Importance

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Abstract

A three-terminal serial-communication peripheral device for low-cost applications is described. The peripheral device comprises a first terminal for receiving a modulated power signal including a source of power and a clocking signal, a second terminal for receiving a reference potential such as a ground reference, and a third terminal for communicating data to and from the peripheral device. The peripheral device further comprises a digital subsystem which exchanges data with an application system. The exchanged data may be stored and retrieved by the digital subsystem, as when the subsystem is a memory unit, or the data may be in the form of measurement data which the peripheral device is supplying to the application system, the measured data being supplied by a sensor of the subsystem. With its three terminals, the peripheral device can communicate data to and from the application system. Because of the low number of required terminals, the peripheral device according to the present invention can be packaged in a low-cost package, thereby significantly reducing its overall cost. The peripheral device further comprises separation/detection circuitry for separating the clocking signal and the source of power on the first terminal. The separation/detection circuit converts the clocking signal into a clock signal having full logic levels suitable for digital logic operation, which is then coupled to the digital subsystem. The clocking signal may take the form of either voltage pulses or current pulses. In a preferred embodiment, the digital subsystem comprises a memory unit and the peripheral device serves as a memory device.

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First Claim