Solid state isolation device using opto-isolators
USRE35901E · kind E · reissue
Assignee
Inventors
Key dates
| Filing date | Feb 20, 1996 |
| Grant date | Sep 22, 1998 |
| Priority date | — |
| Expiry date | Feb 20, 2016 |
Classification
- Technology area (CPC —)General
Abstract
An improved solid state isolation device that uses opto-isolators to provide an electrical barrier between a telephone network and user telephone equipment includes a load and current control circuit, and an adjustable termination circuit to eliminate or reduce signal distortion and insensitivity to low signal levels resulting from low loop current, and lack of complex impedance compensation/termination for diverse telephone system parameters. An improved trans-hybrid return loss circuit reduces internal losses; while loop termination losses are reduced by the use of Shottky diodes in the line coupler circuit. A high pass filter improves common mode rejection ratios in the transmit and receive paths, and adjustable compensation is provided to account for manufacturing variances in the opto-isolators. An additional connection is also provided to adapt the opto-isolator circuit for use with 3-wire ring circuitry.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.