NJM3517

R

i

Figure 15. Power return turn-off circuit

Figure 16. Power return turn-off circuit

for bi-level

Figure 13. Resistance turn-off circuit

Figure 14. Zener diode turn-off circuit

Figure 12. Diode turn-off circuit

0V

Power supply

s INPUT AND OUTPUT SIGNALS FOR DIFFERENT DRIVE MODES

The pulse diagrams, figures 7 through 10, show the necessary input signals and the resulting output signals for

each drive mode.

On the left side are the input and output signals, the next column shows the state of each signal at the cursor

position marked “C.”

STEP is shown with a 50% duty cycle, but can, of course, be with any duty cycle, as long as pulse time (t

within specifications.

P

L

s USER HINTS

1.

Never disconnect ICs or PC-boards when power is supplied.

2.

If second supply is not used, disconnect and leave open V

diodes (D1, D2) with a straight connection.

3.

Remember that excessive voltages might be generated by the motor, even though clamping diodes are used.

4.

Choice of motor. Choose a motor that is rated for the current you need to establish desired torque. A high

supply voltage will gain better stepping performance. If the motor is not specified for the V

limiting resistor will be necessary to connect in series with center tap. This changes the L/R time constant.

5.

Never use L

net. An alternative is to trigger the mono-flip-flop by taking a STEP and then externally pulling the RC pin

(12Pin) low (0V) for the desired on-time.

6.

Avoid V

The common place for ground should be as close as possible to the IC’s ground pin (pin 3).