Charging system, charging method, and power adapter

Patent metadata

Field	Value
Publication number	US-10312712-B2
Application number	US-201715649277-A
Country	US
Kind code	B2
Filing date	Jul 13, 2017
Priority date	Feb 5, 2016
Publication date	Jun 4, 2019
Grant date	Jun 4, 2019

Abstract

The present disclosure discloses a charging system, a charging method and a power adapter. The system includes a power adapter and a terminal. The power adapter includes a first rectifier, a switch unit, a transformer, a second rectifier, a sampling unit, a control unit and a first isolation unit. The control unit outputs a control signal to the switch unit, and adjusts a duty ratio of the control signal according to a current value and/or voltage value sampled by the sampling unit, such that a third voltage with a third ripple waveform outputted by the second rectifier meets a charging requirement. The terminal includes a battery. When the terminal is coupled to the power adapter, the third voltage is applied to the battery.

First claim

What is claimed is:

1. A power adapter, comprising:
a first rectifier, configured to rectify an input alternating current and output a first voltage with a first ripple waveform;
a switch unit, configured to modulate the first voltage according to a control signal and output a modulated first voltage;
a transformer, having a primary winding and a secondary winding, and configured to output a second voltage with a second ripple waveform according to the modulated first voltage;
a second rectifier, coupled to the secondary winding, and configured to rectify the second voltage to output a third voltage with a third ripple waveform, wherein the third voltage is configured to be introduced into a terminal to charge a battery in the terminal when the power adapter is coupled to the terminal;
a sampling unit, arranged at a primary side of the transformer, configured to sample voltage and/or current at the primary winding;
a control unit, arranged at a secondary side of the transformer, coupled to the sampling unit and the switch unit respectively, and configured to output the control signal to the switch unit, wherein the control unit is further configured to change an output of the second rectifier by adjusting a duty ratio of the control signal according to the current sampling value and/or the voltage sampling value such that the third voltage meets a charging requirement of the battery of the terminal when the power adapter is coupled to the terminal; and
a first isolation unit, arranged between the control unit and the sampling unit, and configured to prevent high voltages from affecting the control unit at the secondary side of the transformer receiving signals sent by the sampling unit at the primary side of the transformer.

2. The power adapter according to claim 1 , wherein the control unit is further configured to adjust a frequency of the control signal according to the voltage sampling value and/or the current sampling value.

3. The power adapter according to claim 1 , wherein the control unit is configured to communicate with the terminal so as to obtain status information of the terminal when the power adapter is coupled to the terminal.

4. The power adapter according to claim 3 , wherein the control unit is further configured to adjust the duty ratio of the control signal according to the voltage sampling value and/or the current sampling value and the status information of the terminal.

5. The power adapter according to claim 1 , further comprising:
a driving unit, coupled between the switch unit and the control unit, and configured to drive the switch unit to switch on or off according to the control signal; and/or
a second isolation unit, coupled between the driving unit and the control unit.

6. The power adapter according to claim 5 , further comprising:
an auxiliary winding, configured to generate a fourth voltage with a fourth ripple waveform according to the modulated first voltage; and
a power supply unit, coupled to the auxiliary winding, and configured to convert the fourth voltage and output a direct current, so as to supply power to the driving unit and/or the control unit respectively.

7. The power adapter according to claim 6 , further comprising:
a first voltage detecting unit, coupled to the auxiliary winding and the control unit respectively, and configured to detect the fourth voltage to generate a voltage detecting value, wherein the control unit is further configured to adjust the duty ratio of the control signal according to the voltage detecting value.

8. The power adapter according to claim 1 , wherein a working frequency of the transformer ranges from 50 KHz to 2 MHz.

9. The power adapter according to claim 1 , wherein the sampling unit comprises:
a first current sampling circuit, configured to sample the current at the primary winding so as to obtain the current sampling value via the control unit; and
a first voltage sampling circuit, configured to sample the voltage at the primary winding so as to obtain the voltage sampling value via the control unit.

10. The power adapter according to claim 9 , wherein the first voltage sampling circuit comprises:
a peak voltage sampling and holding unit, configured to sample and hold a peak voltage of the modulated first voltage;
a cross-zero sampling unit, configured to sample a zero crossing point of the modulated first voltage;
a leakage unit, configured to perform a leakage on the peak voltage sampling and holding unit at the zero crossing point; and
an AD sampling unit, configured to sample the peak voltage in the peak voltage sampling and holding unit so as to obtain the voltage sampling value via the control unit.

11. The power adapter according to claim 1 , wherein a waveform of the modulated first voltage keeps synchronous with the third ripple waveform.

12. The power adapter according claim 1 , further comprising:
a second voltage sampling circuit, configured to sample the first voltage, and coupled to the control unit, wherein the control unit is configured to control the switch unit to switch on for a first predetermined time period for discharging when a voltage value sampled by the second voltage sampling circuit is greater than a first predetermined voltage value.

13. The power adapter according to claim 1 , wherein
the power adapter comprises a first charging interface,
the first charging interface comprises: a power wire, configured to charge the battery; and a data wire, configured to communicate with the terminal when the power adapter is coupled to the terminal via the first charging interface;
the control unit is configured to communicate with the terminal via the first charging interface to determine a charging mode, in which the charging mode comprises a first charging mode and a second charging mode, and the second charging mode is different from the first charging mode.

14. The power adapter according to claim 13 , further comprising:
a controllable switch and a filtering unit coupled in series, coupled to a first output end of the second rectifier, wherein the control unit is further configured to control the controllable switch to switch on when determining the charging mode as the first charging mode so as to introduce the filtering unit to perform a filtering function on the output of the second rectifier to realize direct current charging of the terminal when the power adapter is coupled to the terminal, and to control the controllable switch to switch off when determining the charging mode as the second charging mode.

15. The power adapter according to claim 13 , wherein the control unit is further configured to obtain a charging current and/or a charging voltage corresponding to the second charging mode according to the status information of the terminal when the power adapter is coupled to the terminal, and to adjust the duty ratio of the control signal according to the obtained charging current and/or the charging voltage corresponding to the second charging mode, when it is determined that the charging mode is the second charging mode.

16. The power adapter according to claim 15 , wherein the status information of the terminal comprises a temperature of the battery, wherein when the temperature of the battery is greater than a first predetermined temperature threshold or the temperature of the battery is less than a second predetermined temperature threshold, the second charging mode is switched to the first charging mode when a current charging mode is the second charging mode, in which the first predetermined temperature threshold is greater than the second predete

Assignees

• Guangdong Oppo Mobile Telecommunications Corp Ltd

Inventors

• Zhang Jialiang
• Chen Shebiao
• Zhang Jun
• Tian Chen
• Wan Shiming
• Li Jiada

Classifications

• H02J7/825

  Detection of fully charged condition · CPC title

• H02J7/94

  in response to battery current · CPC title

• H02J7/82

  Control of state of charge [SOC] · CPC title

• H02J7/42

  with electronic devices having internal batteries, e.g. mobile phones · CPC title

• H02J7/975

  in response to temperature · CPC title