Charging method, charging system and electronic device

This application claims the benefit of U.S. provisional application Ser. No. 62/583,066, filed Nov. 8, 2017, the subject matter of which is incorporated herein by reference.

The disclosure relates in general to a charging method, a charging system and an electronic device, and more particularly to a charging method, a charging system and an electronic device under a program power source.

Along the development of technology, various electronic devices have been invented. People may carry several electronic devices with its charging adaptors. In order to unify the charging standard, USB adaptor is widely used for those electronic devices.

Now, USB Implementers Forum (USB IF) releases the program power supply (PPS) of USB Power Delivery 3.0. In the PPS, the power source voltage and the power source current are continuously adjustable, so the USB adaptor can be widely used for more electronic devices. However, the charging efficiency is related to the power source voltage and the power source current. For optimizing charging efficiency, it is needed to invent a way to program the power source voltage or the power source current under the program power supply (PPS).

The disclosure is directed to a charging method, a charging system and an electronic device. A power source voltage is swept to let an inputting current being approached an inputting current limit, such that the charging efficiency can optimized.

According to one embodiment, a charging method for optimizing charging efficiency is provided. The charging method includes the following steps: An inputting current limit is set. An inputting current of at least one charger is measured. A power source voltage of a power source is adjusted until a current difference between the inputting current and the inputting current limit is within a predetermined range.

According to another embodiment, an electronic device is provided. The electronic device includes at least one charger, a controller, a current detector and a communication unit. The charger is used for charging a battery. The controller is used for setting an inputting current limit. The current detector is used for measuring an inputting current of the charger. The communication unit is used for sending a programming command to a power source for adjusting a power source voltage of the power source until a current difference between the inputting current and the inputting current limit is within a predetermined range.

According to an alternative embodiment, a charging system for optimizing charging efficiency is provided. The charging system includes at least one charger, a controller, at least one current detector and a programmer. The charger is used for charging a battery. The controller is used for setting an inputting current limit. The current detector is used for measuring an inputting current of the charger. The programmer is used for adjusting a power source voltage of a power source until a current difference between the inputting current and the inputting current limit is within a predetermined range.

FIG. 1 shows a charging system according to one embodiment.

FIG. 2 shows programmable ranges of a power source.

FIG. 3 shows a simplified circuit diagram of the charging system.

FIG. 4 illustrates a relationship between a powersource voltage and an inputting current.

FIG. 5 illustrates a flowchart of a charging method of the charging system according to one embodiment.

FIG. 6 shows a battery current curve, an inputting current curve and a power source voltage curve according to one example of performing the charging method.

FIG. 7 shows another charging system according to another embodiment.

In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing.

Refer to FIG. 1 , which shows a charging system 100 according to one embodiment. The charging system 100 includes an electronic device 110 , a charging adaptor 150 and a cable 170 . The electronic device 110 may be a cell phone, a laptop or a mobile power. The charging adaptor 150 may be a type A USB adaptor, a type B USB adaptor, a type C USB adaptor or a micro USB adaptor. The cable may be a type A USB cable, a type B USB cable, a type C USB cable or a micro USB cable. The cable 170 is used to connect the electronic device 110 and the charging adaptor 150 , such that the electronic device 110 can be charged.

In the embodiment, the electronic device 110 includes two chargers 111 , 112 , a current detector 113 , a communication unit 114 , a controller 115 and a battery 190 . The charger 111 and 112 are used for charging the battery 190 . The current detector 113 is used for measuring a current. The controller 115 is used for outputting a programming command CM to control the charging method. The communication unit 114 is used for sending the programming command CM to the power source 151 . For example, the chargers 111 , 112 , the current detector, the communication unit 114 and the controller 115 may be a circuit, a chip, a firmware, a circuit board or a storage device storing a plurality of program codes.

The charging adaptor 150 includes a power source 151 and a programmer 152 . The power source 151 may be a program power source (PPS). The programmer 152 is used for adjusting a power source voltage VBUS_SRC or a power source current IBUS_SRC of the power source 151 . The programmer 152 may be a circuit, a chip, a firmware, a circuit board or a storage device storing a plurality of program codes.

Please refer to FIG. 2 , which shows programmable ranges R 1 , R 2 of the power source 151 . The power source voltage VBUS_SRC and the power source current IBUS_SRC of the power source 151 can be programmable within the programmable range R 1 or the programmable range R 2 . For example, the power source 151 may be programed at 5V/3 A or 9V/2.8 A. Several combinations of the power source voltage VBUS_SRC and the power source current IBUS_SRC can be selected.

Please refer to FIG. 3 , which shows a simplified circuit diagram of the charging system 100 . The power source 151 has the power source voltage VBUS_SRC and the power source current IBUS_SRC. The cable 170 has a cable resistance R_CABLE. An inputting current IBUS_SNK is inputted into the chargers 111 , 112 , and a system current ISYS and a battery current IBAT are outputted. The battery 190 has a battery voltage. The relationship among the power source voltage VBUS_SRC, the power source current IBUS_SRC, the cable resistance R_CABLE, the battery voltage VBAT, the battery current IBAT, the system current ISYS and the efficiency η is illustrated as the following equation (1).

V BUS_ SRC*I BUS_ SRC−I BUS_ SRC 2 *R _CABLE= V BAT*( I BAT+ I SYS)/η  (1)

The equation (1) can be written via a system power dissipation P_SYS and a cable power dissipation P_CABLE, as the following equation (2)

Generally, the inputting current IBUS_SNK is similar to the power source current IBUS_SRC. Please referring to FIG. 4 , a relationship between the power source voltage VBUS_SRC and the inputting current IBUS_SNK is illustrated. The inputting current IBUS_SNK is varied with the power source voltage VBUS_SRC until the inputting current IBUS_SNK reaches an inputting current limit IBUS_SNK_limit. If the inputting current IBUS_SNK approaches an inputting current limit IBUS_SNK_limit, the battery current IBAT, the system power dissipation P_SYS and the cable power dissipation P_CABLE will satisfy the expected values. In FIG. 4 , point P 0 is the optimal setting of the power source voltage VBUS_SRC. The point P 0 can be found out along a direction D 1 or a direction D 2 . In the direction D 1 , the power source voltage VBUS_SRC can be decreased to reduce a current difference CD between the inputting current IBUS_SNK and the inputting current limit IBUS_SNK_limit. In the direction D 2 , the power source voltage VBUS_SRC can be increased to let the current difference CD being larger than 0. That is to say, if the current difference CD is controlled to be within a predetermined range PR from a bottom bound K 1 to a top bound K 2 , then the inputting current IBUS_SNK approaches the inputting current limit IBUS_SNK_limit and the charging efficiency is optimal. The bottom bound K 1 is larger than 0 and lower than the top bound K 2 . The bottom bound K 1 may be ranged from 0 mA to 2000 mA, such as 1 mA. The top bound K 2 may be ranged from 0 mA to 2000 mA, such as 50 mA.

Please referring to FIG. 5 , a flowchart of a charging method of the charging system 100 according to one embodiment is illustrated. In step S 110 , the controller 115 sets the inputting current limit IBUS_SNK_limit.

In step S 120 , the controller 115 enables the charger 111 and/or the charger 112 .

In step S 130 , the current detector 113 measures the inputting current IBUS_SNK.

In step S 140 , the controller 115 adjusts the power source voltage VBUS_SRC of the power source 151 until the current difference CD is within the predetermined range PR. The step S 140 includes the steps S 141 to S 146 .

In step S 141 , the controller 115 determines whether the current difference CD is within the predetermined range PR. If the current difference CD is less than the bottom bound K 1 of the predetermined range PR, then the process proceeds to the step S 142 ; if the current difference CD is larger than the top bound K 2 of the predetermined range PR, then the process proceeds to the step S 143 ; if the current difference CD is within the predetermined range PR, then the process proceeds to the step S 144 .

In step S 142 , the controller 115 increases the power source voltage VBUS_SRC. In step S 143 , the controller 115 decreases the power source voltage VBUS_SRC. In step S 144 , the controller 115 keeps the power source voltage VBUS_SRC.

In step S 145 , the controller 115 determines whether the power source voltage VBUS_SRC reaches the bound of the programmable range. If the power source voltage VBUS_SRC reaches the bound of the programmable range, then the process proceeds to the step S 144 ; if the power source voltage VBUS_SRC does not reach the bound of the programmable range, then the process proceeds to the step S 130 .

In step S 146 , the controller 115 determines whether the power source voltage VBUS_SRC reaches the bound of the programmable range. If the power source voltage VBUS_SRC reaches the bound of the programmable range, then the process proceeds to the step S 144 ; if the power source voltage VBUS_SRC does not reach the bound of the programmable range, then the process proceeds to the step S 130 .

When the current difference CD is within the predetermined range PR, the step S 144 is performed and the process proceeds to the step S 150 . In step S 150 , the controller 115 determines whether the charging is completed. If the charging is terminated, then the process is terminated.

Please refer to FIG. 6 , which shows a battery current curve C 1 an inputting current curve C 2 and a power source voltage curve C 3 according to one example of performing the charging method. In the step S 142 , the power source voltage VBUS_SRC is increased along the direction D 2 , such that the inputting current IBUS_SNK approaches the point P 0 and the battery current IBAT approaches the point P 1 to optimize the charging efficiency.

In the step S 143 , the power source voltage VBUS_SRC is decreased along the direction D 1 , such that the inputting current IBUS_SNK approaches the point P 0 and the battery current IBAT approaches the point P 1 to optimize the charging efficiency.

Please refer to FIG. 7 , which shows another charging system 200 according to another embodiment. In this embodiment, the electronic device 210 includes two chargers 211 , 212 and two current detectors 213 , 214 . The inputting current IBUS_SNK′ includes two sub-currents I 1 , I 2 . The current detectors 213 , 214 measure the sub-currents I 1 , I 2 of the chargers 211 , 212 respectively. The controller 115 sums up the two sub-currents I 1 , I 2 to obtain the inputting current IBUS_SNK′.

Based on the embodiments described as above, the power source voltage VBUS_SRC is swept to let the inputting current IBUS_SNK being approached the inputting current limit IBUS_SNK_limit, such that the charging efficiency can optimized.

It will be apparent to those skilled in the art that various modifications and variations can be made to the disclosed embodiments. It is intended that the specification and examples be considered as exemplary only, with a true scope of the disclosure being indicated by the following claims and their equivalents.