DISK DRIVE POWER SUPPLY CONTROL CIRCUIT

摘要

PURPOSE: A controlling circuit for power supply to a disk drive is provided to improve reliability on a test through stabling power supplied to a hard disk drive for test. CONSTITUTION: A luminescence diode(52) emits light based on a power control command from outside. A photo transistor(72) is conducted according to luminescent state of the luminescence diode. Electronic switch units(40,42) contain an electric field transistor selectively supplying power of a power supply unit(20) to a disk drive according to conducted state of the photo transistor. An over current apply blocking unit(44) detects over current flowing through inner circuit components of the disk drive by using potential difference between both ends of the circuit components. Thus, the blocking unit controls the electronic switch unit to block power applied to the disk drive through the electronic switch unit.