The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 09, 2001
Filed:
May. 02, 2000
Claudia Castelli, Brugherio, IT;
Francesco Villa, Gorgonzola, IT;
STMicroelectronics S.r.l., Agrate Brianza, IT;
Abstract
A method and apparatus to dynamically modify the internal compensation of a low drop out linear voltage regulator is presented. The process involves using zero mobile compensation; when the output pole of the voltage regulator moves, a compensating zero is moved toward higher frequencies. This compensation zero is used to compensate the effect of a second pole in the loop gain. The circuit includes an input stage having an error amplifier. The error amplifier includes a differential stage output coupled to an output terminal of the buffer stage. An output stage of the circuit includes an output transistor having a conduction terminal connected to an output terminal of the voltage regulator, and having a control terminal coupled to the output terminal of the buffer stage. Additionally, a variable compensation network is connected between the differential stage output and a voltage reference. This variable compensation network can include an RC circuit having a resistive transistor. The resistance value of the resistive transistor is modulated according to the output load current of the voltage regulator, thereby changing the location of the compensating zero.