Selectively powered data interfaces

An apparatus including a plurality of separately powered electrical circuits, comprising:

• a plurality of electrical circuits, wherein each electrical circuit includes one or more power inputs;
• a plurality of power switch circuits, wherein each power switch circuit includes a control input and includes a power output connected to a distinct one of the power inputs of the electrical circuits;
• one or more isolator circuits, the one or more isolator circuits each including an isolator control input, a data input, and a data output;
• and
• a controller circuit characterized by a plurality of states of operation that include a plurality of activation states, wherein each respective activation state corresponds to a distinct respective one of said electrical circuits;
• wherein the controller circuit, when operating in at least one of the activation states, is configured to send at least one signal to at least one of the control inputs so that each of the one or more power switch circuits whose power output is connected to the electrical circuit corresponding to said activation state is enabled and each of the other one or more power switch circuits is disabled;
• wherein the controller circuit, when operating in the at least one of the activation states, is configured to send at least one isolator signal so that at least one isolator circuit associated with the enabled one or more power switch circuits is enabled and so that at least one isolator circuit associated with the disabled one or more power switch circuits is disabled.

An apparatus configured to communicate with a host electrical device external to the apparatus, comprising:

• a plurality of host interface circuits, wherein each host interface circuit includes one or more power inputs;
• a plurality of power switch circuits, wherein each power switch circuit includes:
• (i) a control input;
• (ii) a power input configured to receive power from a host electrical device external to the apparatus, and
• (iii) a power output connected to a distinct one of the power inputs of the host interface circuits;
• one or more isolator circuits, wherein each isolator circuit includes:
• (i) an isolator control input;
• (ii) a data input;
• and
• (iii) a data output;
• and
• a controller circuit that is configured to:
• send an enable signal to the control input of each of the power switch circuits whose power output is connected to a selected one of the host interface circuits;
• send a disable signal to the control input of each of the other power switch circuits;
• send an isolator enable signal to the control input of each of the isolator circuits while it sends said enable signal to each of the plurality of power switch circuits connected to said one electrical circuit;
• and
• send an isolator disable signal to the control input of each of the isolator circuits while it sends said disable signal to each of the plurality of power switch circuits connected to said one electrical circuit.

A non-volatile memory peripheral device, comprising:

• a plurality of host interface circuits, wherein each host interface circuit includes one or more power inputs;
• a plurality of power switch circuits, wherein each power switch circuit includes:
• (i) a control input;
• (ii) a power input configured to receive power from a host electrical device external to the apparatus, and
• (iii) a power output connected to a distinct one of the power inputs of the host interface circuits;
• one or more isolator circuits, wherein each isolator circuit includes:
• (i) an isolator control input;
• (ii) a data input;
• and
• (iii) a data output;
• a controller circuit configured to send an enable signal to the control input of each of the power switch circuits whose power output is connected to a selected one of the host interface circuits, configured to send a disable signal to the control input of each of the other power switch circuits, configured to send an isolator enable signal to the control input of each of the isolator circuits at least partly while it sends said enable signal, and configured to send an isolator disable signal to the control input of each of the isolator circuits at least partly while it sends said disable signal;
• a non-volatile memory;
• and
• a memory controller connected between the non-volatile memory and at least one of the host interface circuits.

An apparatus providing isolation between first and second electrical circuits, comprising:

• first and second circuits, wherein the first circuit includes a number of data inputs, and wherein the second circuit includes said number of data outputs;
• said number of isolator circuits, wherein each respective isolator circuit includes a control input, a data output connected to a respective data input of the first circuit, and a data input connected to a respective data output of the second circuit;
• and
• a power switch circuit having a control input and a power output;
• wherein each isolator circuit, in response to receiving an enable signal at its control input, is configured to couple its data input to its data output;
• wherein each isolator circuit, in response to receiving a disable signal at its control input, is configured to disconnect its data input from its data output and sets its data output to zero volts;
• wherein the first electrical circuit includes a power input connected to the power output of the power switch circuit;
• and
• wherein the power switch circuit, in response to a signal received at its control input, is configured to selectably enable and disable a supply of electrical power to the power input of the first electrical circuit.

A method of receiving electrical power from, and transferring data with, a host electrical device external to an apparatus, the apparatus comprising:

• a plurality of electrical circuits, wherein each electrical circuit includes one or more power inputs;
• a plurality of power switch circuits, wherein each power switch circuit includes a control input and includes a power output connected to a distinct one of the power inputs of the electrical circuits;
• one or more isolator circuits, the one or more isolator circuits each including an isolator control input, a data input, and a data output;
• and a controller, the method comprising:
• receiving electrical power from the host electrical device;
• sending the electrical power to at least one of the plurality of power switch circuits;
• sending, by the controller, at least one signal to at least one of the control inputs so that each of the one or more power switch circuits, whose power output comprises at least a part of the electrical power and is connected to at least one of the electrical circuits, is enabled and each of the other one or more power switch circuits is disabled;
• and
• sending, by the controller, at least one isolator signal so that at least one isolator circuit associated with the enabled one or more power switch circuits is enabled and so that at least one isolator circuit associated with the disabled one or more power switch circuits is disabled.