Motor Controller Oscillator Calibration for Emergency Head Parking
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Solution Overview
Problem
Conventional hard disk drives (HDDs) face inaccuracies in internal clocks due to variations in manufacturing, making emergency parking of read/write heads challenging, as the system clock may be irregular, missing, or not powered, leading to unreliable timing references.
Innovation Solution
A calibration module that evaluates the system's operation to determine if it is in a specific mode and calibrates a first clock source using a second clock source, storing the calibration value to ensure accurate timing, and can power the first clock source using an emergency power supply if necessary, allowing the internal oscillator to be used as a timing reference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an internal oscillator is used as a clock source for the internal clock, then the device complexity is reduced and ease of manufacture is improved, but the measurement precision and reliability of timing references deteriorate due to manufacturing variations in resistive and capacitive elements
Solution Approach 1:
The patent applies preliminary action by performing oscillator calibration during manufacturing or initialization. The calibration process measures the actual oscillation frequency of the internal oscillator and stores calibration values that compensate for manufacturing variations. This preliminary calibration ensures that the internal oscillator provides accurate timing references throughout the device's operation, resolving the contradiction between ease of manufacture and timing precision.
2Reliability
If the system clock is used for timing during emergency parking, then the timing reference is available, but the reliability deteriorates when the system clock is irregular, missing, or not powered
Solution Approach 1:
The patent introduces an intermediary calibration mechanism that mediates between the system clock and the internal oscillator. The calibration module acts as an intermediary layer that can provide accurate timing references from the internal oscillator when the system clock is unavailable or unreliable. This intermediary calibration system ensures continuous reliable timing for emergency parking operations regardless of system clock status.
3Measurement precision
If oscillator calibration is implemented to increase timing accuracy, then the measurement precision improves, but the device complexity and ease of operation worsen due to additional calibration procedures
Solution Approach 1:
The patent applies self-service by implementing automated calibration procedures that require minimal user intervention. The calibration module automatically measures oscillator frequency, determines calibration values, and applies corrections without requiring manual adjustment by operators. This self-calibrating approach maintains high timing accuracy while minimizing the operational complexity and user burden.
Data Source
AI summary
Systems, methods, and apparatuses including computer program products for oscillator calibration include, in at least one implementation, a storage device including: a system including a first clock source, a second clock source, and a motor controller, the motor controller including calibration circuitry configured to calibrate the second clock source according to the first clock source in response to the first clock source operating as expected, and configured to provide to the system the calibrated second clock source as a timing reference instead of the first clock source as the timing reference in response to the first clock source not operating as expected, a head actuator configured to communicate with the motor controller, and a spindle disposed within the system.