Bias Circuit for Power Supply Bus Line
Original Publication Date: 1986-Apr-01
Included in the Prior Art Database: 2005-Mar-08
In a disk memory device which has provisions for powering off one of two actuators for maintenance purposes, data is handled on the other actuator in the head disk assembly. In powering off an actuator, when a negative voltage supply to the actuator is turned off, the negative voltage bus can be pulled above ground through resistive elements in the circuits by the bias from a positive voltage supply, which may remain on. The two actuators share a common Read/Write Data line and a common servo clock line. If the negative voltage bus rises above ground, or even above -0.8 volt, interference with the data handling capability of the powered actuator is produced by a forward bias on the integrated circuit substrates, which degrades the data, and can even limit the voltage swing, on the Read/Write Data and servo clock lines.