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:
Aug. 10, 1999
Filed:
May. 15, 1997
Kozaburo Kurita, Ome, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
A simply structured clock pulse generator operating stably in a wide range of frequencies in response to a timing signal fed from outside a semiconductor integrated circuit. A first frequency signal fed from the external terminal of the semiconductor integrated circuit and a second frequency signal generated within the semiconductor integrated circuit are input to a phase comparator. The output signal of the phase comparator is smoothed by a low-pass filter for conversion to a voltage signal. A compensation circuit uses both a delay signal from a current-controlled delay circuit receiving the first frequency signal and the first frequency signal to generate a current signal corresponding to the frequency of the latter signal. The voltage signal generated by the low-pass filter is converted into a current signal. This current signal is combined with the current signal from the compensation circuit to control the oscillation frequency of a ring oscillator comprising a current-controlled delay circuit the same in structure as the above current-controlled delay circuit. On the basis of the oscillation signal from the ring oscillator, the second frequency signal and clock signals needed in the semiconductor integrated circuit are generated.