Self-powered computer accessory device for power extraction from attached data signals and method of operating thereof
US5438678A · kind A · utility
Inventor
Key dates
| Filing date | Mar 23, 1994 |
| Grant date | Aug 1, 1995 |
| Priority date | — |
| Expiry date | Mar 23, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F1/26
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A self-powered intelligent computer accessory device has a serial data input port and a parallel data output port and is used for interconnection from computer to computer and between a computer and a peripheral device. The accessory device uses a full wave diode bridge to generate bipolar supply voltages referenced to ground from the serial data port to power a microprocessor of the accessory device. A power extraction circuit is provided on the output side of the microprocessor for extracting power from standard pull-up resistors within the peripheral device to power an output buffer circuit. The period of time in which power is extracted from the pullup resistors is maximized by using an enable control signal from the microprocessor to ensure that the output buffer circuit is only driving the external peripheral device during the output data strobe sequence and at all other times is not consuming power. The buffer circuit is constructed and controlled such that it is capable of driving the load of the external peripheral device but draws virtually no power in performing this task.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.