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:
Apr. 05, 2005
Filed:
Oct. 16, 2003
Farhood Moraveji, Saratoga, CA (US);
Farhood Moraveji, Saratoga, CA (US);
Micrel, Incorporated, San Jose, CA (US);
Abstract
A differential charge pump includes common mode circuitry for supplying a common mode voltage to a charging capacitor in the charge pump. The gate voltage of a reference transistor in a biasing branch of the differential charge pump is adjusted until the drain voltage of the reference transistor is equal to the common mode voltage when a specified bias current is flowing through the biasing branch. The same gate voltage and bias current are provided to a first transistor in a first common mode branch and a second transistor in a second common mode branch. The drains of the first transistor and the second transistor are connected to a first plate and a second plate, respectively, of the charging capacitor. In this manner, a desired common mode voltage is supplied to the charging capacitor.