The AP1304/5 is single phase full wave drive design, which is suited for small fans (such as CPU cooling fans). The low switching noise and effective motor drive are another advantage. All functions, including lock shutdown, automatic restart, rotation detection (RD), and speed indication output (FG) have been incorporated into one chip. When the motor is under lock condition, lock shutdown function turns off the output current. When the lock condition is removed, the IC automatically restarts and allows DC fan to run. In addition, the RD function is to detect the motor status and the FG is to provide the rotation speed.