ELM460
Example Applications
Uses for the ELM460 are numerous and only
limited by the imagination of the designer. Any circuit
where events are expected to occur on a regular basis
are typical applications for this device. Two example
uses are shown below.
This type of flasher circuit might seem ideal at first
for burglar alarm type warning LEDs, and it would be for
many installations. Consideration should be given
however, to the fact that the ELM460 draws about 1mA
continuously from the supply. This might be too much
for some battery powered systems.
Figure 2 shows the ELM460 used to continuously
operate a stepper motor, using an ELM311 stepper
motor controller. The ELM460 is connected to
constantly provide a step input at a rate of 10 steps per
second (P1=L, P0=L, M1=L and M0=L).
The ELM460 can be easily employed in many
circuits where timers such as the ‘555 or ‘2240 are
currently used in, without the need for timing capacitors
or charge and discharge resistors. Although the
operating voltage ranges are different, and the output
current drive of the ‘460 is not as great as the ‘555, the
ease in which it is connected, and its ability to be
programmed with logic level signals, are appealing to
the designer. All of these types complement one
another, however, and each should be chosen on its
merits for the particular application.
Figure 3 below shows another use for the ELM460,
directly driving an LED. The circuit is configured to
provide 1 flash every 2 seconds (P1=L, P0=H, M1=L
and M0=H). Although the IC is capable of both sinking
and sourcing relatively high currents, it’s sink
capabilities are slightly greater than it’s source (for a
given output Vds voltage drop) and that is exploited
here, by sinking the LED current. As always, a VDD
bypass capacitor is shown in the schematic, as it is
good practice to include one.
A
+5V
1
2
3
4
8
7
6
5
To winding
drive circuits
B
C
D
0.1µF
1
2
3
4
8
7
6
5
Figure 2. Continuously Running a Stepper Motor
+5V
0.1µF
1
2
3
4
8
7
6
5
300W
+5V
Figure 3. LED Flasher
ELM460DSB
Elm Electronics – Circuits for the Hobbyist
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