The AH5792 smart motor controller from Diodes Inc. can be used to drive low-power, single-coil, brushless dc (BLDC) fans and motors. This single-chip solution integrates a Hall sensor and amplifier, complete digital control circuitry, and a full bridge output driver into a low-profile, SOT553 package (see the figure). These features eliminate the need for external components such as a timing capacitor and suit the device for low-voltage micro-motors and ultra-thin cooling fan applications. Its 1.8- to 5-V operating voltage range aids miniature dc fans requiring low-voltage startup.
The AH5792 serves single-phase, full-wave, BLDC motor control applications via its bi-directional (400-mA peak-current rated) H-bridge output stage and a pair of push-pull output drivers to source and sink current. It also protects motor windings from damage with integrated, locked rotor detection and with automatic self-restart functions that shut down the output driver in the event of a locked rotor and then restart the motor when the rotor is freed. A frequency generator output gives users tachometer-like feedback for external speed monitoring.
Operating temperature ranges from –40°C to 100°C. The controller fully complies with the European Union’s Restrictions on Hazardous Substances (RoHS) with its green molding compound. Available now, the AH5792 costs $0.20 in 1000-unit quantities. Delivery is four to six weeks in production volumes.