DRV8601 Datasheet, PDF (10/20 Pages) Texas Instruments – Haptic Driver for DC Motors (ERMs) and Linear Vibrators (LRAs) with Ultra-Fast Turn-On

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:
æ
V_O,DIFF = _çè V_IN
-
VPWM ö
2 ^÷ø
´
R_F
R_I
(4)
where the only difference from Equation 3 is that the filtering action of the capacitor is not present.
C
2*R
C_R
2*R
Shutdown
Control
R
SE PWM
R*Gain
REFOUT VDD
IN2
OUT-
EN ^DRV8601
IN1
OUT+
GND
2.5 V – 5.5 V
+ _{LRA or}
– ^{DC Motor}
R*Gain
C
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.
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