second output terminal of the first photoelectric coupler. The control end of the controller is connected to an output end of the coupling module.

9. The intelligent fast charging circuit according to claim 8, characterized in that: The coupling module comprises at least a second transformer, One end of the primary winding of the second transformer is connected to the output end of the input module, The other end of the primary winding of the second transformer is connected to the control end of the controller. One end of the secondary winding of the second transformer is connected to the input end of the filter module.

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