Adaptable power rectifier for wireless charger system

• US 10,644,531 B1
• Filed: 03/23/2017
• Issued: 05/05/2020
• Est. Priority Date: 09/22/2016
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Qiu, Weihong, Dayal, Rohan, Moussaoui, Zaki
• Primary Examiner(s): Tso, Edward
• Assistant Examiner(s): Piggush, Aaron
• Application Number:
  US15/468,001
• Time in Patent Office: 1,139 Days
• Field of Search: 320108, 320163, 320166, 363 16, 363 88
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/402 the two or more transmitting or the two or more receiving devices being integrated in the same unit, e.g. power mats with several coils or antennas with several sub-antennas
• CPC Class Codes: H02J 7/02 for charging batteries from ac mains by converters
• CPC Class Codes: H02M 1/32 Means for protecting converters other than automatic disconnection
• CPC Class Codes: H02M 7/219 in a bridge configuration
• CPC Class Codes: H02M 7/25 arranged for operation in series, e.g. for multiplication of voltage

Abstract

A power converter including a rectifier circuit and a method for rectifying an incoming alternating current. The rectifier circuit may alter its output voltage according to varying conditions of the power converter. The variations may include voltage changes at the input or output.

Claims

1. A power converter, comprising:

a first inductive coil configured to output a first induced current;

a second inductive coil configured to output a second induced current;

a rectifier circuit coupled to the first inductive coil and the second inductive coil and comprising a set of voltage-controlled switches, the rectifier circuit configured to operate in a full-wave rectifying mode and a voltage doubler rectifying mode; and

processing circuitry configured to;

cause the rectifier circuit to switch between the full-wave rectifying mode and the voltage doubler rectifying mode;

monitor a voltage at the first inductive coil; and

cause the rectifier circuit to switch to the voltage doubler rectifying mode in response to the voltage being below a threshold;

wherein the rectifier circuit is configured to switch between the full-wave rectifying mode and the voltage doubler rectifying mode by selectively controlling a conduction state of each voltage-controlled switch of the set of voltage-controlled switches.

2. The power converter of claim 1, wherein the processing circuitry is further configured to:

cause the rectifier circuit to switch to the full-wave rectifying mode in response to the voltage exceeding the threshold.

3. The power converter of claim 1, wherein the rectifier circuit is configured to:

controllably pass the first induced current through a full-wave bridge rectifying circuit or a first voltage doubler rectifying circuit; and

pass the second induced current through a second voltage doubler rectifying circuit.

4. The power converter of claim 1, wherein the rectifier circuit is configured to:

controllably pass the first induced current through a first full-wave bridge rectifying circuit or a first voltage doubler rectifying circuit; and

controllably pass the second induced current through a second full-wave bridge rectifying circuit or a second voltage doubler rectifying circuit.

5. The power converter of claim 4, wherein the rectifier circuit is configured to simultaneously pass the first induced current through the first full-wave bridge rectifying circuit and pass the second induced current through the second full-wave bridge rectifying circuit.

6. The power converter of claim 1, wherein the rectifier circuit is configured to:

controllably pass the first induced current through a full-wave bridge rectifying circuit or a first voltage doubler rectifying circuit; and

controllably pass the second induced current through a second voltage doubler rectifying circuit or an impedance matching voltage doubler rectifying circuit.

7. The power converter of claim 1, wherein each of the set of voltage-controlled switches comprises a MOSFET.

8. The power converter of claim 7, wherein:

the processing circuitry is configured to cause the rectifier circuit to switch to the voltage doubler rectifying mode by toggling and holding one of the set of voltage-controlled switches in an on-state.

9. The power converter of claim 1, wherein:

the rectifier circuit further comprises a capacitor coupled to a high-side lead of an input to the rectifier circuit;

the set of voltage-controlled switches comprises;

a first voltage-controlled switch coupled to the capacitor and a low-side lead of the input; and

a second voltage-controlled switch coupled to the capacitor and a high-side lead of an output capacitor; and

the processing circuitry is configured to operate a turn-on timing and a turn-off timing of the first voltage-controlled switch and the second voltage-controlled switch;

wherein

the first voltage-controlled switch is turned off while the second voltage-controlled switch is turned on; and

the second voltage-controlled switch is turned on during at least half of a voltage cycle of an alternating current input signal applied to the rectifier circuit.

10. The power converter of claim 9, wherein the processing circuitry is further configured to monitor an output voltage from the rectifier circuit.

11. The power converter of claim 10, wherein in response to an increase in the output voltage the second voltage-controlled switch is turned on for a longer duration.

12. The power converter of claim 10, wherein in response to a decrease in the output voltage the second voltage-controlled switch is turned on for a shorter duration.

13. The power converter of claim 9, wherein each of the first voltage-controlled switch and the second voltage-controlled switch comprises a MOSFET.

14. The power converter of claim 1, wherein the first inductive coil and the second inductive coil comprise wireless power receivers.

15. A method of rectifying an alternating current, comprising:

operating a first inductive coil to output a first induced current;

operating a second inductive coil to output a second induced current;

operating a rectifier circuit, coupled to the first inductive coil and the second inductive coil, in a full-wave rectifying mode or a voltage doubler rectifying mode;

measuring an incoming voltage to a rectifier;

operating the rectifier in the full-wave rectifying mode in response to the measured incoming voltage exceeding a first threshold; and

operating the rectifier in the voltage doubler rectifying mode in response to the measured incoming voltage falling below a second threshold.

16. The method of claim 15, wherein the first threshold is the same as the second threshold.

17. The method of claim 15, wherein the first threshold is higher than the second threshold.

18. The method of claim 15, wherein the voltage doubler rectifying mode is an impedance matching voltage doubler rectifying mode.

19. The method of claim 15, wherein the rectifier comprises a set of voltage-controlled switches.

20. The method of claim 19, wherein the operating the rectifier circuit in the voltage doubler rectifying mode comprises toggling and holding one of the set of voltage-controlled switches in an on-state.