Current-to-voltage converting circuit, optical pickup head apparatus, and apparatus and method for recording/reproducing data

摘要

The invention provides a current-to-voltage converting circuit and an optical pickup head apparatus using the same. The current-to-voltage converting circuit converts, to a voltage signal, a current signal received from a photodetector which receives a light reflected on the recording medium such as an optical disk and provides a current signal corresponding to amount of the received light, for reproduction of data. The current-to-voltage converting circuit comprises a differential amplifier comprising transistors Q1 and Q2 applied with a negative feedback, current sources I1 and I2 for supplying the differential amplifier with two kinds of idling currents, and switches SW1 and SW2 for selecting current source I1 or I2 to determine the idling current to be supplied to the differential amplifier according to a level of the current signal received from the photodetector or a reflectance of the recording medium.