Driver IC Controls Fan Motor Speeds

The ZXBM1004 pre-driver IC offers flexible, variable-speed control of single-phase brushless DC fans and blowers. The device is compatible with NTC thermistor, voltage and pulse-width modulated (PWM) input signals. It provides thermal control of single-phase motors up to 100W in PC, mainframe and other applications dependent on forced-air cooling. The driver’s adjustable minimum speed setting prevents the fan from running too slowly or being unable to start. An external resistor protects the speed-control circuit against supply voltage fluctuations, ensuring that airflow is maintained at its target level. A built-in automatic restart function is set by a single capacitor. An integral Hall-effect amplifier enables Hall sensors to be wired directly to the controller to detect fan rotation and speed. Two diagnostic outputs are provided: pulsed rotor speed and locked-rotor alarm. The device is packaged in a 16-pin QSOP. Price is $0.88 each/1,000. ZETEX INC., Hauppauge, NY. (631) 360-2222.