5.8 Back-EMF Sampler and Back-EMF Detection

The ATA6847 comes with a fully-integrated Back-EMF detection module, which converts the motor phase voltages into digital feedback signals. The Back-EMF unit includes a resistor network and three high-speed, Zero-Cross Detection comparators (ZCD). The scaled phase signals VSHx are compared with the emulated motor neutral point voltage for estimating the virtual zero crossing. The ZCD comparator outputs provide three digital feedback signals via the BEMF1, BEMF2 and BEMF3 pins.

Back-EMF detection is activated using the GDUCR1 Register.