Axiohm Transaction Solutions, Inc.

Randolph Bullock

James R Del Signore, Ii

Steven M Spano

James Del Signore

A USB interface having improved EMC immunity where the D+, D&#x2212;, and USB ground lines each pass through a common mode choke. The USBV line is AC coupled to the USB ground line outside the choke and routed through a high impedance into the circuit while maintaining the integrity of the signal. In addition, bypass capacitors, such as Tantalum bypass capacitors, and aV Transorb device are added to theV power supply of the controller, and all unused pins are terminated to reduce unwanted ringing transients in the controller leadframe. In addition, small capacitors within the capacitive loading specification allowed by the USB-IF are positioned next to the controller on each data line.

EMC immunity improvements to USB interface

An inrush circuit for electronic devices is particularly useful for point-of-sale printers. The circuit applies an active feedback-controlled voltage ramp to a bulk capacitor by means of a P-channel field effect transistor that is operated linearly after a controlled delay for contact bounce.

Growing community of inventors

Dryden, NY, United States of America

Randolph Bullock