Feedback-controlled low voltage current sink/source
US6172556A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 4, 1999 |
| Grant date | Jan 9, 2001 |
| Priority date | — |
| Expiry date | Mar 4, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05F3/265
- WIPO fieldControl
- WIPO sectorInstruments
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.sub.GS -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.sub.GS -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.sub.DS of the output MOSFET so that the point that output MOSFET no longer operates in its saturation region, the V.sub.GS -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 effec…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.