Power supply for portable electronic processing machine - permits recharge of battery and contains circuit for data transfer

摘要

The portable electronic machine is able to store and process data and is miniaturised to be carried in a pocket. Such a machine is powered from a power unit which allows the batteries to be recharged. It also contains data transmission circuits to permit connection to external equipments. The power supply circuit (10) is connected to a power inlet plug (2) and produces a dc supply (VR) which is connected via a switching transistor (15) controlled from a switching circuit (5). This is controlled from a comparator (13) to allow the machine battery (21) to be recharged when the terminal voltage falls. A diode (22) prevents discharge of the battery during conduction of switching transistors (15,24). An interface circuit (12) and modulator-demodulator (11) are connected to the machine via plugs (3,4) to allow transmission of binary data.