CN112119560A

CN112119560A - Backlight control circuit and method and terminal equipment

Info

Publication number: CN112119560A
Application number: CN201880093519.5A
Authority: CN
Inventors: 姜武爽; 杨永祥; 罗艳彪
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2018-06-04
Filing date: 2018-06-04
Publication date: 2020-12-22
Also published as: WO2019232669A1

Abstract

The application provides a backlight control circuit, a method and a terminal device, comprising: the charging circuit, the first switch circuit, the first adjusting circuit and the processor; the charging circuit is used for receiving a first voltage input by a power supply and inputting a second voltage obtained by conversion processing to the battery; the charging circuit is also used for inputting a preset voltage to the first switching circuit through a preset end, and the preset voltage is a voltage which is not adjusted by the second adjusting circuit of the charging circuit; the processor is used for controlling the first switch circuit to be conducted when the input end of the charging circuit is detected to have voltage; the first adjusting circuit is used for adjusting the preset voltage according to the voltage of the backlight module when the first switch circuit is switched on, and inputting the conditioned third voltage into the backlight module so as to control the display brightness of the backlight module through the third voltage, thereby improving the conversion efficiency of the mobile phone backlight power supply.

Description

Backlight control circuit and method and terminal equipment

Technical Field

The application relates to the technical field of terminal equipment, in particular to a backlight control circuit and method and terminal equipment.

Background

With the continuous development of mobile terminals such as smart phones and tablet computers, in the process of charging the mobile terminal, a user may use the mobile terminal to process other services. Taking a mobile terminal as an example of a mobile phone, when the mobile phone is charged and plays a video, the power consumption of a display screen of the mobile phone accounts for more than 60% of the total power consumption of a mobile phone system, and 90% of the power consumption of the display screen is mainly used for backlight display, so that the mobile phone is charged slowly. By way of example, the Display screen may be a Liquid Crystal Display (LCD), or an Organic Light-Emitting Diode (OLED) Display screen, or other types of Display screens.

In order to improve the charging efficiency of the mobile phone, in the prior art, the conversion efficiency of the backlight power supply is generally improved, so as to achieve the purpose of improving the charging efficiency of the mobile phone. When the conversion efficiency of the backlight power supply is improved, a high-efficiency backlight Integrated Circuit (IC) is replaced, but the price of the high-efficiency backlight IC is high, which increases the cost of the mobile phone, thereby resulting in high cost of the mobile phone.

Therefore, in the process of charging and using the mobile phone, a problem to be solved by those skilled in the art is how to improve the conversion efficiency of the backlight power supply of the mobile phone.

Disclosure of Invention

The application provides a backlight control circuit, a backlight control method and terminal equipment, which are used for improving the conversion efficiency of a backlight power supply of the terminal equipment.

In a first aspect, an embodiment of the present application provides a backlight control circuit, which may include:

the charging circuit, the first switch circuit, the first adjusting circuit and the processor; wherein the charging circuit comprises a second regulating circuit;

the input end of the charging circuit is connected with the output end of the power supply, the input/output end of the charging circuit is connected with the battery, the preset end of the charging circuit is connected with the first end of the first switching circuit, the second end of the first switching circuit is connected with the processor, the third end of the first switching circuit is connected with the input end of the first adjusting circuit, and the output end of the first adjusting circuit is connected with the backlight module of the terminal equipment;

the charging circuit is used for receiving a first voltage input by a power supply and inputting a second voltage obtained by conversion processing to the battery;

the charging circuit is also used for inputting a preset voltage to the first switching circuit through a preset end, and the preset voltage is a voltage which is not adjusted by the second adjusting circuit of the charging circuit;

the processor is used for controlling the first switch circuit to be conducted when the input end of the charging circuit is detected to have voltage;

the first adjusting circuit is used for adjusting the preset voltage according to the voltage of the backlight module when the first switch circuit is conducted, and inputting the conditioned third voltage to the backlight module so as to control the display brightness of the backlight module through the third voltage.

Therefore, in the backlight control circuit provided in the embodiment of the present application, when the power supply supplies voltage to the charging circuit, the first voltage at the input terminal of the charging circuit is first limited by the first current limiting circuit, and a part of the limited voltage is input to the battery through the second MOS transistor to charge the battery, and in addition, another part of the limited voltage is input to the first switching circuit through the first output terminal between the first MOS transistor and the second adjusting circuit after passing through the first MOS transistor, and the processor controls the first switching circuit to be turned on when detecting that the input terminal of the charging circuit has voltage, so that the first adjusting circuit adjusts the preset voltage according to the voltage of the backlight module when the first switching circuit is turned on, and inputs the conditioned third voltage to the backlight module to control the display brightness of the backlight module through the third voltage, therefore, the required voltage is provided for the backlight module, and when the terminal equipment is charged and used, the first voltage is only subjected to primary power conversion of the first adjusting circuit in the process from the first voltage output by the power supply to the required third voltage provided for the backlight module, so that the conversion efficiency of the backlight power supply of the mobile phone is improved.

In a possible implementation manner, the charging circuit further includes a first current limiting circuit, a first MOS transistor, a control sub-circuit, and a second MOS transistor;

the input end of the first current limiting circuit is connected with the output end of the power supply, the output end of the first current limiting circuit is connected with the first end of the first MOS tube and the first end of the control sub-circuit respectively, the second end of the MOS tube is connected with the first end of the second adjusting circuit, the second end of the second adjusting circuit is connected with the second end of the control sub-module and the first end of the second MOS tube respectively, and the second end of the second MOS tube is connected with the battery.

In a possible implementation manner, the preset end is a first output end of the charging circuit, and the second end of the MOS transistor and the first end of the second adjusting circuit are respectively connected to the first switch circuit through the first output end.

In one possible implementation, the preset terminal is an input terminal of the charging circuit.

In one possible implementation, the backlight control circuit may further include a second current limiting circuit;

the input end of the second current limiting circuit is connected with the input end of the charging circuit, and the output end of the second current limiting circuit is connected with the first end of the first switching circuit;

the second current limiting circuit is used for receiving a first voltage input by the power supply and performing current limiting processing on the first voltage to obtain a preset voltage, so that the charger is prevented from being burnt out due to overlarge current, and current limiting control on the preset voltage is realized.

In one possible implementation manner, the first switch circuit is a switch circuit with a current-limiting control function;

the first switch circuit is also used for detecting a preset voltage of the first end of the first switch circuit, and if the preset voltage of the first end of the first switch circuit is smaller than a preset threshold value, a closing request signal is sent to the processor;

the processor is further configured to control the first switch circuit to conduct according to the close request signal.

In a possible implementation manner, the first switch circuit is further configured to send an interrupt request signal to the processor if a preset voltage at the first end of the first switch circuit is greater than a preset threshold;

the processor is also used for controlling the first switch circuit to be disconnected according to the interrupt request signal until the interrupt request signal is not received by the processor.

the processor is also used for controlling and reducing the brightness of the backlight module according to the interrupt request signal until the processor does not receive the interrupt request signal.

In a possible implementation manner, the backlight control circuit may further include a second switch circuit and a switch control circuit;

the first end of the second switching circuit is connected with the second output end of the charging circuit, the second end of the second switching circuit is connected with the processor, and the third end of the second switching circuit is connected with the input end of the first adjusting circuit; the input end of the switch control circuit is connected with the processor, and the output end of the switch control circuit is connected with the third end of the first switch circuit;

the processor is further used for controlling the second switch circuit to be switched on when detecting that the input end of the charging circuit has no voltage and the charging circuit has voltage, and controlling the first switch circuit to be switched off through the switch control circuit, so that the occurrence of error switching can be avoided, and the effect that the input end of the terminal equipment is not connected with the power supply is realized.

In one possible implementation, the switch control circuit may include a first resistor, a second resistor, and a diode;

one end of the first resistor is connected with the output end of the diode, one end of the second resistor is connected with the input end of the diode, the other end of the second resistor is connected with the processor, and the input end of the diode is further connected with the third end of the first switch circuit.

In one possible implementation manner, the second current limiting circuit may include an overcurrent detection circuit, an over-temperature detection circuit, an and gate, and an abnormal state output circuit;

the first end of the over-current detection circuit and the first end of the over-temperature detection circuit are connected with the input end of the charging circuit, the second end of the over-current detection circuit is connected with the first end of the AND gate, the second end of the over-temperature detection circuit is connected with the second end of the AND gate, the third end of the AND gate is connected with the first end of the abnormal state output circuit, and the second end of the abnormal state output circuit is connected with the first end of the first switch circuit.

In one possible implementation, when the second adjusting circuit is a voltage-reducing circuit, the first adjusting circuit is a voltage-boosting circuit; or, when the second conditioning phone is a voltage boosting circuit, the first adjusting circuit is a voltage reducing circuit.

In one possible implementation, the first output terminal is any one of a power intermediate point PMID, an intermediate point MID, a USB intermediate point USB _ MID, a charging power intermediate point CHG _ VMID, and a power intermediate point VMID.

In one possible implementation, the second switching circuit is a switching circuit with a current limiting control function.

In one possible implementation, the first switch circuit is any one of a MOS transistor, a triode, a transistor, and a load switch.

In a second aspect, an embodiment of the present application further provides a backlight control method, which is applied to a backlight control circuit, where the backlight control circuit includes a charging circuit, a first switch circuit, a first adjusting circuit, and a processor, where the charging circuit includes a second adjusting circuit, and the backlight control method may include:

the charging circuit receives a first voltage input by a power supply and inputs a second voltage obtained by conversion processing to the battery;

the charging circuit inputs a preset voltage to the first switching circuit through a preset end of the charging circuit, and the preset voltage is a voltage which is not adjusted by a second adjusting circuit of the charging circuit;

when the processor detects that the input end of the charging circuit has voltage, the processor controls the first switch circuit to be conducted;

when the first switching circuit is switched on, the first adjusting circuit adjusts the preset voltage according to the voltage of the backlight module, and inputs the conditioned third voltage to the backlight module so as to control the display brightness of the backlight module through the third voltage.

In a possible implementation manner, the presetting terminal is a first output terminal of the charging circuit, the charging circuit includes a first current limiting circuit, and the charging circuit inputs a preset voltage to the first switch circuit through the presetting terminal of the charging circuit, which may include:

the first current limiting circuit carries out current limiting processing on the first preset voltage to obtain the preset voltage, and the preset voltage is input to the first switch circuit through the first output end.

In a possible implementation manner, the presetting terminal is an input terminal of the charging circuit, and the charging circuit inputs the preset voltage to the first switch circuit through the presetting terminal of the charging circuit, which may include:

the charging circuit inputs a preset voltage to the first switch circuit through the input end of the charging circuit.

In a possible implementation manner, the backlight control circuit includes a second current limiting circuit, and the first adjusting circuit adjusts the preset voltage according to the voltage of the backlight module when the first switch circuit is turned on, and before inputting the conditioned third voltage to the backlight module, may further include:

the second current limiting circuit receives a first voltage input by a power supply; and carrying out current limiting processing on the first voltage to obtain a preset voltage.

In a possible implementation manner, the first switch circuit is a switch circuit with a current-limiting control function, and the first adjusting circuit adjusts the preset voltage according to the voltage of the backlight module when the first switch circuit is turned on, and before inputting the conditioned third voltage to the backlight module, may further include:

the first switch circuit detects a preset voltage of a first end of the first switch circuit, and sends a closing request signal to the processor if the preset voltage of the first end of the first switch circuit is smaller than a preset threshold value;

the processor also controls the first switch circuit to be conducted according to the closing request signal so as to input a preset voltage to the first adjusting circuit.

In one possible implementation manner, the backlight control method may further include:

if the preset voltage of the first end of the first switch circuit is greater than the preset threshold value, the first switch circuit sends an interrupt request signal to the processor;

the processor controls the first switch circuit to be switched off according to the interrupt request signal until the processor does not receive the interrupt request signal.

if the preset voltage of the first end of the first switch circuit is greater than the preset threshold value, sending an interrupt request signal to the processor;

In one possible implementation, the backlight control circuit further includes a second switch circuit and a switch control circuit, and the method may further include:

when the processor detects that the input end of the charging circuit has no voltage and the charging circuit has voltage, the second switch circuit is controlled to be switched on, and the first switch circuit is controlled to be switched off through the switch control circuit.

In a possible implementation manner, the switching control circuit includes a first resistor, a second resistor, and a diode, and the controlling the first switching circuit to be turned off by the switching control circuit may include:

the processor controls the first switch circuit to be switched off through the first resistor, the second resistor and the diode;

one end of the first resistor is connected with the output end of the diode, one end of the second resistor is connected with the input end of the diode, the other end of the second resistor is connected with the processor, and the input end of the diode is further connected with the first switch circuit.

In a third aspect, an embodiment of the present application further provides a terminal device, where the terminal device may include a battery, a backlight control circuit, and a backlight module;

the backlight control circuit is the backlight control circuit shown in any embodiment of the first aspect.

The backlight control circuit, the backlight control method and the terminal device provided by the embodiment of the application comprise a charging circuit, a first switch circuit, a first adjusting circuit and a processor; wherein the charging circuit comprises a second regulating circuit; the input end of the charging circuit is connected with the output end of the power supply, and the input/output end of the charging circuit is connected with the battery, so that when the power supply provides a first voltage for the charging circuit of the mobile phone, the charging circuit converts the first voltage input by the power supply to obtain a second voltage, and inputs the second voltage to the battery to finish charging the battery; in addition, when the required voltage is provided for the backlight module to control the display brightness of the backlight module, the preset end of the charging circuit is connected with the first end of the first switching circuit, the second end of the first switching circuit is connected with the processor, the third end of the first switching circuit is connected with the input end of the first adjusting circuit, and the output end of the first adjusting circuit is connected with the backlight module of the terminal device; the charging circuit is used for receiving a first voltage input by a power supply and inputting a second voltage obtained by conversion processing to the battery; the charging circuit is also used for inputting a preset voltage to the first switching circuit through a preset end, and the preset voltage is a voltage which is not adjusted by the second adjusting circuit of the charging circuit; the processor is used for controlling the first switch circuit to be conducted when the input end of the charging circuit is detected to have voltage; the first adjusting circuit is used for adjusting preset voltage according to the voltage of the backlight module when the first switch circuit is conducted, and inputting the conditioned third voltage to the backlight module to control the display brightness of the backlight module through the third voltage so as to provide required voltage for the backlight module.

Drawings

Fig. 1 is a schematic structural diagram of a backlight control circuit according to an embodiment of the present disclosure;

fig. 2 is a schematic structural diagram of another backlight control circuit according to an embodiment of the present disclosure;

fig. 3 is a schematic structural diagram of another backlight control circuit according to an embodiment of the present disclosure;

fig. 4 is a schematic structural diagram of another backlight control circuit provided in the embodiment of the present application;

fig. 5 is a schematic structural diagram of a backlight control circuit according to an embodiment of the present disclosure;

fig. 6 is a schematic structural diagram of another backlight control circuit according to an embodiment of the present disclosure;

fig. 7 is a schematic structural diagram of another backlight control circuit according to an embodiment of the present disclosure;

fig. 8 is a schematic structural diagram of another backlight control circuit according to an embodiment of the present disclosure;

fig. 9 is a schematic structural diagram of another backlight control circuit according to an embodiment of the present disclosure;

fig. 10 is a flowchart illustrating a backlight control method according to an embodiment of the present disclosure;

fig. 11 is a schematic structural diagram of a terminal device according to an embodiment of the present application.

Detailed Description

The embodiment of the application can be applied to a scene that the terminal equipment is charged and used, when the power supply provides voltage to the charging IC of the terminal equipment through a Universal Serial Bus (USB) interface, the voltage can be 5V, 9V, 12V, 20V and the like, when the charging IC of the terminal equipment receives the voltage provided through the USB interface, the battery of the terminal equipment can be charged through the input/output interface of the charging IC, and when a user uses the terminal equipment, the voltage is provided for the backlight module through the output end of the charging IC, so that the display brightness of the backlight module is controlled, and the display brightness of the backlight module is provided for the user.

Wherein, terminal equipment can be for having the function of charging, and have the equipment of screen display function, for example cell-phone, panel computer, notebook computer, palm computer, wearable equipment, vehicle mounted terminal, Virtual Reality (VR) equipment etc.. Wherein, wearable equipment for example includes: intelligent wrist-watch, intelligent bracelet. For example, taking a mobile phone as an example, in the process of using the mobile phone while charging, the conversion efficiency of the backlight power supply is usually improved, so as to achieve the purpose of improving the charging efficiency of the mobile phone. When the conversion efficiency of the backlight power supply is improved, the high-efficiency backlight IC is replaced, but the price of the high-efficiency backlight IC is higher, so that the cost of the mobile phone is increased. In order to improve the conversion efficiency of the backlight power supply of the mobile phone on the premise of not increasing the cost, the embodiment of the application provides a backlight control circuit, which comprises a charging circuit, a first switch circuit, a first adjusting circuit and a processor; wherein the charging circuit comprises a second regulating circuit; the input end of the charging circuit is connected with the output end of the power supply, and the input/output end of the charging circuit is connected with the battery, so that when the power supply provides a first voltage for the charging circuit of the mobile phone, the charging circuit converts the first voltage input by the power supply to obtain a second voltage, and inputs the second voltage to the battery to finish charging the battery; in addition, when the required voltage is provided for the backlight module to control the display brightness of the backlight module, the preset end of the charging circuit is connected with the first end of the first switching circuit, the second end of the first switching circuit is connected with the processor, the third end of the first switching circuit is connected with the input end of the first adjusting circuit, and the output end of the first adjusting circuit is connected with the backlight module of the terminal device; the charging circuit is used for receiving a first voltage input by a power supply and inputting a second voltage obtained by conversion processing to the battery; the charging circuit is also used for inputting a preset voltage to the first switching circuit through a preset end, and the preset voltage is a voltage which is not adjusted by the second adjusting circuit of the charging circuit; the processor is used for controlling the first switch circuit to be conducted when the input end of the charging circuit is detected to have voltage; the first adjusting circuit is used for adjusting preset voltage according to the voltage of the backlight module when the first switch circuit is conducted, and inputting the conditioned third voltage to the backlight module to control the display brightness of the backlight module through the third voltage so as to provide required voltage for the backlight module.

The Processor may be an Application Processor (AP) or a Central Processing Unit (CPU). For example, when the terminal device is a mobile phone or a tablet computer, the processor may be an AP, and when the terminal device is a notebook computer, the processor may be a CPU.

It should be noted that, in this embodiment of the application, the preset terminal of the charging circuit is connected to the first terminal of the first switch circuit, so that when the preset voltage is input to the first switch circuit through the charging circuit, the preset terminal may be set in two different manners. In another possible implementation manner, the preset terminal may be an input terminal of the charging circuit, that is, a voltage of the power output terminal is directly input to the first switch circuit, so that the preset voltage is input to the first switch circuit through the charging circuit. In order to more clearly describe possible technical solutions provided by the embodiments of the present application, the technical solutions of the backlight control circuit provided by the embodiments of the present application will be described in detail below with reference to fig. 1 to 4.

In a possible implementation scheme, the preset terminal is a first output terminal of the charging circuit, that is, when the first output terminal of the charging circuit is connected to a first terminal of the first switch circuit, please refer to fig. 1, where fig. 1 is a schematic structural diagram of a backlight control circuit provided in an embodiment of the present application, and the backlight control circuit may include:

the input end of the charging circuit is connected with the output end of the power supply, the input/output end of the charging circuit is connected with the battery, the first output end of the charging circuit is connected with the first end of the first switching circuit, the second end of the first switching circuit is connected with the processor, the third end of the first switching circuit is connected with the input end of the first adjusting circuit, and the output end of the first adjusting circuit is connected with the backlight module of the terminal equipment.

The charging circuit is used for receiving a first voltage input by a power supply and inputting a second voltage obtained by conversion processing to the battery.

The charging circuit is further used for inputting a preset voltage to the first switching circuit through the first output end, wherein the preset voltage is a voltage which is not adjusted by the second adjusting circuit of the charging circuit.

The processor is used for controlling the first switch circuit to be conducted when the voltage at the input end of the charging circuit is detected.

For example, the charging circuit may be a Charge-IC. When the charging circuit can be a Charge-IC, the charging circuit further comprises a first current limiting circuit, a first MOS tube, a control sub-circuit and a second MOS tube. The output end of the first current limiting circuit is connected with the first end of the first MOS tube and the first end of the control sub-circuit respectively, the second end of the MOS tube is connected with the first end of the second adjusting circuit, the second end of the second adjusting circuit is connected with the second end of the control sub-module and the first end of the second MOS tube respectively, and the second end of the second MOS tube is connected with the battery. Illustratively, the power source may be a USB power source.

It should be noted that, when the charging circuit further includes a first current limiting circuit, a first MOS transistor, a control sub-circuit, and a second MOS transistor, the first output terminal in this embodiment of the application is an output terminal between the second terminal of the MOS transistor and the first terminal of the second adjusting circuit, that is, the second terminal of the MOS transistor and the first terminal of the second adjusting circuit are respectively connected to the first switch circuit through the first output terminal, so that a preset voltage is input to the first switch circuit through the first output terminal. For example, in the embodiment of the present application, the first output terminal may be any one of a Power middle Point (PMID), a middle point (MID ), a USB middle point (USB _ MID), a charging Power middle point (CHG _ VMID), and a Power middle point (VMID).

Alternatively, the first switch circuit may be any one of a MOS transistor, a triode, a transistor, and a load switch, and certainly, may also be another circuit having the function of the first switch circuit, and in this embodiment of the present application, the first switch circuit may be any one of a MOS transistor, a triode, a transistor, and a load switch as an example, but the embodiment of the present application is not limited thereto.

The first adjusting circuit may be a voltage boosting circuit or a voltage reducing circuit, and similarly, the second adjusting circuit may be a voltage boosting circuit or a voltage reducing circuit. In the practical charging application process, when the second adjusting circuit is a voltage reduction circuit, the first adjusting circuit is a voltage boosting circuit; or, when the second adjusting circuit is a voltage boosting circuit, the first adjusting circuit is a voltage reducing circuit. In the OTG mode, when the second adjusting circuit is a voltage boosting circuit, the first adjusting circuit is also a voltage boosting circuit.

In the practical application process, taking the first adjusting circuit as a backlight Boost circuit, the second adjusting circuit as a Buck Boost circuit, and taking 5V as an example of a first voltage input by a power supply, the first voltage is firstly converted by a first MOS tube, the on-resistance of the first MOS tube is less than 10mohm, taking 2A current as an example, the voltage converted by the first MOS tube is 4.98V, and the Buck Boost circuit and the second MOS tube input the voltage to a battery so as to realize charging of the battery, meanwhile, the voltage is input to the first switching circuit by a PMID, when the processor detects 4.98V voltage at the input end of a Charge-IC, the processor indicates that the voltage is currently provided for the Charge-IC by the power supply, at the moment, the processor controls the first switching circuit to be on, so that the 4.98V voltage is input to the backlight Boost circuit, when the backlight module comprises 36 lamp beads (LEDs), the 36 lamp beads are connected in series to form 1 group, and then 4 groups of lamps are connected in parallel to form a backlight module structure, the voltage required by each lamp bead is 3V, a 27V voltage is correspondingly provided for the backlight module, because the current voltage is only 4.98V, the 4.98V voltage needs to be boosted through a backlight Boost circuit, the voltage output by the backlight Boost circuit is 27V, the 27V voltage is input to the backlight module, the display brightness of the backlight module is controlled through the 27V voltage, and the required voltage is provided for the backlight module. For example, please refer to table 1:

TABLE 1

It can be seen from table 1 that, when the voltage provided to the Charge-IC by the power supply is 5V, and when a high-efficiency backlight IC is adopted, the voltage passes through the first MOS transistor and the second regulator circuit of the Charge-IC, a voltage of 3.8V is input to the backlight module, the backlight module efficiency is 88%, the conversion efficiency (the conversion efficiency is equal to the charging IC efficiency × the backlight module efficiency) is 79.20%, VBL is 27V, IBL is 80mA, the current consumed by the backlight module is 545mA, the conversion efficiency gain is 2.70%, and the power consumption gain is 20 mA; when the backlight control voltage provided by the embodiment of the application is adopted, after the 5V voltage passes through the first MOS tube of the Charge-IC, the 4.98V voltage is input into the backlight module, the efficiency of the backlight module is 88%, the conversion efficiency (the conversion efficiency is equal to the efficiency of the charging IC plus the efficiency of the backlight module) is 88.00%, VBL is 27V, IBL is 80mA, the current consumed by the backlight module is 490mA, the conversion efficiency gain is 11.5%, and the power consumption gain is 75 mA; therefore, compared with the prior art, the conversion efficiency gain of the backlight power supply of the backlight control circuit provided by the embodiment of the application is improved by 8.80%, and the power consumption gain is improved by 55mA, so that the conversion efficiency of the backlight power supply of the terminal equipment is improved while the terminal equipment is charged.

In addition, it should be noted that, when the voltage is input to the first switch circuit through the PMID, the current supplied from the power supply to the backlight module is reduced, so that the charging current actually entering the battery is increased. For example, see table 2 below:

TABLE 2

It can be seen from table 2 that, when the current supplied to the Charge-IC by the power supply is 2000mA, and when a high-efficiency backlight IC is adopted, the 2000mA is shunted after passing through the first MOS transistor, wherein 545mA of current is input to the backlight module, 1455mA of current passes through the Buck Boost circuit and the second MOS transistor and is input to 1723.03mA to the battery, the charging time is 167.15min, the actual gain of charging is 23.68mA, the gain of charging time is 2.33min, the actual gain of charging current is 1.39%, and the gain of charging time is 1.37%; when the backlight control voltage provided by the embodiment of the application is adopted, the 2000mA is shunted after passing through the first MOS tube, wherein 490mA current is input to the backlight module through the PMID, 1510mA current passes through the Buck Boost circuit and the second MOS tube and is input to 1788.16mA from the battery, the charging time is 161.06min, the actual charging yield is 88.82mA, the charging time yield is 8.42min, the actual charging current yield is 5.22%, and the charging time yield is 4.97%; therefore, compared with the prior art, the actual benefit of the charging current of the backlight control circuit provided by the embodiment of the application is improved by 3.83%, and the benefit of the charging time is improved by 3.6%, so that the conversion efficiency of the backlight power supply of the terminal equipment is improved while the terminal equipment is charged.

The embodiment shown in fig. 1 describes in detail the implementation principle and the beneficial effect of the backlight control circuit provided by the present application when the preset terminal is the first output terminal of the charging circuit. The following will describe in detail the implementation principle and the beneficial effect of the backlight control circuit provided in the present application when the preset terminal is the input terminal of the charging circuit, please refer to the following fig. 2-fig. 4:

in another possible implementation scheme, when the input terminal of the charging circuit is connected to the first terminal of the first switch circuit, to avoid the power source from being burned out, the first switch circuit is a switch circuit having a current-limiting control function, for example, the current-limiting control function may be implemented by a Fault pin, as shown in fig. 2, fig. 2 is a schematic structural diagram of another backlight control circuit provided in an embodiment of the present application, and the backlight control circuit may include:

the input end of the charging circuit is connected with the output end of the power supply, the input/output end of the charging circuit is connected with the battery, the input end of the charging circuit is connected with the first end of the first switching circuit, the second end of the first switching circuit is connected with the processor, the third end of the first switching circuit is connected with the input end of the first adjusting circuit, and the output end of the first adjusting circuit is connected with the backlight module of the terminal equipment.

The charging circuit is further configured to input a preset voltage (i.e., a first voltage) to the first switch circuit through the input terminal, where the preset voltage is a voltage that is not adjusted by the second adjusting circuit of the charging circuit.

For example, the charging circuit may be a Charge-IC. When the charging circuit can be a Charge-IC, the charging circuit further comprises a first current limiting circuit, a first MOS tube, a control sub-circuit and a second MOS tube. The input end of the first current limiting circuit is connected with the output end of the power supply, the output end of the first current limiting circuit is connected with the first end of the first MOS tube and the first end of the control sub-circuit respectively, the second end of the MOS tube is connected with the first end of the second adjusting circuit, the second end of the second adjusting circuit is connected with the second end of the control sub-module and the first end of the second MOS tube respectively, and the second end of the second MOS tube is connected with the battery.

It should be noted that, in this embodiment of the application, because the first switch circuit is a switch circuit having a current-limiting control function, when the processor detects that the input terminal of the charging circuit has a voltage, before controlling the first switch circuit to be turned on, the first switch circuit may first detect a first voltage at the first end of the first switch circuit, and if the first voltage at the first end of the first switch circuit is smaller than a preset threshold, send a close request signal to the processor, so that the processor controls the first switch circuit to be turned on according to the close request signal, so as to provide a required voltage to the backlight module through the power supply, so that the first voltage of the power supply to a third voltage of the backlight module is only converted through a primary power supply of the first adjusting circuit, thereby improving the conversion efficiency of the backlight power supply of the mobile phone.

Conversely, the first switch circuit is further configured to send an interrupt request signal to the processor if the first voltage at the first end of the first switch circuit is greater than the preset threshold; after the processor receives the interrupt request signal, the processor controls the first switch circuit to be switched off according to the interrupt request signal, and gradually reduces the brightness of the backlight module until the processor cannot receive the interrupt request signal; or the brightness of the backlight module is controlled to be reduced according to the interrupt request signal until the interrupt request signal is not received by the processor, so that short-circuit protection is realized, and the charger is prevented from being burnt out.

Therefore, in the backlight control circuit provided in the embodiment of the present application, when the power supply supplies voltage to the charging circuit, the first voltage at the input terminal of the charging circuit is first limited by the first current limiting circuit, and the voltage of the limited voltage is input to the battery through the second MOS transistor to charge the battery, and in addition, the first voltage may be directly input to the first switch circuit through the input terminal of the charging circuit (i.e., the output terminal of the power supply), and when the processor detects that the voltage is present at the input terminal of the charging circuit and the first voltage at the first terminal of the first switch circuit is smaller than the preset threshold, the first switch circuit is controlled to be turned on, so that the first adjusting circuit adjusts the first voltage according to the voltage of the backlight module when the first switch circuit is turned on, and inputs the conditioned third voltage to the backlight module to control the display brightness of the backlight module through the third voltage, therefore, the required voltage is provided for the backlight module, and when the terminal equipment is charged and used, the first voltage is only subjected to primary power conversion of the first adjusting circuit in the process from the first voltage output by the power supply to the required third voltage provided for the backlight module, so that the conversion efficiency of the backlight power supply of the mobile phone is improved.

The first adjusting circuit may be a voltage boosting circuit or a voltage reducing circuit, and similarly, the second adjusting circuit may be a voltage boosting circuit or a voltage reducing circuit. In the practical application process, when the second adjusting circuit is a voltage reduction circuit, the first adjusting circuit is a voltage boosting circuit; or, when the second conditioning phone is a voltage boosting circuit, the first adjusting circuit is a voltage reducing circuit.

In practical application, similarly, taking the first adjusting circuit as a backlight Boost circuit, taking the second adjusting circuit as a Buck Boost circuit, taking the first voltage input by the power supply as 5V as an example, taking 2A current as an example, the first voltage is firstly converted by a first MOS transistor, the on-resistance of the first MOS transistor is less than 10mohm, the voltage converted by the first MOS transistor is 4.98V, and the voltage is input to the battery through the Buck Boost circuit and a second MOS transistor so as to Charge the battery, meanwhile, 4.98V voltage is input to the first switch circuit through the input end, when the processor detects 5V voltage at the input end of the Charge-IC and the current passing through the first switch circuit is less than a preset threshold value, the processor indicates that voltage is currently provided for the Charge-IC through the power supply, at this time, the processor controls the first switch circuit to be turned on, so as to input the 4.98V voltage to the backlight Boost circuit, when the backlight module comprises 36 light beads (LEDs), the composition mode of the 36 light beads is that every 9 light beads are connected in series to form 1 group, then 4 groups are connected in parallel to form the backlight module structure, the voltage required by each light bead is 3V, and the corresponding 27V voltage is provided for the backlight module, because the current voltage is only 5V, the voltage of 5V needs to be boosted by the backlight Boost circuit first, so that the voltage output by the backlight Boost circuit is 27V, and the 27V voltage is inputted into the backlight module to control the display brightness of the backlight module by the 27V voltage, thereby realizing the supply of the required voltage for the backlight module, when the terminal equipment is charged and used, in the process from the 5V voltage output by the power supply to the required 27V voltage provided for the backlight module, the conversion efficiency of the backlight power supply of the mobile phone is improved only by one-time power supply conversion of the first adjusting circuit. Similarly, when the current provided to the Charge-IC by the power supply is 2000mA, the actual charging current gain and the charging time gain of the Charge-IC by the high-efficiency backlight IC adopted in the prior art or by the backlight control circuit provided in the embodiment of the present application can be referred to the above description in table 2 and table 2, and the embodiment of the present application is not further described herein.

In addition, it should be noted that, when the input terminal of the charging circuit is connected to the first terminal of the first switch circuit, and the first switch circuit is a switch circuit without current control function, in order to avoid the power source from being burned out, a second current limiting circuit may be disposed between the input terminal of the charging circuit and the first terminal of the first switch circuit, as shown in fig. 3, fig. 3 is a schematic structural diagram of another backlight control circuit provided in this embodiment, and the backlight control circuit may further include:

the input end of the second current limiting circuit is connected with the input end of the charging circuit, and the output end of the second current limiting circuit is connected with the first end of the first switch circuit.

The second current limiting circuit is used for receiving a first voltage input by the power supply and performing current limiting processing on the first voltage to obtain a preset voltage.

In the embodiment of the application, a second current limiting circuit is arranged between the input end of the charging circuit and the first end of the first switch circuit, so that the first voltage input through the input end of the battery can be subjected to current limiting processing through the second current limiting circuit, for example, the first voltage input through the input end is 5V, the current limiting processing is performed through the second current limiting circuit to obtain 4V voltage, the 4V voltage is input to the first switch circuit, when the processor detects the 5V voltage at the input end of the Charge-IC, the processor indicates that the Charge-IC is currently provided with voltage through a power supply, at this time, the processor controls the first switch circuit to be conducted, so that the 4V voltage is input to the backlight Boost circuit, when the backlight module comprises 36 lamp beads (LEDs), the composition mode of the 36 lamp beads is that every 9 of the lamp beads are connected in series to form 1 group, and then the 4 groups of the lamp beads are connected in parallel to form the backlight module structure, the required voltage of each lamp bead is 3V, 27V voltage is correspondingly provided for the backlight module, because the current voltage is only 4V, the 4V voltage needs to be boosted through the backlight Boost circuit, the voltage output by the backlight Boost circuit is 27V, the 27V voltage is input into the backlight module, the display brightness of the backlight module is controlled through the 27V voltage, and therefore the required voltage is provided for the backlight module.

Optionally, the second current limiting circuit includes an overcurrent detection circuit, an over-temperature detection circuit, an and gate, and an abnormal state output circuit, please refer to fig. 4, where fig. 4 is a schematic structural diagram of another backlight control circuit provided in the embodiment of the present application, and the backlight control circuit may further include:

Of course, in the embodiment of the present application, only the second current limiting circuit including the current detecting circuit, the over-temperature detecting circuit, the and gate, and the abnormal state output circuit is taken as an example for explanation, and other types of current limiting circuits may be used, and the embodiment of the present application is not limited further herein.

Based on the backlight control circuit shown in any one of the embodiments of fig. 1 to 4, when the input terminal of the terminal device is not connected to the power supply but there is a voltage in the charging circuit of the terminal device, in order to avoid controlling the first switch circuit to turn off and provide the required voltage to the backlight module due to false switching, please refer to fig. 5, where fig. 5 is a schematic structural diagram of the backlight control circuit provided in the embodiment of the present application, taking the example that the first output terminal of the charging circuit is connected to the first terminal of the first switch circuit, the backlight control circuit may further include a second switch circuit and a switch control circuit.

The first end of the second switching circuit is connected with the second output end of the charging circuit, the second end of the second switching circuit is connected with the processor, and the third end of the second switching circuit is connected with the input end of the first adjusting circuit; the input end of the switch control circuit is connected with the processor, and the output end of the switch control circuit is connected with the third end of the first switch circuit.

The processor is also used for controlling the second switch circuit to be switched on and controlling the first switch circuit to be switched off through the switch control circuit when the input end of the charging circuit is detected to have no voltage and the charging circuit has voltage.

Alternatively, the second switch circuit may be any one of a MOS transistor, a triode, a transistor, and a load switch, and certainly, may also be another circuit having the function of the first switch circuit, and in this embodiment of the present application, the first switch circuit may be any one of a MOS transistor, a triode, a transistor, and a load switch, which is only used as an example for description, but the embodiment of the present application is not limited thereto.

Optionally, the switch control circuit includes a first resistor, a second resistor, and a diode; one end of the first resistor is connected with the output end of the diode, one end of the second resistor is connected with the input end of the diode, the other end of the second resistor is connected with the processor, and the input end of the diode is further connected with the third end of the first switch circuit.

Of course, the diode in the switch control circuit may also be replaced by an MOS transistor or a triode, that is, the switch control circuit may also include a first resistor, a second resistor and an MOS transistor, or the switch control circuit may also include a first resistor, a second resistor and a triode. For example, when the switch control circuit may also include a first resistor, a second resistor and a MOS transistor, please refer to fig. 6 correspondingly, and fig. 6 is a schematic structural diagram of another backlight control circuit provided in the embodiment of the present application.

In this embodiment, by providing the second switch circuit and the switch control circuit, when the input terminal of the terminal device is not connected to the power supply but there is a voltage in the charging circuit of the terminal device, in order to avoid controlling the first switch circuit to turn off and provide a required voltage to the backlight module due to a false switching, the switch control circuit may control the first switch circuit to turn off and control the second switch circuit to turn on, so that when the second switch circuit is turned on, the required voltage is input to the backlight module through the first adjusting circuit, and the display brightness of the backlight module is controlled through the input voltage, thereby realizing that the required voltage is provided to the backlight module while charging, and controlling the display brightness of the backlight module. It should be noted that, when the second switch circuit is controlled to be turned on and a required voltage is input to the backlight module through the first adjusting circuit, optionally, the second switch control circuit may also be a switch circuit having a current control function in order to prevent an excessive current.

In the embodiment of the present application, when the first switch circuit is controlled by the switch control circuit, the following table 3 may be referred to:

TABLE 3

Status of state	Charging of electricity	USB OTG	USB OTG	Discharge of electricity
GPIO3_USB_ID	1	0	0	1
GPIO2	1	1	0	0

EN state

1

0

As can be seen from table 3 above, GPIO3_ USB _ ID and GPIO2 may be configured in hardware as an or logic gate that, when pulled low, the corresponding GPIO3_ USB _ ID is set to 0, and when the GPIO3_ USB _ ID is 0, the EN state of the corresponding first switch circuit is always 0, and the first switch circuit is disconnected, so that the occurrence of error switching can be avoided, thereby, when the input end of the terminal equipment is not connected with the power supply, but the voltage exists in the charging circuit of the terminal equipment, the switch control circuit can control the first switch circuit to be switched off and the second switch circuit to be switched on, so that when the second switch circuit is switched on, the first adjusting circuit inputs the required voltage to the backlight module and controls the display brightness of the backlight module through the input voltage, therefore, the required voltage is supplied to the backlight module while charging is carried out, so that the display brightness of the backlight module is controlled.

Of course, in the embodiment shown in fig. 5, the technical solution of preventing the mis-switching is described in detail by taking the example that the first output terminal of the charging circuit is connected to the first terminal of the first switch circuit, and of course, when the input terminal of the charging circuit is connected to the first terminal of the first switch circuit, corresponding to fig. 2 to 4, the non-switching may also be prevented by adding the second switch circuit and the switch control circuit, please refer to fig. 7 to 9, fig. 7 is a schematic structural diagram of another backlight control circuit provided in the embodiment of the present application, fig. 8 is a schematic structural diagram of another backlight control circuit provided in the embodiment of the present application, and fig. 9 is a schematic structural diagram of another backlight control circuit provided in the embodiment of the present application.

Fig. 10 is a flowchart of a backlight control method according to an embodiment of the present application, where the backlight control method is applicable to a backlight control circuit, the backlight control circuit includes a charging circuit, a first switch circuit, a first adjusting circuit, and a processor, where the charging circuit includes a second adjusting circuit, as shown in fig. 10, the backlight control method may include:

s1001, the charging circuit receives a first voltage input by a power supply, and inputs a second voltage obtained through conversion processing to the battery.

And S1002, inputting a preset voltage to the first switch circuit by the charging circuit through a preset end of the charging circuit, wherein the preset voltage is not regulated by the second regulating circuit of the charging circuit.

S1003, when the processor detects that the input end of the charging circuit has voltage, the processor controls the first switch circuit to be conducted.

And S1004, when the first switching circuit is turned on, the first adjusting circuit adjusts a preset voltage according to the voltage of the backlight module, and inputs a conditioned third voltage to the backlight module so as to control the display brightness of the backlight module through the third voltage.

Therefore, in the backlight control method provided by the embodiment of the application, when the power supply supplies voltage to the charging circuit, the charging circuit receives the first voltage input by the power supply, on one hand, the second voltage obtained by conversion processing is input to the battery to realize charging of the battery, on the other hand, the preset voltage is input to the first switch circuit through the preset end of the charging circuit, and the preset voltage is the voltage which is not adjusted by the second adjusting circuit of the charging circuit; when the processor detects that the input end of the charging circuit has voltage, the first switch circuit is controlled to be conducted, so that when the first switch circuit is conducted, the first adjusting circuit adjusts preset voltage according to the voltage of the backlight module, conditioned third voltage is input into the backlight module, the display brightness of the backlight module is controlled through the third voltage, and therefore required voltage is provided for the backlight module.

Optionally, the preset end is a first output end of the charging circuit, the charging circuit includes a first current limiting circuit, and the charging circuit inputs a preset voltage to the first switch circuit through the preset end of the charging circuit, including:

the first current limiting circuit carries out current limiting processing on the first preset voltage to obtain the preset voltage, and the preset voltage is input to the first switch circuit through the first output end, so that the charger is prevented from being burnt out due to overlarge current, and current limiting control on the preset voltage is achieved.

Optionally, the preset end is the input end of the charging circuit, and the charging circuit inputs the preset voltage to the first switch circuit through the preset end of the charging circuit, including:

Optionally, the backlight control circuit includes a second current limiting circuit, and the first adjusting circuit adjusts the preset voltage according to the voltage of the backlight module when the first switch circuit is turned on, and inputs a conditioned third voltage to the backlight module, and the backlight control circuit further includes:

the second current limiting circuit receives a first voltage input by a power supply; and the first voltage is subjected to current limiting processing to obtain preset voltage, so that the first voltage input through the battery input end can be subjected to current limiting processing through the second current limiting circuit, the charger is prevented from being burnt out due to overlarge current, and the current limiting control of the preset voltage is realized.

Optionally, the first switch circuit is a switch circuit with a current-limiting control function, and the first adjusting circuit adjusts the preset voltage according to the voltage of the backlight module when the first switch circuit is turned on, and before inputting the conditioned third voltage to the backlight module, the first adjusting circuit further includes:

the first switch circuit detects a preset voltage of the first end of the first switch circuit, and sends a closing request signal to the processor if the preset voltage of the first end of the first switch circuit is smaller than a preset threshold value.

Optionally, the backlight control method may further include:

if the preset voltage of the first end of the first switch circuit is larger than the preset threshold value, the first switch circuit sends an interrupt request signal to the processor.

Optionally, the backlight control method may further include:

and if the preset voltage of the first end of the first switch circuit is greater than the preset threshold value, sending an interrupt request signal to the processor.

Optionally, the backlight control circuit further includes a second switch circuit and a switch control circuit, and the backlight control method further includes:

when the processor detects that the input end of the charging circuit has no voltage and the charging circuit has voltage, the second switch circuit is controlled to be switched on, the first switch circuit is controlled to be switched off through the switch control circuit, the occurrence of error switching can be avoided, and therefore the input end of the terminal equipment is not connected with the power supply, but when the charging circuit of the terminal equipment has voltage, the first switch circuit can be controlled to be switched off through the switch control circuit, the second switch circuit is controlled to be switched on, when the second switch circuit is switched on, the required voltage is input to the backlight module through the first adjusting circuit, the display brightness of the backlight module is controlled through the input voltage, the required voltage is provided to the backlight module while charging is achieved, and the display brightness of the backlight module is controlled.

Optionally, the switch control circuit includes a first resistor, a second resistor and a diode, and controls the first switch circuit to be turned off through the switch control circuit, including:

the processor controls the first switch circuit to be disconnected through the first resistor, the second resistor and the diode.

The backlight control method according to the embodiment of the present application may implement the technical solution of the backlight control circuit according to any one of the embodiments, and the implementation principle and the beneficial effect thereof are similar, and are not described herein again.

Fig. 11 is a schematic structural diagram of a terminal device according to an embodiment of the present application, please refer to fig. 11, where the terminal device may include a battery, a backlight control circuit, and a backlight module.

The backlight control circuit is the backlight control circuit shown in any of the above embodiments.

The terminal device shown in the embodiment of the present application may implement the technical solution of the backlight control circuit shown in any one of the above embodiments, and the implementation principle and the beneficial effect thereof are similar and will not be described herein again.

The above description is only for the specific embodiments of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can easily conceive of the changes or substitutions within the technical scope of the present invention, and all the changes or substitutions should be covered within the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.

Claims

A backlight control circuit, comprising:

the charging circuit, the first switch circuit, the first adjusting circuit and the processor; wherein the charging circuit comprises a second regulating circuit;

the input end of the charging circuit is connected with the output end of a power supply, the input/output end of the charging circuit is connected with a battery, the preset end of the charging circuit is connected with the first end of the first switching circuit, the second end of the first switching circuit is connected with the processor, the third end of the first switching circuit is connected with the input end of the first adjusting circuit, and the output end of the first adjusting circuit is connected with the backlight module of the terminal equipment;

the charging circuit is used for receiving a first voltage input by the power supply and inputting a second voltage obtained by conversion processing to the battery;

the charging circuit is further used for inputting a preset voltage to the first switch circuit through the preset end, wherein the preset voltage is a voltage which is not adjusted by the second adjusting circuit;

the processor is used for controlling the first switch circuit to be conducted when the voltage is detected at the input end of the charging circuit;

the first adjusting circuit is used for adjusting the preset voltage according to the voltage of the backlight module when the first switch circuit is switched on, and inputting a third voltage obtained by conditioning to the backlight module so as to control the display brightness of the backlight module through the third voltage.
The circuit of claim 1, wherein the charging circuit further comprises a first current limiting circuit, a first MOS transistor, a control sub-circuit, and a second MOS transistor;

the input end of the first current limiting circuit is connected with the output end of the power supply, the output end of the first current limiting circuit is respectively connected with the first end of the first MOS tube and the first end of the control sub-circuit, the second end of the MOS tube is connected with the first end of the second adjusting circuit, the second end of the second adjusting circuit is respectively connected with the second end of the control sub-module and the first end of the second MOS tube, and the second end of the second MOS tube is connected with the battery.
The circuit of claim 2,

the preset end is the first output end of the charging circuit, and the second end of the MOS tube and the first end of the second adjusting circuit are respectively connected with the first switch circuit through the first output end.
The circuit of claim 1 or 2,

the preset end is the input end of the charging circuit.
The circuit of claim 4, further comprising a second current limiting circuit;

the input end of the second current limiting circuit is connected with the input end of the charging circuit, and the output end of the second current limiting circuit is connected with the first end of the first switch circuit;

the second current limiting circuit is used for receiving the first voltage input by the power supply and performing current limiting processing on the first voltage to obtain the preset voltage.
The circuit of claim 4, wherein the first switch circuit is a switch circuit with a current limit control function;

the first switch circuit is further configured to detect a preset voltage at the first end of the first switch circuit, and send a close request signal to the processor if the preset voltage at the first end of the first switch circuit is smaller than a preset threshold;

the processor is further configured to control the first switch circuit to conduct according to the close request signal.
The circuit of claim 6,

the first switch circuit is further configured to send an interrupt request signal to the processor if a preset voltage at the first end of the first switch circuit is greater than the preset threshold;

the processor is further configured to control the first switch circuit to be turned off according to the interrupt request signal until the processor does not receive the interrupt request signal.
The circuit of claim 6,

the first switch circuit is further configured to send an interrupt request signal to the processor if a preset voltage at the first end of the first switch circuit is greater than the preset threshold;

the processor is also used for controlling and reducing the brightness of the backlight module according to the interrupt request signal until the interrupt request signal is not received by the processor.
The circuit according to any one of claims 1-8, further comprising a second switching circuit and a switch control circuit;

the first end of the second switching circuit is connected with the second output end of the charging circuit, the second end of the second switching circuit is connected with the processor, and the third end of the second switching circuit is connected with the input end of the first adjusting circuit; the input end of the switch control circuit is connected with the processor, and the output end of the switch control circuit is connected with the third end of the first switch circuit;

the processor is further used for controlling the second switch circuit to be switched on and controlling the first switch circuit to be switched off through the switch control circuit when the input end of the charging circuit is detected to be free of voltage and the charging circuit has voltage.
The circuit of claim 9, wherein the switch control circuit comprises a first resistor, a second resistor, and a diode;

one end of the first resistor is connected with the output end of the diode, one end of the second resistor is connected with the input end of the diode, the other end of the second resistor is connected with the processor, and the input end of the diode is further connected with the third end of the first switch circuit.
The circuit of claim 5, wherein the second current limiting circuit comprises an over-current detection circuit, an over-temperature detection circuit, an AND gate, and an abnormal state output circuit;

the first end of the over-current detection circuit and the first end of the over-temperature detection circuit are both connected with the input end of the charging circuit, the second end of the over-current detection circuit is connected with the first end of the AND gate, the second end of the over-temperature detection circuit is connected with the second end of the AND gate, the third end of the AND gate is connected with the first end of the abnormal state output circuit, and the second end of the abnormal state output circuit is connected with the first end of the first switch circuit.
The circuit according to any one of claims 1-11,

when the second adjusting circuit is a voltage reduction circuit, the first adjusting circuit is a voltage boosting circuit; or, when the second conditioning phone is a voltage boosting circuit, the first adjusting circuit is a voltage reducing circuit.
The circuit of claim 3,

the first output end is any one of a power supply intermediate point PMID, an intermediate point MID, a USB intermediate point USB _ MID, a charging power supply intermediate point CHG _ VMID and a power supply intermediate point VMID.
The circuit according to claim 9 or 10, wherein the second switch circuit is a switch circuit having a current limit control function.
The circuit of any of claims 1-14,

the first switch circuit is any one of an MOS tube, a triode, a transistor and a load switch.
A backlight control method is applied to a backlight control circuit, the backlight control circuit comprises a charging circuit, a first switch circuit, a first adjusting circuit and a processor, wherein the charging circuit comprises a second adjusting circuit, and the method comprises the following steps:

the charging circuit receives a first voltage input by a power supply and inputs a second voltage obtained by conversion processing to the battery;

the charging circuit inputs a preset voltage to the first switch circuit through a preset end of the charging circuit, wherein the preset voltage is a voltage which is not adjusted by a second adjusting circuit of the charging circuit;

the processor controls the first switch circuit to be conducted when detecting that the input end of the charging circuit has voltage;

when the first switch circuit is switched on, the first adjusting circuit adjusts the preset voltage according to the voltage of the backlight module, and inputs a third voltage obtained by conditioning to the backlight module so as to control the display brightness of the backlight module through the third voltage.
The method of claim 16, wherein the predetermined terminal is a first output terminal of the charging circuit, the charging circuit comprises a first current limiting circuit, and the charging circuit inputs a predetermined voltage to the first switching circuit through the predetermined terminal of the charging circuit, and comprises:

the first current limiting circuit carries out current limiting processing on the first preset voltage to obtain the preset voltage, and the preset voltage is input to the first switch circuit through the first output end.
The method of claim 16, wherein the predetermined terminal is an input terminal of the charging circuit, and the charging circuit inputs a predetermined voltage to the first switch circuit through the predetermined terminal of the charging circuit, and comprises:

the charging circuit inputs the preset voltage to the first switch circuit through an input end of the charging circuit.
The method of claim 18, wherein the backlight control circuit comprises a second current limiting circuit, and before the first adjusting circuit adjusts the preset voltage according to the voltage of the backlight module when the first switching circuit is turned on and inputs the conditioned third voltage to the backlight module, the method further comprises:

the second current limiting circuit receives a first voltage of the power supply input; and carrying out current limiting processing on the first voltage to obtain the preset voltage.
The method according to claim 18, wherein the first switch circuit is a switch circuit with a current-limiting control function, and the first adjusting circuit adjusts the preset voltage according to the voltage of the backlight module when the first switch circuit is turned on, and before inputting the conditioned third voltage to the backlight module, further comprises:

the first switch circuit detects a preset voltage of a first end of the first switch circuit, and sends a closing request signal to the processor if the preset voltage of the first end of the first switch circuit is smaller than a preset threshold value;

the processor also controls the first switch circuit to be conducted according to the closing request signal so as to input the preset voltage to the first adjusting circuit.
The method of claim 20, further comprising:

if the preset voltage of the first end of the first switch circuit is greater than the preset threshold value, the first switch circuit sends an interrupt request signal to the processor;

and the processor controls the first switch circuit to be switched off according to the interrupt request signal until the processor does not receive the interrupt request signal.
The method of claim 20, further comprising:

if the preset voltage of the first end of the first switch circuit is greater than the preset threshold value, sending an interrupt request signal to the processor;

the processor is also used for controlling and reducing the brightness of the backlight module according to the interrupt request signal until the interrupt request signal is not received by the processor.
The method of any of claims 16-22, wherein the backlight control circuit further comprises a second switching circuit and a switch control circuit, the method further comprising:

when the processor detects that no voltage exists at the input end of the charging circuit and voltage exists in the charging circuit, the second switch circuit is controlled to be switched on, and the first switch circuit is controlled to be switched off through the switch control circuit.
The method of claim 23, wherein the switch control circuit comprises a first resistor, a second resistor, and a diode, and wherein controlling the first switch circuit to open by the switch control circuit comprises:

the processor controls the first switch circuit to be disconnected through the first resistor, the second resistor and the diode;

one end of the first resistor is connected with the output end of the diode, one end of the second resistor is connected with the input end of the diode, the other end of the second resistor is connected with the processor, and the input end of the diode is further connected with the first switch circuit.
A terminal device is characterized by comprising a battery, a backlight control circuit and a backlight module;

wherein the backlight control circuit is the backlight control circuit of any of claims 1-15 above.