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Patent Searching and Data


Title:
PROTECTION CIRCUIT FOR REMOVABLE CONTROLLER
Document Type and Number:
Japanese Patent JPH03283077
Kind Code:
A
Abstract:
PURPOSE:To prevent destruction of an internal circuit such as an IC circuit, to reduce the cost and to make the device small by connecting a protection diode between a ground terminal and a power input terminal of an operating power supply with a lower voltage in the two power supplies in the reverse polarity. CONSTITUTION:A protection diode 9 is connected between a ground terminal 7b and a power input terminal 7a of an operating power supply with a lower voltage in the two power supplies VDD, ILL in the reverse polarity. When a contact timing of a ground contact 7b is delayed more than that of other two power contacts 7a, 7c at the removal of an operation section 3, a protection diode 9 is conductive by a reverse voltage caused between a voltage difference of the two operating power supplies VDD, ILL. Thus, a reverse voltage caused between the ground GND and the power input terminal 7a at a lower voltage level reaches only a voltage equivalent to a forward voltage drop of the conducted protection diode 9, and an internal circuit such as an IC circuit connecting to the operating power supply VDD at a lower voltage is not destroyed due to the reverse voltage. Thus, the destruction of the internal circuit such as an IC circuit is prevented, the cost is reduced and the device is made small.

Inventors:
KATO KIYOSHI
KIYOURA KAZUHIRO
Application Number:
JP8100890A
Publication Date:
December 13, 1991
Filing Date:
March 30, 1990
Export Citation:
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Assignee:
PIONEER ELECTRONIC CORP
International Classes:
G11B33/00; G11B15/02; G11B33/02; G11B33/12; H02H9/00; (IPC1-7): G11B33/00; G11B33/12