Reference circuit and method

US5910726A · kind A · utility

Assignee

• Motorola, Inc. · US

Inventors

• Vladimir Koifman · Rishon LeZion, IL
• Yachin Afek · Kfar Sava, IL

Key dates

• Filing date: Aug 15, 1997
• Grant date: Jun 8, 1999
• Expiry date: Aug 15, 2017

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S323/907
• WIPO field: Control
• WIPO sector: Instruments

Abstract

A reference circuit (200') has bipolar transistors (216, 226) providing a voltage difference .DELTA.V of base-emitter voltages .vertline.V.sub.BE .vertline. and has resistors (210/R.sub.1, 220/R.sub.2) for adding a current I.sub.R1 resulting from .DELTA.V and a current I.sub.R2 resulting from of base-emitter voltage .vertline.V.sub.BE .vertline. of one bipolar transistor (216 or 226) so that a resulting temperature coefficient TC.sub.TOTAL of said currents I.sub.R1 and I.sub.R2 is compensated. The circuit (200') has voltage transfer units (260, 270) which transfer .DELTA.V to the resistors (210/R.sub.1, 220/R.sub.2) so that the resistors (210/R.sub.1, 220/R.sub.2) do not substantially load the bipolar transistors (216, 226). The voltage transfer units (260, 270) have input stages with n-channel FETs. A control unit (241) which is coupled to the bipolar transistors (216, 226) adjusts input voltages (.vertline.V.sub.CE .vertline.) at the voltage transfer units (260, 270) to temperature changes, so that the n-channel FETs operate in an active region. The control unit (241) has a voltage source (290) providing a voltage V.sub.DS REF which is similary temperature and process depending a…