CN211428963U

CN211428963U - Lithium battery quick charging circuit

Info

Publication number: CN211428963U
Application number: CN202020284724.4U
Authority: CN
Inventors: 林建琰; 林二勇
Original assignee: Xiamen Xdroid Tech Co ltd
Current assignee: Xiamen Xdroid Tech Co ltd
Priority date: 2020-03-10
Filing date: 2020-03-10
Publication date: 2020-09-04
Anticipated expiration: 2030-03-10

Abstract

The utility model provides a lithium cell fills circuit soon, include: the AC-DC switching power supply module is connected with the battery pack connecting ends V + and V-; the constant-voltage constant-current feedback control loop comprises a control chip IC1, a photoelectric coupler PH1, a transformer T1 and a three-terminal regulator U1; t1 is connected between the AC-DC switching power supply module and V + and V-; a Pin3 Pin of the IC1 is connected to a primary coil of the T1 through a capacitor C4 to form a constant current loop; the Pin2 Pin is connected with a primary coil of T1 through a photoelectric triode of PH1, and U1 is connected between a secondary coil of T1 and V + through a light emitting diode of PH1 to form a constant voltage loop; the indicating lamp indicating control module achieves the function of indicating control through the control chip U2, the current limiting resistor R21, the detecting diodes D6 and D7 and the two indicating lamps. The utility model discloses simplify the design degree of difficulty greatly, the cost is reduced to the price/performance ratio has been improved widely.

Description

Lithium battery quick charging circuit

[ technical field ] A method for producing a semiconductor device

The invention relates to a lithium battery quick-charging circuit.

[ background of the invention ]

The lithium battery charger is divided into fast charging and slow charging in the industry at present, and the demand for fast charging is increasingly strong no matter in the communication industry such as mobile phones, handheld electric tools and the like. Although the communication industry has international standards of QC3.0, QC4.0 and the like, at present, a unified protocol standard applied to a quick charging circuit of an electric tool does not exist, and only has a corresponding safety standard. Therefore, how to make a universal power tool charger with high cost performance is a good news for consumers.

Currently, the switching power supply chargers in the power tool industry are roughly classified into two types:

the first is a PSR (primary side control) switching power supply charger, which omits an optocoupler and a three-terminal regulator 431 and can realize constant voltage and constant current output. But the control is not accurate enough, and the deviation of constant voltage and constant current has +/-10%. The PSR switching power supply charger is mainly applied to LED lamp driving, mobile phones 5V/1A and 2A and the like. When the LED lamp is used as a charger driven by the LED lamp, only constant-current charging is needed; as a mobile phone charger, a BMS management system of a mobile phone battery performs DC-DC (direct current to direct current) conversion to calibrate charging. Although the scheme is low in cost, the output power can only be within 20W basically, the control precision is low, and the quick charging of the electric tool cannot be realized, so that the electric tool is gradually eliminated by the industry of electric tool chargers.

The second one is that SSR (secondary side control) constant voltage output, constant current control of LM358, charge and instruct the loop to make up the constant voltage constant current charger, that is to say, if the power to realize the constant voltage, SSR can be realized, the realization mode is photocoupler and three-terminal regulator, but to increase the constant current, need to realize the constant current function through the constant current loop of LM 358. This solution is a charger solution that is widely adopted by the power tool industry. However, in this scheme, the design of the LM358 is complicated, many peripheral resistors and capacitors are needed to cooperate, and it is inevitable that parameters of offset voltage and offset current of the LM358 are parameters, which causes the charging indicator lamp to jump back by misjudgment. At least more than 1W of sampling resistor is needed, an extra sampling resistor is needed to set a cross current point for the LM358 designed constant current power supply, the power of the sampling resistor is large enough, otherwise, once the short-circuit protection of the output power supply is carried out in a safety regulation way, the resistance power is over-regulated, the burning failure is caused, the cost is high, the requirement on the design capability is high, and the application of the constant voltage constant current charger is greatly limited.

[ summary of the invention ]

In view of this, the technical problem to be solved by the present invention is to provide a lithium battery fast charging circuit, which overcomes the technical problems of complicated design and high cost of the present secondary-side controlled constant-voltage constant-current charger, and can greatly improve the cost performance of the secondary-side controlled constant-voltage constant-current charger.

In order to achieve the novel purpose, the embodiment of the invention adopts the technical scheme that: a lithium battery fast charging circuit comprising:

the AC-DC switching power supply module is provided with two commercial power input terminals L, N and is connected with two battery pack connecting ends V + and V-;

the constant-voltage constant-current feedback control loop comprises a control chip IC1, a photoelectric coupler PH1, a transformer T1 and a three-terminal regulator U1; the transformer T1 is connected between the AC-DC switching power supply module and two battery pack connection ends V + and V-; the control chip IC1 is a chip which is controlled by a secondary side and can realize a constant voltage and constant current function, and a Pin3 Pin of the IC1 is connected to a primary coil of the T1 through a capacitance value capacitor C4 which can work in a constant current state to form a constant current loop; a Pin2 Pin of the IC1 is connected with a primary coil of a T1 through a PH1 photoelectric triode, the three-terminal regulator U1 is connected between a secondary coil of a T1 and V + through a PH1 light-emitting diode, and the PH1 photoelectric triode and the light-emitting diode are coupled to form a constant voltage loop; and

the indicating lamp indicating control module comprises a control chip U2, a current limiting resistor R21, detecting diodes D6 and D7, a first color indicating lamp and a second color indicating lamp; the control chip U2 is a chip capable of detecting the voltage of the secondary rectifier diode; the D6 and D7 are connected in parallel with the secondary coil of T1, the anode is connected with the Pin3 Pin of U2 through a current-limiting resistor R21, the Pin4 Pin of U2 is connected with V + through a first color indicator lamp, and the Pin5 Pin of U2 is connected with V + through a second color indicator lamp.

The invention has the advantages that: the lithium battery quick-charging circuit adopts a chip (such as a KP201 chip or a DP2291 chip) which needs secondary side control and can realize a constant-voltage and constant-current function to perform secondary side control constant-voltage and constant-current output, and adopts a chip (such as a UP7358 chip) which can detect the voltage of a secondary rectifier diode to realize a charging indication loop, so that a charger with a constant-voltage and constant-current indicator lamp is combined.

[ description of the drawings ]

The invention will be further described with reference to the following examples with reference to the accompanying drawings.

Fig. 1 is a schematic block diagram of a lithium battery quick charging circuit according to the present invention.

Fig. 2 is a schematic diagram of the overall circuit structure of the lithium battery quick charging circuit of the invention.

Fig. 3 is a schematic circuit structure diagram of an AC-DC switching power supply module in the lithium battery quick charging circuit of the present invention.

Fig. 4 is a schematic circuit structure diagram of a constant voltage and constant current feedback control loop in the lithium battery quick charging circuit of the present invention.

Fig. 5 is a schematic diagram of the voltage and current states of the constant voltage and constant current in the lithium battery quick-charging circuit of the invention.

Fig. 6 is a schematic circuit structure diagram of an indicator light indication control module in the lithium battery quick-charging circuit of the invention.

Fig. 7 is a schematic diagram of a work flow of an indicator light indication control module in the lithium battery quick-charging circuit according to the present invention.

[ detailed description ] embodiments

The embodiment of the invention provides the lithium battery quick-charging circuit, solves the technical problems of complex design and high cost of a constant-voltage constant-current charger adopting secondary side control in the prior art, realizes the technical effects of high control precision and low cost, and greatly improves the cost performance of the lithium battery quick-charging circuit.

In order to solve the above problems, the technical solution in the embodiments of the present invention has the following general idea: the charger is characterized in that a chip (such as a KP201 chip or a DP2291 chip) which needs secondary control and can realize a constant-voltage constant-current function is adopted to perform secondary control constant-voltage constant-current output, and a chip (such as a UP7358 chip) which can detect the voltage of a secondary rectifier diode is adopted to realize a charging indication loop, so that the charger with the constant-voltage constant-current indicator lamp is combined.

The general principle structure block diagram is shown in fig. 1, and the specific implementation functions are as follows:

1. the AC-DC switching power supply module is used for converting commercial power 90V-264 Vac into isolated direct-current voltage and realizing charging current control, belongs to a part of a switching power supply and is controlled by a constant-voltage constant-current feedback control loop;

2. the constant voltage and constant current feedback control loop controls the AC-DC switching power supply module through a control chip (KP201 chip or DP2291 chip) to realize constant voltage and constant current charging, an optical coupler realizes signal feedback of safety isolation, and a three-terminal voltage regulator (431) sets the highest charging voltage and the voltage for stopping charging;

3. the indicating lamp indicating control module is realized by collecting and outputting a current waveform of the rectifier diode by another control chip (UP7358 chip) and matching with the setting of a resistor and a capacitor on the periphery of the chip, and when the charging current is less than or equal to 10 percent of rated charging current, the indicating lamp indicating control module is regarded as full and a green LED lamp is lighted; when the charging current is larger than 10% of the rated charging current, the LED lamp is considered to be charging and the red LED lamp is lightened.

Wherein, the control chip of the constant-voltage constant-current feedback control loop is preferably a KP201 chip produced by Biyi science and technology Limited or a DP2291 chip produced by Shenzhen German electronics Limited; the control chip of the indicator light indication control module is preferably a UP7358 chip manufactured by Shanghai core bright microelectronics Inc.

For better understanding of the above technical solutions, the following detailed descriptions will be provided in conjunction with the drawings and the detailed description of the embodiments.

Example one

Referring to fig. 2 to 6, the present embodiment provides a lithium battery fast charging circuit, which includes a C-DC switching power supply module, an indicator light indication control module, and a constant voltage and constant current feedback control loop.

As shown in fig. 2 and 3, the AC-DC switching power supply module has two mains input terminals L, N and connects two battery pack connection terminals V + and V-; further comprising: fuse F1, rectifier bridge BD1, and the filtering and EMC loop consisting of EC1, EC2, L1; BD1 is a fast recovery rectifier bridge, which means a rectifier bridge with reverse recovery time less than or equal to 50nS, BD1 is a combination of 4 diodes (such as FR and HER series), and has four pins A1, A3, B3 and C4, wherein pin A1 of BD1 is connected to a mains supply input terminal L through a fuse F1, pin A3 is connected to a mains supply input terminal N, pin B3 is connected to a primary coil of T1 through L1, pin C4 is grounded, one end of EC1 is connected to an input end of L1, the other end is grounded, one end of EC2 is connected to an output end of L1, and the other end is grounded, so that EC1, L1 and EC2 form a pi network.

The BD1 is a fast recovery rectifier bridge, and meanwhile, a filter capacitor EC1, EC2 and a general inductor L1 form a pi-type network, so that the output power can be within 60W. Can pass limit tests of the EN55014 CLASS B CLASS by conducted interference (150 KHZ-30 MHz) in electromagnetic compatibility EMC. Therefore, EMC components such as an X capacitor (safety capacitor), a common mode inductor and the like can be omitted, and the EMC design cost is greatly saved.

As shown in fig. 2 and 4, the constant voltage and constant current feedback control loop comprises a control chip IC1, a photocoupler PH1, a transformer T1 and a three-terminal regulator U1; the transformer T1 is connected between the AC-DC switching power supply module and two battery pack connection ends V + and V-; the control chip IC1 is a chip which is controlled by a secondary side and can realize a constant voltage and constant current function, and a Pin3 Pin of the IC1 is connected to a primary coil of the T1 through a capacitance value capacitor C4 which can work in a constant current state to form a constant current loop; the Pin2 Pin of the IC1 is connected with the primary coil of the T1 through the photoelectric triode of PH1, the three-terminal regulator U1 is connected between the secondary coil of the T1 and V + through the light emitting diode of PH1, and the photoelectric triode of PH1 and the light emitting diode are coupled to form a constant voltage loop. The constant-voltage constant-current feedback control loop further comprises voltage regulating resistors R18, R19 and R20; one end of R18 is connected with V +, and the other end is connected with the 3 pin of three-terminal regulator U1 through capacitor C5; and R19 and R20 are connected in parallel and then connected between pin1 and pin2 of the three-terminal regulator U1.

Because the Pin3 Pin of the IC1 is connected to the primary coil of the T1 through a capacitance value capacitor C4 which can work in a constant current state to form a constant current loop, the C4 is a conventional ceramic capacitor, the capacitance value is 10-100 nF, and the constant current loop can work in the constant current state, namely, the battery pack can be directly charged.

Because a constant voltage loop is formed by matching the photoelectric coupler PH1 with the three-terminal voltage regulator U1, the constant voltage output can be realized for charging the battery pack, and different voltage outputs can be realized by regulating the resistance values of the resistors R18, R19 and R20, so that the battery pack is a typical SSR (secondary side controlled flyback switching power supply).

The constant-voltage constant-current feedback control loop further comprises current adjusting resistors R4, R4A and R4B, wherein one end of each of R4, R4A and R4B is connected in parallel with a Pin4 Pin of an IC1 and a primary coil of a T1, and the other end of each of R4, R4A and R4B is connected with a photoelectric triode of PH1 and a capacitor C4; note that the three resistors R4, R4A and R4B are connected in parallel to have a resistance Rcs, as shown in the curve of charging voltage and current in fig. 5:

in the formula I_{CC_OUT}The output current of the lithium battery quick charging circuit is Np and Ns are the primary coil number and the secondary coil number of the transformer T1 respectively.

As shown in fig. 2 and fig. 6, the indicating lamp indicating control module includes a control chip U2, a current limiting resistor R21, detecting diodes D6 and D7, a first color indicating lamp (e.g., LED/R, red LED lamp) and a second color indicating lamp (e.g., LED/G, green LED lamp); the control chip U2 is a chip capable of detecting the voltage of the secondary rectifier diode; the D6 and D7 are connected in parallel with the secondary coil of T1, the anode is connected with the Pin3 Pin of U2 through a current-limiting resistor R21, the Pin4 Pin of U2 is connected with V + through a first color indicator lamp, and the Pin5 Pin of U2 is connected with V + through a second color indicator lamp. The indicating lamp indicating control module further comprises a lamp turning current adjusting resistor R25, an indicating lamp current limiting resistor R24 and an indicating lamp current limiting resistor R26; one end of the R25 is connected with the Pin1 Pin of the U2, the other end of the R25 is connected with the Pin2 Pin of the U2, and the Pin2 Pin of the U2 is also connected between the current-limiting resistor R21 and the Pin3 Pin of the U2 through a capacitor C10.

The charging voltage of the diodes D6 and D7 is detected through the current limiting resistor R21 (only a small-power chip resistor of about 1/10W is needed), and R25 can be used for setting the charging turn-light current value; r24, R26 and LED/R, LED/G are two red and green LED lamps and a current limiting resistor respectively.

The control chip IC1 and the peripheral circuit, the transformer T1, the sensing diodes D6 and D7 (both are rectification Schottky diodes), EC4 (electrolytic capacitor), the photoelectric coupler PH1, the three-terminal voltage regulator U1, the resistor, the capacitor, V + and V-, jointly form a typical switching power supply circuit. The output can be 5V-42V, the charging current is 1A-5A, and the maximum output power is 60W output by adjusting parameters. Meets the safety standard of main countries such as GS, CCC, UL, PSE, etc.

The specific working principle of the indicating lamp indicating control module is as follows: when the charger is in charge, the voltage across the diodes D6 and D7 is irregular due to wave shape (basically divided into three types, namely regular triangular wave, regular trapezoidal wave, indirect irregular triangular wave). Sampling the current of a Pin3 Pin of a control chip U2 through an R21 current-limiting resistor in a control chip U2 (a UP7358 chip), detecting the three waveforms, calculating the area of the three waveforms by utilizing integration, wherein the area is large and represents that constant current is supplied to charge a load, the control chip U2 is judged to be in a charging state at the moment, a red light is turned on, the Pin4 Pin of the control chip U2 outputs a low level, and the Pin5 Pin outputs a high-resistance state; when the battery is in a fast full charge state, the required charging current is slowly reduced until the battery protection board protects that the charging current is not required to be 0. The charger is also in a state where the current gradually decreases. At the moment, waveforms on the diodes D6 and D7 enter triangular waves from trapezoidal waves, and finally enter an indirect triangular wave industry commonly known as Burst-Mode (Burst-Mode), in the whole process that the charging current is reduced, the integral area detected by a Pin3 Pin of a U2 chip is also gradually reduced, meanwhile, a reference value is set to be a lamp turning current by matching with a resistance parameter of R25, at the moment, the U2 chip is judged to be in a full or standby state, a green lamp is turned on, the Pin5 Pin outputs a low level, and the Pin4 Pin outputs a high-impedance state.

In a word, the set current value is compared with the values of the integral areas of D6 and D7 collected by the Pin3 of the chip by setting the resistance value of R25 of the Pin1 of the chip, wherein the former is more than a bright red lamp, and the latter is less than or equal to the former bright green lamp.

When the lithium battery quick-charging circuit in the first embodiment is applied to quick charging on an electric tool, the typical parameter is 12V2.4A for three strings of 18650 power batteries with 2000mA capacity, and the charging can be completed within one hour.

Although specific embodiments of the invention have been described above, it will be understood by those skilled in the art that the specific embodiments described are illustrative only and are not limiting upon the scope of the invention, and that equivalent modifications and variations can be made by those skilled in the art without departing from the spirit of the invention, which is to be limited only by the appended claims.

Claims

1. The utility model provides a lithium cell fills circuit soon which characterized in that: the method comprises the following steps:

2. The lithium battery quick-charging circuit of claim 1, characterized in that: the AC-DC switching power supply module further includes: fuse F1, rectifier bridge BD1, and the filtering and EMC loop consisting of EC1, EC2, L1; BD1 is a fast recovery rectifier bridge formed by combining 4 diodes, and is provided with four pins A1, A3, B3 and C4, wherein the pin A1 of BD1 is connected to a mains supply input terminal L through a fuse F1, the pin A3 is connected to a mains supply input terminal N, the pin B3 is connected to a primary coil of T1 through L1, the pin C4 is grounded, one end of EC1 is connected to an input end of L1, the other end of EC1 is grounded, one end of EC2 is connected to an output end of L1, and the other end of EC1, L1 and EC2 form a pi-type network.

3. The lithium battery quick-charging circuit of claim 1, characterized in that: the constant-voltage constant-current feedback control loop further comprises current adjusting resistors R4, R4A and R4B, wherein one end of each of R4, R4A and R4B is connected in parallel with a Pin4 Pin of an IC1 and a primary coil of a T1, and the other end of each of R4, R4A and R4B is connected with a photoelectric triode of PH1 and a capacitor C4; after three resistors R4, R4A and R4B are connected in parallel, the resistance value is Rcs, then:

wherein, I_{CC_OUT}The output current of the lithium battery quick charging circuit is Np and Ns are the primary coil number and the secondary coil number of the transformer T1 respectively.

4. The lithium battery quick-charging circuit of claim 1, characterized in that: the constant-voltage constant-current feedback control loop further comprises voltage regulating resistors R18, R19 and R20; one end of R18 is connected with V +, and the other end is connected with the 3 pin of three-terminal regulator U1 through capacitor C5; and R19 and R20 are connected in parallel and then connected between pin1 and pin2 of the three-terminal regulator U1.

5. The lithium battery quick-charging circuit of claim 1, characterized in that: the indicating lamp indicating control module further comprises a lamp turning current adjusting resistor R25, an indicating lamp current limiting resistor R24 and an indicating lamp current limiting resistor R26; one end of the R25 is connected with the Pin1 Pin of the U2, the other end of the R25 is connected with the Pin2 Pin of the U2, and the Pin2 Pin of the U2 is also connected between the current-limiting resistor R21 and the Pin3 Pin of the U2 through a capacitor C10.

6. The lithium battery quick-charging circuit of claim 1, characterized in that: the control chip IC1 is a KP201 chip produced by Biyi science and technology Limited company or a DP2291 chip produced by Shenzhen Shenpu microelectronics Limited company; the control chip U2 is a UP7358 chip manufactured by Shanghai core bright microelectronics Inc.