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. 23, 1999
Filed:
Mar. 31, 1997
Applicant:
Inventors:
David S Clarke, Kingsdown, GB;
Ian G Fobbester, Fairford, GB;
Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
H03L / ;
U.S. Cl.
CPC ...
331 17 ; 331-8 ; 331 25 ;
Abstract
A phase-locked loop employing a charge pump 7 for synthesizing RF channels permits a low supply voltage to be used by using two amplifier stages 5a, 5b, between the charge pump and a VCO4. Stage 5a may be a high impedance common emitter pair of complementary transistors allowing a wide voltage swing. Stage 5b may be an operational amplifier with resistive feedback to provide gain less than unity and a low impedance output to provide feedback around a loop filter 6 to source the current from charge pump 7 entering an inverting input of stage 5a. Alternatively, stages 5a, 5b may be reversed.