EUM6261/6261A 1A /18V PWM Fan Motor Driver DESCRIPTION FEATURES EUM6261/6261A is a fan motor driver for the single coil brushless DC motor. With its high efficient direct PWM control mode, EUM6261/6261A controls the speed of brushless DC motor with a built in HALL IC interface. EUM6261/6261A is suitable to drive variable speed motors for personal computer’s power supply radiation fans and CPU coolers. EUM6261/6261A integrates PWM fan speed control, minimum speed mode, fan tachometer, lock protection, auto restart and Hall Bias functions. PWM mode controls fan speed in low noise and low vibration ways by adjusting RCTL voltage. EUM6261/6261A can set minimum fan speed by presetting RMIN voltage. EUM6261/6261A internally limits to the 10% lowest fan speed. If a fan motor is stalled by the external force or obstacles, overdrive current may incur coil overheat and burning. To prevent motor from overheating, the lock protection circuit shuts down the internal power devices for a few seconds after the motor lock is detected. Then the auto restart circuit resumes to power up the internal power devices. If the lock persists, EUM6261/6261A shuts off power devices for a few seconds. The lock protection delay time is externally programmable by a capacitor. EUM6261/6261A has built in motor rotation speed feedback (FG) output, motor rotation detection (RD) output and Hall sensor bias output. z z z z z z z z z z z z Built in 18V Full-wave Fan Driver PWM Fan Speed Control Programmable Minimum Fan Speed Internal 10% Minimum Fan Speed Clamp Built in Soft Switching Function Built in Hall Bias Lock Protection and Auto Restart Fan Rotation Speed Feedback FG Output Fan Rotation Detection RD Output Thermal Shutdown Protection Available in TSSOP-16 Package RoHS Compliant and 100% Lead (Pb)-Free APPLICATIONS z Personal Computer’s Power Supply Radiation Fans and CPU Coolers Application Circuit Figure 1. Typical Application Circuit DS6261/6261A Ver1.1 Oct. 2008 1