ELM ELM712 Led runner Datasheet

ELM712
LED Runner
Description
Features
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.
• 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
VDD
1
8
VSS
LED4
2
7
LED3
LED5
3
6
LED2
start
4
5
LED1
• Holiday Ornaments
Block Diagram
Master Oscillator
VDD
start
ELM712DSB
4
Power
Control
Output Drivers
5
6
7
2
3
LED1
LED2
LED3
LED4
LED5
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ELM712
Pin Descriptions
VDD (pin 1)
This pin is the positive supply pin, and should
always be the most positive point in the circuit.
Internal circuitry connected to this pin is used to
provide power on reset of the microprocessor, so
an external reset signal is not required. Refer to
the Electrical Characteristics section for further
information.
LED1, LED2, LED3, LED4 and LED5
(pins 5, 6, 7, 2 and 3 respectively)
These are the five active high LED drive outputs.
They are energized in the order listed for
approximately 20msec each, at a rate of 10Hz.
Each output is capable of sourcing a maximum
of 25mA of current, when the ELM712 is
operated at the maximum supply level.
start (pin 4)
Momentarily connecting this pin to VSS will
initiate an LED sequence that typically lasts for
about 15 seconds. After this time, the circuit will
revert back to the low power mode, waiting for
another start signal. The circuit automatically
senses a ‘stuck button’ condition as well and
powers down the internal circuits, but not the
internal pull-up resistor.
VSS (pin 8)
Circuit common is connected to this pin. This is
the most negative point in the circuit.
Ordering Information
These integrated circuits are available in either the 300 mil plastic DIP format, or in the 200 mil SOIC surface
mount type of package. To order, add the appropriate suffix to the part number:
300 mil Plastic DIP............................... ELM712P
200 mil SOIC..................................... ELM712SM
Absolute Maximum Ratings
Storage Temperature....................... -65°C to +150°C
Ambient Temperature with
Power Applied....................................-40°C to +85°C
Voltage on VDD with respect to VSS............ 0 to +7.5V
Note:
Stresses beyond those listed here will likely damage
the device. These values are given as a design
guideline only. The ability to operate to these levels
is neither inferred nor recommended.
Voltage on any other pin with
respect to VSS........................... -0.6V to (VDD + 0.6V)
All rights reserved. Copyright ©1999 Elm Electronics.
Every effort is made to verify the accuracy of information provided in this document, but no representation or warranty can be
given and no liability assumed by Elm Electronics with respect to the accuracy and/or use of any products or information
described in this document. Elm Electronics will not be responsible for any patent infringements arising from the use of these
products or information, and does not authorize or warrant the use of any Elm Electronics product in life support devices and/or
systems. Elm Electronics reserves the right to make changes to the device(s) described in this document in order to improve
reliability, function, or design.
ELM712DSB
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ELM712
Electrical Characteristics
All values are for operation at 25°C and a 3V supply, unless otherwise noted. For further information, refer to note 1 below.
Characteristic
Minimum
Typical
Supply Voltage, VDD
3.0
3.0
VDD rate of rise
0.05
Average Supply Current, IDD
Start pin internal pullup resistance
LED Drive Current
Output Pulse Duration
470
Maximum Units
5.5
Conditions
V
see note 2
V/ms
0.60
2.0
mA
During operation
0.1
5
µA
In low power (standby) mode
750
1500
KΩ
see note 3
No series limiting resistor
200Ω series limiting resistor
VDD=3V
9
mA
VDD=5V
13
mA
20
msec
any output
Notes:
1. This integrated circuit is produced with a Microchip Technology Inc.’s PIC12C5XX as the core embedded
microcontroller. For further device specifications, and possibly clarification of those given, please refer to the
appropriate Microchip documentation.
2. This spec must be met in order to ensure that a correct power on reset occurs. It is quite easily achieved
using most common types of supplies, but may be violated if one uses a slowly varying supply voltage, as
may be obtained through direct connection to solar cells, or some charge pump circuits.
3. The value of the pullup resistance is both supply and temperature dependent.
Example Application
Using the ELM712 is straightforward,
requiring little explanation. Typically it is connected
in a circuit as shown at the right. Pressing the start
pushbutton once initiates a sequence of LED
flashes that last approximately 15 seconds.
The value of the resistor shown depends
on the voltage level that the circuit operates at. For
the circuit shown, no resistor is normally used, and
these points are jumpered out. For 5V operation, a
value of about 150 to 300 ohms is generally
inserted.
ELM712DSB
*see
text
8
3V
7
5
start
712
+
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