Use of BridgeSwitch Current Sense Signal Output in Field-oriented Control of BLDC Motors

This function of BridgeSwitch can eliminate commonly used discrete current sense resistors and associated amplifiers, thereby reducing cost and design complexity. A proposed algorithm allows using the small signal output provided by each device through directly measuring, reconstructing, and predicting the full phase current information in 3-phase motor drives utilizing FOC where the motor provides the rotor position information.

BridgeSwitch devices offer an integrated phase current (IPH) output signal. The IPH output provides a small signal current; proportional to the instantaneous-channel current flowing thru the low-side FREDFET (the output does not provide a signal when the diode is conducting). This eliminates the need to add a DC offset to the measured motor current.