Using pulsed biases to represent DC bias for charging

• US 10,404,235 B2
• Filed: 05/31/2017
• Issued: 09/03/2019
• Est. Priority Date: 11/21/2013
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Menzel, Brian C., Alves, Jeffrey M., Keeler, Kevin M., Rich, Zachary C.
• Primary Examiner(s): Luu, An T
• Application Number:
  US15/610,202
• Publication Number:
  US 20170272058A1
• Time in Patent Office: 825 Days
• CPC Class Codes: H03K 3/01 Details
• CPC Class Codes: H03K 5/04 by increasing duration; by decreasing duration
• CPC Class Codes: H03K 5/13 Arrangements having a single output and transforming input signals into pulses delivered at desired time intervals

Abstract

Power transfer systems including a direct current source and a plurality of outputs operable in several modes. A ground mode may couple an output to circuit ground and a current mode may couple the output to the direct current source. The power transfer system may also include a controller configured to iteratively select a pair of outputs from the plurality of outputs. Once a pair is selected, the controller may set a first output of the pair of outputs to the current mode and the second to ground mode for a determined duration. After the duration has passed, the controller may set the first output to the ground mode and the second output to the current mode for the same duration. Thereafter the controller may select another pair of outputs.

Claims

1. An electronic device comprising:

a battery;

three or more inputs, each input comprising;

a ground mode in which the input is coupled to a negative terminal of the battery; and

a current mode in which the input is coupled to a positive terminal of the battery; and

an input controller configured to iteratively select a pair of inputs from the three or more inputs, the pair of inputs comprising a first input and a second input, and, upon each selection, the input controller is configured to;

set the first input of the pair of inputs to the current mode and the second input of the pair of inputs to ground mode;

set the first input to the ground mode and the second input to the current mode.

2. The electronic device of claim 1, wherein the three or more inputs are configured to couple to three or more outputs of a power transfer system.

3. The electronic device of claim 2, wherein the input controller is further configured to coordinate the iterative selection of the pair of inputs with an iterative selection of outputs by the power transfer system.

4. The electronic device of claim 1, wherein each input of the three or more inputs further comprises a float mode in which the input is floating.

5. The electronic device of claim 4, wherein the input controller is configured to, upon each selection, set each of the three or more inputs not selected to the float mode.

6. The electronic device of claim 1, wherein the input controller is configured to select pairs of inputs such that each sequential pair contains two inputs that were not members of the previous pair.

7. The electronic device of claim 1, wherein

the first input of the pair of inputs is set to the current mode and the second input of the pair of inputs is set to ground mode for a determined duration;

and

the determined duration is based in part on a corrosion rate of a material used to form an external surface of at least one input of the pair of inputs.

8. The electronic device of claim 1, wherein

the first input of the pair of inputs is set to the current mode and the second input of the pair of inputs is set to ground mode for a determined duration;

and

the determined duration is based in part on a surface area of each of the inputs of the selected pair of inputs.

9. The electronic device of claim 1, wherein

in the ground mode the input is directly coupled to the negative terminal of the battery;

and

in the current mode the input is directly coupled to the positive terminal of the battery.

10. The electronic device of claim 1, wherein the input controller is configured to select pairs of inputs such that each input of the three or more inputs is selected only a certain number of times per second.

11. An electronic device comprising:

three or more inputs; and

an input controller configured to iteratively select a pair of inputs from the three or more inputs, and upon each selection adapted to;

apply an incoming direct current waveform received at a first input of the selected pair of inputs to a positive terminal of a battery, with a second input of the selected pair of inputs coupling a negative terminal of the battery to ground;

apply an incoming direct current waveform received at the second input to the positive terminal, with the first input coupling the negative terminal to ground.

12. The electronic device of claim 11, wherein the input controller is configured to select pairs of inputs such that each sequential pair contains two inputs that were not members of the previous pair.

13. The electronic device of claim 11, wherein the input controller is configured to, upon each selection, set each of the three or more inputs not selected to float.

14. The electronic device of claim 11, wherein the input controller is further configured to coordinate applying the direct current waveform with a power transfer system coupled to the three or more inputs.

15. The electronic device of claim 11, wherein the input controller is configured to select pairs of inputs such that each input of the three or more inputs is selected only a certain number of times per second.

16. A method of reducing corrosion to power inputs of an electronic device comprising:

defining a plurality of input pairs from three or more inputs;

determining a pair activation sequence such that each sequential pair contains two inputs that were not within the previous pair; and

sequentially activating each pair in the activation sequence, each sequential activation comprising;

coupling a first input of the pair to a positive terminal of a battery;

coupling a second input of the pair to a negative terminal of the battery for a selected duration;

coupling the second input to the positive terminal of the battery;

coupling the first input to the negative terminal for the selected duration; and

causing the first input and the second input to float.

17. The method of claim 16, wherein each sequential activation occurs immediately after the previous activation.

18. The method of claim 16, wherein each sequential activation begins before the previous activation completes.

19. The method of claim 16, wherein the selected duration of each activation is based in part on a surface area of each of the inputs of the selected pair of inputs.

20. The method of claim 16, wherein the selected duration of each activation is based in part on a corrosion rate of a material used to form an external surface of at least one of the two inputs.