Method and device for generating a stable power control signal

Abstract

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.

1. A CD recorder having a power control signal, which has a read level, an erase level and a write level, wherein the read level equals a sum of a reference voltage and a read power control voltage, the erase level equals a sum of the read level and a first write power control voltage, and the write level equals a sum of the erase level and a second write power control voltage, the CD recorder comprising:
 a pickup device for reading, erasing or writing a disk and generating a feedback control signal, the pickup device comprising:
 a laser diode for receiving the power control signal, which enables the laser diode to generate a laser beam to read, erase or write the disk; and 
 a monitor diode for sensing intensity of the laser beam, wherein the CD recorder generates the feedback control signal according to the intensity of the laser beam sensed by the monitor diode; 
 
 a read control circuit having a read target value digital-to-analog converter for storing a plurality of first digital values and converting one of the first digital values into a first analog value, wherein the read control circuit generates the read power control voltage according to the feedback control signal and the first analog value; and 
 a write control circuit having a write target value digital-to-analog converter for storing a plurality of second digital values and converting one of the second digital values into a second analog value, wherein the write control circuit generates the first write power control voltage and the second write power control voltage according to the read power control voltage and the second analog value, wherein the read power control voltage is automatically and dynamically adjusted as the feedback control signal varies, such that the read level, the erase level and the write level of the power control signal are also automatically and dynamically adjusted as the read power control voltage varies. 
 
     
     
       2. The CD recorder according to  claim 1 , wherein the read control circuit further has:
 a sample and hold circuit for receiving the feedback control signal and obtaining a third analog value; 
 a subtracter for subtracting the third analog value from the first analog value and outputting a difference between the first and third analog values; and 
 a first low-pass filter for receiving the outputted difference of the subtracter and obtaining the read power control voltage. 
 
     
     
       3. The CD recorder according to  claim 2 , wherein the write control circuit further has:
 an adder for adding the read power control voltage and the second analog value together to obtain a sum, and outputting the sum to a second low-pass filter so as to obtain the first write power control voltage; and 
 an amplifier for receiving the first write power control voltage and obtaining the second write power control voltage. 
 
     
     
       4. The CD recorder according to  claim 3 , wherein the read power control voltage is generated in a close loop control manner by feeding back the feedback control signal, and the first write power control voltage and the second write power control voltage are generated in an open loop control manner. 
     
     
       5. The CD recorder according to  claim 4 , wherein a magnification power exists in a relationship between the first and second write power control voltages outputted from the write control circuit. 
     
     
       6. The CD recorder according to  claim 5 , wherein the write target value digital-to-analog converter has an optimum setting value obtained after correction before the CD recorder is shipped out. 
     
     
       7. A method for generating a stable power control signal in a read control circuit and a write control circuit of a CD recorder, wherein the CD recorder has a laser diode and a monitor diode, the laser diode generates a laser beam to read, erase or write a disk, the CD recorder generates a feedback control signal according to intensity of the laser beam sensed by the monitor diode, the method enables the read control circuit to generate a read power control voltage and the write control circuit to generate a first write power control voltage and a second write power control voltage, the power control signal for controlling the laser diode has a read level, an erase level and a write level, the read level equals a sum of a reference voltage and the read power control voltage, the erase level equals a sum of the read level and the first write power control voltage, and the write level equals a sum of the erase level and the second write power control voltage, the method comprising the steps of:
 inputting the feedback control signal to the read control circuit to obtain the read power control voltage; and 
 inputting the read power control voltage to the write control circuit to generate the first write power control voltage and the second write power control voltage, wherein the read power control voltage is automatically and dynamically adjusted as the feedback control signal varies, such that the read level, the erase level and the write level of the power control signal are also automatically and dynamically adjusted as the read power control voltage varies. 
 
     
     
       8. The method according to  claim 7 , wherein the read level enables the laser diode to generate a read power, the erase level enables the laser diode to generate an erase power, and the write level enables the laser diode to generate a write power. 
     
     
       9. The method according to  claim 7 , wherein the read power control voltage is generated in a close loop control manner by feeding back the feedback control signal, and the first write power control voltage and the second write power control voltage are generated in an open loop control manner. 
     
     
       10. A control device for generating a stable power control signal in a CD recorder, the CD recorder using a power control signal to access an optical disk, the power control signal having a read level, an erase level and a write level, the read level equaling a sum of a reference voltage and a read power control voltage, the erase level equaling a sum of the read level and a first write power control voltage, and the write level equaling a sum of the erase level and a second write power control voltage, the control device comprising:
 a read control circuit having a read target value digital-to-analog converter for storing a plurality of first digital values and converting one of the first digital values into a first analog value, the read control circuit generating the read power control voltage according to the feedback control signal and the first analog value; and 
 a write control circuit having a write target value digital-to-analog converter for storing a plurality of second digital values and converting one of the second digital values into a second analog value, the write control circuit generating the first write power control voltage and the second write power control voltage according to the read power control voltage and the second analog value, wherein the read power control voltage is automatically and dynamically adjusted as the feedback control signal varies, such that the read level, the erase level and the write level of the power control signal are also automatically and dynamically adjusted as the read power control voltage varies. 
 
     
     
       11. The control device according to  claim 10 , wherein the read control circuit further has:
 a sample and hold circuit for receiving the feedback control signal and obtaining a third analog value; 
 a subtracter for subtracting the third analog value from the first analog value and outputting a difference between the first and third analog values; and 
 a first low-pass filter for receiving the outputted difference of the subtracter and obtaining the read power control voltage. 
 
     
     
       12. The control device according to  claim 11 , wherein the write control circuit further has:
 an adder for adding the read power control voltage and the second analog value together to obtain a sum, and outputting the sum to a second low-pass filter so as to obtain the first write power control voltage; and 
 an amplifier for receiving the first write power control voltage and obtaining the second write power control voltage. 
 
     
     
       13. The control device according to  claim 12 , wherein the read power control voltage is generated in a close loop control manner by feeding back the feedback control signal, and the first write power control voltage and the second write power control voltage are generated in an open loop control manner. 
     
     
       14. The control device according to  claim 13 , wherein a magnification power exists in a relationship between the first and second write power control voltages outputted from the write control circuit. 
     
     
       15. The control device according to  claim 14 , wherein the write target value digital-to-analog converter has an optimum setting value obtained after correction before the CD recorder is shipped out. 
     
     
       16. The control device according to  claim 14 , wherein the CD recorder comprising:
 a pickup device for reading, erasing or writing the optical disk and generating a feedback control signal, the pickup device comprising:
 a laser diode for receiving the power control signal, which enables the laser diode to generate a laser beam to read, erase or write the disk; and 
 a monitor diode for sensing intensity of the laser beam, wherein the CD recorder generates the feedback control signal according to the intensity of the laser beam sensed by the monitor diode. 
 
 
     
     
       17. A method for providing power control signals in an optical disk drive, comprising:
 receiving a feedback control signal that is based on an intensity of a laser output of the optical disk drive;   providing a read power control signal according to the feedback control signal;   providing a first write power control signal according to the read power control signal; and   providing a second write power control signal according to the read power control signal.   
     
     
       18. The method according to claim 17, further comprising:
 inputting the feedback control signal to a read control circuit of the optical disk drive to generate the read power control signal; and   inputting the read power control signal to a write control circuit of the optical disk drive to generate the first write power control signal and the second write power control signal.   
     
     
       19. The method according to claim 17, wherein the laser output has a read level, an erase level, and a write level, further wherein:
 the read level equals a sum of a reference signal of the laser output and the read power control signal;   the erase level equals a sum of the read level and the first write power control signal; and   the write level equals a sum of the erase level and the second write power control signal.   
     
     
       20. The method according to claim 19, wherein the read power control signal is automatically and dynamically adjusted as the feedback control signal varies, such that the read level, the erase level and the write level are also automatically and dynamically adjusted as the read power control signal varies. 
     
     
       21. The method according to claim 19, wherein the read level enables a laser diode associated with the laser output to generate a read power, the erase level enables the laser diode to generate an erase power, and the write level enables the laser diode to generate a write power. 
     
     
       22. The method according to claim 17, wherein the read power control signal is generated in a close loop control manner by feeding back the feedback control signal, and the first write power control signal and the second write power control signal are generated in an open loop control manner. 
     
     
       23. A control device for providing power control signals in an optical disk drive, comprising:
 a feedback control circuit configured to receive a feedback control signal that is based on an intensity of a laser output of the optical disk drive;   a read control circuit configured to provide a read power control signal according to the feedback control signal;   a write control circuit configured to provide a first write power control signal according to the read power control signal, and to provide a second write power control signal according to the read power control signal.   
     
     
       24. The control device according to claim 23, wherein the laser output has a read level, an erase level, and a write level, wherein:
 the read level is approximately equal to a sum of a reference signal of the laser output and the read power control signal;   the erase level is approximately equal to a sum of the read level and the first write power control signal; and   the write level is approximately equal to a sum of the erase level and the second write power control signal.   
     
     
       25. The control device according to claim 24, wherein the read control circuit is configured to automatically and dynamically adjust the read power control signal as the feedback control signal varies, enabling the read level, the erase level and the write level to also be automatically and dynamically adjusted as the read power control signal varies. 
     
     
       26. The method according to claim 23, wherein the read control circuit generates the read power control signal in a close loop control manner by feeding back the feedback control signal, and wherein write control circuit generates the first write power control signal and the second write power control signal in an open loop control manner. 
     
     
       27. A control device for providing power control signals in an optical disk drive, comprising:
 a feedback control means for receiving a feedback control signal that is based on an intensity of a laser output of the optical disk drive;   a read control means for providing a read power control signal according to the feedback control signal;   a write control means for providing a first write power control signal according to the read power control signal, and further to provide a second write power control signal according to the read power control signal.   
     
     
       28. The control device according to claim 27, wherein the laser output has a read level, an erase level, and a write level, wherein:
 the read level is approximately equal to a sum of a reference signal of the laser output and the read power control signal;   the erase level is approximately equal to a sum of the read level and the first write power control signal; and   the write level is approximately equal to a sum of the erase level and the second write power control signal.   
     
     
       29. The control device according to claim 28, wherein the read control means automatically and dynamically adjusts the read power control signal as the feedback control signal varies, enabling the read level, the erase level and the write level to also be automatically and dynamically adjusted as the read power control signal varies.