Head Amplifier IC Pattern Dependent Write Current Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Magnetic disk devices face challenges in efficiently changing the current values of high and low frequency write currents without additional terminals and lines, which is necessary for effective data writing, especially in data dependent write (DDW) or pattern dependent write (PDW) operations.
Innovation Solution
The magnetic disk device includes a head and an integrated circuit that detects patterns of varying frequencies in write data, adjusts current values of write currents accordingly, and outputs these adjusted currents to the head, utilizing a head amplifier IC with specific signal processing circuits to manage high and low frequency patterns without requiring additional terminals or lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If control signals are transmitted from the read/write channel to the head amplifier IC to change current values for pattern dependent write, then the ability to perform PDW is improved, but additional terminals and lines are required which increases device complexity
Solution Approach 1:
The patent combines the PDW control signal transmission with the existing write data signal path. The head amplifier IC integrates the functionality to detect data patterns and generate appropriate write current values without requiring separate control signal lines. This merging of functions eliminates the need for additional terminals while maintaining PDW capability.
Solution Approach 2:
The head amplifier IC is designed to autonomously detect data patterns from the write data input and self-generate the appropriate write current values. This self-service mechanism eliminates the need for external control signals from the read/write channel, thereby removing the requirement for additional terminals and lines while preserving pattern dependent write functionality.
2Manufacturing precision
If separate control signals are used for high frequency and low frequency data patterns, then precise current control is improved, but the number of required terminals and lines increases
Solution Approach 1:
The patent segments the write data signal processing within the head amplifier IC to separately handle high frequency and low frequency patterns. The integrated circuit contains distinct processing paths or detection mechanisms for different frequency ranges, allowing precise current control for each pattern type while using the same physical signal line, thus avoiding additional terminals.
Solution Approach 2:
The head amplifier IC implements a universal signal line that serves multiple functions: it carries write data input and simultaneously enables the IC to detect both high frequency and low frequency patterns. This multi-functional approach allows precise current control for different patterns without requiring separate dedicated control lines for each frequency type.
Data Source
AI summary
According to one embodiment, a magnetic disk device includes a disk, a head configured to write data to the disk, and an integrated circuit configured to acquire a detection signal indicative of a first pattern of a first frequency of write data, change a first current of a second pattern of a write current corresponding to the first pattern on the basis of the detection signal, detect a third pattern of a second frequency which is greater than the first frequency from the write data, change a second current of a fourth pattern of the write current corresponding to the third pattern, and output the write current with the changed first current and the changed second current to the head.