Start-up circuit and method for a self-biased zero-temperature-coefficient current reference
US7915882B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Aug 28, 2008 |
| Grant date | Mar 29, 2011 |
| Priority date | — |
| Expiry date | Apr 5, 2029 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG05F1/468
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A current reference circuit is disclosed. A small startup current is defined as the base current into a bipolar transistor with its collector-emitter path connected in series with a resistor between the power supply voltage and ground. This startup current is conducted via a diode-connected MOS transistor in a first leg of a current mirror. Temperature compensation is maintained by a reference leg in the current mirror that includes a bipolar transistor having an emitter area N times larger than that of a bipolar transistor in a second leg of the current mirror, to establish a temperature-compensated current in the reference leg. A compensation capacitor connected between the collector and base of a bipolar transistor in the first leg suppresses oscillation, and can be modest in size due to the Miller effect.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.