Recording medium driver

Abstract

Abstract PURPOSE:To attain wide band for the signal processing system, low offset and low noise and to make the driver small in size by using a current mirror an output of a detected focusing error signal. CONSTITUTION:A photodetector 1 comprising a PIN photodiode gives an output current IPD proportional to the input line to a current mirror circuit 15. Base potentials of transistors (TRs) 3-8 in the circuit 15 are always identical to each other and an emitter current flowing to each resistor is made equal by adjusting en emitter-base voltage of each TR and a resistance of resistors 9-14 corresponding thereto depending on the required accuracy of the amplifier. Then the circuit 15 acts like an amplifier having a current amplification factor of 5 times.

Inventors

• 👤 Kyosuke Yoshimoto
• 👤 Kyoji Shimoda

Bibliographic Details