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:
May. 07, 1996
Filed:
May. 17, 1995
Bharat Bhushan, Cupertino, CA (US);
Christopher G Arcus, San Jose, CA (US);
Paul D Ta, San Jose, CA (US);
VLSI Technology, Inc., San Jose, CA (US);
Abstract
A ring-style, multi-stage VCO of a phase lock loop circuit includes two or more differential amplifier stages. The phase lock loop includes a lowpass filter connected between a control voltage terminal and a voltage-to-current converter stage, which includes a first source-follower MOS transistor M1 with a source resistor R1 and a second diode-connected MOS transistor M2 connected to its drain terminal. A differential amplifier stage includes a current-source MOS transistor M10 having a gate terminal connected to the drain of the first MOS transistor M1 to current mirror the drain current of M1. The differential amplifier stage also includes a pair of MOS transistors M4 and M5 connected to the drain terminal of the current-source MOS transistor M10. The gate terminal of MOS transistor M4 is an IN terminal and the gate terminal of MOS transistor M5 is an IN.sub.-- terminal. The drain terminal of MOS transistor M4 provides an OUT.sub.-- signal for the differential amplifier stage and the drain terminal of MOS transistor M5 provides an OUT signal for the differential amplifier stage. A MOS transistor M6 forms a load impedance for MOS transistor M4 and a MOS transistor M7 forms a load impedance for MOS transistor M5. The gate terminals of M6 and M7 are connected to the voltage control input terminal of the phase lock loop.