Datasheet

 
SLUS318B – APRIL 1999 – REVISED JANUARY 2002
13
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APPLICATION INFORMATION
By pulse width modulating both the upper and lower power devices (QUAD=1), motor current always decays
during the PWM off time, eliminating any uncontrolled circulating currents. In addition, current always flows
through the current sense resistor, providing a suitable feedback signal. Figure 11 illustrates the current paths
during a four-quadrant torque reversal. Motor drive waveforms for both two- and four-quadrant operation are
illustrated in Figure 12.
UDG–01121
IPHASE
+ BEMF –
VMOT
IOFF
ION
S1
S3 S5
S2
S4
S6
Figure 11. Four-Quadrant Reversal