Abstract: An improved portable data entry machine is disclosed, wherein data may be keyed, viewed for accuracy, recorded on magnetic tape, recalled from magnetic tape, and telephonically transmitted for data processing. Improvements include a search feature to locate previously recorded data, an automatically controlled power switching unit to prolong the times that batteries may be used prior to recharging, microcomputer controlled circuitry to prevent attempted data entry under low-battery conditions, an electronic shutdown to prevent cell reversal, a voltage reference technique to minimize the power drain from the batteries, a unique mechanism and circuitry to preclude the inadvertent destruction of data, a low cost modem for communicating entered data to a remote location, an automatic interlock for the tape compartment, a highly effective display technique, a novel high voltage power supply, and an out-of-sequence detector.

Abstract: A novel high voltage power supply is disclosed which generates an unregulated output voltage from a dc input voltage. The magnitude of the unregulated output voltage may exceed the magnitude of the applied dc voltage. This output voltage appears across a capacitor which is in series with an inductor and a switch. The dc voltage is applied across the inductor and switch, and the switch is periodically closed by an oscillator. While the switch is closed, the voltage across the capacitor increases from energy supplied by the dc voltage. When the switch is open, the voltage on the capacitor is further increased by energy that was stored in the inductor while the switch was closed. A sensing circuit controls the opening and closing of the switch. The high voltage power supply is especially adaptable for use with a display of the gas discharge or plasma type.