Dismiss
InnovationQ will be updated on Sunday, Oct. 22, from 10am ET - noon. You may experience brief service interruptions during that time.
Browse Prior Art Database

Optical Fiber LED Driver

IP.com Disclosure Number: IPCOM000110237D
Original Publication Date: 1992-Nov-01
Included in the Prior Art Database: 2005-Mar-25
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Kobayashi, Y: AUTHOR

Abstract

Disclosed is a circuit for driving multiple LEDs which consists of a constant-current regulator and shunt regulators. This new circuit enables multiple serially-connected LEDs to be independently controlled (turn-on and turn-off), with minimum power consumption and electro-magnetic interference (EMI). (Image Omitted)

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

Optical Fiber LED Driver

       Disclosed is a circuit for driving multiple LEDs which
consists of a constant-current regulator and shunt regulators.  This
new circuit enables multiple serially-connected LEDs to be
independently controlled (turn-on and turn-off), with minimum power
consumption and electro-magnetic interference (EMI).

                            (Image Omitted)

      A shunt regulator attached to each LED controls the current of
that LED. The maximum current of the LED is defined by the
constant-current regulator 1.  The pedestal current, which is the
minimum current of an LED, is defined by a shunt regulator 2.
maximum-LED-current = (current of constant-current regulator)
minimum-LED-current = (current of constant-current regulator)
                    - (maximum current  of  shunt regulator);

      The LED currents can be controlled independently, although all
the LEDs are connected serially and regulated by a common
constant-current regulator.

      Some pairs of LEDs and shunt regulators are serially connected
in order to reduce power-consumption.  This circuitry also reduces
EMI.