Emulation of LED input characteristics in BICMOS process
US9484913B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 9, 2015 |
| Grant date | Nov 1, 2016 |
| Priority date | — |
| Expiry date | Mar 9, 2035 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L25/0266
- WIPO fieldBasic communication processes
- WIPO sectorElectrical engineering
Abstract
An LED input emulator to interface a signal source designed for use with an LED optocoupler, to capacitive or other galvanic isolation circuitry, emulating LED forward and reverse bias voltages. VR reverse blocking circuitry includes MP1 and MP2 PMOS transistors coupled to an emulator anode port, and to emulate LED reverse bias voltage. VF control circuitry includes a variable resistance (MP3) coupled between anode and cathode ports, and a current control circuit coupled to an output node, and to control current through the variable resistance to maintain a desired forward voltage at the output node. In an example embodiment, the VF control circuitry is implemented with an amplifier and a bandgap voltage reference circuit coupled to the output node, generating both reference and feedback voltages input to the amplifier to control the variable resistance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.