futaba presentation futaba europe gmbh november 2009

Futaba Presentation

Futaba Europe GmbH November 2009

VFD Operation Principle

- applied voltage heats up filament which causes thermionic emission

- when positive voltage is applied to grids, electrons are accelerated towards anodes

- when positive voltage is applied to phosphor coated anode, electrons collide with anodes and excite phosphor resulting in light emission

Function of Grids and Anodes

Non Light Emmision

(Grid - & Anode +/-)

Light Emmision

(Grid + & Anode +)

Non Light Emmision

(Grid + & Anode -)

Lead

Getter

ExhaustTip

Grid

GlassSubstrate

ContactLead

AnodeWiring

InsulationLayer

Filament

Anode

VFD Construction

GND

Grid

Ano

de

CLK

LAT

SI

BK

VDD

VH

Filament

ＶＦＤDriv

er C

hip

VFD Driver

Base Glass

Filament LeadIC Input LeadFilament Lead

CIG (Chip-in-Glass) VFD Construction

How to drive a Graphic CIG VFD ?

CIG Shift Registor Operation

Driver

Block Diagram

Driver

Timing Chart

Grid Scan Timing

Anode & Grid Construction (e.g. GP1184AI)

Anode & Grid Timing (e.g. GP1184AI)

Grid 1 Grid 2

Anode & Grid Timing Sequence

Grid 1 Grid 2

Anode & Grid Timing Sequence

Grid 3Grid 2

Anode & Grid Timing Sequence

Anode & Grid Timing Sequence (e.g. GP1184AI)

Anode & Grid Timing Sequence

Anode & Grid Timing Sequence

Shift Register Block Diagram

Anode Data (128bit) Grid Data (64 bit)

Shift Register Assignment

Anode Data

Grid Data

Dimming

VFD Power Supply Methods

Power Supply Solution 1: Royer circuit

Advantage: low component cost & high input voltage possible

Disadvantage: custom designed transformer required

Power Supply Solution 2:

For small Displays(high voltage)

LM9022

MC34063

Disadvantage:

higher component cost

& max. 5Vdc input

Advantage:

only standard

components required

Cut-off Bias Requirement (Ek)

Background: Electron Leakage