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:
May. 14, 1996

Filed:

Aug. 12, 1993
Applicant:
Inventors:

Solomon K Ng, Singapore, SG;

Gee H Loh, Singapore, SG;

Attorneys:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G05F / ;
U.S. Cl.
CPC ...
323315 ; 323901 ; 323907 ; 323312 ;
Abstract

A circuit for providing a reference current comprises first and second matched transistors, each of which has a control node and a controllable path and each of which is connected so that a current setting resistor is in the controllable path of the second matched transistor, the current setting resistor having a value, current set in the controllable path of the second matched transistor is related to a difference in voltage characteristics between the first and second matched transistors and to the value of the current setting resistor, and third and fourth matched transistors, each of the third and fourth matched transistors having a controllable path connected respectively to the controllable paths of the first and second matched transistors, and control electrodes of the third and fourth matched transistors connected together; a set of output transistors connected to the circuit to supply the reference current in dependence on a set current; and a fifth transistor having a controllable path between a bias node related to a first supply voltage level and a node set at one voltage characteristic relative to a second supply voltage level so as to maintain a voltage across one of the third and fourth matched transistors at a value which is independent of the first supply voltage level to reduce a magnitude of changes in the reference current as a function of the first supply voltage, the fifth transistor having a control electrode connected to the conductive path of the first matched transistor.


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