CD Recorder Power Control Circuit Feedback Adjustment
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Solution Overview
Problem
Conventional CD-RW recorders experience errors in write quality due to temperature-induced shifts in read, erase, and write power control voltages, as the read power control voltage is generated in an open loop system, leading to instability over long-term usage.
Innovation Solution
A CD recorder with a pickup device, read control circuit, and write control circuit that dynamically adjusts the read power control voltage based on feedback signals, ensuring the read, erase, and write levels are automatically adjusted, maintaining constant read, erase, and write powers through a combination of closed-loop and open-loop control systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the read power control voltage is generated in an open loop system, then the device complexity is reduced, but the stability of the power control signal deteriorates due to temperature-induced shifts
Solution Approach 1:
The patent introduces a feedback mechanism where the read power control voltage is dynamically adjusted based on the feedback control signal from the monitor diode. The read control circuit receives both the feedback control signal and a read target value, processes them to generate an adjusted read power control voltage. This closed-loop feedback system compensates for temperature-induced shifts and maintains stable power control signals throughout long-term usage.
2Stability of the object's composition
If the read power control voltage is dynamically adjusted based on feedback signals, then the stability of the power control signal is improved, but the device complexity increases
Solution Approach 1:
The read control circuit serves multiple functions: it receives the feedback control signal from the monitor diode, processes the read target value, dynamically adjusts the read power control voltage, and simultaneously generates control signals for the erase and write operations. By making the read control circuit multi-functional, the patent reduces the need for separate dedicated circuits for each function, thereby limiting the increase in overall device complexity while achieving stable power control.
3Manufacturing precision
If the read level, erase level and write level are automatically adjusted, then the write quality is improved, but the difficulty of detecting and measuring increases
Solution Approach 1:
The patent introduces a read control circuit as an intermediary that automatically processes the feedback control signal and read target value to generate adjusted power control voltages. This intermediary circuit handles the complex measurements and adjustments internally, shielding the user from the complexity of detecting and measuring power levels. The user simply provides the read target value, and the read control circuit manages all the dynamic adjustments needed to maintain write quality.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution maintains consistent read, erase, and write powers despite temperature variations, thereby enhancing the write quality and stability of the CD recorder by dynamically adjusting power levels in response to feedback signals.
Implementation Method 1
The laser diode receives the power control signal, which enables the laser diode to generate a laser beam to read, erase or write the disk
Implementation Method 2
The monitor diode senses intensity of the laser beam
Data Source
AI summary
Method and device for generating a stable power control signal in a CD recorder. The power control signal for controlling a laser diode may be a read level, an erase level and a write level. A pickup device outputs a feedback control signal to a read control circuit, and a read power control voltage is thus obtained. Then, the read power control voltage is inputted to a write control circuit, which generates first and second write power control voltages. The read level equals a reference voltage added by the read power control voltage, the erase level equals the read level added by the first write power control voltage, and the write level equals the erase level added by the second write power control voltage, so the read power control voltage and thus the read, erase and write levels are automatically and dynamically adjusted as the feedback control signal varies.