Charging circuit and mobile terminal

It is provided a charging circuit and a mobile terminal. The charging circuit is configured to electrically couple a charging interface and a battery of a terminal, and includes a first circuit, a magnetic coupling element, and a second circuit connected in series.

TECHNICAL FIELD

The present disclosure relates to mobile terminal field, and particularly to a charging circuit and a mobile terminal.

BACKGROUND

With the growing popularity of mobile terminal use, terminal charging has become a focused issue of mobile terminal providers.

SUMMARY

Disclosed herein are implementations of a charging circuit, configured to electrically couple a charging interface and a battery, comprising a first circuit, a magnetic coupling element, and a second circuit connected in series, wherein the first circuit is configured to receive a first current from the charging interface and convert the first current to a second current with at least one of a changed magnitude and a changed direction, the magnetic coupling element comprises a first coil and a second coil, the first coil connecting with the first circuit, the second coil connecting with the second circuit, the first coil and the second coil separated from each other to disconnect a direct-current (DC) path of the charging circuit, the magnetic coupling element is configured to transfer energy from the first coil to the second coil in an electromagnetic induction manner by utilizing the second current with the at least one of the changed magnitude and the changed direction to generate a third current, and the second circuit is configured to adjust the third current to a fourth current suitable for battery charging to charge the battery.

Disclosed herein are also implementations of a mobile terminal, comprising a charging interface, a battery, and a charging circuit arranged between the charging interface and the battery, wherein the charging circuit comprises a first circuit, a magnetic coupling element, and a second circuit connected in series successively between the charging interface and the battery, the first circuit is configured to receive a first current from the charging interface and convert the first current to a second current with at least one of a changed magnitude and a changed direction, the magnetic coupling element comprises a first coil and a second coil, the first coil connecting with the first circuit, the second coil connecting with the second circuit, the first coil and the second coil separated from each other to disconnect a direct-current (DC) path of the charging circuit, the magnetic coupling element is configured to transfer energy from the first coil to the second coil in an electromagnetic induction manner by utilizing the second current with the at least one of the changed magnitude and the changed direction to generate a third current, and the second circuit is configured to adjust the third current to a fourth current suitable for battery charging to charge the battery.

Disclosed herein are also implementations of a charging circuit, comprising a first circuit, a magnetic coupling element, and a second circuit connected in series, the magnetic coupling element comprising a first coil and a second coil, the first coil connecting with the first circuit, the second coil connecting with the second circuit, the first coil and the second coil being separated from each other to disconnect a direct-current (DC) path of the charging circuit.

DETAILED DESCRIPTION

FIG. 1is a circuit diagram illustrating a charging circuit used in a mobile terminal. This charging circuit is known as BUCK circuit, which includes a MOS transistor, a control circuit, a diode, an inductor, and a battery. Upon charging, the control circuit controls the MOS transistor to turn-on/turn-off to generate a changing square wave current. The square wave current flows to the inductor from the MOS transistor, and then flows to the battery after voltage stabilization conducted by the inductor.

The above mentioned charging process has a risk of MOS transistor breakdown. Upon MOS transistor breakdown, the current will flow through the inductor, a current/voltage detecting circuit, and the battery directly; this will cause the battery to exceed a limit voltage and may even lead to more serious consequences.

The cause of the damage to the MOS transistor can be as follows.

The MOS transistor is mis-energized; the voltage at both ends of the MOS transistor exceeds a maximum voltage that can be withstood; electrostatic breakdown or surge.

The MOS transistor is of poor quality; or, there is an integrated manufacture technology issue.

There can be other defects.

In order to avoid the above problems and improve the reliability of the MOS transistor, the value of on-resistance (RDSON) of the MOS transistor has been increased so as to improve the voltage resistance of the MOS transistor. On the other hand, high resistance, in turn, would cause the charging circuit to be easy to heat, low energy transmission efficiency and so on.

Technical solutions of the implementations of the present disclosure will be described clearly and completely taken in conjunction with the accompanying drawings; it will be apparent to one of ordinary skill in the art that, the implementations described below are merely a part of the disclosure and other implementations obtained out of them without creative work will fall into the protection range of the present disclosure either.

According to implementation 1 of the present disclosure, it provides a charging circuit. In the following, the components of the charging circuit will be described in detail. A person skilled in the art will be able to arrange or assemble the charging circuit in accordance teaching of the description by using routine methods of experimentation or analysis without undue efforts. Any method used to assemble the charging circuit of the present disclosure will fall into the protection scope defined by the appending claims.

FIG. 2is block schematic diagram illustrating the charging circuit. As shown inFIG. 2, a charging circuit30is arranged between a charging interface10and a battery20of a terminal for electrically coupling the charging interface10and the battery20. The charging circuit30includes a first circuit31, a magnetic coupling element33, and a second circuit32connected in series successively between the charging interface10and the battery20. The magnetic coupling element33includes a first coil331and a second coil332. The first coil331connects with the first circuit31, and the second coil332connects with the second circuit32, the first coil331and the second coil332separated apart from each other so as to disconnect a direct-current (DC) path of the charging circuit30.

Configurations and operations of the components of the charging circuit will be described in detail below.

The first circuit31is configured to receive a first current from the charging interface10and convert the first current to a second current with changed magnitude and/or direction.

The magnetic coupling element33is configured to transfer energy from the first coil331to the second coil332in an electromagnetic induction manner by utilizing the second current with changed magnitude and/or direction, so as to generate a third current (in other words, the third current is generated at the second coil332and is output to the second circuit32).

The second circuit32is configured to adjust alternating current (AC), which is coupled to the second circuit32by the first circuit31through the magnetic coupling element33, to DC which is suitable for battery charging.

In this technical scheme, a DC path of the charging circuit is separated by the magnetic coupling element. That is to say, there is no DC path in the charging circuit. DC current from the charging interface would not be output directly to the second circuit and the battery upon failure of the first circuit, whereby reliability of the charging circuit is improved.

FIG. 3is a circuit diagram illustrating a charging circuit according to Example 1. As shown inFIG. 3, the first circuit31includes a half-bridge circuit312and a control circuit311controlling the half-bridge circuit. With the aid of the half-bridge circuit312, efficiency of the whole circuit can be improved.

The half-bridge circuit312includes a first switch transistor T1and a second switch transistor T2. A first end of the first switch transistor T1connects with the charging interface10, a second end of the first switch transistor T1connects with a first end of the first coil331, and a control end of the first switch transistor T1connects with the control circuit311. A first end of the second switch transistor T2connects with the second end of the first switch transistor T1, a second end of the second switch transistor T2connects to ground, and a control end of the second switch transistor T2connects to the control circuit311. A second end of the first coil331connects to ground. Furthermore, two ends of the second coil332can connect with the second circuit32and ground respectively. Besides, the second circuit32can be grounded.

Typically, a switch transistor (such as a MOS transistor), which is easy breakdown, is arranged within the first circuit. When breakdown of the switch transistor occurs, the first circuit could not convert DC to AC via the switch transistor; this cause DC input at the charging interface being applied to a subsequent component of the charging interface or a battery directly. However, in this example, with the aid of the magnetic coupling element arranged between the first circuit and the second circuit, a DC path of the charging circuit can be disconnected. That is to say, DC input at the charging interface cannot flow to the second circuit or the battery even if the switch transistor in the first circuit is broke down or failure, whereby the reliability of the charging circuit of the mobile terminal can be improved.

In addition, the magnetic coupling element has good isolation performance. Thus, instead of increasing the on-resistance so as to increase the voltage resistance of the MOS transistor and then improve the reliability of the circuit like in the prior art, in implementations of the present disclosure, a lower on-resistance of the switch transistor in the first circuit is allowed, and this will improve the energy transfer efficiency of the whole charging circuit while reducing heating and loss.

FIG. 4is a circuit diagram illustrating a charging circuit according to Example 2. As shown inFIG. 4, the first circuit31includes a full-bridge circuit313and a control circuit311controlling the full-bridge circuit. A difference between example 1 and example 2 is that, in example 2, the full-bridge circuit313is used to replace the half-bridge circuit312in example 1. With the aid of the full-bridge circuit313, efficiency of the whole circuit can be further improved.

The full-bridge circuit313includes a first switch transistor T1, a second switch transistor T2, a third switch transistor T3, and a fourth switch transistor T4. A first end of the first switch transistor T1connects with the charging interface10, a second end of the first switch transistor T1connects with a second end of the first coil331, and a control end of the first switch transistor T1connects with the control circuit311. A first end of the second switch transistor T2connects with the second end of the first switch transistor T1, a second end of the second switch transistor T2connects to ground, and a control end of the second switch transistor T2connects with the control circuit311. A first end of the third switch transistor T3connects with the charging interface10, a second end of the third switch transistor T3connects with the first end of the first coil331, and a control end of the third switch transistor T3connects with the control circuit311. A first end of the fourth switch transistor T4connects with the second end of the third switch transistor T3, a second end of the fourth switch transistor T4connects to ground, and a control end of the fourth switch transistor T4connects with the control circuit311. In addition, two ends of the second coil332can connect with the second circuit32, and the second circuit can be grounded.

A switch transistor (such as a MOS transistor), which is easy breakdown, is arranged within the first circuit. When breakdown of the switch transistor occurs, the first circuit could not convert DC to AC via the switch transistor; this cause DC input at the charging interface being applied to a subsequent component of the charging interface or a battery directly. However, in this example, with the aid of the magnetic coupling element arranged between the first circuit and the second circuit, a DC path of the charging circuit can be disconnected. That is to say, DC input at the charging interface cannot flow to the second circuit or the battery even if the switch transistor in the first circuit is broke down or failure, whereby the reliability of the charging circuit of the mobile terminal can be improved.

In addition, the magnetic coupling element has good isolation performance. Thus, instead of increasing the on-resistance so as to increase the voltage resistance of the MOS transistor and then improve the reliability of the circuit like in the prior art, in implementations of the present disclosure, a lower on-resistance of the switch transistor in the first circuit is allowed, and this will improve the energy transfer efficiency of the whole charging circuit while reducing heating and loss.

FIG. 5is a circuit diagram illustrating a charging circuit according to Example 3. As shown inFIG. 5, the first circuit31includes a switch transistor317and a control circuit311controlling the switch transistor. A difference between example 3 and example 1-2 is that, in example 3, a switch transistor is used to replace the half-bridge circuit/full bridge circuit, whereby the cost of the circuit can be reduced.

A first end of the switch transistor317connects with the charging interface10, a second end of the switch transistor317connects with a first end of the first coil331, and a control end of the switch transistor317connects with the control circuit311. A second end of the first coil331connects to ground.

In short, as can be seen from the above description, technical schemes of the implementations of the present disclosure can improve the reliability of the charging circuit through a minor modification to the related art.

The switch transistor in the first circuit referred to herein includes multiple metal oxide semiconductor field effect transistors (MOSFET).

As an implementation, the second circuit32referred to herein can include a rectifier circuit321and a filter circuit322.

According to Implementation 2 of the present disclosure, it is provided a mobile terminal.FIG. 6is a block schematic diagram illustrating the mobile terminal. As shown inFIG. 6, a mobile terminal60includes a charging interface61, a battery62, and a charging circuit63. The charging circuit63can adopt any of the implementations of the charging circuit30described above.

For details of the charging circuit63, please refer to the charging circuit30described above with refer toFIG. 2-FIG. 5, and it will not be described here again in order to avoid redundancy.

In the technical scheme described above, a DC path of the charging circuit is separated by the magnetic coupling element. That is to say, there is no DC path in the charging circuit. DC current from the charging interface would not be output directly to the second circuit and the battery upon failure of the first circuit, whereby reliability of the charging circuit is improved.

As an implementation, the charging interface51is a USB interface or any other interface corresponds to related industry standards of terminal charging interface.

As an implementation, the battery20is lithium battery.

As an implementation, the mobile terminal50supports a normal charging mode and a fast charging mode, wherein charging current is larger in the fast charging mode than in the normal charging mode.

It should be understood that the phenomenon of MOS transistor breakdown is particularly serious in the mobile terminal which supports fast charging. As to the problem of circuit unreliability upon fast charging caused by MOS transistor breakdown, the mobile terminal according to the implementation of the present disclosure can be a good solution.

A person skilled in the art will understand, exemplary units or algorithm steps described in any of the implementations can be achieved via electronic hardware or a combination of electronic hardware and computer software. Whether hardware or software should be adopted depends on design constraints and specific applications of the technical schemes. Respective specific application can use different methods or manners to achieve the function described in the implementations, which will fall into the protection scope of the present disclosure.

Specific operations of the device, system, and the unit or module can cross-refer to corresponding descriptions according to the implementation, and will not go into much detail here.

In the implementations of the present disclosure, the device and system described herein can be achieved in other manners. The configuration of the device according to the implementation described above is only exemplary; the division of units in the device is a kind of division according to logical function, therefore there can be other divisions in practice. For example, multiple units or components can be combined or integrated into another system; or, some features can be ignored while some units need not to be executed. On the other hand, various function units can be integrated into one processing unit; two or more than two units can be integrated into one unit; or, each unit is physically separate.

Furthermore, various function units can be integrated into one processing unit; two or more than two units can be integrated into one unit; or, each unit is physically separate.

Operations or functions of technical schemes according to the implementations of the present disclosure, when achieved in the form of software functional units and sold or used as an independent product, can be stored in a computer readable storage medium. According to this, all or a part of the technical schemes of the present disclosure can be realized in the form of software products which can be stored in a storage medium. The storage medium includes USB disk, Read Only Memory (ROM), Random Access Memory (RAM), magnetic disk, CD, and any other medium that can be configured to store computer-readable program code or instructions. The computer-readable program code, when executed on a data-processing apparatus (can be personal computer, server, or network equipment), adapted to perform all or a part of the methods described in the above-mentioned implementations.

The foregoing descriptions are merely preferred implementations of the present disclosure, rather than limiting the present disclosure. Various modifications and alterations may be made to the present disclosure for those skilled in the art. Any modification, equivalent substitution, improvement or the like made within the spirit and principle of the present disclosure shall fall into the protection scope of the present disclosure.