TB6575FNG

2006-3-6

7

8.

Lead angle control

The motor runs with a lead angle of 0° in forced commutation mode at startup. After switching to natural

commutation, the lead angle automatically changes to the value set by the LA pin.

9.

Overlap commutation

When SEL_LAP

= high, the TB6575FNG is configured to allow for 120° commutation. When SEL_LAP =

low, it is configured to allow for overlap commutation. In overlap commutation, there is an overlap period

during which both the outgoing transistor and incoming transistor are conducting (as shown in the shaded

areas). This period varies according to the lead angle.

(3) Lead angle of 15°

OUT_WN

OUT_VN

OUT_WP

Back-EMF

PWM signal

(1) Lead angle of 0°

OUT_UP

OUT_UN

OUT_VP

OUT_VN

OUT_WP

OUT_WN

(2) Lead angle of 7.5°

OUT_UP

OUT_UN

OUT_VP

OUT_UP

OUT_UN

OUT_VP

OUT_VN

OUT_WP

OUT_WN

UV

W

30°

22.5°

15°

*OS

= High

(2) Lead angle of 15°

OUT_WN

OUT_VN

OUT_WP

Back-EMF

PWM signal

(1) Lead angle of 7.5°

OUT_UP

OUT_UN

OUT_VP

OUT_UP

OUT_UN

OUT_VP

OUT_VN

OUT_WP

OUT_WN

UV

W

*OS

= High