Apple is working on an universal power adapter that could simultaneously charge a Mac laptop and an iOS device, per a new patent (number 20110278923) for a multi-output power supply at the US Patent & Trademark Office.

Per the patent, an apparatus for providing power to an electronic device may include a power input configured to receive an input voltage from a power supply, and a rectifier operatively connected to the power input and configured to convert the input voltage to a first voltage. The rectifier may further be configured to transmit the first voltage to a first power output operatively connected to the rectifier.

The apparatus may further include a power converter operatively connected to the rectifier and configured to convert the first voltage to a second voltage different than the first voltage and a first relay operatively connected to the rectifier to selectively prevent the first voltage from being transmitted through the first power output. The power converter may further be configured to transmit the second voltage to a second power output operatively connected to the power converter. The inventors are Aleksandar Pance, Nicholas Alan Rundle and John Douglas Field.

Here's Apple's background and summary of the invention: "Power adapters may be used to supply power to a variety of portable electronic devices, including laptop computers, personal digital assistants (PDAs), cell phones, digital media players, cameras, and so on, to operate such devices and/or to charge a rechargeable battery in such devices. The power supplied from power adapters is typically received from an external power source supplying alternating currently (AC) voltage. The power adapter may then convert the AC voltage into a direct current (DC) voltage that can be used by a connected electronic device.

"Most commercially available adapters do not include multiple outputs for supplying different DC voltage levels for powering multiple electronic devices and/or multiple internal batteries. As such, users may often purchase a device-specific adapter for powering a device. However, this requires that the user carry a separate adapter for each device, which can be cumbersome when a user is traveling, as many users may forget to bring all of the associated adapters required for various devices.

"Additionally, many adapters may be relatively heavy and bulky, making them difficult to carry while in transit. Likewise, having multiple adapters in a stationary location (such as a home or office) may be confusing. What is needed is a way to supply power to multiple connected electronic devices so that a user does not have to carry additional power adapters while traveling with multiple portable electronic devices.

"Generally, embodiments discussed herein may provide power to multiple electronic devices using a single power adapter. The embodiments typically, but not necessarily, include a DC-to-DC converter and multiple outputs for supplying power to two or more electronic devices. The DC-to-DC converter may be provided in the adapter itself, or may be provided in a cord or a connector that may be connected to the adapter and an electronic device. Additionally, some embodiments include a relay for intelligently controlling power supplied through the outlets so that power is supplied only to voltage or manufacturer compatible electronic devices.

"One embodiment takes the form of an apparatus for providing power to an electronic device may include a power input configured to receive an input voltage from a power supply, and a rectifier operatively connected to the power input and configured to convert the input voltage to a first voltage. The rectifier may further be configured to transmit the first voltage to a first power output operatively connected to the rectifier.

"The apparatus may further include a power converter operatively connected to the rectifier and configured to convert the first voltage to a second voltage different than the first voltage and a first relay operatively connected to the rectifier to selectively prevent the first voltage from being transmitted through the first power output. The power converter may further be configured to transmit the second voltage to a second power output operatively connected to the power converter.

"In one embodiment, the apparatus may include a second relay operatively connected to the power converter to selectively prevent the second voltage from being transmitted through the second power output. In another embodiment, the first relay may include a first logic configured to determine whether an electronic device operatively connected to the first power output is compatible with the first voltage. In a further embodiment, the second relay may include a second logic configured to determine whether an electronic device operatively connected to the second power output is compatible with the second voltage.

"In another embodiment, the first logic may be operatively connected to a first control line. In some embodiments, first control line and the first power output may be contained within a single output connector. In other embodiments, the connector may terminate in a magnetic connector. In another embodiment, the first logic may be configured to determine whether an electronic device is compatible with the first voltage based at least partially on whether the control line is in an active or inactive state. A further embodiment may include a housing enclosing at least the first power output and the second power output.

"Another embodiment takes the form of a method for supplying power to two or more electronic devices. The method may include receiving a first voltage of a first current type having a first voltage level and converting the first voltage to a second voltage of the first current type. The second voltage may have a second voltage level. The method may further include determining whether a first device is compatible with the first voltage level, determining whether a second device is compatible with the second voltage level, and in the event that the first device is compatible with the first voltage level, supplying the first voltage to the first power output. The method may also include supplying the second voltage to the second power output in the event that the second device is compatible with the second voltage level.

"Another embodiment takes the form of a connector cable. The connector cable may include a power input configured to receive a first voltage and a power converter operatively connected to the power input. The power converter may be configured to convert the first voltage to a second voltage having a second voltage level. The connector cable may further include a first connector operatively connected to the power input, a second connector operatively connected to the power converter, and a connector housing enclosing at least the first and second connectors."

-- Dennis Sellers