Motor positioning servo loop using oversampling bitstream DAC

摘要: A Hard Disk Drive VCM positioning servo loop comprises an oversampling bitstream Digital to Analog converter. The DAC is a sigma-delta converter which yields higher resolution and lower noise than Nyquist-rate DACs. This allows driving the with finer level of current control for track density. approach can be implemented in driver chip (“combo chip”) or microprocessor device either hardware software, reducing significantly development manufacturing cost. Furthermore this utilized combination actuation method known as “voltage mode drive” wherein output represents voltage applied directly actuator. optical data storage motor loops any other where high dynamic needed.