Kirk Wallace wrote: > I'm a little confused about the bldc comps. My study of bldc so far > indicates that the top and bottom of three half-bridges need to to be > controlled, so I though the comps would need six outputs instead of the > three (3 digital top, 3 PWM bottom). What am I missing? > There are a couple ways to control a 3-phase motor. The classic six-step scheme, which I use in my brushless servo amps, have a bridge high, a bridge low, and a bridge set to open circuit. So, that does require six wires. It is also possible to drive a motor in PWM sinewave mode, where all 3 bridges are active all the time. If the power stage can control the deadtime between high side and low side transistors, then you would only need 3 signals to control it.
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