Overview

The LB8107M is a portable CD player mechanism actuator driver. It operates on a 2.4 V power supply, which corresponds to two rechargeable Ni-Cd cells.

Functions and Features

? Four H bridge driver channels on chip, one each for the four CD actuators; focus coil, tracking coil, spindle motor and sled motor

? Built-in step-up circuit to power the associated 5.0 V CD LSIs, including the DSP and microprocessor. (The drive transistor, L, Di and C are external components: step-up circuit) Io 150 mA, maximum

? Extremely low loss drive can be achieved, since the LB8107M detects the largest signal of the four drive channels and supplies that voltage to the H bridge driver blocks in each of the four channels using PWM voltage conversion. (The drive PNP transistor, L, Di and C are external components: step-down circuit)

? System start and stop can be performed at the microprocessor output.

? Support for switching between step drive mode, which has a high current reduction effect, and normal V control for the sled motor drive (The other three channels all are V type drive only.)

? Built-in battery check comparator

? Built-in integrating amplifier to handle the application of digital servo control to earlier spindle motors (This function integrates the PWM output.)

? A defect function is provided. This function improves the tracking ability by setting the voltage supplied to the H bridge drivers to the maximum in the presence of disk defects during playback.