Voltage regulator using depletion mode pass driver and boot-strapped, input isolated floating reference

US8294440B2 · kind B2 · utility

Inventor

• Brian Lowe · Greer, US

Key dates

• Filing date: Mar 20, 2010
• Grant date: Oct 23, 2012
• Expiry date: Nov 23, 2030

Classification

• Technology area (CPC G): Physics
• CPC primary: G05F1/56
• WIPO field: Control
• WIPO sector: Instruments

Abstract

Multiple embodiments of a linear voltage regulator are described that use a bipolar output transistor to deliver current and a regulated voltage to a load. The bipolar output transistor assures low output impedance providing isolation from load induced noise. A first depletion mode field effect transistor FET drives the output transistor dependent on a correction signal from an error amplifier. The error amplifier compares a fixed voltage reference to a portion of the output voltage to set a control voltage for the FET gate. Output voltage is set with an offset voltage referenced to circuit ground and can be generated with a single resistor to circuit ground by a current through the resistor which is set from VREF and the regulated output voltage. Output current is limited with a second depletion mode FET that senses the difference in regulator output voltage and voltage at said first FET transistor drain. All circuitry except the output transistor and 2 FET drivers are bootstrap powered from the regulated output voltage to isolate almost all circuit elements from noise present on the input power source.