Figure III
Different from the circuit in former MTK solution, the MT1389 is integrated with preposition
signal processing circuit, so the tray open/close control signals are accomplished by MT1389, that
is to say, the close control signal is accomplished by the Pin 51 of MT1389, while the open control
signal by Pin 39 of MT1389.
When we press the open button, the Pin 51 of MT1389 is in high power level, while the Pin 39 is
in low power level, and then the triode V308 will be on-state. Through resistor R323, the base of
V306 will be made to be in low power level, and V306 will be on-state, with the current direction
as the following figure:
Power voltage VCC ? V306E-C junction ? motor negative terminal
LOAD- ? motor positive Load +? V308 C-E junction ? grounding
So the motor will rotate clockwise to accomplish the action of tray closing.
When we press the open button, the Pin 51 of MT1389 is in low power level, while the Pin 39 is in
high power level, and then the triode V307 will be conducted. Through resistor R324, the base of
V309 will be made to be in low power level, and V309 will be conducted, with the current
direction as the following figure:
Power voltage VCC ? V309E-C junction ? motor negative terminal
LOAD- ? motor positive Load +? V307 C-E junction? grounding
So the motor will rotate anti-clockwise to accomplish the action of tray opening.
3. The main shaft motor braking circuit is as the Figure IV:
To prolong the lifespan of motor and reduce the influence of start- up impact current, with the
installation of disc, our R&D personnel design the main shaft motor to be in the state of constant
operation, so that even if the STOP button is pressed, the disc will not be stopped. Therefore, when
we press the OPEN button, a braking signal is required to stop the rotation of main shaft motor
immediately to accomplish the opening action in a short time.
