L6223A ST Microelectronics, Inc., L6223A Datasheet - Page 26

• Manufacturer Part Number: L6223A
• Description: Dmos Programmable High Speed Unipolar Stepper Motor Driver
• Manufacturer: ST Microelectronics, Inc.

Matching the L6223A with the motor.
For the correct design of the application the fol-
lowing notes must be considered.
* For low motor resistance and high supply volt-
* Only in single device application, for very low
* The correct motor winding execution is very im-
L6223A
26/33
age the L6223A minimum duty cycle may limit
the minimum current at a value higher than re-
quested.
In this case we suggest to reduce the window
protection time changing the RC oscillator net-
work. (See Fig. 21a and External RC Network).
motor resistance, a large current imbalance
may affect the correct motor rotation. Motor re-
sistance value higher than 7 Ohm are generally
recommended for 35V Power Supply.
portant for the motor and the L6223A efficiency.
A simple test is the measurement of the stray
inductance between the central tap and the
ends shorted together of each winding. Theo-
retically the inductance would be zero; values
higher than 50 H may show poor motor quality.
Computer Aided Development Board
An improvement in the application development
and in system debugging can be obtained by
means of the Personal Computer.
Interfacing the appliction with the PC, the motor
can be driven directly by this in real time opera-
tion. This permits the testing in very short time
and a lot of different motion configurations, during
application debugging and optimization. More-
over, by paralleling more application boards, an
efficient reliability test can be implemented.
The development board designed to drive
L6223A in Single and Dual Device configuration
is shown in Fig. 32a-b. Fig. 33 is the correspond-
ing electrical circuit. On the board are mounted
three L6223A: two for the Dual Device configura-
tion and one for the Single Device. The three con-
nectors J1, J2, J3 allow the application board to
be interfaced with the PC and to be paralleled
with another one. The remaining connectors pro-
vide the interface with the motor and the power
and logic supply. The ground area has been sized
to act as heatsink (35 micron thickness). When
the copper area is not sufficient to dissipate the
heat an external heatsink is required.