Datasheet

PWM
F
O,DIFF IN
I
R
V
V = V
2 R
æ ö
- ´
ç ÷
è ø
VDD
GND
LRA or
DC Motor
2.5 V – 5.5 V
C
R
OUT-
OUT+
IN2
C
REFOUT
IN1
EN
DRV8601
R*Gain
R*Gain
C
SE PWM
Shutdown
Control
R
2*R
2*R
–
+
DRV8601
SLOS629B –JULY 2010– REVISED JANUARY 2012 www.ti.com
When driving motors which can sufficiently reject the PWM frequency by themselves, the feedback capacitor
may be eliminated. For this example, the output voltage is given by:
(4)
where the only difference from Equation 3 is that the filtering action of the capacitor is not present.
Figure 17. Differential Feedback with External Reference
SELECTING COMPONENTS
Resistors R
I
and R
F
Choose R
F
and R
I
in the range 20 kΩ – 100 kΩ for stable operation.
Capacitor C
R
This capacitor filters any noise on the reference voltage generated by the DRV8601 on the REFOUT pin, thereby
increasing noise immunity. However, a high value of capacitance results in a large turn-on time. A typical value
of 1 nF is recommended for a fast turn-on time. All capacitors should be X5R dielectric or better.
vertical spacer
vertical spacer
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Product Folder Link(s): DRV8601