ELM413

Elm Electronics – Circuits for the Hobbyist

< http://www.elmelectronics.com/ >

LED Driver

The ELM413 is both an LED controller and a

circuit startup timer in an 8 pin package. The high

current capabilities of its outputs allow most LEDs to

be directly driven, usually only requiring a single

current limiting resistor.

The circuit startup, or warmup feature is useful

for allowing a stabilizing time period to pass before

enabling other circuits. This type of function is often

used in audio amplifier circuits where it is desirable

to block the speaker outputs until the amplifier

stages have stabilized. This can eliminate the

annoying

‘pop’

occasionally

heard

from

audio

amplifiers.

The duration of the warmup period is selected

by logic levels on two input pins, providing four

discrete time intervals. All circuit timing is derived

from internal circuitry, and no additional timing

components are required for circuit operation.

Description

• Pilot ‘lamp’ circuits

• Sequentially enabled systems

• Delay on operate circuits

• Audio amplifier power managers

• Monostable (one-shot) circuits

Applications

Block Diagram

1 of 4

• Low power CMOS design - typically 1mA at 5V

• Operates over a supply range of 3.0 to 5.5 volts

• Schmitt trigger controlled operation

• Requires no external timing components

• Warmup periods from 0.1 to 5 seconds

• Auxiliary output active after warmup period

• High current drive outputs - up to 25 mA

Features

ELM413DSA

Connection Diagram

PDIP and SOIC

(top view)

1

2

3

4

8

7

6

5

AuxOut

Trigger

W1

W0

Red

Green

W1

W0

Period

L

H

0.5 sec

0.1 sec

5 sec

1 sec

H

H

H

L

L

L

Warmup Period

4

5

Trigger

2

Flasher

7

3

Control

and

Timing

6

Red

W0

W1

Green

AuxOut