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:
Jan. 09, 2001
Filed:
Mar. 04, 1999
John S. Prentice, Palm Bay, FL (US);
Intersil Corporation, Inc., Palm Bay, FL (US);
Abstract
A low voltage MOSFET-configured current sink/source has an output node coupled to the drain of an output MOSFET, that is current mirror coupled with a diode-connected reference current MOSFET. The output MOSFET has its gate resistor-coupled to the gate of the reference current MOSFET and its drain coupled to the source a third V,-feedback control MOSFET of a feedback circuit, that includes a further current mirror circuit. This third MOSFET has its gate electrode coupled in common with the drain-gate connection of the reference current MOSFET. The V,-feedback control MOSFET is coupled with a further current mirror, the output of which is coupled to the gate-coupling resistor. In response to a drop in the drain-source voltage V,of the output MOSFET so that the point that output MOSFET no longer operates in its saturation region, the V,-feedback control MOSFET turns on, causing the flow of drain current in the feedback control MOSFET. The further current mirror circuit mirrors this drain current through the gate-coupling resistor, causing a voltage drop across it, so that the value of gate-source voltage applied to the output MOSFET is increased. The effect of this increase in the value of V,of the output MOSFET for a reduced value of its drain-source voltage V,is to shift the knee or (saturation-linear) transition region of the output (drain-to-source) current I,of the output MOSFET to a lower knee point, thereby reducing the amount of headroom voltage required of a given sink/source current at the output terminal.