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:
Feb. 24, 2009
Filed:
Apr. 03, 2006
Shu-ing Ju, Palo Alto, CA (US);
Shu-Ing Ju, Palo Alto, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A PFM buck-or-boost converter is provided. The converter includes, inter alia, a hysteretic comparator, current sense circuitry, a logic circuit, drivers, current sense circuitry, a first buck switch, and a first boost switch. The current sense circuitry asserts signal Z if the current through the boost switch (from the load to the inductor) is greater than zero, and unasserts Z otherwise. Additionally, the current sense circuitry asserts signal I if the current through the buck switch is greater than a fixed current limit value, and unasserts I otherwise. The logic circuit employs the hysteretic comparator output, signal Z, and signal I to control the switches, and to determine whether to operate in buck regulation mode or boost regulation mode.