International Business Machines Corporation

Rafael Pelc

Gilbert B Nebgen

There is disclosed an improved drive circuit for a print element actuator wherein the current applied to the actuator has a fast rise mode which is terminated when a predetermined level has been reached. Current is allowed to slowly decay through the circuit until it reaches a second and lower predetermined level. The circuit is self-timing and self-compensating for variations in voltage or actuator impedance.

Self-timing and self-compensating print wire actuator driver

A logic driver circuit repowers signals in either direction along a line, without requiring any external direction-control signal. Two back-to-back driver halves each include a gate, an open-collector transmitter and a latch. The latch is connected to the gate and transmitter to prevent race conditions.

Self-switching bidirectional digital line driver

A resistor senses low-level drive current is a logic circuit. When the output is shorted, excessive drive current turns on a sensor transistor, which causes drive voltage to the output stage to be clamped to ground, and to remain clamped until the fault is removed.

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Rochester, MN, United States of America

Rafael Pelc