APPLICATION NOTES
BRIDGE DRIVE CONSIDERATIONS
It is important that the logic used to turn ON and OFF the various transistors allow sufficient "dead time" between a high side
transistor and its low side transistor to make sure that at no time are they both ON. When they are, this is called "shoot-through",
and it places a momentary short across the power supply. This overly stresses the transistors and causes excessive noise as well.
See Figure 1.
This deadtime should allow for the turn on and turn off time of the transistors, especially when slowing them down with gate
resistors. This situation will be present when switching motor direction, or when sophisticated timing schemes are used for servo
systems such as locked antiphase PWM'ing for high bandwidth operation.
Figure 1
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Rev. - 5/01
MSK [ M.S. KENNEDY CORPORATION ]
