An accelerated charging circuit and charging control method

Abstract

The present invention discloses an accelerated charging circuit and charging control method. The circuit includes a power input module, a PWM module, an output constant voltage and constant current control module, a charging control module, and a central control module. The output end of the power input module is connected to the PWM module, the output end of the PWM module is connected to the charging control module, the input end of the output constant voltage and constant current control module is connected to the charging control module, the output end of the output constant voltage and constant current control module is connected to the feedback end of the PWM module, and the central control module is connected to the control end of the charging control module. The present invention only adds a few detection circuits outside the MCU. Combined with MCU control, the present invention improves the performance of the charger at a very low cost, greatly improves resource utilization, and significantly enhances the competitiveness of the product.

Description

Technical Field

[0001] The present invention discloses a charging circuit, in particular an accelerated charging circuit and a charging control method, which can be widely used in smart homes, mobile energy storage, new energy, various chargers, etc. Background Art

[0002] With the widespread use of lithium batteries, lead-acid batteries, and various rechargeable batteries, chargers have become ubiquitous in our daily lives, work, entertainment, and leisure. At the same time, as the pace of life accelerates, people are demanding higher charging speeds for all types of batteries. Therefore, higher-power chargers are needed to speed up charging. However, higher-power chargers undoubtedly increase the direct cost of the product, hindering its promotion to consumers.

[0003] At present, the conventional technical solution to solve the problem of fast charging is to install a fan on the charger so that the charger can output greater power and provide a larger charging current. However, some applications require waterproofing, and installing a fan is not conducive to waterproof design. In addition, some chargers already have fans, so to increase the charging speed, the cost of the power supply can only be increased. Summary of the Invention

[0004] In response to the above-mentioned disadvantage of the prior art that increasing the charging speed of the charger requires increasing the direct cost of the product, the present invention provides an accelerated charging circuit and a charging control method, which adopt a special circuit structure design and can increase the cost very little on the basis of the conventional charging circuit in the prior art, and can achieve the requirement of accelerating the charging speed.

[0005] The technical solution adopted by the present invention to solve its technical problems is: an accelerated charging circuit, which includes a power input module, a PWM module, an output constant voltage and constant current control module, a charging control module and a central control module, the output end of the power input module is connected to the PWM module, the output end of the PWM module is connected to the charging control module, the input end of the output constant voltage and constant current control module is connected to the charging control module, the output end of the output constant voltage and constant current control module is connected to the feedback end of the PWM module, and the central control module is connected to the control end of the charging control module.

[0006] A charging control method, the control method comprising the following steps:

[0007] Step S1: When the AC power is connected and the charger temperature is room temperature, super power charging is adopted;

[0008] Step S2: When the temperature of the charger reaches the rated value, the charging power is reduced to the rated power. At this time, it is time point T1;

[0009] Step S3: When charging reaches time T2, the central control module starts to monitor the charging current. When the current drops to about 80% of the constant current point, it reaches time T3;

[0010] Step S4: After reaching time T3, the central control module controls the constant current point to 0.8 times the rated current for constant current charging, and controls the constant voltage of the charger to increase so that a certain voltage difference is maintained between the charger and the battery until the battery voltage reaches the set value, which is time T4.

[0011] Step S5: When time T4 is reached, the central control module controls the constant voltage value of the charger to drop back to the normal value. At this time, the voltage difference between the charger and the battery is extremely small, and the charging current will quickly drop to the turning light current point. This is time T5, and charging is completed.

[0012] The technical solution adopted by the present invention to solve the technical problem further includes:

[0013] The power input module adopts a rectifier and filter module, which includes a power input interface CON1, a bridge rectifier DB1 and a filter capacitor EC1. The bridge rectifier DB1 is connected to the power input interface CON1, and the filter capacitor EC1 is connected to the output end of the bridge rectifier DB1. A fuse F1 is connected in series to the input line of the power input interface CON1, and a thermistor NTC1 is also connected in series to the input line of the power input interface CON1.

[0014] The rectifier and filter module also includes an EMI unit, which includes a capacitor CX1, a resistor R1, a resistor R2 and an excitation coil LF1. The capacitor CX1 is connected across the live wire and the neutral wire of the power input interface CON1, the resistor R1 and the resistor R2 are connected in series between the live wire and the neutral wire of the power input interface CON1, and the excitation coil LF1 is connected in series to the input line of the power input interface CON1.

[0015] The PWM module includes a switching power supply chip U1 and a MOS transistor Q1. The power supply terminal of the switching power supply chip U1 is connected to the positive power supply terminal of the power input module, the gate of the MOS transistor Q1 is connected to the PWM output terminal of the switching power supply chip U1, the source of the MOS transistor Q1 is grounded, and the drain of the MOS transistor Q1 is connected to the positive power supply terminal of the power input module.

[0016] The positive power supply end of the power input module is connected to a transformer T1, and the output end of the transformer T1 is divided into a main output and an auxiliary output. A diode D4 is connected in series to the main output, and a filter capacitor EC2 is also connected between the positive power supply end of the main output and the ground; a diode D8 is connected in series to the auxiliary output, and a filter capacitor EC3 is also connected between the positive power supply end of the auxiliary output and the ground.

[0017] The output constant voltage and constant current control module includes a differential amplifier chip U2, the VCC terminal of the differential amplifier chip U2 is connected to the positive power supply, a capacitor C5 is connected between the positive power supply and the ground, a resistor R29 and a reference voltage regulator chip U3 are connected in series between the positive power supply and the ground, the control terminal of the reference voltage regulator chip U3 is connected to the standard voltage, the IP2+ interface of the differential amplifier chip U2 is connected to a data terminal of the central control module through a resistor R34 connected in series, and a resistor R29 is connected between the IP2+ interface of the differential amplifier chip U2 and the ground. Resistor R35, capacitor C9 is connected in parallel with resistor R35, capacitor C6 is connected between the OP2 interface and IP2- interface of differential amplifier chip U2, resistor R33 and capacitor C7 are connected in series in parallel with capacitor C6, OP2 interface of differential amplifier chip U2 is connected to the negative electrode of diode D7 through resistor R32 in series, resistor R36, light emitting diode of optocoupler OC1 and reference voltage regulator chip U4 are connected in series between the positive power supply and ground, and the light emitting diode of optocoupler OC1 is connected in parallel with the resistor R36. There is a resistor R37, the phototransistor of the optocoupler OC1 is connected between the feedback terminal of the switching power supply chip U1 and the ground, and a capacitor C3 is connected in parallel with the phototransistor of the optocoupler OC1. The control terminal of the reference voltage regulator chip U4 is connected to a data terminal of the central control module through a diode D6, a resistor R42 and a resistor R43 connected in series in sequence. A resistor R39 is connected between the control terminal of the reference voltage regulator chip U4 and the ground, and a resistor R40 and a capacitor C13, a resistor R42 and a resistor R43 are connected in parallel with the resistor R39. A capacitor C14 is connected between the common end and the ground. The control end of the reference voltage regulator chip U4 is connected to the positive power supply of the main output of the transformer T1 through a resistor R38 connected in series. A capacitor C11 is connected between the positive electrode and the control end of the reference voltage regulator chip U4. A resistor R41 and a capacitor C12 connected in series are connected in parallel with the capacitor C11. A resistor R31 is connected between the negative power supply of the main output of the transformer T1 and IP2- of the differential amplifier chip U2. A capacitor C8 is connected between IP2- of the differential amplifier chip U2 and the ground.

[0018] The charging control module includes a MOS transistor Q2, a transistor Q3, a power output interface CON2, a resistor R15, a resistor R16, a resistor R17, a resistor R18 and a capacitor C23. The source of the MOS transistor Q2 is connected to the positive power output end of the PWM module, the drain output of the MOS transistor Q2 is connected to the power output interface CON2, the resistor R15 is connected between the source of the MOS transistor Q2 and the gate of the MOS transistor Q2, the gate of the MOS transistor Q2 is connected to the collector of the transistor Q3 through the resistor R16, the emitter of the transistor Q3 is grounded, the base of the transistor Q3 is connected to the data end of the central control module through the resistor R17 connected in series, the base of the transistor Q3 is grounded through the resistor R18, and the capacitor C23 is connected in parallel with the resistor R18.

[0019] The output constant voltage and constant current control module is connected to a rotating light control module, which includes a resistor R19, a two-color LED lamp LED1, a resistor R20, a transistor Q4, a resistor R21, a resistor R22, a resistor R23, a resistor R24, a resistor R25, a resistor R26, a resistor R27, a resistor R28, a diode D5 and a capacitor C10. One end of the resistor R19 is connected to a +5V power supply, and the other end is connected to the two-color LED lamp LED1. The two-color LED lamp LED1 includes two LED lamps, a red LED and a green LED. The two LED lamps adopt a common anode design. The cathode of the green LED lamp is connected in series with a diode D5, a resistor R28, a resistor R27, a resistor R26 and a capacitor C10, and is connected to the ground. The resistor R27 and the resistor R2 6 is connected to the OP1 pin of the differential amplifier chip U2, the common end of the resistor R26 and the capacitor C10 is connected to the IP1+ pin of the differential amplifier chip U2, the common end of the resistor R28 and the resistor R27 is connected to one end of the resistor R21, the other end of the resistor R21 is connected to one end of the resistor R22, and the other end of the resistor R22 is grounded, the cathode of the red LED is connected to the collector of the transistor Q4 through the resistor R20, the emitter of the transistor Q4 is grounded, the base of the transistor Q4 is connected to the common end of the resistor R21 and the resistor R22, the resistor R23 and the resistor R24 ​​are connected in series between the reference voltage source and the ground, the common end of the resistor R23 and the resistor R24 ​​is connected to the IP1- pin of the differential amplifier chip U2, and the resistor R25 is connected in parallel with the resistor R24.

[0020] The auxiliary output of the PWM module is connected to an LDO power supply module, and the LDO power supply module adopts a linear regulator U5.

[0021] A battery voltage detection unit is connected to one data terminal of the central control module, and the battery voltage detection unit is connected to the output interface of the charging control module. The battery voltage detection unit includes a resistor R46, a resistor R47 and a capacitor C21. One end of the resistor R46 is connected to the output interface of the charging control module, the other end of the resistor R46 is connected to one end of the resistor R47, the other end of the resistor R47 is grounded, the capacitor C21 is connected in parallel with the resistor R47, the common end of the resistor R46 and the resistor R47 is connected to the data terminal of the central control module, and the other data terminal of the central control module is connected to the temperature detection unit. The temperature detection unit is connected to Connected to the output interface of the charging control module, the temperature detection unit includes a thermistor NTC2, a resistor R49 and a capacitor C24. One end of the thermistor NTC2 is connected to the output interface of the charging control module, the other end of the thermistor NTC2 is connected to one end of the resistor R49, the other end of the resistor R49 is grounded, the capacitor C24 and the resistor R49 are connected in parallel, the common end of the thermistor NTC2 and the resistor R49 is connected to the data terminal of the central control module, the third data terminal of the central control module is connected to the reference voltage through a series resistor R48, and a capacitor C22 is connected in series between the third data terminal of the central control module and the ground.

[0022] The beneficial effects of the present invention are as follows: the present invention intelligently controls the charging rate at each stage of the charging process through a combination of software and hardware, thereby significantly improving the charging speed while ensuring the safety of the charger and battery. The present invention only adds a few detection circuits around the MCU and combines them with MCU control to improve the performance of the charger at a very low cost, generating great benefits for resource utilization and significantly enhancing the competitiveness of the product.

[0023] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a circuit block diagram of the present invention.

[0025] Figure 2 This is a partial circuit schematic diagram of the rectifier and filter module of the present invention.

[0026] Figure 3 This is a partial circuit schematic diagram of the PWM module of the present invention.

[0027] Figure 4 This is a partial circuit schematic diagram of the output constant voltage and constant current control module of the present invention.

[0028] Figure 5 This is a partial circuit schematic of the turn signal control module of the present invention.

[0029] Figure 6 This is a partial circuit schematic diagram of the LDO power supply module of the present invention.

[0030] Figure 7 This is a partial circuit schematic diagram of the charging control module of the present invention.

[0031] Figure 8 This is a partial circuit schematic diagram of the central control module of the present invention.

[0032] Figure 9 This is a line graph of current and voltage during the conventional charging process.

[0033] Figure 10 This is a line graph of current and voltage during the charging process of the charging method of the present invention. DETAILED DESCRIPTION

[0034] This embodiment is a preferred implementation manner of the present invention. Other embodiments whose principles and basic structures are the same or similar to those of this embodiment are within the protection scope of the present invention.

[0035] Please refer to the attached Figure 1 To the attached Figure 8 The present invention mainly includes a power input module, a PWM module, an output constant voltage and constant current control module, a charging control module and a central control module. The power input module outputs power to the PWM module, the PWM module outputs power to the charging control module, the input end of the output constant voltage and constant current control module is connected to the charging control module, the output end of the output constant voltage and constant current control module is connected to the feedback end of the PWM module, and the central control module is connected to the control end of the charging control module.

[0036] In this embodiment, the power input module utilizes a rectifier and filter module for converting input AC power into DC power. The rectifier and filter module includes a power input interface CON1, a bridge rectifier DB1, and a filter capacitor EC1. The power input interface CON1 is used for AC power input. The bridge rectifier DB1 is connected to the power input interface CON1 and converts the AC power into a unidirectional power source. The filter capacitor EC1 is connected to the output of the bridge rectifier DB1 and converts the rectified unidirectional power into DC power. In this embodiment, a fuse F1 is connected in series with the input line of the power input interface CON1 for overcurrent protection. A thermistor NTC1 is also connected in series with the input line of the power input interface CON1 for overheating protection. In this embodiment, the rectifier and filter module also includes an EMI unit, which includes a capacitor CX1, a resistor R1, a resistor R2, and an excitation coil LF1. The capacitor CX1 is connected across the live wire and the neutral wire of the power input interface CON1, the resistors R1 and R2 are connected in series between the live wire and the neutral wire of the power input interface CON1, and the excitation coil LF1 is connected in series to the input line of the power input interface CON1, which can filter out EMI interference in the input power.

[0037] In this embodiment, the PWM module includes a switching power supply chip U1 and a MOS transistor Q1. The power supply terminal (i.e., VDD) of the switching power supply chip U1 is connected to the positive power supply terminal of the power input module. The gate of the MOS transistor Q1 is connected to the PWM output terminal (i.e., GATE pin) of the switching power supply chip U1. The source of the MOS transistor Q1 is grounded, and the drain of the MOS transistor Q1 is connected to the positive power supply terminal of the power input module. The PWM chip U1 controls the MOS transistor Q1 to perform high-frequency switching, thereby controlling the current of the input transformer T1 to be converted into high-frequency alternating current for voltage conversion. In this embodiment, the output end of the transformer T1 is divided into a main output and an auxiliary output. A diode D4 is connected in series to the main output to rectify the main output and form a unidirectional power supply. A filter capacitor EC2 is further connected between the positive power supply end of the main output and ground to filter the main output power to form a direct current (DC) to supply power to the charging control module. A diode D8 is connected in series to the auxiliary output to rectify the auxiliary output and form a unidirectional power supply. A filter capacitor EC3 is further connected between the positive power supply end of the auxiliary output and ground to filter the main output power to form a DC power (i.e., VCC) to supply power to the present invention.

[0038] In this embodiment, the output constant voltage and constant current control module includes a differential amplifier chip U2. The VCC terminal of differential amplifier chip U2 is connected to the positive power supply. A capacitor C5 is connected between the positive power supply (VCC) and ground. A resistor R29 and a reference voltage regulator chip U3 are connected in series between the positive power supply (VCC) and ground. The control terminal of the reference voltage regulator chip U3 is connected to a standard voltage (Vref). In this embodiment, the IP2+ interface of differential amplifier chip U2 is connected to a data terminal (P2.3 port, serving as I_PWM) of the central control module via a series resistor R34. A resistor R35 is connected between the IP2+ interface of differential amplifier chip U2 and ground, and a capacitor C9 is connected in parallel with resistor R35. A capacitor C6 is connected between the OP2 interface and the IP2- interface of differential amplifier chip U2. A resistor R33 and a capacitor C7 are connected in series with capacitor C6. The OP2 interface of differential amplifier chip U2 is connected to the cathode of diode D7 via a series resistor R32. Resistor R36, the light-emitting diode of the optocoupler OC1, and the reference voltage regulator chip U4 are connected in series between the positive power supply (VCC) and the ground. Resistor R37 is connected in parallel with the light-emitting diode of the optocoupler OC1. The phototransistor of the optocoupler OC1 is connected between the feedback terminal (i.e., the FB interface) of the switching power supply chip U1 and the ground. Capacitor C3 is connected in parallel with the phototransistor of the optocoupler OC1. The control terminal of the reference voltage regulator chip U4 is connected to a data terminal (P0.5 port, serving as V_PWM) of the central control module through diode D6, resistor R42, and resistor R43 connected in series. ) are connected. Resistor R39 is connected between the control terminal of reference voltage regulator chip U4 and ground. Resistor R40 and capacitor C13 are connected in parallel with resistor R39. Capacitor C14 is connected between the common terminal of resistors R42 and R43 and ground. The control terminal of reference voltage regulator chip U4 is connected to the positive power supply of transformer T1's main output through a series resistor R38. Capacitor C11 is connected between the positive electrode of reference voltage regulator chip U4 and the control terminal. Resistor R31 is connected between the negative power supply of transformer T1's main output and IP2- of differential amplifier chip U2. Capacitor C8 is connected between IP2- of differential amplifier chip U2 and ground. By detecting the output voltage and current, the differential amplifier controls the optocoupler to provide feedback to the primary switching power supply chip U1, controlling the PWM amplitude to achieve constant voltage and current.

[0039] In this embodiment, the charging control module includes a MOS transistor Q2, a transistor Q3, a power output interface CON2, resistors R15, R16, R17, R18, and a capacitor C23. The source of the MOS transistor Q2 is connected to the positive power output terminal of the PWM module, the drain of the MOS transistor Q2 is connected to the power output interface CON2, the resistor R15 is connected between the source of the MOS transistor Q2 and the gate of the MOS transistor Q2, the gate of the MOS transistor Q2 is connected to the collector of the transistor Q3 via the resistor R16, the emitter of the transistor Q3 is grounded, the base of the transistor Q3 is connected to the data terminal of the central control module (in this embodiment, the general I / O port P0.4 is used as the output terminal of K1) via a series resistor R17, the base of the transistor Q3 is grounded via a resistor R18, the base of the transistor Q3 is grounded via a resistor R18, and the capacitor C23 is connected in parallel with the resistor R18. The central control module controls the on / off of the transistor Q3, thereby controlling the on / off of the MOS transistor Q2, thereby controlling the charging / charging stop. In this embodiment, an excitation coil LF2 is connected in series between the charging control module and the PWM module, which can be used to filter out EMI interference at the output end of the charging control module.

[0040] In this embodiment, the output constant voltage and constant current control module is connected to a rotating light control module, which includes a resistor R19, a dual-color LED lamp LED1, a resistor R20, a transistor Q4, a resistor R21, a resistor R22, a resistor R23, a resistor R24, a resistor R25, a resistor R26, a resistor R27, a resistor R28, a diode D5, and a capacitor C10. The resistor R19 serves as a current limiting resistor, one end of which is connected to a +5V power supply (i.e., VCC), and the other end is connected to the dual-color LED lamp LED1. The dual-color LED lamp LED1 includes two LED lamps, a red LED and a green LED. The two LED lamps adopt a common anode design. In specific implementation, other forms of LED lamps can also be used. Among them, the cathode of the green LED lamp is connected in series with a diode D5, a resistor R28, a resistor R27, a resistor R26, and a capacitor C1. 0, and finally connected to ground, the common end of resistor R27 and resistor R26 is connected to the OP1 pin of the differential amplifier chip U2, the common end of resistor R26 and capacitor C10 is connected to the IP1+ pin of the differential amplifier chip U2, the common end of resistor R28 and resistor R27 is connected to one end of resistor R21, the other end of resistor R21 is connected to one end of resistor R22, and the other end of resistor R22 is grounded. The cathode of the red LED is connected to the collector of transistor Q4 through resistor R20, the emitter of transistor Q4 is grounded, and the base of transistor Q4 is connected to the common end of resistor R21 and resistor R22. Resistor R23 and resistor R24 ​​are connected in series between the reference voltage source (Vref) and ground, the common end of resistor R23 and resistor R24 ​​is connected to the IP1- pin of the differential amplifier chip U2, and resistor R25 is connected in parallel with resistor R24. After the charging current drops to the preset value, the battery is determined to be fully charged, and the LED state is switched to remind the user of the charging status. The smaller the current detected by the rotating light, the more fully charged the battery is. However, the longer the charging time, the lower the current set for the rotating light may cause the light to not turn on.

[0041] In this embodiment, the auxiliary output of the PWM module is connected to an LDO power supply module. This LDO power supply module utilizes a linear voltage regulator U5. In this embodiment, linear voltage regulator U5 utilizes an R1524 linear voltage regulator chip. However, other linear voltage regulator chips may be used in place of these chips. The LDO power supply module steps down and stabilizes the auxiliary output voltage of the PWM module to 3.3V or 5V, providing power to the central control module.

[0042] In this embodiment, the central control module uses a single-chip microcomputer chip U6 of model MT006. During specific implementation, other types of single-chip microcomputer chips may also be used instead. A battery voltage detection unit is connected to a data terminal of the central control module (in this embodiment, the general I / O port P1.5 is selected, which has an ADC function. If a port without an ADC function or a single-chip microcomputer without an ADC function is selected, an external analog-to-digital conversion module is required). The battery voltage detection unit is connected to the output interface of the charging control module. The battery voltage detection unit includes a resistor R46, a resistor R47 and a capacitor C21. One end of the resistor R46 is connected to the output interface of the charging control module, the other end of the resistor R46 is connected to one end of the resistor R47, the other end of the resistor R47 is grounded, the capacitor C21 is connected in parallel with the resistor R47, and the common end of the resistor R46 and the resistor R47 is connected to the data terminal of the central control module. Another data terminal of the central control module (in this embodiment, the general I / O port P1.6 is selected, which has an ADC function. If a port without an ADC function or a single-chip microcomputer without an ADC function is selected, an external analog-to-digital conversion module is required) is connected. A temperature detection unit is connected to the output interface of the charging control module. The temperature detection unit includes a thermistor NTC2, a resistor R49, and a capacitor C24. One end of the thermistor NTC2 is connected to the output interface of the charging control module, the other end of the thermistor NTC2 is connected to one end of the resistor R49, and the other end of the resistor R49 is grounded. Capacitor C24 and resistor R49 are connected in parallel. The common end of the thermistor NTC2 and resistor R49 is connected to the data terminal of the central control module. In this embodiment, the third data terminal of the central control module (in this embodiment, the general I / O port P0.7 with built-in ADC function is selected. If a port without ADC function or a single-chip microcontroller without ADC function is selected, an external analog-to-digital conversion module is required) is connected to the reference voltage (i.e., Vref) via a series resistor R48. A capacitor C22 is connected in series between the third data terminal of the central control module (in this embodiment, the data terminal connected to resistor R48) and ground. The central control module of the present invention can be used to collect peripheral information and control peripheral circuits.

[0043] When the present invention is in use, after AC power is input, it passes through the rectification and filtering module and is given to the PWM module. The constant current and constant voltage power supply is output through PWM and transformer conversion. The central control module will monitor the temperature of the highest temperature device in real time through NTC2 and change the comparator constant current sampling reference voltage through PWM to control the output constant current value. At the same time, the central control module will monitor the voltage of the charger output port. When the battery voltage needs to be detected, charging can be stopped by controlling the MOS tube of the charging control module. At this time, the charging current is 0A, eliminating the voltage deviation caused by line loss. After quickly detecting the battery voltage, charging can be resumed. The central control module uses another PWM to slightly change the constant voltage value of the charger to achieve the required control curve.

[0044] Please refer to the attached Figure 9 and attached Figure 10 ,When the present invention is used, it can be compared with the charging process of a conventional charger.

[0045] The charging process of a conventional charger is as follows:

[0046] 1. The conventional charging method is that when the mains is just connected, the charger charges the battery at the rated constant current. At this time, the temperature of the charger components slowly rises from a low temperature. After about 1 hour of charging, the temperature rise rate of the charger components slows down. After 2 hours of charging, the temperature of the charger components tends to stabilize and no longer rises, reaching a stable charging temperature. At this time, the battery reaches the attached temperature. Figure 9 T1 moment in

[0047] 2. After charging to time T1, the battery voltage gradually increases to near the charger voltage stabilization point. When charging continues after time T1, the difference between the battery voltage and the charger voltage will become smaller and smaller, and the charging current will automatically decrease until the charging current is less than the set turning light current point. At this time, the battery reaches the charging current point. Figure 9 At T2, the light turns from orange / red to green / blue, reminding the user that the battery is fully charged. The process from T1 to T2 is very slow, especially when the light transition point is set to a small time. The process from T1 to T2 may even take longer than the time from 0 to T1, seriously affecting the charging speed.

[0048] The charging process of the present invention is as follows:

[0049] 1. To increase the charging speed, when the AC power is just connected and the charger temperature is detected to be very low (usually room temperature), an overpower charging mode is adopted (1.2 to 1.5 times the rated power, the rated power is set according to the specific setting of the charger, usually the rated power of the charger); although overpower charging will cause the temperature of the charger components to rise faster, the central control module is used to monitor the temperature of the components. Before reaching the rated temperature of the charger (in this embodiment, the rated temperature is set to 100°C), the charging power is reduced to the rated power. At this time, Figure 10At time T1, the temperature of each charger component is maintained at the rated operating temperature, which greatly improves the charging speed.

[0050] 2. When the battery voltage approaches the no-load charger voltage (in this embodiment, the voltage is not fixed and is determined by the length of the wire, the internal resistance of the device, etc., and is usually selected as 0.3V, that is, when the difference between the battery voltage and the no-load charger voltage is less than or equal to 0.3V, it can be determined that the battery voltage is close to the no-load charger voltage), the charging current begins to slowly decrease from the constant current value. Figure 10 At time T2 in the figure, when charging reaches time T2, the central control module starts to monitor the charging current. When the current drops to about 80% of the constant current point, it reaches time T3.

[0051] 3. After reaching time T3, the central control module controls the constant current point to 0.8 times the rated current for constant current charging, and controls the constant voltage of the charger to maintain a certain voltage difference between the charger and the battery (in this embodiment, the voltage difference is automatically adjusted to prevent the current from decreasing at this time. The size of the voltage difference is related to the internal resistance of the battery and the internal resistance of the wire, and is usually 0.1V~1.0V is normal), until the battery voltage reaches the set value (the battery voltage and the port voltage detected after the charger output, due to the voltage difference caused by factors such as the connecting wire, there will be deviations in the detected battery voltage during the charging process. Here, it is necessary to use the central control module to control a brief stop of charging during the charging process. At this time, the charging current drops to 0A, and the voltage difference of the connecting wire is also eliminated. The central control module quickly detects the voltage on the battery and immediately resumes charging, which can more accurately test the battery voltage at this time). Figure 10 At time T4 in the embodiment, the short-term charging stop is usually 2 seconds to reduce the charging current to 0A. If multiple charging stops are required, the power outage frequency is once every minute.

[0052] 4. This is moment T4. The charging speed is accelerated from T3 to T4. When reaching moment T4, the central control module controls the constant voltage value of the charger to drop back to the normal value (that is, the set charging voltage value). At this time, the voltage difference between the charger and the battery is extremely small, and the charging current will quickly drop to the turning light current point. At this moment, Figure 10 Therefore, the process from T4 to T5 will be very short. This method can greatly shorten the charging speed.

[0053] Compared with the above optimization of the charging curve, the present invention can greatly utilize the energy of the charger, increase the charging speed of the charger without increasing the cost, and greatly improve the cost performance and competitiveness of the product.

[0054] The present invention intelligently controls the charging rate at each stage of the charging process through a combination of software and hardware, significantly improving the charging speed while ensuring the safety of the charger and battery. The present invention only adds a few detection circuits around the MCU and combines them with MCU control to improve the performance of the charger at a very low cost, generating great benefits for resource utilization and significantly enhancing the competitiveness of the product.

Claims

1. An accelerated charging circuit, characterized in that: The circuit includes a power input module, a PWM module, an output constant voltage and constant current control module, a charging control module and a central control module. The output end of the power input module is connected to the PWM module, the output end of the PWM module is connected to the charging control module, the input end of the output constant voltage and constant current control module is connected to the charging control module, the output end of the output constant voltage and constant current control module is connected to the feedback end of the PWM module, and the central control module is connected to the control end of the charging control module. A battery voltage detection unit is connected to one data terminal of the central control module, and the battery voltage detection unit is connected to the output interface of the charging control module. The battery voltage detection unit includes a resistor R46, a resistor R47 and a capacitor C21. One end of the resistor R46 is connected to the output interface of the charging control module, the other end of the resistor R46 is connected to one end of the resistor R47, the other end of the resistor R47 is grounded, the capacitor C21 is connected in parallel with the resistor R47, the common end of the resistor R46 and the resistor R47 is connected to the data terminal of the central control module, and the other data terminal of the central control module is connected to the temperature detection unit. The temperature detection unit is connected to Connected to the output interface of the charging control module, the temperature detection unit includes a thermistor NTC2, a resistor R49, and a capacitor C24. One end of the thermistor NTC2 is connected to the output interface of the charging control module, the other end of the thermistor NTC2 is connected to one end of the resistor R49, the other end of the resistor R49 is grounded, the capacitor C24 and the resistor R49 are connected in parallel, the common end of the thermistor NTC2 and the resistor R49 is connected to the data terminal of the central control module, the third data terminal of the central control module is connected to the reference voltage via a series resistor R48, and a capacitor C22 is connected in series between the third data terminal of the central control module and ground; The charging control method includes the following steps: Step S1: When the AC power is connected and the charger temperature is room temperature, super power charging is adopted; Step S2: When the temperature of the charger reaches the rated value, the charging power is reduced to the rated power. At this time, it is time point T1; Step S3: When the battery voltage approaches the no-load charger voltage, it is time point T2. When the charging reaches time T2, the central control module starts to monitor the charging current. When the current drops to 80% of the constant current point, it reaches time point T3. Step S4: After reaching time T3, the central control module controls the constant current point to 0.8 times the rated current for constant current charging, and controls the constant voltage of the charger to increase so that a certain voltage difference is maintained between the charger and the battery until the battery voltage reaches the set value, which is time T4. Step S5: When time T4 is reached, the central control module controls the constant voltage value of the charger to drop back to the normal value. At this time, the voltage difference between the charger and the battery is extremely small, and the charging current will quickly drop to the turning light current point. This is time T5, and charging is completed.

2. The accelerated charging circuit according to claim 1, wherein: The power input module adopts a rectifier and filter module, which includes a power input interface CON1, a bridge rectifier DB1 and a filter capacitor EC1. The bridge rectifier DB1 is connected to the power input interface CON1, and the filter capacitor EC1 is connected to the output end of the bridge rectifier DB1. A fuse F1 is connected in series to the input line of the power input interface CON1, and a thermistor NTC1 is also connected in series to the input line of the power input interface CON1.

3. The accelerated charging circuit according to claim 2, wherein: The rectifier and filter module also includes an EMI unit, which includes a capacitor CX1, a resistor R1, a resistor R2 and an excitation coil LF1. The capacitor CX1 is connected across the live wire and the neutral wire of the power input interface CON1, the resistor R1 and the resistor R2 are connected in series between the live wire and the neutral wire of the power input interface CON1, and the excitation coil LF1 is connected in series to the input line of the power input interface CON1.

4. The accelerated charging circuit according to claim 1, wherein: The PWM module includes a switching power supply chip U1 and a MOS transistor Q1. The power supply terminal of the switching power supply chip U1 is connected to the positive power supply terminal of the power input module, the gate of the MOS transistor Q1 is connected to the PWM output terminal of the switching power supply chip U1, the source of the MOS transistor Q1 is grounded, and the drain of the MOS transistor Q1 is connected to the positive power supply terminal of the power input module.

5. The accelerated charging circuit according to claim 1, wherein: The positive power supply end of the power input module is connected to a transformer T1, and the output end of the transformer T1 is divided into a main output and an auxiliary output. A diode D4 is connected in series to the main output, and a filter capacitor EC2 is also connected between the positive power supply end of the main output and the ground; a diode D8 is connected in series to the auxiliary output, and a filter capacitor EC3 is also connected between the positive power supply end of the auxiliary output and the ground.

6. The accelerated charging circuit according to claim 1, wherein: The output constant voltage and constant current control module includes a differential amplifier chip U2, the VCC terminal of the differential amplifier chip U2 is connected to the positive power supply, a capacitor C5 is connected between the positive power supply and the ground, a resistor R29 and a reference voltage regulator chip U3 are connected in series between the positive power supply and the ground, the control terminal of the reference voltage regulator chip U3 is connected to the standard voltage, the IP2+ interface of the differential amplifier chip U2 is connected to a data terminal of the central control module through a resistor R34 connected in series, and a resistor R29 is connected between the IP2+ interface of the differential amplifier chip U2 and the ground. Resistor R35, capacitor C9 is connected in parallel with resistor R35, capacitor C6 is connected between the OP2 interface and IP2- interface of differential amplifier chip U2, resistor R33 and capacitor C7 are connected in series in parallel with capacitor C6, OP2 interface of differential amplifier chip U2 is connected to the negative electrode of diode D7 through resistor R32 in series, resistor R36, light emitting diode of optocoupler OC1 and reference voltage regulator chip U4 are connected in series between the positive power supply and ground, and the light emitting diode of optocoupler OC1 is connected in parallel with the resistor R36. There is a resistor R37, the phototransistor of the optocoupler OC1 is connected between the feedback terminal of the switching power supply chip U1 and the ground, and a capacitor C3 is connected in parallel with the phototransistor of the optocoupler OC1. The control terminal of the reference voltage regulator chip U4 is connected to a data terminal of the central control module through a diode D6, a resistor R42 and a resistor R43 connected in series in sequence. A resistor R39 is connected between the control terminal of the reference voltage regulator chip U4 and the ground, and a resistor R40 and a capacitor C13, a resistor R42 and a resistor R43 are connected in parallel with the resistor R39. A capacitor C14 is connected between the common end and the ground. The control end of the reference voltage regulator chip U4 is connected to the positive power supply of the main output of the transformer T1 through a resistor R38 connected in series. A capacitor C11 is connected between the positive electrode and the control end of the reference voltage regulator chip U4. A resistor R41 and a capacitor C12 connected in series are connected in parallel with the capacitor C11. A resistor R31 is connected between the negative power supply of the main output of the transformer T1 and IP2- of the differential amplifier chip U2. A capacitor C8 is connected between IP2- of the differential amplifier chip U2 and the ground.

7. The accelerated charging circuit according to claim 1, wherein: The charging control module includes a MOS transistor Q2, a transistor Q3, a power output interface CON2, a resistor R15, a resistor R16, a resistor R17, a resistor R18 and a capacitor C23. The source of the MOS transistor Q2 is connected to the positive power output end of the PWM module, the drain output of the MOS transistor Q2 is connected to the power output interface CON2, the resistor R15 is connected between the source of the MOS transistor Q2 and the gate of the MOS transistor Q2, the gate of the MOS transistor Q2 is connected to the collector of the transistor Q3 through the resistor R16, the emitter of the transistor Q3 is grounded, the base of the transistor Q3 is connected to the data end of the central control module through the resistor R17 connected in series, the base of the transistor Q3 is grounded through the resistor R18, and the capacitor C23 is connected in parallel with the resistor R18.

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