Datasheet

xOUT1
xOUT2
1
2
3
Drive Current
Slow decay
Fast decay
xVM
1
2
3
DRV8834
SLVSB19C –FEBRUARY 2012–REVISED JUNE 2013 www.ti.com
Figure 2. Decay Modes
The DRV8834 supports fast, slow, and also mixed decay modes. With DC motors, slow decay is nearly always
used to minimize current ripple and optimize speed control; with stepper motors, the decay mode is chosen for a
given stepper motor and operating conditions to minimize mechanical noise and vibration.
In mixed decay mode, the current recirculation begins as fast decay, but at a fixed period of time (determined by
the state of the xDECAY pins shown in Table 2) switches to slow decay mode for the remainder of the fixed
PWM period.
Table 2. Decay Pin Configuration
RESISTANCE ON xDECAY PIN -OR- VOLTAGE FORCED ON xDECAY PIN % OF PWM CYCLE IS FAST DECAY
< 1 kΩ < 0.1 V 0%
20 kΩ ±5% 0.2 V ±5% 25%
50 kΩ ±5% 0.5 V ±5% 50%
100 kΩ ±5% 1 V ±5% 75%
> 200 kΩ > 2 V 100%
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