A charging voltage compensation circuit and charger

Abstract

The embodiment of the present application discloses a charging voltage compensation circuit and a charger, which are used for charging current limiting and can improve the charging efficiency of the battery. The circuit of the present application includes: a voltage converter structure, a first circuit structure, a second circuit structure, a third circuit structure, a fourth circuit structure and a voltage data interface; the voltage converter structure includes a DC voltage converter, a first capacitor and a third capacitor; the voltage converter structure is connected to the first circuit structure and the third circuit structure respectively; the first circuit structure includes a first inductor, and the first circuit structure is connected to the positive pole of the voltage data interface; the second circuit structure includes a first resistor, and the second circuit structure is coupled with the first circuit structure and the third circuit structure; the third circuit structure includes a second resistor, and the third circuit structure is connected to the negative pole of the voltage data interface; the fourth circuit structure includes a second capacitor and a sampling resistor, and one end of the fourth circuit structure is connected to the first circuit structure, and the other end is connected to the third circuit structure.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of circuit compensation technology, and in particular to a charging voltage compensation circuit and a charger. Background Art

[0002] With the continuous development of society, lithium-ion batteries have been widely used in digital communication products such as portable computers, mobile phones, and music players. For example, with the advent of the large-scale replacement of 5G mobile phones, lithium batteries have accelerated the replacement of original lead batteries.

[0003] Compared with traditional nickel-cadmium batteries, lithium-ion batteries have the advantages of high energy, high operating voltage, long life, and no memory effect. However, the long charging time and short battery life have become one of the main bottlenecks hindering the development of lithium batteries. Summary of the invention

[0004] The embodiments of the present application provide a charging voltage compensation circuit and a charger for improving charging efficiency.

[0005] In a first aspect, the present application provides a charging voltage compensation circuit, comprising:

[0006] A voltage converter structure, a first circuit structure, a second circuit structure, a third circuit structure, a fourth circuit structure, and a voltage data interface;

[0007] The voltage converter structure includes a DC voltage converter, a first capacitor and a third capacitor, wherein the third capacitor is used for circuit filtering;

[0008] The voltage converter structure is respectively connected to one end of the first circuit structure and one end of the third circuit structure;

[0009] The first circuit structure includes a first inductor, the other end of the first circuit structure is connected to the positive electrode of the voltage data interface, and the first inductor is used for energy storage and release in the voltage conversion process;

[0010] The second circuit structure includes a first resistor, and the second circuit structure is coupled to the first circuit structure and the third circuit structure;

[0011] The third circuit structure includes a second resistor, the other end of the third circuit structure is connected to the negative electrode of the voltage data interface, and the first resistor and the second resistor are used for circuit output voltage division feedback;

[0012] The fourth circuit structure includes a second capacitor and a sampling resistor. One end of the fourth circuit structure is connected to the first circuit structure, and the other end is connected to the third circuit structure.

[0013] Optionally, the charging voltage compensation circuit further includes a sampling structure;

[0014] The sampling structure includes a sampling chip, a fourth capacitor, a fifth circuit structure and a sixth circuit;

[0015] The fifth circuit structure comprises a third resistor and a fourth resistor, one end of the fifth circuit structure is connected to the first circuit structure, and the other end is grounded, and the third resistor and the fourth resistor are used for circuit voltage division;

[0016] One end of the sixth circuit is connected to the sampling chip, and the other end is connected between the third resistor and the fourth resistor;

[0017] One end of the fourth capacitor is connected to the sixth circuit, and the other end is connected to the fifth circuit structure. The fourth capacitor is used for circuit filtering.

[0018] Optionally, one end of the first capacitor is connected to a power supply, and the other end is grounded.

[0019] Optionally, an end point is provided between the second capacitor and the sampling resistor and is grounded.

[0020] Optionally, the voltage data interface includes a low-voltage constant-voltage charging module, and the low-voltage constant-voltage charging module is used to connect to a device with an input low-voltage constant-voltage device for charging.

[0021] Optionally, the voltage data interface includes a linear charging module, and the linear charging module is used to connect to a device having a linear charging circuit device for charging.

[0022] In a second aspect, the present application provides a charger, comprising a charging voltage compensation circuit as described in any one of the first aspects.

[0023] It can be seen from the above technical solutions that the embodiments of the present application have the following advantages:

[0024] The charging voltage compensation circuit is provided with a voltage converter structure, a first circuit structure, a second circuit structure, a third circuit structure, a fourth circuit structure and a voltage data interface, wherein the third circuit structure includes a second resistor, one end of the third circuit is connected to the voltage converter, and the other end is connected to the negative pole of the voltage data interface; the fourth circuit structure includes a second capacitor and a sampling resistor, one end of the fourth circuit structure is connected to the first circuit structure, and the other end is connected to the third circuit structure. By connecting one end of the third circuit to the negative pole of the voltage data interface, and adding a sampling resistor to the fourth circuit structure, the larger the current flowing through the circuit, the smaller the output voltage, which will reduce the input and output voltage drops on the circuit, thereby improving the charging efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0026] Figure 1 This is the Buck voltage circuit structure diagram;

[0027] Figure 2 This is the Buck voltage circuit structure diagram with sampling structure;

[0028] Figure 3 A schematic diagram of the structure of an embodiment of a voltage compensation circuit for improving the charging efficiency of a lithium battery provided in the present application;

[0029] Figure 4 A schematic diagram of the structure of another embodiment of a voltage compensation circuit for improving the charging efficiency of a lithium battery provided in the present application. DETAILED DESCRIPTION

[0030] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inside", "outside", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only used to illustrate the relative positional relationships between the various components or components, and do not particularly limit the specific installation orientations of the various components or components.

[0031] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0032] In addition, the terms "installed", "set", "provided with", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements, or components. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0033] In addition, the structures, proportions, sizes, etc. drawn in the drawings in the present application are only used to match the contents disclosed in the specification for the technical personnel in this field to understand and read, and are not used to limit the restrictive conditions under which the present application can be implemented. Therefore, they have no substantive technical significance. Any structural modification, change in proportional relationship or adjustment of size should still fall within the scope of the technical content disclosed in the present application without affecting the effects and purposes that can be achieved by the present application.

[0034] As mobile phones demand simplified interfaces, charging interfaces need to take into account data transmission needs. Many manufacturers have developed their own two-in-one interfaces. While meeting data transmission needs, pins are reserved for charging lithium batteries in devices. Split chargers have emerged, and charging heads and charging cables / data cables have become independent of each other. However, long charging time and short battery life are still one of the main bottlenecks hindering the development of lithium batteries. The main charging circuits and related voltage and current sampling circuits are as follows: Figure 1 , Figure 2 As shown, Figure 1 The charging circuit in the circuit cannot achieve self-regulation. When R1 is larger, the output voltage is larger. It cannot limit the current and it is easy to affect the life of the charging equipment. Figure 2 The number of components used for voltage sampling and current sampling is large, and the sampling process is complicated.

[0035] Based on this, an embodiment of the present application provides a charging voltage compensation circuit and a charger, by connecting one end of the third line with the negative pole of the voltage data interface, and by adding a sampling resistor to the fourth circuit structure, the greater the current flowing through the circuit, the smaller the output voltage, thereby reducing the input and output voltage drops on the circuit, thereby achieving the purpose of improving the charging efficiency of the device.

[0036] The embodiment of the present application is a circuit designed based on a BUCK circuit as a carrier. Figure 3 , Figure 4 shown.

[0037] See also Figure 3The present application provides a charging voltage compensation circuit from a first aspect, and the charging voltage compensation circuit includes: a voltage converter structure, a first circuit structure, a second circuit structure, a third circuit structure, a fourth circuit structure and a voltage data interface 2; the voltage converter structure includes a DC voltage converter 1, a first capacitor C1 and a third capacitor C3, and the third capacitor C3 is used for circuit filtering; the voltage converter structure is respectively connected to one end of the first circuit structure and one end of the third circuit structure; the first circuit structure includes a first inductor L1, and the other end of the first circuit structure is connected to the positive electrode of the voltage data interface 2, and the first inductor L1 is used for energy storage and release during the voltage conversion process; the second circuit structure includes a first resistor R1, and the second circuit structure is coupled with the first circuit structure and the third circuit structure; the third circuit structure includes a second resistor R2, and the other end of the third circuit structure is connected to the negative electrode of the voltage data interface 2, and the first resistor R1 and the second resistor R2 are used for circuit output voltage division feedback; the fourth circuit structure includes a second capacitor C2 and a sampling resistor Rs, and one end of the fourth circuit structure is connected to the first circuit structure, and the other end is connected to the third circuit structure.

[0038] Specifically, the DC voltage converter 1 is a DC-DC converter, one end of the first capacitor C1 is connected to the VIN end of the DC voltage converter 1, and the other end is grounded, and the VIN end is the power supply end; one end of the first line structure is connected to the SW end of the DC voltage converter 1, and an end point is set between the first inductor L1 and the SW end; one end of the third capacitor C3 is connected to the BST end of the DC voltage converter 1, and the other end is connected to the end point between the first inductor L1 and the SW end; the FB end line of the DC voltage converter 1 extends to the end point set between the first resistor R1 and the second resistor R2. An end point is set between the second capacitor C2 and the sampling resistor Rs and is grounded.

[0039] Optionally, the voltage data interface 2 may include a low-voltage constant-voltage charging module and may also include a linear charging module, wherein the low-voltage constant-voltage charging module can be used to connect to a device with an input low-voltage constant-voltage device for charging, and the linear charging module can be connected to a device with a linear charging circuit device for charging. The specific charging voltage and charging current are not limited here.

[0040] For further information, see Figure 4, the charging voltage compensation circuit may also include a sampling structure, which can sample the current and voltage of the voltage compensation circuit. The sampling structure includes a sampling chip 3, a fourth capacitor C4, a fifth circuit structure and a sixth circuit; the fifth circuit structure includes a third resistor R3 and a fourth resistor R4, one end of the fifth circuit structure is connected to the first circuit structure, and the other end is grounded, and the third resistor R3 and the fourth resistor R4 are used for circuit voltage division; one end of the sixth circuit is connected to the V_DBT port of the sampling chip 3, and the other end is connected between the third resistor R3 and the fourth resistor R4; one end of the fourth capacitor C4 is connected to the sixth circuit, and the other end is connected to the fifth circuit structure, and the fourth capacitor C4 is used for circuit filtering. Among them, the sampling chip 3 can perform voltage sampling through the third resistor R3, the fourth resistor R4 and the fourth capacitor C4. The high end of the sampling resistor Rs is connected to the low end of the second resistor R2 of the circuit. The sampling chip 3 can be an MCU chip. By sampling the output voltage of the DC voltage converter 1 circuit, the output voltage and output current of the DC voltage converter 1 can be detected.

[0041] In the embodiment of the present application, assuming that the terminal voltage between the sampling resistor Rs and the second resistor R2 is Vrs, and the terminal voltage between the first resistor R1 and the second resistor R2 is VFB, then Figure 3 , we can know that for the output voltages V0 and Vrs, we can have the following calculation formulas (1) and (2):

[0042] VO=VFB+R1*(VFB-Vrs) / R2 Formula (1)

[0043] Vrs=Iout*Rs formula (2)

[0044] Wherein, Iout is the output current of the charging voltage compensation circuit. It can be understood that when Iout is larger, VO will be smaller.

[0045] In some specific embodiments, for example, since the first resistor R1 and the second resistor R2 are fixed values, after connecting to the charging device, when the sampling resistor Rs is 0.2 ohms and the Iout output is 1A, Vrs1=0.2V, VO1=(2VFB-0.2)V; when the Iout output increases to 1.5A, Vrs2=0.3V, VO2=(2VFB-0.3)V, VO1 is greater than VO2, the larger the Iout output, the smaller the output voltage VO, if the voltage data interface output of this charging voltage compensation circuit is connected to a linear charging circuit, then when the output current is larger, the voltage data interface of this compensation circuit, i.e., the input of the line charging circuit, is lower, and when the battery voltage connected to the line charging circuit remains unchanged, the input and output voltage drop of the linear charging circuit is reduced, the linear charging loss is reduced, and the charging efficiency is improved.

[0046] Furthermore, if the voltage data interface output of this compensation circuit is connected to a low-voltage constant-voltage charging circuit, when VO is equal to the minimum constant-voltage charging value of the charging device, that is, when it is in a constant-voltage charging state, the current of the entire charging circuit will no longer increase, thereby achieving the purpose of charging current limiting.

[0047] In the embodiment of the present application, further, by Figure 4 From the circuit diagram, we can see that when the AD sampling accuracy is ignored, the sampling chip 3 can sample the voltage of VO when it is unloaded and loaded through the circuit. Assuming the unloaded voltage is V03 and the loaded voltage is VO4, then:

[0048] When the wireless charging device is plugged in, the voltage compensation circuit is determined to be in a no-load state. At this time, Iout=0A, and the no-load output voltage V03 is as shown in calculation formula (3):

[0049] V03=VFB+R1 / R2*VFB Formula (3)

[0050] When a linear charging device is inserted, it is determined that the voltage compensation circuit is in a loaded state. At this time, Iout=IO'A, and the loaded output voltage VO4 is as shown in calculation formula (4):

[0051] VO4=VFB+R1*(VFB-I0'*Rs) / R2 formula (4)

[0052] The first resistor R1, the second resistor R2, and the sampling resistor Rs are fixed values, and the corresponding output current I0' can be obtained according to the sampling values ​​of the no-load voltage V03 and the loaded voltage VO4.

[0053] An embodiment of the present application also provides a charger, which is provided with the voltage compensation circuit provided by the embodiment of the present application, and can support charging of devices that charge low-voltage constant-voltage devices, such as mobile phones, etc.; it can also support charging of devices that charge linear charging circuit devices, such as electronic toys, etc.

[0054] Optionally, the voltage compensation circuit provided in the embodiment of the present application can also be applied to all circuit topologies with FB (Vref) feedback, such as Boost, Buck-boost, Flayback and other topologies.

Claims

1. A charging voltage compensation circuit, characterized in that: The charging voltage compensation circuit comprises: A voltage converter structure, a first circuit structure, a second circuit structure, a third circuit structure, a fourth circuit structure, and a voltage data interface; The voltage converter structure includes a DC voltage converter, a first capacitor and a third capacitor, wherein the third capacitor is used for circuit filtering; The voltage converter structure is respectively connected to one end of the first circuit structure and one end of the third circuit structure; The first circuit structure includes a first inductor, the other end of the first circuit structure is connected to the positive electrode of the voltage data interface, and the first inductor is used for energy storage and release in the voltage conversion process; The second circuit structure includes a first resistor, and the second circuit structure is coupled to the first circuit structure and the third circuit structure; The third circuit structure includes a second resistor, the other end of the third circuit structure is connected to the negative electrode of the voltage data interface, and the first resistor and the second resistor are used for circuit output voltage division feedback; The fourth circuit structure comprises a second capacitor and a sampling resistor, one end of the fourth circuit structure is connected to the first circuit structure, and the other end is connected to the third circuit structure; One end of the second capacitor is connected to one end between the first line structure and the voltage data interface, the other end of the second capacitor is connected to one end of the sampling resistor, the other end of the sampling resistor is connected to the other end of the voltage data interface, and an end point is set between the second capacitor and the sampling resistor to be grounded.

2. The charging voltage compensation circuit according to claim 1, characterized in that: The charging voltage compensation circuit also includes a sampling structure; The sampling structure includes a sampling chip, a fourth capacitor, a fifth circuit structure and a sixth circuit; The fifth circuit structure comprises a third resistor and a fourth resistor, one end of the fifth circuit structure is connected to the first circuit structure, and the other end is grounded, and the third resistor and the fourth resistor are used for circuit voltage division; One end of the sixth circuit is connected to the sampling chip, and the other end is connected between the third resistor and the fourth resistor; One end of the fourth capacitor is connected to the sixth circuit, and the other end is connected to the fifth circuit structure. The fourth capacitor is used for circuit filtering.

3. The charging voltage compensation circuit according to claim 2, characterized in that: One end of the first capacitor is connected to the power supply, and the other end is grounded.

4. The charging voltage compensation circuit according to claim 3, characterized in that: An end point is provided between the second capacitor and the sampling resistor and is grounded.

5. The charging voltage compensation circuit according to any one of claims 1 to 4, characterized in that: The voltage data interface includes a low-voltage constant-voltage charging module, and the low-voltage constant-voltage charging module is used to connect with a device with an input low-voltage constant-voltage device for charging.

6. The charging voltage compensation circuit according to any one of claims 1 to 4, characterized in that: The voltage data interface includes a linear charging module, and the linear charging module is used to connect with a device having a linear charging circuit device for charging.

7. A charger, characterized in that: The charger comprises the charging voltage compensation circuit as claimed in any one of claims 1 to 6.

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