Granted Patent B2

US 6,965,334 · App. 10/944,510 · Granted Nov 15, 2005

Assignee: Sigmatel, Inc.

Abstract

Claims (12)

1. A variable bandgap module comprises:

fixed bandgap reference source to produce a fixed reference voltage; and

supply voltage dependent voltage adjust module operably coupled to convert the fixed reference voltage into a reference voltage when a ratio between a supply voltage and the reference voltage is not substantially equal to a desired ratio.

2. The variable bandgap module of claim 1 , wherein the supply voltage dependent voltage adjust module further comprises:

supply voltage sensing module operably coupled to sense the supply voltage and the reference voltage, wherein the supply voltage sensing module generates an adjust setting based on the sensed supply voltage and the desired ratio; and

adjustable voltage follower module operably coupled to produce the reference voltage from the fixed reference voltage based on the adjust setting.

3. The variable bandgap module of claim 2 , wherein the adjustable voltage follower module further comprises:

an operational amplifier having a unity gain compensation network; and

a variable resistance coupled to an output of the operational amplifier, wherein the variable resistance is set based on the adjust setting.

4. The variable bandgap module of claim 2 , wherein the adjustable voltage follower module further comprises:

an operational amplifier having an adjustable gain compensation network, wherein an output of the operational amplifier produces a voltage greater than the fixed reference voltage; and

a variable resistance coupled to the output of the operational amplifier, wherein the variable resistance is set based on the adjust setting.

Assignments (9)

Continuity (3)