JP6976982B2 - Charging circuit and mobile terminal - Google Patents

Description

The present application relates to the field of mobile terminals, in particular to charging circuits and mobile terminals.

With the widespread use of mobile terminals, charging circuits have become a hot issue for mobile terminal operators.

FIG. 1 is a circuit diagram showing a charging circuit used in a mobile terminal in the prior art. This charging circuit is known as a BUCK circuit including a MOS transistor, a control circuit, a diode, an inductor, and a battery. During charging, the control circuit controls the MOS transistor to turn on and off to generate a changing square wave current. The square wave current flows from the MOS transistor to the inductor and then to the battery after voltage stabilization by the inductor.

The charging process described above has a list of MOS transistor destruction. When the MOS transistor is destroyed, the current flows directly to the inductor, current / voltage inspection circuit, and battery. This may cause the battery to exceed the voltage limit, leading to more serious consequences.

The causes of damage to the MOS transistor are as follows.

The MOS transistor is erroneously energized. The voltage across the MOS transistor exceeds the maximum voltage it can withstand. Electrostatic destruction or surge.

It is a poor quality MOS transistor. Or there is a problem with integrated manufacturing technology.

It can have other defects.

In order to avoid the above problems and improve the requestability of the MOS transistor, the value of the on-resistance (RDSON) of the MOS transistor is increased, thereby improving the voltage resistance of the MOS transistor. On the other hand, high resistance in turn causes the charging circuit to easily generate heat and low energy transfer efficiency.

The present invention provides a charging circuit and a mobile terminal for the purpose of improving the requestability of the charging circuit in the mobile terminal.

According to the first aspect of the present invention, a charging circuit is provided. The charging circuit arranged between the charging interface and the battery of the mobile terminal includes a first circuit, a capacitive coupling element, and a second circuit. The first circuit, the capacitive coupling element, and the second circuit are sequentially connected in series between the charging interface and the battery (battery). The capacitive coupling element disconnects the direct current (DC) current path of the charging circuit. The first circuit includes a bridge arm circuit and a control circuit that controls the bridge arm circuit. The bridge arm circuit connects to the charging interface and charges / discharges the capacitance in the capacitive coupling element under the control of the control circuit in order to convert the DC output from the charging interface and used for charging to AC. It is composed of. The second circuit is configured to adjust the AC coupled to the second circuit through the capacitive coupling element by the first circuit to a DC suitable for battery charging.

Based on the first embodiment, in one embodiment, the capacitive coupling element includes a capacitance, and the bridge arm circuit which is a half bridge circuit includes a first switch transistor and a second switch transistor. The first end of the first switch transistor is connected to the charging interface, the second end of the first switch transistor is connected to the first end of the capacitance, and the control end of the first switch transistor is connected to the control circuit. The first end of the second switch transistor is connected to the second end of the first switch transistor, the second end of the second switch transistor is grounded, and the control end of the second switch transistor is connected to the control circuit. The second end of the capacitance is grounded via the second circuit.

Based on the first embodiment or any of the above embodiments, in another embodiment, the capacitive coupling element comprises a first capacitance and a second capacitance, and the bridge arm circuit which is a full bridge circuit. , A first switch transistor, a second switch transistor, a third switch transistor, and a fourth switch transistor. Connect the first end of the first switch transistor to the charging interface, connect the second end of the first switch transistor to the first end of the first capacitance, and connect the control end of the first switch transistor to the control circuit. .. The first end of the second switch transistor is connected to the second end of the first switch transistor, the second end of the second switch transistor is grounded, and the control end of the second switch transistor is connected to the control circuit. Connect the first end of the third switch transistor to the charging interface, connect the second end of the third switch transistor to the first end of the second capacitance, and connect the control end of the third switch transistor to the control circuit. .. The first end of the fourth switch transistor is connected to the second end of the third switch transistor, the second end of the fourth switch transistor is grounded, and the control end of the fourth switch transistor is connected to the control circuit. The second end of the first capacitance is connected to the second circuit and the second end of the second capacitance is connected to the second circuit.

Based on the first embodiment or any of the above embodiments, in another embodiment, the capacitance in the capacitive coupling device is one of a capacitance composed of a printed circuit board (PCB) and a capacitance composed of a flexible printed circuit board (FPC) substrate. It can be done.

Based on the first embodiment or any of the above embodiments, in another embodiment the size, shape, or thickness of the capacitance in the capacitive coupling device is designed based on the structure of the mobile terminal.

Based on the first embodiment or any of the above embodiments, in another embodiment, the bridge arm circuit comprises one or more metal oxide semiconductor field effect transistors (MOSFETs).

Based on the first embodiment or any of the above embodiments, in another embodiment the second circuit comprises a rectifier circuit and a filter circuit.

A mobile terminal is provided based on the second aspect of the present invention. The mobile terminal includes a charging interface, a battery, and a charging circuit according to the first embodiment or any embodiment of the first embodiment. The charging circuit is located between the charging interface and the battery.

Based on the second aspect, in one embodiment, the charging interface is a USB interface.

Based on the second embodiment or any of the above embodiments, in one embodiment, the mobile terminal supports a normal charging mode and a quick charging mode, and the charging current in the quick charging mode is larger than the charging current in the normal charging mode. ..

In the above technical scheme, the DC current path of the charging circuit is separated by a capacitive coupling element. That is, the charging circuit does not have a DC current path. When the first circuit fails, the DC current from the charging interface does not output directly to the second circuit and the battery, thereby improving the reliability of the charging circuit.

In order to more clearly illustrate the technical schemes of the present invention or the prior art, brief description of the accompanying drawings as used herein is provided below. Obviously, it should be noted that the drawings shown below are only a few embodiments of the invention and one of ordinary skill in the art can obtain other drawings based on these drawings without any creative labor. Is.
It is a circuit diagram which shows the charging circuit in the prior art. It is a schematic block diagram which shows the charging circuit which concerns on embodiment of this invention. It is a circuit diagram which shows the charging circuit which concerns on embodiment of this invention. It is a circuit diagram which shows the charging circuit which concerns on embodiment of this invention. It is a schematic block diagram which shows the mobile terminal which concerns on embodiment of this invention.

The technical scheme in embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention. It will be apparent to those skilled in the art that the embodiments described below are only partial embodiments of the invention and that any other embodiment obtained without creative labor falls within the scope of the invention. Is.

FIG. 2 is a schematic configuration diagram showing a charging circuit according to an embodiment of the present invention. As shown in FIG. 2, the charging circuit 30 is arranged between the charging interface 10 and the battery 20 of the terminal. The charging circuit 30 includes a first circuit 31, a capacitive coupling element 33, and a second circuit 32. The first circuit 31, the capacitive coupling element 33, and the second circuit 32 are sequentially connected in series between the charging interface 10 and the battery 20. The capacitive coupling element 33 cuts the direct current (DC) current path of the charging circuit 30.

Specifically, the first circuit 31 includes a bridge arm circuit 312 and a control circuit 311 that controls the bridge arm circuit. The bridge arm circuit 312 connects to the charging interface 10 and reduces the capacitance in the capacitive coupling element 33 under the control of the control circuit 311 in order to convert the DC output from the charging interface 10 and used for charging into AC. It is configured to charge / discharge.

The second circuit 32 is configured to adjust the alternating current (AC) coupled to the second circuit 32 through the capacitive coupling element 33 by the first circuit 31 to a direct current suitable for battery charging.

In this technical scheme, the DC current path of the charging circuit is separated by a capacitive coupling element. That is, the charging circuit does not have a DC current path. When the first circuit fails, the DC current from the charging interface does not output directly to the second circuit and the battery, thereby improving the reliability of the charging circuit.

As shown in one embodiment, as shown in FIG. 3, the capacitive coupling element 33 includes the capacitance C1, and the bridge arm circuit, which is a half-bridge circuit, includes the first switch transistor T1 and the second switch transistor T2. ,including. The first end of the first switch transistor T1 is connected to the charging interface 10, the second end of the first switch transistor T1 is connected to the first end of the capacitance C1, and the control end of the first switch transistor T1 is a control circuit. Connect to 311. The first end of the second switch transistor T2 is connected to the second end of the first switch transistor T1, the second end of the second switch transistor T2 is grounded, and the control end of the second switch transistor T2 is connected to the control circuit 311. do. The second end of the capacitance C1 is grounded via the second circuit 32. Ground the battery 20.

In an embodiment of the present invention, a switch transistor (such as a MOS transistor) that is easily destroyed is arranged in the first circuit. If the switch transistor is destroyed, the first circuit cannot convert DC to AC via the switch transistor. This gives the DC input in the charging interface directly to subsequent components or batteries in the charging interface. However, the capacitive coupling element arranged between the first circuit and the second circuit can cut the DC current path of the charging circuit, and therefore the AC is energized when the DC is cut off. That is, even if the switch transistor in the first circuit is destroyed or failed, the DC input in the charging interface cannot flow to the second circuit, thereby improving the reliability of the charging circuit of the mobile terminal. Can be made to.

In addition, the capacitive coupling element has good isolation performance. Therefore, in order to increase the withstand voltage of the MOS transistor and then improve the reliability of the circuit as in the prior art, instead of increasing the on-resistance, in the embodiment of the present invention, the switch transistor in the first circuit is used. Low on-resistance is possible, which reduces heat generation and loss while improving the energy transfer efficiency of all charging circuits.

As in one embodiment, the capacitive coupling element 33 includes a first capacitance C1 and a second capacitance C2, and the bridge arm circuit 312, which is a full bridge circuit, has a first switch transistor T1 and a first. It includes a two-switch transistor T2, a third switch transistor T3, and a fourth switch transistor T4. The first end of the first switch transistor T1 is connected to the charging interface 10, the second end of the first switch transistor T1 is connected to the first end of the first capacitance C1, and the control end of the first switch transistor T1 is connected. Connect to the control circuit 311. The first end of the second switch transistor T2 is connected to the second end of the first switch transistor T1, the second end of the second switch transistor T2 is grounded, and the control end of the second switch transistor T2 is connected to the control circuit 311. do. The first end of the third switch transistor T3 is connected to the charging interface 10, the second end of the third switch transistor T3 is connected to the first end of the second capacitance C2, and the control end of the third switch transistor T3 is connected. Connect to the control circuit 311. The first end of the fourth switch transistor T4 is connected to the second end of the third switch transistor T3, the second end of the fourth switch transistor T4 is grounded, and the control end of the fourth switch transistor T4 is connected to the control circuit 311. do. The second end of the first capacitance C1 is connected to the second circuit 32, and the second end of the second capacitance C2 is connected to the second circuit 32.

In an embodiment of the present invention, a switch transistor (such as a MOS transistor) that is easily destroyed is arranged in the first circuit. When the switch transistor is destroyed, the first circuit cannot convert DC to AC via the switch transistor. This gives the DC input in the charging interface directly to subsequent components or batteries in the charging interface. However, the capacitive coupling element arranged between the first circuit and the second circuit can cut the DC current path of the charging circuit, and therefore the AC is energized when the DC is cut off. That is, even if the switch transistor in the first circuit is destroyed or failed, the DC input in the charging interface cannot flow to the second circuit, thereby improving the reliability of the charging circuit of the mobile terminal. Can be made to.

In addition, the capacitive coupling element has good isolation performance. Therefore, in order to increase the withstand voltage of the MOS transistor and then increase the reliability of the circuit as in the prior art, instead of increasing the on-resistance, in the embodiment of the present invention, the switch transistor in the first circuit is used. Low on-resistance is possible, which reduces heat generation and loss while improving the energy transfer efficiency of all charging circuits.

The capacitance in the capacitive coupling element 33 can be one of the capacitance composed of a printed circuit board (PCB) and the capacitance composed of a flexible printed circuit board (FPC).

Specifically, the capacity made of PCB can be the capacity made of a PCB sheet and a copper foil on the sheet. The capacity made of an FPC board can be a capacity made of an FPC designed by the FPC. The main advantage of the capacity consisting of PCBs and the capacity consisting of FPC boards is that the capacity can have any shape, any size and any thickness, depending on the shape and structure of the mobile terminal such as a smartphone. Can be designed.

As in one embodiment, the size, shape, or thickness of the capacitance in the capacitive coupling device is designed based on the structure of the mobile terminal.

As in one embodiment, the bridge arm circuit comprises one or more metal oxide semiconductor field effect transistors (MOSFETs).

As in one embodiment, the second circuit includes a rectifier circuit and a filter circuit.

FIG. 5 is a schematic configuration diagram showing a mobile terminal according to an embodiment of the present invention. As shown in FIG. 5, the mobile terminal 50 includes a charging interface 51, a battery 52, and a charging circuit 53. The charging circuit 53 can adopt any of the above-described embodiments of the charging circuit 30.

In the above technical scheme, the DC current path of the charging circuit is separated by a capacitive coupling element. That is, the charging circuit does not have a DC current path. When the first circuit fails, the DC current from the charging interface does not output directly to the second circuit and the battery, thereby improving the reliability of the charging circuit.

As in one embodiment, the charging interface 51 is a USB interface.

As in one embodiment, the mobile terminal 50 supports a normal charging mode and a quick charging mode, and the charging current in the quick charging mode is larger than the charging current in the normal charging mode.

It should be understood that the phenomenon of MOS transistor destruction is particularly significant in mobile terminals that support fast charging. Mobile terminals according to embodiments of the present invention can be a good solution to the problem of circuit unreliability caused by the destruction of MOS transistors during rapid charging.

Those skilled in the art will appreciate that the exemplary unit or exemplary algorithmic process set forth in any of the embodiments can be accomplished through electronic hardware or a combination of electronic hardware and computer software. Hardware or software should be adopted depending on the specific application and design constraints of the technical scheme. Each of the specific applications may use different methods or methods to achieve the functions set forth in the embodiments of the invention, which are within the scope of the invention.

Devices, systems, units or modules can refer to corresponding descriptions of methods according to embodiments of the invention and are not described in detail herein.

The devices, systems and methods shown in the embodiments of the present invention can be achieved in other ways. The structure of the device according to the above-described embodiment is only an example of the present invention. Since the division of a unit in a device is a kind of division according to a logical function, other divisions may actually exist. For example, multiple units or components may be combined or integrated into different systems. Alternatively, some features may be ignored, but some units need not be executed. On the other hand, the above-mentioned coupling or direct coupling or communication connection with each other can be via an interface, and the indirect coupling or communication connection of devices or units can be electrical, mechanical, or other forms.

The units described as the components of the division described above may or may not be physically separated. The component shown as a unit may be a physical unit, or the component may not be a physical unit. That is, they are in one place or distributed by multiple net units. Units of those parts or all units can be selected according to the actual need to realize the embodiments of the present invention.

In addition, various functional units can be integrated into one processing unit. Two or more units can be combined into one unit. Alternatively, each of the units is physically separated.

The work or function of the technical scheme according to the disclosed embodiments of the present invention may be achieved in the form of software functional units and for sale, or stored in computer-readable storage media when used as an independent commodity. According to this, all or a part of the technical scheme of the present invention can be realized in the form of a software product that can be stored in a storage medium. The storage medium may be configured to store a USB disk, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, a CD, and computer-readable program code or computer-readable program instructions. Including any medium. The computer-readable program code, when executed in a data processing device (which can be a personal computer, server or network device), is adapted to perform all or part of the methods described in the embodiments described above.

The above description is only a preferred embodiment of the present invention, but is not limited to the present invention. Those skilled in the art may make multiple changes and modifications for the present invention. On the premise that it does not deviate from the idea of the present invention, it should be understood that any modification, equivalent substitution, improvement, etc. made by a person skilled in the art belongs to the scope of protection of the present invention.

Claims (8)

A charging circuit located between the charging interface of a mobile terminal and the battery of the mobile terminal.
A first circuit, a capacitive coupling element, a second circuit, and a direct current (DC) current path of the charging circuit cut by the capacitive coupling element are included, and the capacitive coupling element includes a capacitance.
The first circuit, the capacitive coupling element, and the second circuit are sequentially connected in series between the charging interface and the battery.
The first circuit includes a bridge arm circuit and a control circuit for controlling the bridge arm circuit.
The bridge arm circuit is connected to the charging interface and charges the capacitance in the capacitive coupling element under the control of the control circuit in order to convert the DC output from the charging interface and used for charging into AC. / Configured to discharge ,
The second circuit is configured to adjust the alternating current (AC) coupled to the second circuit through the capacitive coupling element by the first circuit to a direct current suitable for charging the battery.
In it, the first circuit and the second circuit are grounded to the same ground, the first circuit is connected to one end of the capacity, the second circuit is connected to the other end of the capacity and the battery.
The capacitance in the capacitive coupling element can be one of a capacitance made of a printed circuit board (PCB) and a capacitance made of a flexible printed circuit board (FPC) . The bridge arm circuit connects to the charging interface, and in order to convert the DC provided from the charging interface into AC, the DC input from the charging interface under the control of the control circuit is referred to the capacity. The charging circuit according to claim 1, wherein the charging circuit is configured to charge and discharge the capacity to the ground under the control of the control circuit. The charging circuit according to claim 2, wherein the first circuit includes at least one switch transistor, and at least one of the at least one switch transistor and the second circuit are grounded to the same ground. The capacitive coupling element includes a first capacitance and a second capacitance.
The bridge arm circuit is a full bridge circuit.
The bridge arm circuit includes a first switch transistor, a second switch transistor, a third switch transistor, and a fourth switch transistor.
The first switch transistor has a first end configured to be connected to the charging interface, a second end connected to the first end of the first capacitance, and a control end connected to the control circuit. And have
The second switch transistor has a first end connected to the second end of the first switch transistor, a second end configured to be grounded, and a control end connected to the control circuit. Have and
The third switch transistor has a first end configured to be connected to the charging interface, a second end connected to the first end of the second capacitance, and a control end connected to the control circuit. And have
The fourth switch transistor has a first end connected to the second end of the third switch transistor, a second end configured to be grounded, and a control end connected to the control circuit. Have and
The first capacitance has a second end connected to the second circuit.
The charging circuit according to claim 1, wherein the second capacitance has a second end connected to the second circuit. The charging circuit according to any one of claims 1 to 4 , wherein the bridge arm circuit includes one or more metal oxide semiconductor field effect transistors (MOSFETs). The charging circuit according to any one of claims 1 to 5 , wherein the second circuit includes a rectifier circuit and a filter circuit. A mobile terminal comprising a charging interface, a battery, and the charging circuit according to any one of claims 1 to 6.
The charging circuit is a mobile terminal arranged between the charging interface and the battery. The mobile terminal supports a normal charge mode and quick charging mode, charging current in the quick charging mode mobile terminal according to the charging current is greater than, claim 7 in the normal charge mode.

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