A constant power large current charging system

Abstract

A constant power large current charging system, including charging chip, inductance L1, L2, L3, switch transistor, diode D1, D2, D3 and capacitor C1, lithium ion battery is connected between the output end of the charging chip and the chip ground, the opposite end of inductance L2, the same end of inductance L3 and the opposite end of inductance L1 are connected with the chip ground, the same end of inductance L2 is connected with the input end of the charging chip through diode D2, the same end of inductance L3 is connected with the input end of the charging chip through diode D3, and the capacitor C1 is connected between the input end of the charging chip and the chip ground, wherein the load of inductance L1 is constant power, the energy stored in inductance L1 is induced to inductance L2 and inductance L3, so that the source of the charging chip is also constant power. Therefore, the application not only realizes the charging mode of trickle, constant power, constant current and constant voltage, but also considers the demand of large current charging and full charging.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of lithium ion battery, and relates to a constant power large current charging system. BACKGROUND

[0002] Lithium ion battery is an ideal reversible battery. In the prior art, the charging process of lithium ion battery can be generally divided into three stages, namely, trickle charging (low voltage charging), constant current charging and constant voltage charging. The understanding mode of the lithium ion battery charging system formed by the charging chip generally includes that the charging chip is in a floating ground state or the charging chip is in a real ground state.

[0003] Referring to Figure 1 , Figure 1 , a lithium ion battery charging system (chip ground in a floating ground state) in the prior art is shown. As shown in Figure 1 , the system includes a series charging chip, an inductor L1, a switching transistor and a diode. The lithium ion battery is connected between the output end of the charging chip and the chip ground. A constant power load, the inductor L1 and the switching transistor are connected in series between the AC power supply end and the ground end. The connection point of the constant power load and the inductor L1 is connected to the chip ground. The diode is connected in parallel with the series-connected constant power load and the inductor L1.

[0004] Referring to Figure 2 , Figure 2 , a lithium ion battery charging system (chip ground in a real ground state) in the prior art is shown. The system includes a charging chip, an inductor L1, a switching transistor and a diode. The lithium ion battery is connected between the output end of the charging chip and the chip ground. The switching transistor, the inductor L1 and the constant power load are connected in series between the AC power supply end and the ground end. The connection point of the constant power load and the inductor L1 is connected to the chip ground. The ground end of the constant power load is connected to the chip ground. The diode is connected in parallel with the series-connected constant inductor L1 and power load.

[0005] It is clear to those skilled in the art that, since the current-voltage of the LED lamp load is in an E exponential relationship, the fluctuation of the current does not obviously affect the voltage, and the LED lamp load also requires constant current driving, so P=I*V. In the case that the current and the voltage are constant, the LED lamp load is a typical constant power load.

[0006] As shown in Figure 1 and Figure 2 , the charging chip extracts current from the load V of the switching power supply to charge the battery. This charging mode is limited by the maximum value of the AC system application current. Taking the LED driving system as an example, the current is generally less than 150 mA. Therefore, a constant power large current charging system cannot be formed.

[0007] Referring to Figure 3 , Figure 3Another prior art lithium ion battery charging system is shown. As shown Figure 3 As shown, in addition to including a charging chip, an inductor L1, a switching transistor and a diode, an inductor L3 is also included, which, together with a capacitor and a diode, serves as a power supply for the charging chip during discharging:

[0008] L3 = K*L1.

[0009] Under test conditions (testing the load-carrying capacity of the auxiliary winding with an electronic load):

[0010] Uac = 220V, Uo = 140.5V, Rcs = 1.9R

[0011] The power output at this time is:

[0012] Uo (V) Io (A) Po (W) 2.4 1.45 3.480 2.5 1.41 3.525 2.6 1.369 3.559 2.7 1.33 3.591 2.8 1.288 3.606 2.9 1.245 3.611 3 1.2 3.600 3.1 1.155 3.581 3.2 1.11 3.552 3.3 1.065 3.515 3.4 1.015 3.451 3.5 0.967 3.385 3.6 0.918 3.305 3.7 0.865 3.201 3.8 0.813 3.089 3.9 0.759 2.960 4 0.702 2.808 4.1 0.647 2.653

[0013] As can be seen from the above, the current is about 1A and the power is about 3W, thus it cannot meet the demand of a constant-power large-current charging system. SUMMARY

[0014] To solve the above technical problems, the present application proposes a constant-power large-current charging system for providing a suitable solution for constant-power large-current charging.

[0015] To achieve the above object, the technical solution of the present application is as follows:

[0016] The application discloses a constant-power large-current charging system, which comprises a charging chip, an inductor L1, a switching transistor and a diode D1, wherein a lithium ion battery is connected between the output end of the charging chip and the chip ground; a constant-power load, the inductor L1 and the switching transistor are connected in series between an AC power supply end and a ground end, the connection point of the constant-power load and the inductor L1 is connected to the chip ground; and the diode is connected in parallel with the series-connected constant-power load and the inductor L1.

[0017] To achieve the above object, the application further provides a technical scheme as follows.

[0018] The application discloses a constant-power large-current charging system, which comprises a charging chip, an inductor L1, a switching transistor and a diode D1, wherein a lithium ion battery is connected between the output end of the charging chip and the chip ground; a constant-power load, the inductor L1 and the switching transistor are connected in series between an AC power supply end and a ground end, the connection point of the constant-power load and the inductor L1 is connected to the chip ground; and the diode is connected in parallel with the series-connected constant-power load and the inductor L1.

[0019] Further, the charging chip comprises a constant-current constant-voltage temperature switching operational amplifier, a driving module, a trickle current comparator, a trickle current setting module, a switching MOS driving module, a switching transistor and a charger, the input end of the constant-current constant-voltage temperature switching operational amplifier is connected to a battery voltage divider and a reference voltage, and the output end is connected to the input end of the driving module; the input end of the trickle current comparator is connected to a battery voltage and a trickle current reference voltage, the output end is connected to the input end of the trickle current setting module, the output end of the trickle current setting module is connected to the input end of the driving module, and the charger receives a constant-voltage input source and the output of the driving module to charge the lithium ion battery.

[0020] The input end of the switch MOS drive module is connected with a battery voltage divider and a switch reference voltage, the input end of the switch tube receives the output end of the switch MOS drive module, the port connected with the switch MOS drive module of the switch tube is a control end, and the port connected with the constant power input source of the switch tube is an input end of the switch tube; and the output end of the switch tube is connected with the positive end of the lithium ion battery.

[0021] The charging stage of the lithium ion battery comprises, in sequence, a first time period of trickle charging, a second time period of constant power charging, and a fourth time period of constant voltage charging.

[0022] When in the second time period of constant power charging, the switch tube receives the constant power input source for providing charging for the lithium ion battery under the driving of the switch MOS drive module.

[0023] Further, between the second time period of constant power charging and the fourth time period of constant voltage charging, the third time period of constant current charging is further included.

[0024] Further, the switch tube is a PMOS transistor or an NMOS transistor.

[0025] Further, the charging time of the second time period of constant power charging is greater than or equal to the third time period of constant current charging.

[0026] Further, the charging time of the second time period of constant power charging plus the time of the third time period of constant current charging is equal to the time of the time period of constant current charging in the prior art.

[0027] It can be seen from the above technical solution that the present application provides a constant power large current charging system which can provide faster charging and alleviate the charging anxiety problem of light-on charging. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 Fig. 1 shows a schematic diagram of a lithium ion battery charging system in the prior art

[0029] Figure 2 Fig. 2 shows a schematic diagram of another lithium ion battery charging system in the prior art

[0030] Figure 3 Fig. 3 shows a schematic diagram of still another lithium ion battery charging system in the prior art

[0031] Figure 4 Fig. 4 shows a preferable circuit schematic diagram of a constant power large current charging system in an embodiment of the present application

[0032] Figure 5 Fig. 5 shows a schematic diagram of a lithium ion battery fast charging device in an embodiment of the present application

[0033] Figure 6 The charging curve (four stages of trickle charging, constant power charging, constant current charging and constant voltage charging) in the embodiment is shown Figure 5 The schematic diagram of the constant power and large current charging system in the embodiment of the application is shown DETAILED DESCRIPTION

[0034] The specific embodiments of the application will be further described below with reference to the accompanying drawings. Figure 4 The specific embodiments of the application will be further described below with reference to the accompanying drawings.

[0035] It should be noted that the fast charging solution of the application utilizes the leakage inductance of the skeleton-wound inductor to provide a constant power and large current charging solution. The solution in combination with the chip can achieve good charging effect, that is, not only the trickle charging, constant power charging, constant current charging and constant voltage charging modes are realized, but also the large current charging and full charging requirements are considered.

[0036] The lithium ion battery charging system (chip ground is in a floating ground state) in Figure 1 and the ion battery charging system (chip ground is in a real ground state) in Figure 2 will be described below.

[0037] Embodiment 1 (chip ground is in a floating ground state)

[0038] Please refer to Figure 1 Please refer to Figure 4 As shown in Figure 1 , the system can include a charging chip, an inductor L1, a switching transistor and a diode D1, the lithium ion battery is connected between the output end of the charging chip and the chip ground; a constant power load, the inductor L1 and the switching transistor are connected in series between the alternating current power supply end and the ground end, the connection point of the constant power load and the inductor L1 is connected to the chip ground; the diode is connected in parallel with the series-connected constant power load and the inductor L1.

[0039] Please refer to Figure 4 , Figure 4 The preferred circuit schematic diagram of the constant power and large current charging system in the embodiment of the application is shown. As shown in Figure 4 , the system can further include an inductor L2, an inductor L3, a capacitor C1, a diode D2 and a diode D3; the non-name end of the inductor L2, the same name end of the inductor L3 and the non-name end of the inductor L1 are connected to the chip ground, the same name end of the inductor L2 is connected to the input end of the charging chip through the diode D2, the diode D3 is connected between the non-name end of the inductor L3 and the input end of the charging chip, and the capacitor C1 is connected between the non-name end of the inductor L2 and the input end of the charging chip; wherein when the load of the inductor L1 is constant power, the energy stored in the inductor L1 is induced to the inductor L2 and the inductor L3, so that the source of the charging chip is also constant power.

[0040] Example 2 (chip ground is the ground state)

[0041] Please refer to Figure 2 Please refer to Figure 4 As Figure 2 shown, the system can include a charging chip, an inductor L1, a switch transistor and a diode, a lithium ion battery is connected between the output end and the ground end of the charging chip; the switch transistor, the inductor L1 and the constant power load are connected in series between the AC power supply end and the ground end, the ground end of the constant power load is grounded, and the diode D1 is connected in parallel between the connection point of the constant inductor L1 and the switch transistor and the ground end.

[0042] Please refer to Figure 4 , Figure 4 As shown in the preferred circuit schematic diagram of the constant power large current charging system in the embodiment of the application. As Figure 4 shown, the system can also include an inductor L2, an inductor L3, a capacitor C1, a diode D2 and a diode D3; the non-ground end of the inductor L2 is connected to the non-ground end of the inductor L1, the ground end of the inductor L2 is connected to the input end of the charging chip through the diode D2, the diode D3 is connected between the non-ground end of the inductor L3 and the input end of the charging chip, and the capacitor C1 is connected between the non-ground end of the inductor L2 and the input end of the charging chip, wherein when the load of the inductor L1 is constant power, the energy stored in the inductor L1 is induced to the inductor L2 and the inductor L3, so that the source of the charging chip is also constant power.

[0043] The working principle of the above two embodiments is as follows:

[0044] The left inductor L1 is the inductance of the AC (AC) system, and the right inductor L2 and inductor L3 are the inductance of the auxiliary winding, and the same name end of the inductance is represented by the asterisk. The design method is to utilize the peak current constant characteristic of the AC LED system, the output voltage almost unchanged characteristic and the mutual inductance of the skeleton winding inductance to generate constant power auxiliary power, which is supplied to the energy storage device such as lithium ion battery through the charging chip.

[0045] The energy stored in the inductor L1 is induced to the inductor L2 and the inductor L3 through the coil, and since the load of the inductor L1 is constant power, L2=K2*L1 (when charging), L3=K2*L1 (when discharging), and finally through the diodes D1 and D2, it is given to the charging chip, so that the source of the charging chip is also constant power.

[0046] Please refer to Figure 5 , Figure 5The figure is a schematic diagram of the fast charging device for lithium ion battery in the embodiment of the present application. In the preferred embodiment of the present application, the fast charging of lithium ion battery can include constant current constant voltage temperature switching operational amplifier, driving module, trickle current comparator, trickle current setting module, charger, switch MOS driving module and switch tube. The charging stages of the lithium ion battery include first time period of trickle charging, second time period of constant power charging, third time period of constant current charging and fourth time period of constant voltage charging in turn.

[0047] In the first time period of trickle charging in the embodiment of the present application, the input end of the trickle current comparator is connected with the battery voltage and the trickle current reference voltage, the output end is connected with the input end of the trickle current setting module, the output end of the trickle current setting module is connected with the input end of the driving module, the charging device receives the constant power input source and the output of the driving module to charge the lithium ion battery.

[0048] The first time period of trickle charging can be completely the same as the charging mode of the time period in the prior art, and the circuit used can also follow the module in the prior art, which will not be described here.

[0049] When in the second time period of constant power charging, the switch tube receives the constant power input source to provide charging for the lithium ion battery under the driving of the switch MOS driving module. The switch tube can be PMOS transistor or NMOS transistor.

[0050] The input end of the switch MOS driving module is connected with the battery voltage and the switch reference voltage, the input end of the switch tube receives the output end of the switch MOS driving module and the input of the constant voltage input source, and the output end of the switch tube is connected with the lithium ion battery. When in the second time period of constant power charging, the switch tube receives the constant power input source to provide charging for the lithium ion battery under the driving of the switch MOS driving module.

[0051] In the third time period of constant current charging, the input end of the constant current constant voltage temperature switching operational amplifier is connected with the battery voltage and the reference voltage, and the output end is connected with the input end of the driving module; the constant current constant voltage temperature switching operational amplifier is switched to the constant current charging mode. The third time period of constant current charging can be completely the same as the charging mode of the constant current charging time period in the prior art, and the circuit used can also follow the module in the prior art, which will not be described here. In some embodiments of the present application, the third time period of constant current charging can be omitted.

[0052] In the fourth time period of constant voltage charging, the input end of the constant current constant voltage temperature switching operational amplifier is connected to the battery voltage divider and the reference voltage, and the output end is connected to the input end of the driving module; the constant current constant voltage temperature switching operational amplifier is switched to the constant voltage charging mode, and the third time period of constant voltage charging can be exactly the same as the charging mode of the constant voltage charging time period in the prior art, and the circuit used can also use the module in the prior art, which will not be repeated here.

[0053] Please refer to Figure 6 , Figure 6 Shown Figure 5 The schematic diagram of the charging curve (four stages: trickle charging, constant power charging, constant current charging and constant voltage charging) in the embodiment shown. Figure 4 As shown, the first time period of trickle charging is low current charging, and the second time period of constant power charging jumps to a high current charging I1 charging, which gradually decreases over time, usually until it drops to the current I2 of the constant current stage in the prior art; in the third time period of constant current charging, charging is performed with current I2.

[0054] Preferably, the charging time of the second constant power time period is greater than or equal to the third constant current charging time period. The charging time of the second constant power time period plus the time of the third constant current charging time period is equal to the time of the constant current charging time period in the prior art.

[0055] During the fourth time period of constant voltage charging, the charging current starts at current I2 and then gradually decreases until the lithium-ion battery is fully charged, as in the prior art.

[0056] Could you please provide me a method to calculate the power consumption?

[0057] Rdson is the on-resistance of the switch tube.

[0058] In summary, the present invention can significantly reduce charging time while maintaining low power consumption, and alleviate the anxiety of charging while the light is on. Under the test conditions of Uac = 220V, Uo = 139.9V, and Rcs = 1.9R, the power output (the load capacity of the original auxiliary winding + the newly added winding tested using an electronic load is shown in the table below):

[0059] Uo(V) Io(A) Po(W) 2.4 2.03 4.872 2.5 2.01 5.025 2.6 1.966 5.112 2.7 1.921 5.187 2.8 1.88 5.264 2.9 1.836 5.324 3 1.788 5.364 3.1 1.738 5.388 3.2 1.685 5.392 3.3 1.63 5.379 3.4 1.572 5.345 3.5 1.512 5.292 3.6 1.44 5.184 3.7 1.372 5.076 3.8 1.3 4.940 3.9 1.228 4.789 4 1.14 4.560 4.1 1.063 4.358

[0060] From the above, it can be seen that the current is about 2A and the power is about 5W, thus satisfying the demand of the constant-power large-current charging system.

[0061] The above-described is only the preferred embodiment of the present application, which is not used to limit the patent protection scope of the present application, thus any equivalent structural change made according to the content of the specification and drawings of the present application should be included in the protection scope of the present application.

Claims

1. A constant-power, high-current charging system comprising a charging chip, an inductor L1, a switching transistor, and a diode D1. A lithium-ion battery is connected between the output terminal of the charging chip and the chip ground. A constant-power load, an inductor L1, and a switching transistor are connected in series between the AC power supply terminal and the ground terminal. The connection point between the constant-power load and the inductor L1 is connected to the chip ground. A diode is connected in parallel with the series-connected constant-power load and inductor L1. The system is characterized in that: It also includes an inductor L2, an inductor L3, a capacitor C1, a diode D2, and a diode D3; the opposite-name end of the inductor L2, the same-name end of the inductor L3, and the opposite-name end of the inductor L1 are connected to the chip ground, the same-name end of the inductor L2 is connected to the input end of the charging chip through the diode D2, the diode D3 is connected between the opposite-name end of the inductor L3 and the input end of the charging chip, and the capacitor C1 is connected between the input end of the charging chip and the ground end of the charging chip; When the load of the inductor L1 is constant power, the energy stored in the inductor L1 is induced to the inductor L2 and the inductor L3, so that the source of the charging chip is also constant power; The charging chip includes a constant current, constant voltage, and temperature switching operational amplifier, a driver module, a trickle comparator, a trickle setting module, a switch MOS driver module, a switch tube, and a charger. The input terminal of the constant current, constant voltage, and temperature switching operational amplifier is connected to the battery voltage divider and the reference voltage, and the output terminal is connected to the input terminal of the driver module; the input terminal of the trickle comparator is connected to the battery voltage and the trickle reference voltage, and the output terminal is connected to the input terminal of the trickle setting module. The output terminal of the trickle setting module is connected to the input terminal of the driver module. The charger receives the constant voltage input source and the output of the driver module to charge the lithium-ion battery. The input end of the switch MOS driver module is connected to the battery voltage division and the switch reference voltage, the input end of the switch tube receives the output end of the switch MOS driver module, the port of the switch tube connected to the switch MOS driver module is the control end, and the port of the switch tube connected to the constant power input source is the input of the switch tube; the output end of the switch tube is connected to the positive terminal of the lithium-ion battery; The charging stages of the lithium-ion battery sequentially include a first time period of trickle charging, a second time period of constant power charging, and a fourth time period of constant voltage charging; During the second time period of constant power charging, the switch tube receives the constant power input source under the driving of the switch MOS driving module to charge the lithium-ion battery; Between the second time period of constant power charging and the fourth time period of constant voltage charging, a third time period of constant current charging is also included; The switch tube is a PMOS transistor or an NMOS transistor.

2. The constant power and high current charging system according to claim 1, characterized in that: The charging time of the second constant-power charging time period is greater than or equal to the third constant-current charging time period.

3. The constant power and high current charging system according to claim 1, characterized in that: The charging time of the second constant power time period plus the time of the third constant current charging time period is equal to the time of the constant current charging time period in the three-stage charging of trickle charging, constant current charging and constant voltage charging.

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