AH276 are integrated Hall sensors with output drivers, mainly designed for electronic commutation of brush-less DC Fan. This IC internally includes
the regulator, protecting diode, Hall plate, amplifier,
comparator, and a pair of complementary
open-collector outputs (DO, DOB).
While the magnetic flux density (B) is larger than
operate point (Bop), DO will turn on (low), and
meanwhile DOB will turn off (high). Each output is
latched until B is lower than release point (Brp),
and then DO、DOB transfer each state.
For DC fan application, sometimes need to test
power reverse connection condition. Internal diode
only protects chip-side but not for coil-side. If
necessary, add one external diode to block the reverse current from coil-side.