The Melexis US168 is a one-chip solution for driving single-coil brushless DC (BLDC) fans and motors.
The IC includes Hall-effect sensor, chopping amplifier for offset cancellation, digital control circuitry and full bridge output driver.
The use of Soft Switching-concept lowers the acoustic and electrical motor noise and provides smoother operation.
The US168 device includes reverse voltage protection, locked rotor protection and thermal protection. Therefore, the IC robustness perfectly suits for consumer and automotive-on-board applications.
The integrated tachometer (FG) output follows the Hall sensor signal which allows determining the rotation speed. Its open-drain output facilitates the connectivity with external interface for hardware monitoring.
The built-in locked rotor protection automatically shuts off the coil current when the rotor is mechanically blocked for more than 0.4 second. The fan tries to restart every 2.8 seconds until the rotor is released. This on/off cycling reduces the average current by factor of 7. It is enough to prevent fans from overheating or damage.