DRV8800 Datasheet, PDF (14/20 Pages) Texas Instruments – DMOS FULL-BRIDGE MOTOR DRIVERS

DRV8800
DRV8801
SLVS855A – JULY 2008 – REVISED JULY 2008 ............................................................................................................................................................... www.ti.com
DRV8800
VBB
1
3
2
1 Drive Current
2 Fast decay with synchronous rectification (reverse)
3 Slow decay with synchronous rectification (brake)
DRV8801
VBB
4
1
3
2
1 Drive Current
2 Fast decay with synchronous rectification (reverse)
3 Slow decay with synchronous rectification (brake) Low Side
4 Slow decay with synchronous rectification (brake) High Side
Figure 3. Current Path
Fast Decay With Synchronous Rectification
This decay mode is equivalent to a phase change where the opposite drivers are switched on. When in fast
decay, the motor current is not allowed to go negative (direction change). Instead, as the current approaches
zero, the drivers turn off. The power calculation is the same as the drive current calculation (see Equation 1).
14
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