The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.

The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.

Date of Patent:
Dec. 07, 1999

Filed:

May. 16, 1997
Applicant:
Inventors:

Junichi Nagata, Okazaki, JP;

Junji Hayakawa, Okazaki, JP;

Hiroyuki Ban, Aichi-ken, JP;

Assignee:

Denso Corporation, Kariya, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
H03K / ;
U.S. Cl.
CPC ...
327538 ; 327540 ; 327541 ; 327108 ; 361 91 ;
Abstract

An output MOS transistor and a current-detecting MOS transistor are connected commonly at their drains and gates. A gate voltage is fed to the gates of these transistors via signal lines. When the voltage of an output terminal is increased in response to excessive load current, a current-mirror circuit consisting of first and second transistors pulls in current from the signal line to reduce the gate voltage. Thus, the output current of output MOS transistor is limited within a predetermined level. Furthermore, a diode, provided in the signal line, produces a voltage drop equivalent to the base-emitter voltage of first transistor. By the function of this diode, the gate-source voltage of output MOS transistor is equalized with the gate-source voltage of current-detecting MOS transistor. As a result, the same operating point can be set for the output transistor and the current-detecting transistor.


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