Systems and methods for charging via USB port
A power supply terminal, and a charging control method are disclosed. The power supply terminal includes a USB port, a switch, a power source module, and a processor, where the USB port is configured to connect to a power receiving terminal; one end of the power source module is connected to a power source pin VBUS of the USB port and is configured to charge the power receiving terminal by using the power source pin VBUS; a first end of the switch is connected to the data pin D+ and a second end of the switch is connected to the data pin D−; when the switch is on and the processor detects that a drop amplitude of the output voltage of the power source module exceeds a preset value, in a process in which the power source module outputs a voltage to charge the power receiving terminal.
1. A charging control method, comprising:
performing control during a process in which a power source outputs an output voltage on a power source pin VBUS of a Universal Serial Bus (USB) port to charge a power receiving terminal connected to the USB port, when a switch is on and a drop amplitude of the output voltage of the power source exceeds a preset value, to turn off the switch and stop the power source from outputting the output voltage at the power source pin VBUS of the USB port, wherein a first end of the switch is connected to a data pin D+ of the USB port and a second end of the switch is connected to a data pin D− of the USB port, and when the switch is on, the first end and the second end of the switch are electrically connected;
communicating with the power receiving terminal using the data pin D+ and the data pin D− of the USB port in accordance with a communications protocol to reduce a charging current required by the power receiving terminal below a maximum charging current capability of the power source, wherein the communications protocol is an OTG (On The Go) protocol; and
controlling, when the switch is turned off and after communicating with the power receiving terminal using the data pin D+ and the data pin D−, the power source to continue charging the power receiving terminal by outputting the output voltage at the power source pin VBUS of the USB port.
2. The method according to claim 1 , wherein the charging current required by the power receiving terminal in accordance with the OTG protocol is 500 milliamperes (mA).
3. The method according to claim 2 , wherein the charging current required by the power receiving terminal when the switch is on is greater than 1 ampere (A).
4. The method according to claim 1 , wherein the output voltage is 5 volts (V) when the charging current required by the power receiving terminal is less than the maximum charging current capability of the power source.
5. A power supply terminal, comprising a USB port, a switch, a power source, and a processor, wherein:
the USB port is configured to connect the power supply terminal to a power receiving terminal;
one end of the power source provides an output voltage to a power source pin VBUS of the USB port, wherein the output voltage is configured to charge the power receiving terminal via the power source pin VBUS;
a first end of the switch is connected to a data pin D+ of the USB port and a second end of the switch is connected to a data pin D− of the USB port, wherein when the switch is on, the first end and the second end of the switch are electrically connected; and
the processor is configured to:
when the switch is on, control the power source to provide the output voltage at the power source pin VBUS of the USB port to charge the power receiving terminal,
responsive to detecting that a drop amplitude of the output voltage of the power source exceeds a preset value, perform control to turn off the switch and stop the power source from outputting the output voltage at the power source pin VBUS,
communicate, according to a communications protocol, with the power receiving terminal using the data pin D+ and the data pin D− to reduce a charging current required by the power receiving terminal below a maximum charging current capability of the power source, wherein the communications protocol is an OTG (On The Go) protocol, and
when the switch is off and after communicating with the power receiving terminal using the data pin D+ and the data pin D−, control the power source to provide the output voltage at the power source pin VBUS of the USB port to continue charging the power receiving terminal.
6. The power supply terminal according to claim 5 , wherein the charging current required by the power receiving terminal in accordance with the OTG protocol is 500 milliamperes (mA).
7. The power supply terminal according to claim 6 , wherein the charging current required by the power receiving terminal when the switch is on is greater than 1 ampere (A).
8. The power supply terminal according to claim 5 , wherein the output voltage is 5 volts (V) when the charging current required by the power receiving terminal is less than the maximum charging current capability of the power source.