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:
Mar. 27, 2007
Filed:
Oct. 21, 2004
Apparatus and method for dual features of frequency setting and frequency synchronization in one pin
Faruk Jose Nome Silva, Sunnyvale, CA (US);
Kwok-fu Chiu, San Jose, CA (US);
Faruk Jose Nome Silva, Sunnyvale, CA (US);
Kwok-Fu Chiu, San Jose, CA (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
An integrated circuit includes an oscillator circuit, where a frequency of an oscillator output signal provided by the oscillator circuit is adjustable by either coupling a resistor to an input pin, or by applying an external clock signal to the input pin. The oscillator circuit includes a comparator, a follower, a current-controlled oscillator, and a switch circuit. The switch circuit is coupled between the input pin and a node that is coupled to the current-controlled oscillator. Also, the follower is arranged to cause the voltage at the node to be at a pre-defined voltage unless the voltage at the node is overdriven by an external clock signal. The comparator circuit is arranged to determine whether the signal at the input pin is a clock signal. If it is determined that the signal at the input pin is a clock signal, the switch circuit is opened.