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:
Dec. 27, 2011
Filed:
Jun. 18, 2009
David Dearn, Malmesbury, GB;
David Dearn, Malmesbury, GB;
Micrel, Inc., San Jose, CA (US);
Abstract
In an average-current mode control type buck-boost PWM converter, a sample and hold circuit is inserted in the current loop to avoid problems associated with ripple of the average inductor current demand signal. The rippling average inductor current is generated by a differential transconductance amplifier having applied to its inputs an error signal and a signal corresponding to the instantaneous current through the inductor, where the output of the amplifier is filtered. The rippling average inductor current is sampled and held at the beginning of each switching cycle, prior to the average inductor current demand signal being compared to buck and boost sawtooth waveforms. By using the sample and hold circuit, the feedback loops are easier to stabilize, and the converter cannot switch modes during a switching cycle.