Constant Power Circuit for Hard Disk Drive Magnetoresistive Head
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Solution Overview
Problem
Existing power delivery systems in hard disk drives and similar devices face challenges in maintaining a constant power supply to loads, such as magnetoresistive heads, which affects their performance and reliability due to variations in voltage and current.
Innovation Solution
A constant power circuit comprising a voltage detection module, comparator module, power regulation module, and current source, along with multipliers and control modules, that adjust the power delivered to the load based on feedback loops to ensure a predetermined power level is maintained, using digital and analog feedback mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional power delivery systems are used, then the system structure is simple, but the power delivery varies due to voltage and current variations
Solution Approach 1:
The patent implements a feedback mechanism where the actual power delivered to the load is continuously monitored and compared with the desired power level. The controller adjusts the power delivery based on the difference between actual and desired power, ensuring constant power delivery despite voltage and current variations. This closed-loop feedback system resolves the contradiction by adding control complexity only where necessary to maintain power stability.
Solution Approach 2:
The patent replaces complex analog power regulation circuits with a digital control system that uses multiplication of voltage and current signals to calculate actual power. This substitution simplifies the overall system architecture while maintaining the ability to deliver constant power, as the digital controller can precisely regulate power output based on real-time measurements.
2Stability of the object's composition
If power regulation is implemented to maintain constant power, then power stability is improved, but the control system complexity increases
Solution Approach 1:
The patent replaces traditional analog power regulation circuits with a digital control implementation that multiplies voltage and current signals to determine actual power. This approach simplifies the control system by using straightforward digital signal processing rather than complex analog circuitry, while still achieving precise power stability through the calculated power feedback.
Solution Approach 2:
The patent changes the control parameter from regulating voltage or current separately to regulating power directly by multiplying voltage and current signals. This parameter transformation simplifies the control objective to maintaining a constant power level, which is achieved by adjusting the voltage or current based on the power calculation feedback, rather than managing multiple independent parameters.
3Adaptability or versatility
If voltage and current variations are allowed, then the system is more adaptable, but power delivery becomes inconsistent
Solution Approach 1:
The patent allows voltage and current to vary independently to maintain adaptability, while simultaneously using a feedback mechanism that continuously monitors the product of voltage and current (actual power). The controller adjusts either voltage or current based on the power feedback to maintain consistent power delivery, thus resolving the contradiction between flexibility and consistency.
Solution Approach 2:
The patent transforms the control approach from fixing voltage or current to fixing power by multiplying the two variables. This parameter change allows the system to adapt to different operating conditions through voltage and current variations while maintaining reliable and consistent power delivery to the load, as the control objective is explicitly defined in terms of power rather than individual electrical parameters.
Data Source
AI summary
A device for delivering a desired power to a load comprises a voltage detection module, a comparator module, a power regulation module, and a current source. The voltage detection module generates a voltage signal based on a voltage across the load. The comparator module compares a first value based on the voltage signal to a power reference signal. The power reference signal is based on the desired power. The power regulation module generates a digital code based on the comparison. The current source provides a current to the load. The current is based on a predetermined constant current and a second value. The second value is based on the digital code.