ELM712
LED Runner
Description
The ELM712 is a handy circuit for controlling up
to five LEDs in novelty devices. One pushbutton
press is all it takes to initiate about 15 seconds of
LED activity, before the circuit reverts back to its
very low current standby mode.
All of the logic required for circuit operation is
contained wholly within this 8 pin integrated circuit.
Normally only a pushbutton, the LEDs, and a battery
are all that are needed for a complete circuit. At
higher voltages, a single current limiting resistor may
be required to limit LED current.
The ELM712 drives each LED output in a
sequential fashion, at approximately 10 Hz. By only
driving one output at a time, peak current and thus
battery requirements are reduced.
Features
• Low power CMOS design
• Wide supply range - 3.0 to 5.5 volt operation
• Auto-off mode conserves batteries
• Single push-button to activate
• Direct drive high current outputs
• No external timing components required
Connection Diagram
PDIP and SOIC
(top view)
Applications
• Campaign buttons
• Battery operated toys
• Dress ties
• Signs
• Holiday Ornaments
V
DD
LED4
LED5
start
1
2
3
4
8
7
6
5
V
SS
LED3
LED2
LED1
Block Diagram
Master Oscillator
V
DD
start
4
Power
Control
Output Drivers
5
6
7
2
3
LED1
LED2
LED3
LED4
LED5
ELM712DSB
Elm Electronics – Circuits for the Hobbyist
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