Power interface for peripheral devices

Abstract

An interface (12) is disclosed for coupling a peripheral device (18) to the serial port (14) of a computer (16). In one application, the interface allows the serial port to provide the power required by a scanner for operation. To reduce power consumption, the scanner is typically operated in either a reduced-power, nonscanning mode or a higher power scanning mode. The interface may include an energy storage device (36) for storing energy from the serial port when the scanner is operated in the nonscanning mode and providing energy to the scanner when it is operated in the scanning mode. Thus, a scanner that requires more power than the serial port can provide at any one time can be used. The interface also includes a shutdown circuit (46) that prevents the scanner from being operated in conditions that might lead to the erroneous interpretation of data. Further, an input leakage isolation circuit (48) is included to prevent the discharge of the storage device when the scanner is not in use.

Dependencies are inferred from the claim text.