INTERNAL CLOCK GENERATION

STAND-BY FUNCTION

VOLTAGE SET-UP CONVERSION FUNC-

TION

ANTI-RADIATION TRAPEZOIDAL WAVE FOR

E.L. DISPLAY DRIVING

CONSTANT

CURRENT

CHARGE/DIS-

CHARGE OF E.L. DISPLAY

2-STEP BRIGHTNESS CONTROL (NORMAL

OR DIMMED LUMINANCE)

PROTECTIONS WITH AUTOMATIC RESET:

- COIL-SWITCHING MOS OVERCURRENT

- CHIP OVERTEMPERATURE

DESCRIPTION

The TDA7475 is a new BCD OFF-LINE technol-

ogy device intended for EL display lighting in car-

radio applications. Time-extended luminance is

achieved by driving the display with constant-cur-

rent pulses, which will automatically compensate

for the ageing-related capacitance loss by provid-

ing more elevated voltage pulses.

November 2001

®

LSW

DSW

INTERNAL

VOLTAGE

SOURCE

OVER

VOLTAGE

PROTECTION

STAND-BY

CURRENT

LIMITER

OVER THERMAL

PROTECTION

QS

R

-

+

-

+

ERR. AMP.

PWM COMP

GATE

DRIVER

VCC

SENSE

CCHG

CCO

EL DRIVER CONTROL

DIMMER

CONTROL

VDC-sen

1/4 ~ 1/32

DIVIDER

CLK OSC

f=8,4,2,1KHz

f=32KHz

3

CEL

11

VDC

EL1

13

GATE

15

VCCO

16

VCC

10

9

EL2

2

VSB

4

ISET-N

5

ISET-D

6

VDM

7

CLKC

CCLK

8

CLKR

RCLK

1

TAB-GND

14

P-GND

RD

RN

D98AU980

ICP

ICN

BLOCK DIAGRAM

PowerSO16

ORDERING NUMBER: TDA7475A

TDA7475A

ELECTRO-LUMINESCENT DISPLAY DRIVER

BCD OFF-LINE TECHNOLOGY

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