Power saving system for rotating disk data storage apparatus

Claim 1

In an apparatus for data transfer with a rotating data storage disk having a multiplicity of annular, concentric tracks including a reference track, a power saving system comprising: (a) a transducer for reading or writing data on a rotating data storage disk; (b) positioning means for positioning the transducer on any of the tracks on the disk; (c) power supply means for providing a supply voltage; (d) a voltage detector circuit connected to the power supply means for providing an output signal indicative of whether the supply voltage has built the to a predetermined value; (e) recalibration means connected to the positioning means for causing the same to position the transducer on the reference track on the disk when the supply voltage builds up to the predetermined value; (f) power save signal means for providing a power save signal having a first state indicative of the fact that the apparatus should be held powered, and a second state indicative of the fact that the apparatus may be held unpowered; and (g) a power saving circuit connected to all of the voltage detector circuit and the recalibration means and the power save signal means for holding a desired component of the apparatus unpowered when the power save signal is in the second state, the power saving circuit comprising means for permitting the recalibration means to cause the transducer to be positioned on the reference track when the apparatus is turned on, and for preventing the recalibration means from causing the transducer to be positioned on the reference track when the power save signal changes from the second to the first state, including: (i) first circuit means for providing a first power saving signal which is similar to the power save signal except for delayed transition from the second to the first state; (ii) second circuit means for providing a second power saving signal which is similar to the power save signal except for delayed transition from the first to the second state, the second power saving signal being applied to the voltage detector circuit for holding the same unpowered during the second state thereof; and (iii) logic circuit means having a first input connected to the first circuit means for inputting the first power saving signal, a second input connected to the voltage detector circuit for inputting the output signal thereof, and an output connected to the recalibration means; (h) whereby any desired component of the apparatus can be held unpowered when the power save signal is in the second state without recalibration taking place each time the power save signal changes from the second to the first state.