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.
Patent No.:
Date of Patent:
May. 28, 1991
Filed:
Dec. 07, 1989
Yasuhiro Sugimoto, Yokohama, JP;
Kabushiki Kaisha Toshiba, Kawasaki, JP;
Abstract
Through first and second external terminals, fixed potentials are applied to both ends of a first ladder resistor network. A second ladder resistor network is connected at one end to a second transistor. The first external terminal is connected to a first transistor through a resistor, the resistor and the resistors of the first and second ladder resistor networks being of the same kind. A positive input terminal of an operational amplifier is connected to a node between the resistor and the first transistor. A negative input terminal of the amplifier receiving a reference voltage is connected to the second external terminal. The first and second transistors are driven by the output signal of the amplifier. The amplifier cooperates with the first transistor such that a potential at the node is equal to the potential of the reference voltage. As a result, a current flowing through the resistor is proportional to a current flowing through the first ladder resistor network. Since the current, which is based on the operation of the second transistor, flows into the second ladder resistor network, the current flowing through the first transistor is proportional to a current flowing through the second ladder resistor network.