Communication using bi-directional LEDs
US7072587B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 19, 2002 |
| Grant date | Jul 4, 2006 |
| Priority date | — |
| Expiry date | Dec 23, 2023 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02D30/70
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical communications transceiver includes an LED coupled in series with a resistor. A microprocessor has one I/O pin connected to the LED. In a first mode or transmit mode, the LED is periodically driving in forward bias to emit light to transmit data. In a second or receive mode, the LED is periodically not driven in reverse bias, e.g., reverse bias or zero bias. Then, the LED is allowed to change charge of the capacitance of the LED's junction using a photo-current. The change in charge is measured using a timer. When the change in charge exceeds a predetermined threshold, input light is sensed. Thus, the LED can be used to receive data in the second mode.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.