EM6821 datasheet(46/68 Pages) EMMICRO

46 / 68 page

EM6821

www.emmicroelectronic.com

14. LCD Driver

The EM6821 has a built-in Liquid Crystal Display (LCD) driver. A maximum of 80 Segments can be displayed

using the 20 Segment driver outputs (SEG[20:1) in 4:1 multiplex ,60 Segments in the case of 3:1 multiplex, and

the 4 back-planes (COM[4:1]).

The LCD driver has its own voltage regulator (1.05 Volt) and voltage multiplier to generate the driver bias

voltages VL1, VL2 and VL3 (VLCD). Using the metal1 mask the user can choose higher LCD reference

voltages. Please check with EM Marin the possible values and their impact on power consumption.

The special architecture of this LCD driver allows the user to freely specify the data and address for each

individual Segment using the interconnect metal2 mask . It therefore adapts to every possible LCD display with

a maximum of 80 independent segments. The LCD clock frequency is 256Hz. Thus the frame frequency is

256/8 Hz if 4:1 multiplex, or 256/6 if 3:1 multiplex.

Figure 35. LCD Architecture

RefLCD

LCD External

Supply

LCD Blank

Address

Bus

SEG[n]

Enable

Voff

LCD Off

Von

MUX

Output

Switches

Voltage

Multiplier

Phase

Selection

Data

Latches

Data

Bus

Phase 1 to 4

VL1

VL2

VL3

EM6821 Datasheet(PDF) 46 Page - EM Microelectronic - MARIN SA