Title:
PROTECTIVE CIRCUIT AGAINST OVERVOLTAGE AND SURGE IN HARD DISK DRIVE
Document Type and Number:
Japanese Patent JP3652508
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To protect the circuit components inside a drive by applying the level of a second power source to the inner circuit which is extremely much lower than the level of the first power source, using the first power source applied to the input end of the second power source, when overvoltage is applied to the input end of the first power source, with the first and second power sources applied in reverse.
SOLUTION: In the case of reversely applying voltage, the power of +5 V applied through the input end 24 to a +12 V power source is applied to the gate terminal of an NMOS transistor 12, being divided by resistors 14 and 16 for voltage division, and this voltage partially turns on an NMOS transistor 12. Therefore, the power of +12 V applied through the input end 22 of the +5 V power source drops in voltage by the components of its resistance, when supplied to the inner circuit 26 of a hard disc drive through an NMOS transistor 12, so that the voltage of the source terminal falls below +5 V. Accordingly, the voltage supplied to the inner circuit 26 of the hard disc drive is free of the possibility of damaging the inner circuit.
Inventors:
Kim Satoshi
Application Number:
JP15423598A
Publication Date:
May 25, 2005
Filing Date:
June 03, 1998
Export Citation:
Assignee:
Samsung Electronics Co.,Ltd.
International Classes:
G11B33/00; G11B33/12; H02H7/20; H02H9/04; H02H11/00; (IPC1-7): H02H9/04; G11B33/00; H02H11/00
Domestic Patent References:
| JP8211969A | ||||
| JP7239722A | ||||
| JP55079625A |
Attorney, Agent or Firm:
Miaki Kametani
Tetsuo Kanamoto
Tetsuo Kanamoto
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