High voltage hybrid charging system and method
A system includes a receiver coil configured to be magnetically coupled to a transmitter coil, a rectifier connected to a voltage bus through a switch, a first power converter and a second power converter connected in cascade between the switch and a battery and a load switch connected between the voltage bus and a power port configured to be connected to a power source.
1. An apparatus comprising:
a rectifier configured to convert an alternating current voltage into a direct current voltage;
a load switch has a first terminal connected to a power source and a second terminal coupled to an output of the rectifier;
a first power converter connected to the output of the rectifier; and
a second power converter having an input connected to an output of the first power converter, wherein the first power converter and the second power converter are connected in cascade to provide power to a load.
2. The apparatus of claim 1 , wherein:
the first power converter is a first charge pump power converter, and wherein an output voltage of the first charge pump power converter is equal to one half of an input voltage of the first charge pump power converter; and
the second power converter is a second charge pump power converter configured to function as a voltage divider, and wherein an output voltage of the second charge pump power converter is equal to one half of an input voltage of the second charge pump power converter.
3. The apparatus of claim 1 , wherein:
the first power converter is a hybrid converter comprising:
a first switch, a capacitor and a second switch connected in series between an input voltage source and an output filter;
a third switch connected between a common node of the first switch and the capacitor, and a common node of the second switch and the output filter; and
a fourth switch connected between a common node of the capacitor and the second switch, and ground; and
the second power converter is a charge pump power converter configured to function as a voltage divider.
4. The apparatus of claim 1 , wherein:
the power source is a USB port configured to be connected with an adaptor through a USB cable.
5. The apparatus of claim 1 , wherein:
the alternating current voltage is generated by a receiver coil configured to be magnetically coupled to a transmitter coil of a wireless power transfer system.
6. The apparatus of claim 1 , wherein:
the rectifier, the first power converter and the second power converter are connected in cascade between a receiver coil and the load, wherein the second terminal of the load switch is connected to a voltage bus between the rectifier and the first power converter.
7. The apparatus of claim 1 , wherein:
the rectifier, the first power converter and the second power converter are connected in cascade between a receiver coil and the load, wherein the second terminal of the load switch is connected to a voltage bus between the first power converter and the second power converter.
8. A method comprising:
configuring a hybrid charging system to operate in a wireless charging mode to charge a battery after a power source has been cut off from the hybrid charging system, wherein the hybrid charging system comprises:
a rectifier configured to convert an alternating current voltage into a direct current voltage;
a load switch connected between and a voltage bus and a power port configured to be connected to the power source;
a first power converter and a second power converter connected in cascade between the rectifier and the battery; and
configuring the hybrid charging system to operate in a wired charging mode to charge the battery after the power source has been connected to the hybrid charging system.
9. The method of claim 8 , further comprising:
prior to the step of configuring the hybrid charging system to operate in the wireless charging mode, detecting a voltage drop at the voltage bus;
comparing the voltage drop with a first predetermined threshold;
turning off the load switch after the voltage drop is below the first predetermined threshold; and
turning on a switch connected between the rectifier and the voltage bus.
10. The method of claim 8 , further comprising:
prior to the step of configuring the hybrid charging system to operate in the wired charging mode, detecting a voltage at the power port;
comparing the voltage at the power port with a second predetermined threshold;
turning off a switch connected between the rectifier and a voltage bus after the voltage at the power port is greater than the second predetermined threshold; and
after a predetermined delay, turning on the load switch connected between the power port and the voltage bus.
11. The method of claim 8 , wherein:
the voltage bus is between the rectifier and the first power converter.
12. The method of claim 8 , wherein:
the voltage bus is between the first power converter and the second power converter.
13. The method of claim 8 , wherein:
the alternating current voltage is generated by a receiver coil configured to be magnetically coupled to a transmitter coil of a wireless power transfer device;
the first power converter is a first charge pump power converter, and wherein an output voltage of the first charge pump power converter is equal to one half of an input voltage of the first charge pump power converter; and
the second power converter is a second charge pump power converter, and wherein an output voltage of the second charge pump power converter is equal to one half of an input voltage of the second charge pump power converter.
14. The method of claim 13 , further comprising:
during the wireless charging mode, regulating an output voltage of the hybrid charging system through adjusting operating parameters of a transmitter circuit coupled to the transmitter coil; and
during the wired charging mode, regulating the output voltage of the hybrid charging system through adjusting operating parameters of the power source.
15. The method of claim 8 , wherein:
the first power converter is a hybrid converter comprising:
a first switch, a capacitor and a second switch connected in series between an input voltage source and an output filter;
a third switch connected between a common node of the first switch and the capacitor, and a common node of the second switch and the output filter; and
a fourth switch connected between a common node of the capacitor and the second switch, and ground; and
the second power converter is a charge pump power converter configured to function as a voltage divider.
16. The method of claim 15 , further comprising:
regulating an output voltage of the hybrid charging system through regulating an output voltage of the hybrid converter.
17. A system comprising:
a receiver coil configured to be magnetically coupled to a transmitter coil;
a rectifier connected to a voltage bus through a switch;
a first power converter and a second power converter connected in cascade between the switch and a battery, wherein the first power converter and the second power converter are configured to provide power to the battery; and
a load switch connected between the voltage bus and a power port configured to be connected to a power source.
18. The system of claim 17 , wherein:
the voltage bus is between the first power converter and the second power converter.
19. The system of claim 17 , wherein:
the power port is a USB port connected to the power source through a cable.
20. The system of claim 17 , wherein:
the first power converter is a first charge pump power converter, and wherein an output voltage of the first charge pump power converter is equal to one half of an input voltage of the first charge pump power converter; and
the second power converter is a second charge pump power converter, and wherein an output voltage of the second charge pump power converter is equal to one half of an input voltage of the second charge pump power converter.