High slew-rate operational amplifier architecture
AssigneeAgere Systems Guardian Corp.
InventorRobert W. Walden
Life of this patent
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Abstract
An amplifier architecture wherein a primary or main operational amplifier is combined with a secondary or auxiliary high power operational amplifier to maintain the charge on a large load capacitor which operates as voltage reference source for a high precision analog circuit module. The auxiliary amplifier is activated only during brief periods for which a very high slew rate is required. This is achieved by additionally including a control circuit which regulates the operation of the auxiliary amplifier so that it operates only during very short intervals of very high load while the main operational amplifier accommodates all other normal operating conditions.
Claims35
An amplifier architecture comprising:
- A capacitive load circuit for providing an output voltage of a predetermined amplitude;
- a first amplifier circuit, operable as a main amplifier, connected to the load circuit for powering the load circuit under normal operating condition;
- a second amplifier circuit, operable as an auxiliary amplifier, connected to the load circuit for additionally powering the load circuit together with the main amplifier during relatively short intervals and where a relatively high slew rate is required for the output voltage;
- and,
- wherein said first and second amplifier circuits comprise same type amplifier circuits for powering the capacitance load circuit.
An integrated circuit comprising:
- a capacitive load circuit for providing an output voltage of a predetermined amplitude;
- a first amplifier circuit, operable as a main amplifier, connected to the load circuit for powering the load circuit under normal operating condition;
- a second amplifier circuit, operable as an auxiliary amplifier, connected to the load circuit for additionally powering the load circuit together with the main amplifier during relatively short intervals and where a relatively high slew rate is required for the output voltage;
- and,
- wherein said first and second amplifier circuits comprise same type power amplifier circuits.
A method of powering an intermittently used reference voltage source including a load capacitor, comprising the steps of:
- supplying power to charge the load capacitor to a predetermined voltage from a first source of current during a first operational mode;
- additionally supplying power to the load capacitor from a second source of current during a second operational mode occurring during intermittent relatively short time intervals where a relatively high slew rate of charge to said predetermined voltage is required;
- and,
- wherein the first and second source of current are comprised of same type power amplifiers.
An amplifier architecture comprising:
- A capacitive load circuit for providing an output voltage of a predetermined amplitude;
- a first amplifier circuit, operable as a main amplifier, connected to the load circuit for powering the load circuit under normal operating condition;
- and
- a second amplifier circuit, operable as an auxiliary amplifier, connected to the load circuit for additionally powering the load circuit together with the main amplifier during relatively short intervals and where a relatively high slew rate is required for the output voltage;
- wherein the load circuit includes a load capacitor which is charged by both said amplifier circuit;
- and
- wherein said second amplifier circuit includes a first auxiliary amplifier circuit which is active when the output voltage exceeds an input reference voltage and a second auxiliary amplifier which is active when the voltage falls below the input reference voltage.
An integrated circuit comprising:
- a capacitive load circuit for providing an output voltage of a predetermined amplitude;
- a first amplifier circuit, operable as a main amplifier, connected to the load circuit for powering the load circuit under normal operating condition;
- and
- a second amplifier circuit, operable as an auxiliary amplifier, connected to the load circuit for additionally powering the load circuit together with the main amplifier during relatively short intervals and where a relatively high slew rate is required for the output voltage;
- wherein the load circuit includes a load capacitor which is charged by both said amplifier circuits;
- and
- wherein said second amplifier circuit includes a first auxiliary power amplifier circuit which is active when the output voltage exceeds an input reference voltage and a second auxiliary power amplifier which is active when the voltage falls below the input reference voltage.
A method of powering an intermittently used reference voltage source including a load capacitor, comprising the steps of:
- supplying power to charge the load capacitor to a predetermined voltage from a first source of current during a first operational mode;
- and
- additionally supplying power to the load capacitor from a second source of current during a second operational mode occurring during intermittent relatively short time intervals where a relatively high slew rate of charge to said predetermined voltage is required;
- and
- said second source of current supplying charging current of a first polarity to the load capacitor when the voltage thereacross exceeds an input reference voltage and a second polarity when the voltage thereacross falls below the input reference voltage.
Dependencies are inferred from the claim text.