Diodes has introduced the single-chip fan driver with high-output drive capability for fan and motor drive applications. Designed for driving single-phase BLDC (brushless DC) fans and motors, the AH5795 can provide an average motor current up to 500mA. With the help of DFN (dual flat no lead) packaging technology, the fan driver is claimed to integrate a high-sensitivity Hall effect sensor, amplifier and an internal H-bridge driver output stage, suitable for single-coil fan motor applications. A PWM speed control pin provides motor speed control by varying the duty ratio of the PWM signal, in addition to the supply voltage.
The driver is claimed to operate at 1.8 to 6V caters for BLDC fans requiring low-voltage start-up in both Vdd (drain supply) and PWM speed control modes. The driver's bi-directional full-bridge driver uses soft switching to minimise audible switching noise and EMI.
To protect the coil from overheating, the latest motor controller includes integrated locked rotor detection and automatic self-restart functions, which serve to shutdown the output driver in the event of a locked rotor and then restart the motor when the rotor is freed. A tachometer output is provided by an open-drain frequency generator, which allows external speed monitoring. The all-in-one motor controller is claimed to eliminate the need for the external components, including a timing capacitor.
The driver operates from -40 to 105°C. The driver is available in DFN2020-6 and TSOT23-6 packages, and is RoHs-compliant with green molding compound.
