EUM6862/a/b ds6862/a/b ver1.4 jun. 2011 1 24v pwm fan motor driver description EUM6862/a/b is a fan motor driver for the single co il brushless dc motor. with its high efficient direct pwm control mode, EUM6862/a/b controls the speed of brushless dc motor with a built in hall ic interface. EUM6862/a/b is suitable to drive variabl e speed motors for personal computers power supply radiation fans and cpu coolers. EUM6862/a/b integrates pwm fan speed control, minimum speed mode, soft start, fan tachometer, loc k protection, auto restart and hall bias functions. p wm mode controls fan speed in low noise and low vibrat ion ways by adjusting rctl voltage. EUM6862/a/b can set minimum fan speed by presetting rmin voltage. with soft start function, EUM6862/a/b can drive motor from slow speed to fast speed in a settable t ime by setting the external capacitor between ss and gn d. if a fan motor is stalled by the external force or obstacles, overdrive current may incur coil overhea t and burning. to prevent motor from overheating, the lock protection circuit shuts down the internal pow er 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 , EUM6862/a/b shuts off power devices for a few seconds. the lock protection delay time is external ly programmable by a capacitor. EUM6862 has built in motor rotation speed feedback (fg) output, motor rotation detection (rd) output and hall sensor bias output. application circuit features built in 24v full-wave motor driver for fan motor built in kickback voltage protection, no zener diode need external programmable soft start and soft restart function wide input range 3v~28v pwm fan speed control programmable minimum fan speed built in soft switching function built in hall bias lock protection and auto restart fan rotation speed feedback fg output (EUM6862/b) fan rotation detection rd output (EUM6862/a) thermal shutdown protection available in tssop-16 and tdfn-14 packages rohs compliant and 100% lead (pb)-free halogen-free applications pc/server fan motor, cpu coolers and printer cooling fan figure 1. tssop -16 24v and 12v typical application circuit
EUM6862/a/b ds6862/a/b ver1.4 jun. 2011 2 application circuit (continued) figure 2. tdfn-14 24v and 12v typical application c ircuit functional block diagram tssop-16 short together vcc and pvcc, separate pgnd and gnd tdfn-14 separate vcc and pvcc, short together pgnd and gnd figure 3. functional block diagram
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