SM8144B

NIPPON PRECISION CIRCUITS—2

BLOCK DIAGRAM

PIN DESCRIPTION

Pin number

Name

I / O

Function

1

C H V

I

High-voltage DC input

2

L D R

O

Booster coil driver output

3

V S S

–

Ground

4

O S C

I

Coil and EL driver oscillator (oscillator frequency determined by external resistor)

5

E N A

I

Enab le input (built-in pull-down resistor)

6

V D D

–

Supply

7

OUT2

O

Output 2

8

OUT1

O

Output 1

VSS

OSC

VDD

CHV

LDR

OUT2

OUT1

Oscillator for

Boosting and EL driving

Switching Circuit

Dividing Circuit

1/4

Dividing Circuit

1/1024

ENA

Boosting Block

ENA from microcontroller

EL sheet

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When ENA is logical "H", SM8144B is active.

Oscillation Block