Comtec Information Systems Inc.

David L St Jean

John A Navakauskas

A battery pack having an electrical circuit including a battery array of one or more batteries, a thermostat switch, and a positive temperature coefficient resistor (PTCR). Preferably, the thermostat and PTCR are disposed in a trianguloid channel formed by the nip of adjacent cylindrical batteries in a multiple battery pack so that the finished pack may have the same size and shape as a non-protected pack for the same application. Preferably, the batteries are rechargeable and the pack includes a charging plug connected across the battery array in series with the thermostat and PTCR. Preferably, the pack is wrapped in a film of a heat-shrinkable polymer to provide physical integrity.

Short circuit and overcharge protected battery pack

A self-contained, high power, solid state, battery voltage switching system applies battery voltage to a thermal printhead when the printer is turned on and disconnects voltage from the battery to the thermal printhead when the printer is turned off, thereby conserving battery power and increasing battery life. FET switches connect the battery to the printhead and to a circuit for applying operating voltage to a drive and control circuit for the printhead. Gate voltage is applied to the FET, or FETs when a plurality thereof are connected in parallel, to enable the FETs to provide the connection between the battery and the printhead. The gate voltage is supplied from a flip-flop and a FET driver which are self-contained with the FETs and the other circuitry in the printer. Command signals from keys on a keypad or from a computer control unit in the printer or from a communication channel (radio or a communications link) set and reset the flip-flop so that the gate voltage is supplied and the printer is turned on when an on command signal is provided and maintained on until an off command signal occurs.

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Chepachet, RI, United States of America

David L St Jean