| 摘要 |
The subject invention provides a digital Storage System such as a Winchester Hard Disk Drive System having a motorized hard disk drive assembly which interacts with a head positioner to read and write data and timing instructions onto a plurality of disks driven by the assembly. The drive system includes a data separation circuit for reconstruction of data recorded on the hard disk. The data separation circuit includes a phase-locked loop system. The phase-locked loop system includes a phase comparison circuit, a voltage controlled oscillator, a control circuit including a capacitor for controlling said oscillator, and a charge pump for pumping up and pumping down the control circuit. Except for the phase comparison circuit, the entire phase-locked loop system is provided on a monolithic integrated chip. Included within the integrated circuitry is the charge pump which has lateral PNP transistors which provide a steady current source and also has NPN transistors which provide fast, dynamic switching, including selective diversion of the constant current, enabling the capacitor of the control circuit to both charge up and charge down on command of the charge pump using the high speed NPN transistors.
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