UDN2916A
The circuit will stand any order of turn-on or turn-
off the supply voltages V
S
and V
SS
. Normal dV/dt
values are then assumed.
Preferably, V
Ref
should be tracking V
SS
during
power-on and power-off if V
S
is established.
APPLICATION INFORMATIONS
(Note 1)
Some stepper motors are not designed for contin-
uous operation at maximum current. As the circuit
drives a constant current through the motor, its
temperature might increase exceedingly both at
low and high speed operation.
Also, some stepper motors have such high core
losses that they are not suited for switch mode
current regulation.
Unused inputs should be connected to proper
voltage levels in order to get the highest noise im-
munity.
As the circuit operates with switch mode current
regulation, interference generation problems
might arise in some applications. A good measure
might then be to decouple the circuit with a 100nF
capacitor, located near the package between
power line and ground.
The ground lead between R
s
, and circuit GND
should be kept as short as possible.
A typical Application Circuit is shown in Fig. 3.
Note that C
t
must be NPO type or similar else.
To sense the winding current, paralleled metal
film resistors are recommended (R
s
)
Note 1
- Other information is available as ”Smart
Power Development System”: HWPC2916A.
Figure 3:
Typical Application Circuit.
6/8
STMICROELECTRONICS [ STMICROELECTRONICS ]
